PROTOCOL FOR STRANGLES OUTBREAK
RUSH, BONNIE R., DVM, MS, DIP ACVIM
In a strangles outbreak, the rectal temperature of all exposed horses should be obtained twice daily, and horses that develop a fever should be isolated. The incubation period of strangles is 3-14 days. The initial sign is a fever spike (103-106 degrees F), which subsides for several days until submandibular lymphadenopathy develops and abscesses form. Administering penicillin during this early stage of infection (within 24 hours of fever onset) will usually abort infection. The disadvantage of early antimicrobial treatment is failure to mount a protective immune response, rendering horses highly susceptible to infection after cessation of therapy. Older animals with residual immunity may develop an atypical or catarrhal form of the disease. Horses with atypical strangles will have mucoid nasal discharge, cough, and mild fever. Submandibular or retropharyngeal abscess formation is rare. Monitoring rectal temperature twice daily will help identify horses with atypical disease, which, if undetected, can serve as a reservoir of infection for the nonisolated portion of the herd.
COENZYME Q10 THERAPY FOR DCM
GOODWIN, JOHN-KARL, DVM & KEITH N. STRICKLAND, DVM
In several studies, coenzyme Q10 exerted a protective effect against oxidative injury to the myocardium. A multi-center clinical trial investigating the efficacy of coenzyme Q10 in dogs with dilated cardiomyopathy is under way. In the authors' experience, coenzyme Q10 supplementation (2-5 mg/kg, BID or TID) improves clinical status, slows the progression of clinical signs, and stabilizes body weight. No adverse effects of Q10 supplementation are known.
CARPROFEN USE IN THE HORSE
BLIKSLAGER, ANTHONY T., DVM
There are anecdotal reports of carprofen use in treating horses with musculoskeletal disease in order to decrease the chances of developing such GI side effects as right dorsal colitis. However, there are little if any data on the relative selectivity of NSAIDs for cyclooxygenases in horses, and such data tend to be specific to the assay and species tested. Studies indicate that at a once-daily dose of 0.7 mg/kg, carprofen provides good analgesia in horses with musculoskeletal disease, but the antiinflammatory properties of this drug do not appear to relate to inhibition of prostaglandin production. Therefore, equine practitioners should be cautious about any off-label use of a purported COX-2 inhibitor until compelling data indicate that it is safe and efficacious in horses.
MANGE IN GUINEA PIGS AND THEIR TREATMENTS
MESSONNIER, SHAWN, D.V.M.
Demodex caviae or Trixacarus caviae, a sarcoptid mite, cause mange in guinea pigs. Demodex sp also cause mange in gerbils and hamsters, and Notoedres cause mange in hamsters. As with dogs and cats, demodectic mange in older pet rodents often indicates a serious underlying internal disorder. You can diagnose demodectic mange with skin scrapings or skin biopsies. To treat this condition, apply 250 ppm of amitraz as a whole-body dip once a week. Continue treatment 4 weeks after the results of a skin scraping are negative. Treat Trixacarus mange in guinea pigs and notoedric mange in hamsters with whole body lime-sulfur dips (treat once a week; continue for 2 dips after skin scrapings are negative) or, preferably, with ivermectin (200-400 micrograms/kg, SQ, every 10 to 14 days until skin scrapings are negative).
DIAGNOSING THE MOST PREVALENT INTESTINAL PARASITE
JAFFE, STEPHEN, DVM
Although Giardia is among the most prevalent of the intestinal parasites of dogs and cats, giardiasis often goes undetected. Reasons for this may include failure to consider it in the differential diagnosis, failure to recognize the organism in a test sample, use of inappropriate methods for fecal analysis, and the intermittent excretion of organisms in feces of infected individuals. The most common diagnostic tool for patients with diarrhea is fecal flotation. This test is currently performed in most clinics to detect the presence of intestinal parasites. However, if this method is used to detect Giardia, it is often inaccurate. Many clinics use floatation solutions such as sucrose and magnesium sulfate. While these solutions are adequate to detect infections with hookworms and roundworms, they fail to detect the presence of Giardia. The ideal flotation solution for the detection of Giardia is zinc sulfate and the sample must be centrifuged for 5 minutes and read immediately. The centrifugation step is necessary to force the Giardia cyst to float in zinc sulfate. The slide must be read soon after centrifugation because the cysts shrink with time and lose the characteristic internal morphologic appearance. Unfortunately today's busy practices often do not make the time to centrifuge the sample but, these steps are critical if you want to accurately diagnose Giardia infection.
RELAPSE RATE AND THE WESTERN BLOT TESTS
FENGER, CLARA K., DVM, PHD, DIP ACVIM
Among horses treated until the Western blot tests for Sarcocystis neurona antibodies in their CSF were negative, the relapse rate is less than 5%. In contrast, the relapse rate among horses treated until 4 weeks after the resolution of neurologic signs is 25%. Among horses in which the CSF Western blot is still positive when treatment is discontinued, the relapse rate is over 90%. Therefore, it is highly recommended that horses be treated until the Western blot of their CSF is negative, which takes an average of 5-6 months. The recommended regimen is pyrimethamine (1 mg/kg, PO, SID) with sulfadiazine (20 mg/kg, PO, SID or in divided doses).
LLAMAS AND RABIES
WALDRIDGE, BRYAN M., DVM, MS ET AL.
Llamas represent a small percentage of reported rabies cases in domestic animals. However, the possibility of rabies should be considered when examining camelids for abnormal behavior, ataxia, or suspected CNS disease. Llamas that are actively shedding rabies virus and continue to spit would greatly increase the risk of human exposure. In some management situations, the short duration of a rabid llama's abnormal behavior could go unnoticed. Therefore, rabies should be included as a possible cause of sudden death in llamas, especially if the animal exhibited clinical signs of CNS abnormalities before death. No rabies vaccine has been approved for use in camelids. Products licensed for other species may be used when there is a demonstrated need and evidence that some efficacy can be expected. Vaccines should not be used off-label unless you have diagnosed the specific disease or are aware of its prevalence in the area. A killed rabies vaccine approved for use in sheep and cattle may be given to camelids in areas where the virus is prevalent. Rabies vaccines should be given annually beginning as early as 3-6 months of age. However, because vaccine efficacy in camelids is unknown, animals should be considered nonvaccinates if exposed to a rabid animal.
RECOMMENDATIONS FOR COLIFORM MASTITIS
CONSTABLE, PETER D., BVSC, MS, PHD, DIP ACVIM
Based on likely bacterial sensitivity, cost, pharmacokinetics, and meat residue concerns, if antibiotic therapy is indicated for coliform mastitis, (systemic signs of illness), this author recommends (extra-label use-appropriate withdrawal times needed): oxytetracycline (16.5 mg/kg, IV, q24h, for 3-5 days, or 10 mg/mg, IV, q12h) and intramammary cephapirin (200 mg, Cefa-Lak, Today) after the last quarter stripping for the day. This treatment regimen also has good efficacy against severe gram-positive mastitis. If the animal does not respond to treatment, alter antibiotics depending upon culture and sensitivity. If milk culture results are unavailable, then a second line antibiotic treatment (extra-label use-appropriate withdrawal times needed) is florfenicol, 1500 mg (5 ml) into the affected quarter, q12h, for 3 consecutive milkings. This treatment returns milk production faster and clears bacteria faster from the infected quarter than untreated animals in an experimental mastitis model. Florfenicol is well absorbed from the normal gland, and combined intramammary infusion and parenteral injection of 3 ml/100 lb, IM, q48h is theoretically of benefit. Extra-label Polymyxin B sulfate dissolved in sterile saline may be used intramammary. Milk withhold at least 9 milkings.
GETTING A GOOD GLUCOSE CURVE IN THE CAT
KIRBY, REBECCA, DVM, DIP ACVIM
It is difficult to get a good glucose curve in the hospital. Many cats have a significant stress response which makes the curve invalid. This author has been teaching owners to take a small lancet, commonly used by human diabetics, to make a small puncture in the antitragus of the ear. A glucose test strip is cut into thirds, with the excess plastic strip trimmed away to allow the small drop of blood covering this smaller strip. The owner can then compare the color change to the guidelines on the bottle.
HYPOCALCEMIC COWS WITH RETAINED FETAL MEMBRANES
HERNANDEZ, JORGE, DVM, MPVM, PHD ET AL.
Hypocalcemic cows with retained fetal membranes (RFM) can have low blood calcium concentrations for up to 7 days after parturition. Calcium treatment of cows with RFM would be expected to help restore blood calcium concentrations and promote normal function of organs that contain substantial amounts of smooth muscle. In this study, administration of CaCl2 gel 24 and 48 hours after parturition did not have a significant effect on serum normalized calcium, total calcium, magnesium, or phosphorus concentrations or on incidence of metritis or left displacement of the abomasum, days to first insemination, pregnancy status after first insemination, or milk production.
THIRD-GENERATION ORAL CEPHALOSPORIN
PAPICH, MARK G., D.V.M., M.S., DIP ACVCP
Since most 2nd and 3rd generation cephalosporins and the carbapenems are only administered parenterally, an oral drug is valuable when convenience is needed to treat resistant infections on an outpatient basis. Cefixime (Suprax:Lederle) is one of the only two oral third-generation cephalosporins. It is available as a liquid suspension and tablets and has been administered to dogs (10 mg/kg, q12h) when oral therapy is desired.
COMBINATIONS FOR EQUINE INJECTABLE ANESTHESIA
HUBBELL, JOHN A.E., DVM, MS, DIP ACVA
The combination of xylazine and Telazol can be used to produce good quality anesthesia for 30-40 minutes in the horse. Xylazine (1.1 mg/kg) is administered IV in order to produce profound sedation and relaxation. Telazol (1.1 mg/kg) is given following the onset of full sedation. The quality of anesthesia is similar to that with xylazine-diazepam-ketamine in that muscle relaxation is excellent. Respiration is depressed but remains adequate for the period of recumbency. Recoveries are not as crisp as seen with the xylazine-ketamine combination because of the greater degree of muscle relaxation.
THERAPY FOLLOWING C-SECTION IN THE SMALL
RUMINANT ANDERSON, DAVID E., DVM, MS, DIP ACVS
Following cesarean section in the small ruminant, the uterus should be thoroughly lavaged clean of all blood clots prior to being replaced into the abdomen. The author prefers to place an OB solution into the abdomen which is composed of 1 liter isotonic saline solution containing antibiotics (potassium penicillin G, 22,000 U/kg; ampicillin, 20 mg/kg, or ceftiofur, 1 mg/kg), antiinflammatory drugs (flunixin, 1 mg/kg), and anticoagulants (heparin, 20 U/kg) and is infused into the abdomen immediately prior to closure of the incision. Carboxy methylcellulose (14 ml/kg body weight, IP) has been evaluated and advocated for prophylaxis against postoperative adhesions.
TRAMADOL FOR CANINE ANALGESIA - TWO-PRONGED ATTACK
HANSEN, BERNIE D., DVM, MS, DIP ACVIM
Tramadol (Ortho-McNeil) binds to opiate receptors and also inhibits reuptake of norepinephrine and serotonin. This agent provides a two-pronged attack to stimulate the endogenous, antinociceptive mechanism in the spinal cord and brain stem. Anecdotally, the analgesic dosage for dogs has been extrapolated from humans-0.5-1.0 mg/kg, SID-TID.
IBUPROFEN FOR ENDOTOXEMIA OR SEPSIS IN HORSES
BREUHAUS, BABETTA A., DVM, PHD ET AL.
Ibuprofen may have efficacy for treatment of endotoxemia or sepsis in horses that is superior to that of other NSAIDs currently used in this species. This study found that ibuprofen can be safely given to healthy foals at dosages greater or less than 25 mg/kg, q8h, for up to 6 days.
SIGNS ASSOCIATED WITH FERRET HYPERADRENOCORTICISM
WEISS, CHARLES A., DVM ET AL.
There are many clinical signs associated with hyperadrenocorticism in ferrets. Every ferret in this study had at least 1 of 3 clinical signs that are considered indicative of hyperadrenocorticism-bilaterally symmetric alopecia, a large vulva (in spayed female ferrets), and return to male sexual behavior (in castrated male ferrets). Diagnosis is confirmed on exploratory celiotomy by finding 1 or 2 large adrenal glands. An ACTH stimulation test and dexamethasone suppression test was not used because they are ineffective in diagnosing hyperadrenocorticism in ferrets. Of clinical signs suggestive of hyperadrenocorticism, alopecia is the most common. Alopecia in affected ferrets is usually bilaterally symmetric and can develop anywhere on the body. Most common areas of hair loss include the tail, dorsal surface of the hind feet, dorsal surface of the lumbar area of the back, and over the shoulder blades. Hair loss involving only the tail can develop seasonally and alone is not considered an important finding. A common finding associated with alopecia is a shiny, wax-paper appearance of the skin. Return to male sexual behavior in castrated male ferrets is likely to be a result of high serum androgens levels. These ferrets attempt to mate with spayed female ferrets and sometimes other male ferrets. It is common for these ferrets to drag a female ferret around by the scruff of the neck. Most ferrets with hyperadrenocorticism have a strong musky odor.
ANTIBIOTICS TO TREAT GERMAN SHEPHERD PYODERMA
ROSSER, EDMUND J., JR., D.V.M.
Antibiotics commonly used to treat German Shepherd pyoderma. Cephalexin at 33 mg/kg, q12h or 22 mg/kg, q8h. Erythromycin at 11 mg/kg, q8h. Clindamycin at 11 mg/kg, q12h. Amoxicillin-clavulanate at 13.75 mg/kg, q12h. Ormetoprim-sulfadimethoxine at 55 mg/kg on day 1, then 27.5 mg/kg/day. Trimethoprim-sulfadiazine at 30 mg/kg, q12h. Ciprofloxacin at 11 mg/kg, q12h; ciprofloxacin should only be used in cases in which bacterial sensitivity testing indicates that this is the only effective antibiotic, as occurs most often with resistant strains of Pseudomonas or Proteus spp.
FOLIC ACID DEFICIENCY DURING PYRIMETHAMINE THERAPY
REED, STEPHEN M., D.V.M., DIP ACVIM
When horses are treated using dihydrofolate reductase inhibitors, folic acid deficiency and anemia may be side effects of the treatment. In humans megaloblastic anemia is a common side effect of treatment with pyrimethamine. To combat this problem, the author recommends frequent evaluation of the CBC in horses while on treatment and if evidence of anemia is identified, the treatment should be discontinued and supplementation of folic acid (Folic Acid & Vitamin E Pak: Buckeye Feed Mills, PO Box 505, Dalton, OH 44618) implemented at a rate of 1 oz/day. The protozoa cannot utilize preformed folate that allows use of folic acid without severely compromising the antimicrobial effect of the pyrimethamine and sulfadiazine. Folic acid administration has two potential problems in the horse-the first is that the drug is poorly absorbed form the intestinal tract and the second is that to convert the folate to the active form of tetrahydrofolate requires dihydrofolate reductase which is being inhibited by the treatment.
TREATMENT OF INFILTRATIVE INTESTINAL DISEASE
JONES, SAMUEL L., DVM, PHD, DIP ACVIM
Treatment of infiltrative intestinal disease in the horse is generally unrewarding. Supportive care and immunosuppressive glucocorticoid treatment are often necessary. Fluid administration may be required if diarrhea is present. Serum electrolyte concentration abnormalities should be corrected either by IV administration of electrolyte solutions or oral supplementation. Protein loss may be severe, and large volumes of plasma may be required to correct the serum albumin concentration. Serum albumin levels should be maintained above 4 gm/dl if possible. Dexamethasone (0.04-0.1 mg/kg, IV or IM, BID) should be considered in most cases. While treatment is generally ineffective, some cases do respond favorably. Treatment should be continued for at least 4 weeks and may require continued administration of low doses of dexamethasone. Horses with eosinophilic enterocolitis should be treated with larvicidal anthelmintics in the event that cyathostomes are the cause.
FLUOXETINE FOR SEVERE INTERCAT AGGRESSION
OVERALL, KAREN L., BA, MA, VMD, PHD, DIP ACVB
This report describes a case of severe intercat aggression, which, in addition to behavior modification, required medication. For the aggressor (assuming a non-remarkable CBC, serum chemistry profile, and urinalysis), try a selective serotonin reuptake inhibitor that affects outburst or impulsive forms of aggression. The drug of choice for such aggression in cats, dogs, and people is fluoxetine hydrochloride (0.5 mg/kg, PO, q24h for 2 months to start). Fluoxetine inhibits reuptake of serotonin. Most forms of aggression are anxiety based, and redirected and intercat aggressions are no exception. The hypervigilance and hyperreactivity are associated with uncertainty about perceived threats, attacks, and thwarted behavior. Fluoxetine's side effects, which can include GI distress, are rare if a cat is able to metabolize the drug. It's important to treat the cat for at least 2 months because 3-5 weeks may be required for the receptor conformation changes to occur. Treatment may be long-term, and withdrawal from the medication should be gradual because you may find that the animal needs a constant, albeit small, baseline dose.
WHEN TO PASS A NASOGASTRIC TUBE
MOORE, RUSTIN M., DVM, PHD, DIP ACVS
Passage of a nasogastric tube should be considered an extension of a physical examination in horses with abdominal pain. Nasogastric intubation not only provides diagnostic information, but evacuation of fluid and decompression of gas also provides therapeutic potential by relieving pain and preventing gastric rupture. It is the author's opinion that passage of a nasogastric tube is indicated in all horses with colic. This can usually be done after the remainder of the exam has been completed, and combined with administration of fluids or laxatives for treatment. However, in horses that are severely painful, and particularly those that appear anxious, are sweating, and have respiratory difficulty, the nasogastric tube should be passed immediately to relieve gastric distention. The largest bore tube that can safely be passed should be used, with openings at the ends and perforations on the sides to prevent clogging of the tube. Fluid may not drain readily from the stomach initially, and a siphon should be performed by priming the tube with water and holding the end of the tube below the level of the horse's stomach. Normal horses should not have more than 1-2 L of net reflux. If appreciable amounts of net gastric reflux are obtained, then the tube should probably be maintained indwelling for serial monitoring or decompression.
THORACOCENTESIS OR TUBE DRAINAGE?
KING, ROBERT R., DVM, PHD, DIP ACVIM
Specific guidelines are not well-defined for determining when thoracocentesis or tube drainage of the pleural space should be initiated. Studies in humans with infected pleural effusions suggest that tube thoracostomy is superior to repeated thoracocenteses (this also seems true for animal patients). The decision to institute tube drainage in these patients is usually based on examination of the gross appearance of the fluid and the gram stain of the fluid. If the diagnostic thoracocentesis yields thick pus or if the gram stain is positive for bacteria, immediate tube thoracostomy is recommended. Also useful is the level of glucose and the pH. For example, when the initial thoracocentesis sample is not thick pus and the gram stain is negative, a pleural fluid pH <7.00 or a glucose level <40 mg/dl suggests early changes associated with septic effusions and tube thoracostomy is indicated. In borderline cases, evaluation of serial thoracocenteses at 12-24 hour intervals can provide useful information. Since studies on pleural fluid glucose and pH in cats are limited, the primary criteria for placement of chest tube(s) in them should probably be the presence of thick pus or a positive gram stain of the pleural fluid.
THERAPY FOR EDM
REED, STEPHEN M., DVM & BONNIE MOORE, DVM
It is the authors' opinion that use of antiinflammatory agents such as IV DMSO at a rate of 0.9 gm/kg as a 10% solution is helpful in cases of EHV-1 myelitis or myeloencephalopathy. This means that a 500 kg horse would receive 50O ml of DMSO diluted in 5,000 ml of normal saline. This is routinely used once daily for 3 days then once every other day for 3-4 additional treatments or longer if necessary. Also, the authors find that corticosteroids such as dexamethasone (0.05-0.1 mg/kg, IV) or prednisone (1 mg/kg/day) are useful. Larger doses of steroids have sometimes been recommended but it is important to maintain as short a course as possible. Careful use of NSAIDs is essential since so many of the horses may be unable to walk to water in order to drink and, therefore, dehydration is a serious complication. The daily water needs for an affected horse should be 60-80 ml/kg. Along with the water it is important to feed a gruel or if the horse can eat to provide a highly palatable source of energy and protein daily. The prognosis is guarded to favorable if one is willing and able to provide long-term management for the horse.
INJECTION ABSCESSES IN HORSES - VERY SERIOUS!
BROWN, CHRISTOPHER M., BVSC, PHD, DIP ACVIM
The most serious bacterial infections resulting from IM injections in horses are caused by Clostridium spp. Fortunately these are rare, but the outcome is often fatal. Owners usually blame the person who injected the horse, alleging that "incorrect" technique was used. There is no relationship between the development of the infection and the technique used to prepare the skin or to fill the syringe. This rare problem develops only when non-antibiotic agents are injected, and in recent years flunixin meglumine has been the most common cause in the author's area. Typically, signs develop 2-5 days post-injection, and progress rapidly. Initially, there is swelling and heat at the injected site, but the lesion expands rapidly with widespread edema and often crepitation due to gas production. The skin at the center of the lesion may become cold and leathery. Systemic signs develop rapidly and are severe, with anorexia, fever, tachycardia and tachypnea. Early aggressive therapy is essential if there is to be any chance of survival. An aspirate should be taken for anaerobic culture. There are 3 main components to treatment-antibiotics, fluids and surgical drainage. IV penicillin is the drug of choice at high and frequent dosages (20,000-40,000 U/kg, q2-4h). The affected areas should be surgically exposed and drained. This may require multiple, large (20-30 cm long) incisions over large areas. As much necrotic tissue as possible should be removed and good drainage established. The wounds should be irrigated frequently. The prognosis in these cases is very grave and the cost of treatment high. If the acute problem is overcome, the convalescent period may extend over several weeks. Occasionally horses with clostridial myositis develop immune-mediated hemolytic anemia. A veterinarian should not be liable if an acceptable injection technique has been followed, and an acceptable product used.
AMITRAZ USE IN GERBILS, HAMSTERS AND RATS
TYNES, VALARIE V., DVM
Amitraz can be used to treat demodicosis in gerbils, hamsters, and rats. You can dilute it with water according to package directions and wash the animal at 2 week intervals for 3-6 treatments. However, diluting amitraz 5 times the recommended amount ( i.e. 10.6 ml or 1 bottle per 10 gal water) is even safer in rodents because their surface area to body weight ratio is greater than that of dogs, the species amitraz was formulated for. After treatment, keep the animal in a warm, draft-free location until it is dry.
TREATING CLUB LAMB FUNGUS
Club lamb fungus. Fulvicin at 10 mg/kg, for 7-10 days in lambs is thought to be effective. No efficacy trials have ever been conducted, however, anecdotal reports have been positive. Thiabendazole has been used. A veterinary labeled product is no longer available, however a human product is still available-1 lb. of petrolatum jelly, 20 gms of thiabendazole, and 15 ml isopropyl alcohol. Liquefy the Vaseline, stir in powder, and add the alcohol. Makes an approximately 4% ointment. Over the counter human topical products such as Tinactin, may be effective. WDT must be established. The efficacy of various fungicidal shampoos is questionable due to the short exposure time on the skin. Iodine compounds have not shown to be very effective against other dermatophytes. However these compounds may reduce the infectivity of the lesions. Captan (available at garden centers)-1 lb in 15-20 gal water- may be used to spray down the premises and soak clippers, brushes, etc.
TREATMENT OF CHOICE FOR BILATER ADRENAL DISEASE
WEISS, CHARLES A., DVM ET AL.
Surgery is the treatment of choice for ferrets with bilateral adrenal disease; subtotal bilateral adrenalectomy is used in treatment of bilateral adrenal gland tumors or hyperplasia. In this study the larger affected adrenal gland was completely removed and 50%-60% of the smaller adrenal gland was removed. Subtotal bilateral adrenalectomy was associated with a low incidence of complications and a low mortality rate (<2%). Hematogenous metastasis is rare, even when the histologic diagnosis is carcinoma. As reported with subtotal bilateral adrenalectomy in the ferret, glucocorticoid and mineralocorticoid replacement after surgery is usually not necessary. If lethargy or anorexia develops within the first week after surgery then the Na:K ratio should be determined. If it is <25:1 then DOCP should be administered at 1 mg/lb, IM. If a complete response is not obtained, then prednisone should be added to the regimen at 0.2 mg/lb, PO, q24h. If the ratio is >25:1, then prednisone alone should be administered. After unilateral adrenalectomy the reported recurrence rate involving the contralateral adrenal gland is 17%. Although subtotal bilateral adrenalectomy was an effective treatment of bilateral adrenal tumors and adrenal hyperplasia in the study, recurrences of clinical signs after surgery did develop in 15% of ferrets 7-22 months after surgery. Upon recurrence of clinical signs following a subtotal bilateral adrenalectomy, medical or surgical treatment can be instituted. In the authors' experience, mitotane has been disappointing in ferrets with hyperadrenocorticism.
TREATING EQUINE INDOLENT ULCERS
WARD, DAN, DVM
Indolent ulcers in the horse fail to heal because the newly created epithelial tissue doesn't adhere to the underlying stroma. The loose rim should be debrided with a sterile Q-tip, and the ulcer bed scarified using a grid keratotomy or superficial punctate keratotomy. In the former, small perpendicular scratches 1 mm apart are made with a 22 ga. needle across the ulcer (extending 1 mm into normal tissue), and in the latter small punctures are made with a 22 ga. needle 1 mm apart. The ulcer is then treated as any other superficial uncomplicated ulcer (i.e., triple antibiotic and atropine), and most will heal within 1-2 weeks. Occasionally the keratotomy needs to be repeated, and on very rare occasions the lesion won't heal at all. In these cases a conjunctival graft may be needed. Some ophthalmologists have advocated medical therapy of these ulcers using polysulfated glycosaminoglycans. Adequan can be diluted 1:1 with artificial tears and used 2-3 times daily. There is good evidence for the efficacy of this treatment in dogs. There is no literature regarding its use for this syndrome in horses, but it would probably be equally effective.
THE SINGLE MOST INFORMATIVE DIAGNOSTIC TEST
ABBOTT, JONATHAN A., DVM, DIP ACVIM
In most cases, the single most informative diagnostic test in the evaluation of coughing patients is thoracic radiography. Thoracic radiographs must be obtained and interpreted with careful attention to patient body type, phase of respiration during which the exposure was made, and radiographic technique. It should be recognized that the ability of the plain thoracic radiograph to resolve the individual chambers of the heart is very limited. Despite this however, the chest X-ray can usually provide an estimate of left atrial size that is adequate for clinical purposes. This is fortunate because assessment of left atrial size is crucial in making the determination of the relative importance of cardiac disease to the clinical presentation of coughing dogs with murmurs of mitral valve regurgitation. With very few exceptions, a diagnosis of heart disease or failure as a cause of cough is simply untenable in the absence of radiographic left atrial enlargement. Mitral valve endocardiosis is a chronic disease and therefore enlargement of the left atrium and ventricle precedes the development of pulmonary edema. Obviously, the left atrium must be enlarged before it can be incriminated as a cause of bronchial compression.
VITAMIN C IN THE GUINEA PIG
MESSONNIER, SHAWN, D.V.M.
Unlike other pet rodents, guinea pigs require an exogenous source of vitamin C. Guinea pigs should receive fresh guinea pig pellets and vitamin C in their drinking water. Signs of scurvy (vitamin C deficiency) include subcutaneous and joint hemorrhages, anorexia, a poor hair coat, weight loss, lethargy, arthralgia, and nasal discharge. Suspect this condition in any sick guinea pig. This author uses a vitamin C injection (100 mg/guinea pig, IM or SQ) as a routine treatment in all sick guinea pigs and instructs owners about home supplementation. Vitamin C is also injected into hospitalized guinea pigs daily.
COW COLOSTRUM USE IN NEWBORN LAMBS AND KIDS
SHULAW, WILLIAM P., DVM, MS
Be cautious when using cow colostrum for newborn lambs or kids. Infected cows may shed Mycobacterium paratuberculosis in their colostrum and milk, and many dairy herds are infected. Pasteurization of colostrum may render it physically undesirable, and will not reliably destroy M paratuberculosis (145 degrees F for 30 minutes is not always effective). Be also aware that acute, fatal anemia has been reported in lambs following the use of cow colostrum.
COLLOIDS AND THEIR USE FOR PIT VIPER ENVENOMATIONS
PETERSON, MICHAEL E., DVM, MS
Generally colloids are not used to treat pit viper envenomations. Antivenin is the only definitive treatment for pit viper envenomation, and it binds venom proteins responsible for the hypotensive state. Synthetic colloids can increase the risk of bleeding diathesis. Their use in treating pit viper envenomations may confound coagulation monitoring, and anaphylaxis may occur. In cases of pit viper envenomations, crystalloids work well in combination with antivenin.
PHOTIC HEADSHAKING IN THE HORSE
MCDONNELL, SUE M., PHD
Photic headshaking in the horse. It has been found that some headshaking in horses appears to be light- or sound-induced trigeminal-mediated nasal irritation similar to the photic sneeze syndrome in humans. The type of head shaking in such cases is a more violent and irregular, snorting toss, compared to the more rhythmic traditional head bobbing or nodding seen as a classic stereotypy. The horse may appear to be trying to scratch its nose on a foreleg or even on the ground as it snorts, even going along at a trot or canter. This form of head shaking almost always worsens under work, and immediately subsides as the animal is returned to the barn or rest, so is easily misinterpreted as a purely behavioral problem. In most cases, photic headshaking is seasonal, and will stop immediately when the eyes are covered or the area is darkened. Dark goggles or sun-blocking face masks may be all that is needed for some individuals. Cyproheptadine (0.3 mg/kg, BID, PO) can effectively relieve most cases.
RECOMMENDATIONS FOR PREVENTING HEAT STRESS
ANDERSON, DAVID E., DVM, MS, DIP ACVS
Recommendations for prevention of heat stress in llamas. 1) All llamas and alpacas should be sheared before June 1 every year. Barrel cuts seem to work OK. 2) Lots of shade should be available. Most critical is that there is enough shade for all of the animals to be shaded at the same time whenever they want. 3) A good breeze. The most important thing is that the wind can get underneath the animals where the "thermal window" is located. Fans should blow across the barn at floor level (not down from a height). 4) Straw is bad in summer. This thick bedding closes off the thermal window and decreases access to ventilation. Sand bedding, especially slightly moist, is very good at absorbing heat from the animals. Concrete is hard, but cool and easy to clean and wet down. 5) Pools. Llamas and alpacas will seek out puddles, ponds, etc. to get cool. This tends to make hair fall out if they lay around in water too much of the time, but pools are very effective at allowing the animals to self-regulate temperature. The pool should be in the shade and freshened daily. 6) Monitoring. If they spend a lot of time eating, standing, walking around and being active then they are probably happy and healthy. If they lay around most of the day and are not active, then they may have subclinical heat stress (early stage) and intervention may be warranted. 7) Eating and digesting hay takes a lot of work and generates a lot of heat. Some have suggested that less hay, more grass and grains cause less heat stress risk because heat production from digestion is minimized. 8) Electrolytes, vitamin E, selenium, zinc, and copper.
SINGLE AGENT THERAPY FOR CANINE LYPHOMA
KITCHELL, BARBARA E., D.V.M., DIP ACVIM
Single agent therapy is not considered the standard of care for canine lymphoma by most veterinary cancer authorities. However, in the setting of medicine practiced without third party payment to cover costs, veterinarians must often compromise to offer the best help for the patient given the client's financial limitations. The simplest and cheapest therapy is therefore corticosteroids, with most dogs attaining a short remission and improved quality of life while on therapy. One study reported a median survival time of 53 days for dogs treated with steroids alone, as compared with untreated dogs that live roughly 30 days on average. However, treating dogs with corticosteroids alone may jeopardize their ability to attain a durable remission with the subsequent use of combination therapy.
TREATING CLOSED-HEAD INJURIES
JANDREY, KARL E., DVM
Current treatment standards for patients with closed-head injuries vary among institutions and clinicians. For the control of intracranial hypertension or in the face of a declining neurologic status, guidelines for using mannitol suggest intermittent boluses with dosages of 0.25-1.0 gm/kg, IV, over 20-30 minutes. Prevent hypovolemia by instituting fluid replacement therapy. Serum osmolality should not exceed 320 mOsm/L.
FELBAMATE TO REDUCE SEIZURES
PODELL, MICHAEL, MSC, DVM, DIP ACVM
Felbamate (Felbatol:Wallace) is believed to increase seizure threshold and prevent seizure spreading by reducing excitatory neurotransmission in the brain. In dogs, the drug has a high bioavailability and protein binding capability. The elimination half-life of 6 hours is relatively short, with steady state concentrations reached after 1 day. The author has the most success in using felbamate to control dogs with initial complex partial seizures, but has seen improved seizure control in dogs with generalized seizures refractory to prior phenobarbital (PB) and bromide (BR) therapy. For these dogs, the goal is to replace the PB with felbamate therapy while maintaining BR serum concentrations >300 micrograms/ml to reduce potential drug-drug interaction and hepatotoxicity. The recommended starting dosage is 20 mg/kg, PO, TID. Liver function should be monitored when the total dose is above 3000 mg/day. Felbamate is a non-sedating drug, but has been reported with a higher incidence of aplastic anemia and liver toxicity in people. No information is available on the use of felbamate in cats.
LAMENESS FROM LACERATIONS OF THE PASTERN
STASHAK, TED S., D.V.M., M.S., DIP ACVS
Lameness from lacerations of the pastern is variable and depends on the duration since injury, the extent of laceration, and whether the wound becomes infected. Generally, with the acute injury, the deeper the laceration the greater the lameness. However, there can be an anesthesia effect if the digital nerve has been transected. Since the major digital artery and vein are commonly lacerated, hemorrhage can be excessive, resulting in shock. These horses often appear very nervous, making it tempting to administer a tranquilizer or sedative before a physicalexamination is performed. If the shock is severe enough, even low doses of phenothiazine tranquilizers or sedatives can cause sufficient hypotension to result in fainting. Selection of sedation and tranquilization should be done after the cardiovascular status has been assessed. Control of hemorrhage can be accomplished by pressure wrapping for 30-60 minutes and/or occasionally with ligature. With a chronic laceration, the wound is usually infected and the horse may be reluctant to bear full weight.
UTERINE DAMAGE FROM SEMINAL BY-PRODUCTS
LEBLANC, MICHELLE M., DVM, DIP ACT
The longer seminal by-products remain in the uterine lumen, the greater the inflammatory response and the greater the endometrial damage. Therefore, treatment of the susceptible mare is directed at rapid removal of fluids. This can be accomplished by uterine lavage and administration of oxytocin (10-20 IU, IV or IM) performed between 4 and 8 hours after breeding. Treatment is delayed until 2 hours to ensure that no viable sperm are prematurely washed from the uterus. Treatment is conducted prior to 8 hours because the inflammatory response is greatest between 8 and 12 hours after breeding. As inflammatory by-products irritate the endometrium and their presence in the uterine lumen escalate the inflammatory response it is best to remove them before their numbers become too great.
SISSON, DAVID, DVM, DIP ACVIM
Reported benefits of diltiazem treatment in cats with hypertrophic cardiomyopathy (without LV outflow tract obstruction) include improved clinical signs, reduced pulmonary congestion, improved LV relaxation, improved ventricular filling, and reduced left ventricular wall thickness. Diltiazem is not particularly effective for reducing heart rate, particularly when sympathetic tone is high. Diltiazem, like all calcium channel blockers, has vasodilating effects. While this effect is not pronounced, diltiazem can worsen dynamic outflow tract obstruction. Reports indicating that hypertrophy regresses in more than one-half of the cats treated with diltiazem are greatly exaggerated; but this phenomenon does happen occasionally. The recommended oral dose of Cardizem CD in cats is 10 mg/kg, SID. Dilacor is a long-acting diltiazem preparation that has been used in cats. Dilacor capsules of varying strengths contain 2-4 tablets each of which contains 60 mg of diltiazem. Pharmacokinetic studies in cats have not been performed with this particular formulation, but dosages of 30-60 mg/cat, q24h, appear to be effective.
TREATING INTERCAT AGGRESSION
OVERALL, KAREN L., BA, MA, VMD, PHD, DIP ACVB
Intercat aggression. The drug of choice for the victim include tricyclic antidepressants such as amitriptyline HCl or nortriptyline HCl (both given at 0.5-1 mg/kg, PO, q12-24h, for 30 days to start), or a benzodiazepine such as diazepam (starting at a low dose but working up to 0.2-0.4 mg/kg, PO, q12-24h). If there is any hepatic impairment, diazepam is not advisable, especially if the cat is obese. The advantage of diazepam is that it is fast-acting, it slightly scrambles short term memory so the cat doesn't fully absorb how horrid the aggressor is, and it stimulates the cat's appetite, making food treats easy to use. Tricyclic antidepressants have the advantage of relieving anxiety, not inducing physiologic tolerance (as diazepam does), and having fewer long-term risks. Nortriptyline is the active intermediate metabolite of amitriptyline, so if the cat improves but is sedated while receiving amitriptyline (a common side effect), treating it with nortriptyline at the same dosage should eliminate the sedation but retain the beneficial effects.
DOUBLE CONTRACT CYSTOGRAPHY
REED, ANN L., DVM, MS, DIP ACVR
Double contrast cystography can be performed after excretory urography, after a positive contrast cystogram, or as a separate study. This study provides good mucosal detail and is good for identifying structural abnormalities of the urinary bladder and cystic calculi. Complications of these techniques include iatrogenic rupture, introduction of cystitis, kinkage of the urinary catheter and air emboli in pulmonary arteries due to vesicoureteral reflux of air. Because of this, it is recommended to keep the animal in left lateral recumbency to keep air in the nondependent right atrium.
LACK OF WATER INCREASES RISK OF COLIC
FREEMAN, DAVID E., MVB, PHD, DIP ACVS
Horses that have access to pasture or drylot without constant access to water have a significantly increased risk of colic. Because horses are continuous feeders and consume a high-fiber diet, both small and large intestinal processes demand enormous volumes of digestive secretions. After consumption of a single large meal, a horse's plasma volume can decrease by as much as 15%, apparently because of fluid loss into the intestine from parotid, gastric, biliary, pancreatic, and small intestinal (approximately 30 L/100 kg/day of all combined) and large intestinal (approximately 7 L/100 kg/day) secretions. The resulting hypovolemia combines with the high potassium in the diet to activate the renin-angiotensin-aldosterone system. The resulting aldosterone secretion can increase colonic absorption of sodium and water which could dehydrate colonic contents to the point of impaction. Therefore, a combination of episodic feeding of grain and hay, as opposed to a more even and continuous feeding regimen, combined with inadequate water access, could cause colic. Although horses (ponies) seem to prefer cold water to warm water if they have a choice, they tend to drink a greater volume of warm water than cold. Thus, providing warm water would increase the volume of water consumed and decrease the risk of large colon impaction during cold weather.
REGIONAL IV INJECTIONS OF CEFTIOFUR IN CATTLE
NAVARRE, CHRISTINE B., DVM, MS, DIP ACVIM ET AL.
The objective of this study was to evaluate the efficacy of regional intravenous injection of ceftiofur in delivery of this drug to joint fluid and plasma in a limb distal to a tourniquet in beef cattle. A tourniquet was positioned in the mid-metacarpal region, and 500 mg of ceftiofur was administered through a catheter in the dorsal common digital vein. The higher the concentrations that can be achieved initially, the longer the drug will remain above therapeutic concentrations, prolonging the dosing interval, and making this type of therapy more practical. Regional intravenous injection appears to be a feasible technique to produce rapid distribution of ceftiofur within the limb well above therapeutic concentrations. At 45 minutes post-dosing, regional IV perfusion of ceftiofur at 500 mg resulted in plasma as well as synovial fluid ceftiofur concentrations that are much higher than MIC values for even resistant organisms. No complications were observed during the procedure and up to 2 months afterwards, indicating that the regional IV administration of ceftiofur is a safe and efficient procedure for treating cattle foot infections. bovine rot naxcel
ACARBOSE USE IN THE DIABETIC CAT
GRECO, DEBORAH S., DVM, PHD, DIP ACVIM
The alpha-glucosidase inhibitors impair glucose absorption from the intestine by decreasing fiber digestion and hence glucose production from food sources. Acarbose is used as initial therapy in obese patients suffering from insulin resistance or as adjunct therapy with sulfonylureas or biguanides to enhance the hypoglycemic effect in patients with NIDDM. Side effects include flatulence, loose stool and diarrhea at high dosages. They are not indicated in patients of low body weight because of their effects on nutrition. Acarbose may be administered at a dosage of 12.5-25 mg/cat with meals. Side effects are more common at the high end of the dose and include semi-formed stool or in some cases overt diarrhea. The glucose lowering effect of acarbose alone is mild with blood glucose concentrations decreasing only into the 250-300 mg/dl range. However, acarbose is an excellent agent when combined with insulin or other oral hypoglycemic agents, such as the sulfonylureas and transition metals, to improve glycemic control.
STABILIZING THE DYSPNEIC CAT
SMITH, FRANCIS W.K., JR., D.V.M., DIP ACVIM
Treatment for emergency stabilization of the dyspneic cat prior to diagnostic testing (in addition to oxygen). If the initial diagnostics suggest a cardiac cause for the severe dyspnea, administer furosemide (2-4 mg/kg, IV or IM, PRN) along with 2% nitroglycerin ointment (1/8-1/4 in., TID), applied to the gums or inside the pinna. If hypertrophic cardiomyopathy is suspected, or a supraventricular tachycardia is noted, diltiazem (1-2.5 mg/kg, PO, TID) may be helpful. If the initial diagnostics suggest an asthmatic crisis, administer aminophylline (5 mg/kg SQ, IM, or very slowly IV, BID-TID). Institute steroid therapy with a rapidly acting preparation such as prednisolone sodium succinate (10 mg/kg, IV) or dexamethasone (0.2-1 mg/kg, IV). Epinephrine (0.1 mg, SQ) may be lifesaving in severe cases. If the cat is pale, try to obtain a PCV early in the diagnostic work-up. If severely anemic (PCV <15), obtain enough blood for diagnostic testing and then administer a blood transfusion. If there is evidence of regeneration without blood loss, consider instituting therapy with prednisone (2 mg/kg/day) and a tetracycline while awaiting the results of additional tests (Coombs' and screening for blood parasites). If heart sounds are muffled and ventral lung sounds are absent, pleural effusion is likely. Reduced lung sounds and tympani on percussion suggest pneumothorax. Thoracentesis is often lifesaving. If history and physical findings are inconclusive, tap chest to rule out pneumothorax and pleural effusion. If the tap is negative, treat with furosemide, aminophylline and continue oxygen. Expand the data base as patient allows.
CSF IMMUNOBLOT TESTING IN THE HORSE
BENTZ, BRADFORD G., VMD, MS ET AL.
Equine protozoal myeloencephalitis (EPM). Because of an apparent high yield of positive results and the ambiguity of interpretation, some clinicians no longer perform the CSF immunoblot. However, because negative immunoblot results are uncommon in horses with EPM, these authors advocate the CSF immunoblot as part of the routine EPM evaluation. When a negative CSF immunoblot result occurs, time and money are saved by minimizing the diagnostic pursuit and treatment of the wrong disease. If clinical signs are acute in onset, it may be worthwhile to perform a repeat CSF immunoblot in a few weeks to allow time for intrathecal antibody production. At this time, a negative result on a CSF immunoblot performed and interpreted with consideration of all of the diagnostic tests' limitations, precludes the diagnosis of EPM.
TREATING WOUNDS IN AMPHIBIANS
CRAWSHAW, GRAHAM J., BVETMED, MRCVS
Wounds in amphibians should be debrided and flushed with large quantities of sterile fluids. Antiseptics, including iodine compounds and chlorhexidine should be used sparingly, if at all, owing to the potential for systemic absorption and toxicosis. Bleeding wounds can be closed by suturing with flexible absorbable or nonabsorbable suture and atraumatic needles. Local anesthetics are effective and useful in amphibian practice. Lidocaine can be injected or applied topically but should be diluted or the volumes limited, to reduce systemic anesthetic effects. A local anesthetic cream (EMLA: Astra Pharm) has proved very effective. When applied to the skin with a cotton-tipped applicator, it results in analgesia of the treated area within a few minutes. Excessive application must be avoided because systemic absorption leads to anesthesia in the same fashion as occurs with the systemic amphibian anesthetics, MS-222 and benzocaine.
TREATING EQUINE GASTRIC ULCER SYNDROME
ANDREWS, F.M., DVM, MS, DIP ACVIM & J. ORSINI, DVM
If clinical signs are compatible with equine gastric ulcer syndrome, there is no reason not to treat if endoscopy is not an option. Response to therapy is relatively quick, Within 24-48 hours, such signs as poor appetite generally improve, with gradual resolution of other clinical signs during the treatment period. Treatment should continue for 2 weeks because if a horse has colic for reasons other than ulcers, the medication may appear to be working the first week but the colic will return by the second week. Recurrent colic would not rule out ulcers but would indicate additional problems in the GI tract.
ALTERNATIVE TO SURGICAL TREATMENT
KATZ, LISA M., DVM & CLAUDE A. RAGLE, DVM
Rectal tears in the horse that involve the mesocolon are graded IIIb and are conventionally managed surgically and have a much poorer prognosis for survival. Results in this study indicated that those horses with grade IIIb rectal tears that are >10 cm in diameter are considered to be ideal candidates for treatment using repeated manual evacuation. Repeated manual evacuation may be a viable alternative to surgical treatment if there is proper horse selection, early initiation of treatment, and adequate technical support.
MONITORING THE DIABETIC CAT...NOT CRUCIAL
NORSWORTHY, GARY D., DVM, DIP ABVP
In general, close regulation of diabetic cats is not feasible and, fortunately, not required because cats do not develop diabetic cataracts or renal failure. Even if diabetic cats are polyuric, they usually urinate in litter boxes in contrast to diabetic dogs, which often require outdoor walks during the night or urinate on the floor. In addition, because hyperglycemia is better than hypoglycemia, maintaining the blood glucose level within the ideal 100-300 mg/dl range is not critical. If blood glucose levels reach 400 mg/dl but clinical signs, especially weight loss, are under control, practitioners should not be concerned.
CONTROLLING STATUS EPILEPTICUS
BOWCKH, ALBERT, DVM
In cases of status epilepticus, the use of an intravenous bolus of diazepam (0.5-1.0 mg/kg) is indicated as the first-choice therapy. If seizures are not controlled, an intravenous bolus of phenobarbital (4 mg/kg) should be administered. If necessary, this bolus administration can be repeated up to a total of 16 mg/kg, allowing at least a 20-minute interval between boluses. If seizures are still uncontrolled, a constant-rate infusion of pentobarbital (5 mg/kg/hour) is indicated. As soon as the animal can swallow, long-term oral maintenance therapy of phenobarbital should be initiated at 2 mg/kg, twice daily or continued at an increased level.
TREATING DERMATOPHYTOSIS IN GUINEA PIGS AND RATS
TYNES, VALARIE V., DVM
Dermatophytosis occasionally occurs in guinea pigs and rats, usually caused by Trichophyton mentagrophytes. Before beginning treatment, make sure the client is aware of the zoonotic potential. Treatment must clear up the lesions as well as eliminate the organism from the environment, so thoroughly cleaning and disinfecting the cage and accessories are critical. In pet rats, topical therapy consisting of one-time povidone-iodine application followed by oral griseofulvin (25 mg/100 gm, 3 times, 10 days apart) has been effective. For guinea pigs, griseofulvin is also the treatment of choice. An oral dosage of 15-75 mg/kg/day, for 14-28 days is recommended, but doses up to 100 mg/kg/day have been reported. Griseofulvin is teratogenic and should not be given to pregnant animals. Topical antifungals applied once a day for 2-4 weeks may be successful for a guinea pig with mild or localized disease.
TRAUMATIC SYNOVITIS OF THE TIBIOTARSAL JOINT
MAJOR, MICHAEL D., DVM, MS, DIP ACVS
Traumatic synovitis of the tibiotarsal joint can manifest with effusion and lameness. If no lesions are found on radiographs, usual treatment consists of at least 3 weeks rest with NSAID administration. The synovitis can be treated effectively with HA in combination with a short or intermediate acting corticosteroid. Pay attention to the clarity of the synovial fluid when the joint is drained. The possibility of hematogenous septic arthritis should always be considered before steroid injection, even in adult horses. A mixture of triamcinolone (12 mg), amikacin (250 gm), and atropine (9 mg) instilled after needle drainage has been helpful in some cases of chronic, recurrent bog spavin with no lameness.
TREATING GRAM-NEGATIVE INFECTIONS IN FOALS
WILSON, W. DAVID, BVMS, MS, MRCVS
It should be assumed that foals showing signs of infection are infected with a gram-negative organism. Because the neonatal immune system is immature and many septic foals have suboptimal passive transfer of colostral antibodies, it is preferable to parenterally administer antibiotics which have a bactericidal action as well as an excellent spectrum of activity against gram-negative bacteria. None of the antibiotics, except certain 3rd-generation cephalosporins, in current use are sufficiently active against the important bacterial isolates from septic foals to recommend that they be used alone to initiate therapy while awaiting culture results. For these reasons, the aminoglycoside antibiotics, amikacin or gentamicin, in combination with a penicillin or 1st-generation cephalosporin, are the drugs of choice for initial therapy unless specific contraindications exist. The renal mechanisms involved in the elimination of these drugs are functional at birth and elimination is sufficiently rapid that the dosage schedules used for adults need only minor modification (usually widening of the dosage interval). Third-generation cephalosporin antibiotics and ticarcillin/clavulanate are useful for treating those patients with aminoglycoside-resistant infections or in which aminoglycoside treatment is otherwise contraindicated. Potentiated sulfonamides are useful for continued oral therapy in foals which are no longer critically ill and from which susceptible bacteria have been isolated.
REPLACING INEFFECTIVE LONG-ACTING INSULIN IN CATS
NELSON, RICHARD W., D.V.M., DIP ACVIM
Slow or inadequate absorption of subcutaneous insulin is most commonly observed in diabetic cats receiving ultralente insulin, a long-acting insulin which has a slow onset and prolonged duration of effect. In approximately 20% of cats in the author's hospital, ultralente insulin is absorbed from the subcutaneous site of deposition too slowly for it to be effective in maintaining acceptable glycemic control. In these cats, the blood glucose concentration may not decrease until 6-10 hours after the injection or, more commonly, it decreases minimally despite insulin doses of 8-12 U/cat given every 12 hours. As a consequence, the blood glucose concentration remains >300 mg/dl for most of the day. Success has been obtained in these cats by switching from ultralente to Lente or NPH insulin given twice a day. When switching type of insulin, the insulin dose is decreased (usually to amounts initially used to regulate the diabetic cat) to avoid hypoglycemia. The duration of effect of the insulin becomes shorter as the potency of the insulin increases, which may create problems with short duration of insulin effect.
NEW THOUGHTS ON THERAPY FOR CHF PATIENTS
DE MORAIS, HELIO AUTRAN, DVM, PHD, DIP ACVIM
The key-words for diuretics and heart failure are edema and congestion. Only patients that show signs of fluid retention should receive diuretics (if they are not wet, there are no reasons to dry them). Long-term use of diuretics may lead to deleterious effects. Diuretics activate the renin-angiotensin system enhancing progression of heart disease. Thus, chronically-used diuretics should always be given at the lowest effective dosage. A substantial number of dogs and cats with CHF cannot be totally withdrawn from diuretic therapy without showing signs of congestion. That, in itself, suggests that diuretics are necessary in the chronic management of CHF, despite activation of the renin-angiotensin system. To counterbalance renin-angiotensin activation, an ACE inhibitor should be used whenever diuretics are to be given chronically to CHF patients.
Female rabbits have a large fold of skin over the throat known as the dewlap. Breeding does pull fur from this area to line their nests before kindling. In older breeding does, the dewlap can be large and easily mistaken for an abscess. Moist dermatitis often develops in this area. Rabbits are strongly territorial and both sexes have three glands used in scent-marking behavior. The size of the glands and degree of marking is androgen-dependent and related to the level of sexual activity.
Submandibular glands opening onto the underside of the chin and known as chin glands are used extensively in marking. Anal glands mark the feces with a distinctive odor. These glands do not need to be manually expressed as with dogs. Finally, next to the anal orifice are a pair of pocket like perineal glands, called the inguinal glands. The inguinal glands are often mistaken as the anal orifice by the inexperienced when inserting a thermometer. In older animals, the inguinal glands are filled with a white, caseous secretion.
NEW THOUGHTS ON BOVINE PARASITISM
REINEMEYER, CRAIG R., D.V.M., PH.D.
Mature cows develop effective, albeit incomplete, acquired immunity to important nematode pathogens such as Ostertagia. Slaughter surveys of cull beef and dairy cows reveal that about 80% of such cows carry fewer than 2,000 worms, even with no history of recent deworming. Cattle producers who deworm mature cattle are not preventing a disastrous calamity; at best, they may increase productivity as measured by various parameters. There is a common notion that beef cows must be dewormed in autumn to prevent loss of body condition and other clinical signs of parasitism during winter. Anecdotes abound regarding "down cows" with positive fecals that recovered following deworming and dietary improvement. A skeptic could argue that the clinical features are not conclusive because the occurrence of worm eggs in a cow's feces is not surprising, and the clinical improvement may have resulted from an increased plane of nutrition alone. There are virtually no data to confirm or refute that such cows carry larger than normal worm burdens. If this syndrome is primarily due to parasitism, deworming cows once during autumn is unlikely to have much protective effect several months later.
TRANQUILLI, WM. J., D.V.M., M.S., DIP ACVA
Recent studies have assessed the anesthetic and hemodynamic actions of medetomidine pre-medication with propofol or etomidate anesthesia. Low doses of medetomidine (15 micrograms/kg, IM) induce moderate sedation that allows induction with low doses of propofol (2 mg/kg, IV) or etomidate (0.5 mg/kg, IV), easy tracheal intubation, and rapid, smooth emergence from approximately 35 minutes of stable anesthesia. Medetomidine appears to be an excellent analgesic, muscle relaxant adjunct with favorable hemodynamic actions when combined with propofol. The short elimination half-life of propofol and etomidate and reversal of medetomidine with atipamezole provide for precise control of duration of anesthesia following nonpain-producing procedures.
DISTINGUISING FOOD ALLERGY FROM ATOPY
MARSELLA, ROSANNA, DVM, DIP ACVD
Food allergy is uncommon in dog and cats. Reported incidence in small animals varies from 1%-20%. Food allergy can occur at any age, even at very young age (<6 months). This characteristic is different from inhalant allergies (atopy) and allows ranking the likelihood of specific allergies according to the age of onset. Atopy usually starts at 1-3 years of age. It is slowly progressive, initially seasonal and responsive to steroids. Food allergy may start at a really young age or at old age. It starts suddenly, with non-seasonal pruritus, usually not very responsive to steroids. Food allergy should then be strongly suspected in a pruritic animal that is younger than 6 months or older than 6 years. Onset of clinical signs is not related to a change in the diet. Actually, 70% of cases diagnosed with a food allergy, have allergies to a food that has been fed for many years (>2 years). Food allergy can develop to virtually any ingredient in the diet.
CORRECTION OF HYPOTHERMIA IN THE ILL FOAL
MADIGAN, JOHN, DVM
Correction of the hypothermia (99 degrees F rectal temperature) when present should be one of the primary objectives of the care of the ill foal. Removing the foal from cross drafts and into a closed environment such as a warm room with a temperature of 76-80 degrees F is the first objective. Immersion of an extremely cold foal in a warm water bath has been described as helpful. A sheep skin fleece or thick blankets may be placed under the foal with an insulating pad. A man's or woman's down or nylon vest can be placed on the foal with front legs through the arm holes. Blankets such as a space blanket placed over the foal will prevent heat loss but will reflect externally applied heat. Water heating pads under the foal and warm water bottles placed adjacent to the foal may be beneficial.