Dynamic exophthalmos and lateral strabismus in a dog caused by masticatory muscle myositis.

CASE DESCRIPTION: A 5.5-year-old neutered male mixed-breed dog was presented for evaluation of a 5-month history of deviation of the right globe upon opening the mouth and a 1-month history of conjunctivitis in the same eye. Clinical findings, diagnostic imaging results, treatment and follow-up are described. CLINICAL FINDINGS: When the mouth was opened, the right globe deviated rostrally and laterally. There was no pain or resistance to opening the mouth, or resistance to retropulsion of the globe. No other abnormalities were observed. Computed tomography was performed, revealing a contrast-enhancing region associated with the right masseter muscle impinging into the right orbit; this was more pronounced with the mouth open. Cytology revealed a small number of mildly to moderately atypical mesenchymal cells. Histopathology was consistent with polyphasic myositis, with a predominance of lymphocytes and plasma cells. No infectious agents were identified. Serum antibody titers for Toxoplasma gondii and Neospora caninum were negative. Serum titers for 2 M antibody were positive at 1:500, consistent with a diagnosis of masticatory muscle myositis. TREATMENT AND OUTCOME: Therapy with prednisone was initiated. During a follow-up period of 5 months, there was no recurrence of clinical signs, and the dose of prednisone was reduced by 25%. CLINICAL SIGNIFICANCE: To the authors' knowledge, this is the first reported case of masticatory muscle myositis causing dynamic exophthalmos and strabismus in a dog.

Correlation between urine anion gap and urine ammonia-creatinine ratio in healthy cats and cats with kidney disease.

BACKGROUND: Ammonium excretion decreases as kidney function decreases in several species, including cats, and may have predictive or prognostic value in patients with chronic kidney disease (CKD). Urine ammonia measurement is not readily available in clinical practice, and urine anion gap (UAG) has been proposed as a surrogate test. OBJECTIVES: Evaluate the correlation between urine ammonia-to-creatinine ratio (UACR) and UAG in healthy cats and those with CKD and determine if a significant difference exists between UAG of healthy cats and cats with CKD. ANIMALS: Urine samples collected from healthy client-owned cats (n = 59) and those with stable CKD (n = 17). METHODS: Urine electrolyte concentrations were measured using a commercial chemistry analyzer and UAG was calculated as ([sodium] + [potassium]) - [chloride]. Urine ammonia and creatinine concentrations had been measured previously using commercially available enzymatic assays and used to calculate UACR. Spearman's rank correlation coefficient between UAG and UACR was calculated for both groups. The UAG values of healthy cats and cats with CKD were assessed using the Mann-Whitney test (P < .05). RESULTS: The UAG was inversely correlated with UACR in healthy cats (P < .002, r0 = -0.40) but not in cats with CKD (P = .55; r0 = -0.15). A significant difference was found between UAG in healthy cats and those with CKD (P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: The UAG calculation cannot be used as a substitute for UACR in cats. The clinical relevance of UAG differences between healthy cats and those with CKD remains unknown.

Magnet-assisted endoscopic removal of ferromagnetic metallic gastric foreign bodies in 4 dogs.

OBJECTIVE: Describe presenting signs, diagnostic findings, and magnet-assisted endoscopic removal method of ferromagnetic gastric foreign bodies (FBs) in dogs. CLINICAL PRESENTATION: Four dogs presented with ingestion of sharp metallic FBs. The presence of gastric FBs was confirmed by abdominal radiography. RESULTS: In 3 cases, initial attempts at endoscopic removal were unsuccessful because of ingesta and fluid in the stomach. A magnet contained within a Roth net was introduced endoscopically. Magnet and attached objects were successfully removed from the stomach. In the fourth case, removal with a magnet was judged to be the most expedient method of removal because multiple metallic objects were present. CLINICAL RELEVANCE: An endoscopic technique was used for the removal of difficult-to-visualize or multiple metallic FBs. The use of this technique allows the removal of ferromagnetic gastric FBs without surgery or risk of complications associated with the passage of sharp material through the gastrointestinal (GI) tract.

Development of a reference interval for urinary ammonia-to-creatinine ratio in feline patients.

BACKGROUND: Disruption of acid-base homeostasis can lead to many clinical problems. Ammonia excretion by the kidneys is critical to maintaining acid-base homeostasis through bicarbonate production. Measurement of ammonia excretion may help determine if the kidneys are properly functioning in maintaining acid-base balance. Reference intervals are essential tools for clinical decision-making but do not currently exist for urinary ammonia-to-creatinine ratio (UACR) in feline patients. OBJECTIVE: This study aimed to generate a reference interval (RI) for UACR in healthy adult cats. METHODS: The study used samples from client-owned adult healthy cats that presented to the University of Florida Primary Care and Dentistry service (n = 92). Physical examination, serum biochemistry, urinalysis, urine ammonia, and creatinine concentrations were measured. Cats were excluded if there were significant abnormalities in their urinalysis or biochemistry panel. The RI for UACR was calculated according to the recommendation of the American Society for Veterinary Clinical Pathology. The UACR was evaluated for correlation with serum bicarbonate, weight, age, and sex. RESULTS: The RI for UACR was 3.4-20.7 with 90% confidence intervals for the lower and upper limits of (3.0-3.7) and (16.0-23.7), respectively. No significant correlation with age, sex, or weight was found. There was no discernable relationship between serum bicarbonate and UACR. CONCLUSIONS: Establishing an RI for UACR in healthy adult cats will allow further studies to determine if changes in UACR are observed during specific disease states.

Diagnosis and management of atypical hypoadrenocorticism in a variable flying fox (Pteropus hypomelanus).

A 19-yr-old intact female variable flying fox (Pteropus hypomelanus) presented with lethargy, behavior changes, and substantial weight loss. Initial clinical pathology revealed hypoglycemia and reduced ionized serum calcium, and imaging, including computed tomography, did not lead to a diagnosis. An adrenocorticotropic hormone (ACTH) stimulation test revealed baseline and post-ACTH cortisol concentrations that were lower than reported normal baseline cortisol concentrations in this species. Treatment with prednisolone resolved the clinical signs and laboratory abnormalities. Repeated attempts to decrease the prednisolone dose caused recurrence of clinical signs and weight loss. Based on diagnostic test results and response to therapy, a diagnosis of atypical hypoadrenocorticism was made.

Gastroduodenal ulceration in dogs with liver disease.

BACKGROUND: Liver disease is frequently cited as a cause of gastroduodenal ulceration (GDU) in dogs but studies regarding GDU and liver disease are limited. OBJECTIVES: To document the presence of GDU in dogs with liver disease. ANIMALS: Forty dogs that underwent liver biopsy, computed tomographic (CT) angiography or both at the University of Florida Small Animal Hospital to diagnose congenital or acquired liver disease. METHODS: Cross-sectional study. Dogs had gastroduodenoscopy performed with photographic and video documentation in a standardized fashion. Lesions (hemorrhage, erosions, ulcers) in the esophagus, stomach, and duodenum were scored based on a grading scale. Presence of esophageal varices was recorded. Dogs were categorized into 4 groups according to cause of liver disease (inflammatory disease, cirrhosis, congenital, other). Presence or absence of ulcers, erosions or both as well as total endoscopic scores were compared among groups. RESULTS: Forty dogs were enrolled with the following distribution: 13 congenital, 13 inflammatory, 3 cirrhosis, and 11 other. Four dogs had GDU (10%; 95% confidence interval [CI], 3%-24%) and 6 dogs had erosions (15%; 95% CI, 6%-30%). No difference was found in total endoscopic score (P = .21) or in the proportion of dogs with ulcers, erosions or both versus those without (P = .25) among the groups. CONCLUSIONS AND CLINICAL IMPORTANCE: Gastroduodenal ulceration was found in 10% of dogs with liver disease in this population. Additional studies are warranted to confirm these findings in larger numbers of dogs with specific disease etiologies.

Ultrasonographic and radiographic features of a true gastrogastric intussusception with spontaneous resolution in a cat.

An 11-year-old, female spayed, domestic shorthair cat with a 1-week history of vomiting was diagnosed with a gastrogastric intussusception using ultrasound. Distinguishing ultrasonographic findings included invagination of the gastric fundus into the body and were correlated to radiographs acquired at the time of the evaluation. Spontaneous resolution of the gastrogastric intussusception was observed on a positive-contrast upper gastrointestinal fluoroscopic study done the following day. Due to worsening comorbidities, which most significantly included chronic renal disease and pancreatitis, and declining quality of life, the patient was humanely euthanized 10 months later. Necropsy revealed no gross and histopathologic abnormalities associated with the stomach. A definitive cause for the intussusception remains unknown.

Evaluation of a novel technique involving ultrasound-guided, temporary, percutaneous gastropexy and gastrostomy catheter placement for providing sustained gastric decompression in dogs with gastric dilatation-volvulus.

OBJECTIVE: To evaluate the feasibility of ultrasound-guided, temporary, percutaneous T-fastener gastropexy (TG) and gastrostomy catheter (GC) placement for providing sustained gastric decompression in dogs with acute gastric dilatation-volvulus (GDV) and to compare findings with those of trocarization. ANIMALS: 16 dogs with GDV. PROCEDURES: Dogs were randomly assigned to undergo gastric decompression by means of percutaneous trocarization (trocar group; n = 8) or temporary TG and GC placement (TTG+GC group; 8) with ultrasound guidance. The gastric volvulus was then surgically corrected, and the decompression sites were examined. Outcomes were compared between groups. RESULTS: The proportion of dogs with successful decompression did not differ significantly between the TTG+GC (6/8) and trocar (7/8) groups; median procedure duration was 3.3 and 3.7 minutes, respectively. After the failed attempts in the TTG+GC group, the procedure was modified to include ultrasound guidance during T-fastener placement. The decrease in intragastric pressure by 5 minutes after trocar or GC insertion was similar between groups. For dogs in the TTG+GC group, no significant difference in intragastric pressure was identified between 5 and 60 minutes after GC insertion. Complications included inadvertent splenic or jejunal placement in 2 dogs (TTG+GC group) and malpositioned and ineffective trocar placement in 1 dog (trocar group). All dogs survived for at least 2 weeks. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasound-guided, temporary, percutaneous TG and GC placement was safe and effective at providing sustained gastric decompression in dogs with GDV, suggesting that this technique would be ideal for dogs in which surgical delays are anticipated or unavoidable.

Suspected albuterol toxicosis in a dog.

CASE DESCRIPTION: A 6-year-old male castrated Shetland Sheepdog was evaluated because of severe hypokalemia and progressive paresis. CLINICAL FINDINGS: Physical examination revealed fever, tachypnea, mydriasis, hyperemic mucous membranes, severe forelimb paresis, and hind limb paraplegia. The dog had superficial and deep pain sensation in all 4 limbs. Forelimb spinal reflexes were considered normal, but hind limb reflexes were normal to slightly hyperreflexive. The panniculus reflex was considered to be normal, and cranial nerve reflexes were intact. A CBC revealed mild leukocytosis and erythrocytosis, and serum biochemical analysis revealed severe hypokalemia. Thoracic and abdominal imaging did not reveal relevant findings. Blood pressure and ECG findings were within reference limits. Questioning of the owner revealed possible exposure to albuterol via ingestion of medication intended for the owner's horse. Results of serum testing via immunoassay were suggestive of albuterol toxicosis. TREATMENT AND OUTCOME: Treatment included IV administration of an electrolyte solution and supplemental potassium chloride. The rate of potassium chloride supplementation was slowly decreased as serum potassium concentration increased. No other medical intervention was required, and the dog made a rapid and complete recovery. CLINICAL RELEVANCE: Ingestion of albuterol can lead to profound physical and serum biochemical abnormalities. Appropriate historical information should be obtained to identify possible sources and routes of exposure to intoxicants. Albuterol-induced hypokalemia can be successfully managed medically.

Chromobacterium violaceum infection in two dogs.

Chromobacterium violaceum is a saprophyte of soil and water in tropical and subtropical environments that is associated with rare but highly fatal infections in animals and humans. Systemic infection was diagnosed in two critically ill dogs from Florida. Fever was absent in both dogs. Both dogs were treated surgically and provided with intensive care, but only one survived. The identification of characteristic, violet-pigmented bacterial colonies on routine microbial cultures should alert microbiologists and clinicians to the likelihood of this dangerous pathogen. Because of the rapidly progressive nature of this infection, empirical antibiotic administration with fluoroquinolones should be employed pending susceptibility testing.

Temporary percutaneous T-fastener gastropexy and continuous decompressive gastrostomy in dogs with experimentally induced gastric dilatation.

OBJECTIVE To evaluate a percutaneous, continuous gastric decompression technique for dogs involving a temporary T-fastener gastropexy and self-retaining decompression catheter. ANIMALS 6 healthy male large-breed dogs. PROCEDURES Dogs were anesthetized and positioned in dorsal recumbency with slight left-lateral obliquity. The gastric lumen was insufflated endoscopically until tympany was evident. Three T-fasteners were placed percutaneously into the gastric lumen via the right lateral aspect of the abdomen, caudal to the 13th rib and lateral to the rectus abdominis muscle. Through the center of the T-fasteners, a 5F locking pigtail catheter was inserted into the gastric lumen and attached to a device measuring gas outflow and intragastric pressure. The stomach was insufflated to 23 mm Hg, air was allowed to passively drain from the catheter until intraluminal pressure reached 5 mm Hg for 3 cycles, and the catheter was removed. Dogs were hospitalized and monitored for 72 hours. RESULTS Mean ± SD catheter placement time was 3.3 ± 0.5 minutes. Mean intervals from catheter placement to a ≥ 50% decrease in intragastric pressure and to ≤ 6 mm Hg were 2.1 ± 1.3 minutes and 8.4 ± 5.1 minutes, respectively. After catheter removal, no gas or fluid leakage at the catheter site was visible laparoscopically or endoscopically. All dogs were clinically normal 72 hours after surgery. CONCLUSIONS AND CLINICAL RELEVANCE The described technique was performed rapidly and provided continuous gastric decompression with no evidence of postoperative leakage in healthy dogs. Investigation is warranted to evaluate its effectiveness in dogs with gastric dilatation-volvulus.

Response rates and survival times for cats with lymphoma treated with the University of Wisconsin-Madison chemotherapy protocol: 38 cases (1996-2003).

OBJECTIVE: To determine response rates and survival times for cats with lymphoma treated with the University of Wisconsin-Madison chemotherapy protocol. DESIGN: Retrospective study. ANIMALS: 38 cats with lymphoma. PROCEDURE: Medical records were reviewed, and information on age, sex, breed, FeLV and FIV infection status, anatomic form, clinical stage, and survival time was obtained. Immunophenotyping was not performed. RESULTS: Mean +/- SD age of the cats was 10.9 +/- 4.4 years. Overall median survival time was 210 days (interquartile range, 90 to 657 days), and overall duration of first remission was 156 days (interquartile range, 87 to 316 days). Age, sex, anatomic form, and clinical stage were not significantly associated with duration of first remission or survival time. Eighteen of the 38 (47%) cats had complete remission, 14 (37%) had partial remission, and 6 (16%) had no response. Duration of first remission was significantly longer for cats with complete remission (654 days) than for cats with partial remission (114 days). Median survival time for cats with complete remission (654 days) was significantly longer than median survival time for cats with partial remission (122 days) and for cats with no response (11 days). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that a high percentage of cats with lymphoma will respond to treatment with the University of Wisconsin-Madison chemotherapy protocol. Age, sex, anatomic form, and clinical stage were not significantly associated with duration of first response or survival time, but initial response to treatment was.

Stereotactic radiosurgery for treatment of osteosarcomas involving the distal portions of the limbs in dogs.

Stereotactic radiosurgery (SRS) involves precise delivery of a single large dose of radiation to a designated tumor target. This report describes use of SRS in combination with a frameless stereotactic localization system to treat 11 dogs with appendicular osteosarcomas. Five dogs were treated with SRS alone; 6 were treated with a combination of SRS and chemotherapy. Overall median survival time was 363 days (range, 145 to 763 days), with 6 dogs still alive 90, 142, 234, 367, 633, and 763 days after SRS. Limb function was good or excellent in all 6 dogs that were still alive. Results in these dogs suggest that SRS may be a viable option for dogs with appendicular osteosarcoma, with the potential to provide long-term local tumor control and improvement in limb function, especially when combined with chemotherapy. Because of the destructive nature of osteosarcoma and limitations of SRS, dogs with tumors that are small and have caused minimal bone destruction would likely be the best candidates for this procedure.

Intravesical instillation of amikacin for treatment of a lower urinary tract infection caused by Pseudomonas aeruginosa in a dog.

CASE DESCRIPTION: A 9-year-old neutered male Golden Retriever was evaluated because of recurrent lower urinary tract infection subsequent to placement of a permanent cystostomy tube. CLINICAL FINDINGS: The dog was clinically normal except for the presence of malodorous urine. Bacteriologic culture of a urine sample obtained by cystocentesis yielded growth of Pseudomonas aeruginosa, which was susceptible to amikacin, gentamicin, imipenemcilastatin, and ticarcillin-clavulanic acid. TREATMENT AND OUTCOME: The dog was administered amikacin sulfate (15 mg/kg [6.8 mg/lb], SC, q 24 h) for 14 days before treatment was discontinued because of the presence of casts in the urine. The cystostomy tube was replaced, and intravesical instillation of amikacin (15 mg/kg diluted in 30 mL of saline [0.9% NaCl] solution, q 12 h) was initiated. On day 25 of instillation treatment, bacterial culture of a urine sample yielded no growth, urinalysis revealed no casts, and SUN and creatinine concentrations were within reference intervals. On day 27 of instillation treatment, gross hematuria was observed, which resolved following discontinuation of amikacin instillation. CLINICAL RELEVANCE: In this dog, treatment of a lower urinary tract infection caused by a multidrug-resistant strain of P aeruginosa was successfully achieved with intravesical instillation of amikacin. Results of serial serum biochemical analyses remained within reference limits, and urine casts were not identified on urinalyses during the treatment period, which suggested that systemic absorption of amikacin was minimal. Intravesical instillation of antimicrobials may be a viable treatment option for dogs with lower urinary tract infections caused by multidrug-resistant bacteria.

Effects of maropitant, acepromazine, and electroacupuncture on vomiting associated with administration of morphine in dogs.

OBJECTIVE: To evaluate effects of maropitant, acepromazine, and electroacupuncture on morphine-related signs of nausea and vomiting in dogs and assess sedative effects of the treatments. DESIGN: Randomized controlled clinical trial. ANIMALS: 222 dogs. PROCEDURES: Dogs received 1 of 6 treatments: injection of saline (0.9% NaCl) solution, maropitant citrate, or acepromazine maleate or electroacupuncture treatment at 1 acupoint, 5 acupoints, or a sham acupoint. Morphine was administered after 20 minutes of electroacupuncture treatment or 20 minutes after injectable treatment. Vomiting and retching events and signs of nausea and sedation were recorded. RESULTS: Incidence of vomiting and retching was significantly lower in the maropitant (14/37 [37.8%]) group than in the saline solution (28/37 [75.7%]) and sham-acupoint electroacupuncture (32/37 [86.5%]) groups. The number of vomiting and retching events in the maropitant (21), acepromazine (38), 1-acupoint (35), and 5-acupoint (34) groups was significantly lower than in the saline solution (88) and sham-acupoint electroacupuncture (109) groups. Incidence of signs of nausea was significantly lower in the acepromazine group (3/37 [8.1%]) than in the sham-acupoint group (15/37 [40.5%]). Mean nausea scores for the saline solution, maropitant, and sham-acupoint electroacupuncture groups increased significantly after morphine administration, whereas those for the acepromazine, 1-acupoint electroacupuncture, and 5-acupoint electroacupuncture groups did not. Mean sedation scores after morphine administration were significantly higher in dogs that received acepromazine than in dogs that received saline solution, maropitant, and sham-acupoint electroacupuncture treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Maropitant treatment was associated with a lower incidence of vomiting and retching, compared with control treatments, and acepromazine and electroacupuncture appeared to prevent an increase in severity of nausea following morphine administration in dogs.

Disseminated mycotic infection caused by Westerdykella species in a German Shepherd dog.

CASE DESCRIPTION: A 5-year-old 34.3-kg (75.5-lb) neutered male German Shepherd Dog was evaluated because of chronic azotemia that was unresponsive to typical medical management. CLINICAL FINDINGS: Urinalysis revealed pyuria and fungal hyphae. Fungal culture of a urine sample grew a sterile mold that was identified as Westerdykella spp via PCR assay. TREATMENT AND OUTCOME-: he dog was treated empirically with itraconazole orally and amphotericin B IV for 5 weeks. Because of progressive azotemia, treatment was modified to oral administration of posaconazole. The dog improved but then developed progressive azotemia, hyperphosphatemia, and suspected diskospondylitis. Treatment was again modified to oral administration of terbinafine on the basis of results of antifungal susceptibility testing. The dog was euthanized after 5 months of antifungal treatment because of a deteriorating clinical condition and progressive azotemia. CLINICAL RELEVANCE: Westerdykella spp are filamentous hyphal organisms from the family Sporomiaceae and had not previously been reported to cause infections in dogs. Fungal PCR assay and antifungal susceptibility testing may be useful for a patient with a suspected fungal infection that does not respond to empirical treatment or when traditional culture methods for fungal identification are unsuccessful. Westerdykella spp should be considered as a possible etiologic agent when systemic mycosis is diagnosed.

Dysuria caused by a partially obstructing urethral membrane in a female dog.

CASE DESCRIPTION: A 3.5-year-old spayed female Labrador Retriever was examined for dysuria of unknown duration. CLINICAL FINDINGS: Urogenital examination revealed a recessed vulva and a persistent hymen. The hymen was broken down digitally. Results of urinalysis at the referral examination were unremarkable, and no clinically relevant abnormalities were detected on clinicopathologic analysis of blood and serum samples or cytologic evaluation of a vaginal smear. After clinical signs persisted, retrograde contrast vaginourethrocystography was performed; results were considered normal. During uroendoscopic examination, a translucent membranous structure was detected that partially obstructed the urethral lumen near the junction of the urethra and bladder. TREATMENT AND OUTCOME: Passage of the endoscope into the urinary bladder ruptured the membranous structure. The dog recovered from the procedure uneventfully and was treated with colchicine (0.03 mg/kg [0.014 mg/lb], PO, q 24 h for 14 days). One month later, the owner reported resolution of clinical signs. Fourteen months later, the patient was evaluated for recurrence of dysuria of several months' duration. Uroendoscopic examination revealed a membranous structure similar to that originally detected; this tissue was also ruptured during endoscopy. The patient was discharged and the owner was instructed to administer colchicine at the same dosage. Recurrence of dysuria was reported again 10 months following the second procedure. CLINICAL RELEVANCE: To the authors' knowledge, this type of membranous urethral obstruction has not been previously described in a dog. Administration of colchicine did not prevent recurrence, but potential effects of drug administration on time to recurrence could not be evaluated.

Effect of antivenin dose on outcome from crotalid envenomation: 218 dogs (1988-2006).

OBJECTIVE: To determine whether the dose of antivenin administered is associated with a difference in survival of crotalid-envenomated dogs. A secondary objective was to determine whether other covariables affect survival. DESIGN: Retrospective study (1988-2006). SETTING: Private referral center and university small animal teaching hospital. ANIMALS: Two hundred and eighteen dogs with evidence of crotalid envenomation and treatment with equine-derived antivenin. INTERVENTIONS: Administration of antivenin. MEASUREMENTS AND MAIN RESULTS: Patient signalment, physical and clinicopathologic data at time of presentation, treatments, complications of antivenin therapy, length and cost of hospitalization, and outcome were recorded. Confidence intervals were determined for the difference in median number of vials administered and for median dosage for patients that lived versus died. Penalized logistic regression was performed to evaluate the effect of other covariables on survival. The median age of affected dogs was 3 years (range 6 w-12 y) with a median weight of 25.7 kg (range 1.95-86.4 kg). The median number of antivenin vials administered was 1.0 (range 1.0-10.0). Acute and chronic reactions were reported in 7% (16/218) and 0.9% (2/218) of dogs, respectively. Nine of 218 dogs (4.1%) died. The median number of vials administered to the nonsurvivors and survivors were 2.0 (range 1-5 vials) and 1.0 (range 1-10 vials), respectively. The median number of vials received was significantly different in dogs that died versus those that lived (P<0.05). Increased heart rate (P=0.02) and petechiation (P=0.04) were associated with decreased likelihood of survival, while diphenhydramine (P=0.02) and fluoroquinolone (P=0.046) administration was associated with increased likelihood of survival. The median duration of hospitalization was 1.0 day (range 2 h-22 d). The median cost of hospitalization was US$1592.00 (range US$267.20-US$6738.00). CONCLUSION: The administration of more vials of antivenin is potentially associated with negative outcome; however, a causal relationship has not been established. Controlled, prospective studies are needed to optimize antivenin administration.