What is your diagnosis? Marked hyperchloremia in a dog

Abstract: A 5‐year‐old neutered male Cavalier King Charles Spaniel was evaluated for a 3‐week history of progressive paresis. The dog had been receiving potassium citrate capsules to acidify urine for the past 2 years because of an earlier history of urolithiasis. Results of neurologic examination, spinal cord radiography, and magnetic resonance imaging of the skull and spinal cord revealed no lesions that could have accounted for the neurologic signs. The main abnormalities on a clinical chemistry profile were marked hyperchloremia (179 mmol/L, reference interval 108–122 mmol/L) and an anion gap of ?50.4 mmol/L (reference interval 16.3–28.6 mmol/L). Because of the severe hyperchloremia, serum bromide concentration was measured (400 mg/dL; toxic concentration >150 mg/dL; some dogs may tolerate up to 300 mg/dL). Analysis of the potassium citrate capsules, which had been compounded at a local pharmacy, yielded a mean bromide concentration of 239 mg/capsule. Administration of the capsules was discontinued and there was rapid resolution of the dog's neurologic signs. This case of extreme bromide toxicity, which apparently resulted from inadvertent use of bromide instead of citrate at the pharmacy, illustrates the importance of knowing common interferents with analyte methodologies and of pursing logical additional diagnostic tests based on clinical and laboratory evidence, even when a patient's history appears to rule out a potential etiology.     

Prevalence of serum antibodies against Bartonella species in the serum of cats with or without uveitis

Bartonella henselae has been implicated as a causative agent of chronic uveitis in people and in some cats. The objective of this study was to determine whether Bartonella species seroprevalence or titer magnitude varies among cats with uveitis, cats without ocular diseases recorded and healthy cats, while controlling for age and risk of flea exposure based on state of residence. There was no difference in seroprevalence rates or titer magnitude between cats with uveitis and cats with non-ocular diseases. Healthy cats were more likely to be seropositive for Bartonella species than cats with uveitis. The median Bartonella species titer was 1:64 for all groups, although healthy cats were more likely to have higher titers than cats with uveitis and cats with non-ocular disease. The results suggest that serum antibody tests alone cannot be used to document clinical uveitis associated with Bartonella species infection.     

Packed red blood cell transfusions in dogs with gastrointestinal hemorrhage: 55 cases (1999-2001)

Fifty-five dogs received packed red blood cell (PRBC) transfusions for gastrointestinal (GI) hemorrhage during a 26-month period (1999 to 2001), accounting for 11.7% of the PRBC transfusions in that time. Thirty-nine (61%) dogs had an intestinal pathology (primary or secondary) as the cause of GI hemorrhage, including intestinal masses, gastroenteritis, hepatic disease, and renal disease. Nonsteroidal and steroidal anti-inflammatory drug use was found frequently in dogs with GI hemorrhage. Sixteen (39%) dogs were identified as having immune-mediated thrombocytopenia (IMT) and associated GI hemorrhage. Dogs with IMT received more transfusions of PRBC than nonIMT dogs (P<0.03) and received a significantly larger total volume of PRBC (P<0.01) during hospitalization.     

A case of methicillin-resistant Staphylococcus pseudintermedius (MRSP) pyoderma in a Labrador retriever dog

An 8-year-old, neutered male Labrador retriever dog with generalized pruritis had a history of recurring atopic dermatitis and superficial pyoderma. Cocci and yeast were found on cytology and methicillin-resistant Staphylococcus pseudintermedius was cultured. A regimen of marbofloxacin, dexamethasone, ketoconazole, and cyclosporine in addition to bathing with 2% chlorhexidine shampoo resulted in marked improvement.     

Plasma and urine electrolyte and mineral concentrations in Thoroughbred horses with recurrent exertional rhabdomyolysis after consumption of diets varying in cation-anion balance

OBJECTIVE: To determine whether plasma, urine, and fecal electrolyte and mineral concentrations differ between clinically normal horses and Thoroughbreds with recurrent exertional rhabdomyolysis (RER) after consumption of diets varying in cation-anion balance. ANIMALS: 5 Thoroughbred mares with RER and 6 clinically normal mixed-breed mares. PROCEDURE: Each of 3 isocaloric diets designated as low, medium, and high on the basis of dietary cation-anion balance (DCAB) values of 85, 190, and 380, respectively, were fed to horses for 14 days. During the last 72 hours, 3 horses with RER and 3 control horses had daily urine and fecal samples obtained by total 24-hour collection. Remaining horses had urine samples collected daily by single catheterization. RESULTS: For each diet, no differences existed between horses with RER and control horses in plasma pH, electrolyte concentrations, and creatine kinase activity or in urine pH and renal fractional excretion (FE) values. Plasma pH, strong ion difference, bicarbonate and total carbon dioxide concentrations, and base excess decreased and plasma chloride and ionized calcium concentrations increased with decreasing DCAB. Urine pH decreased with decreasing DCAB. The FE of chloride and phosphorus were greatest for horses fed the low diet. The FE values for all electrolytes exept magnesium did not differ between urine samples obtained by single catheterization and total 24-hour collection. Daily balance of calcium, phosphorus, sodium, chloride, and potassium did not differ significantly among horses fed the various diets. CONCLUSIONS: In clinically normal horses and in horses with RER, the DCAB strongly affects plasma and urine pH and the FE of sodium, potassium, chloride, and phosphorus.     

Transdermal absorption of a liposome-encapsulated formulation of lidocaine following topical administration in cats

OBJECTIVE: To determine plasma disposition after dermal application of a liposome-encapsulated formulation of lidocaine in cats. ANIMALS: 6 healthy adult cats with a mean (+/- SD) body weight of 4.1 +/- 0.44 kg. PROCEDURE: CBC determination and biochemical analysis of blood samples were performed for all cats. Cats were anesthetized by use of isoflurane, and catheters were placed IV in a central vein. The next day, blood samples were obtained from the catheters before and 1, 2, 3, 4, 6, 8, 10, 12, and 24 hours after applying a 4% liposome-encapsulated lidocaine cream (15 mg/kg) to a clipped area over the cephalic vein. Plasma concentrations of lidocaine were analyzed with a high-performance liquid chromatography assay. Results-Two cats had minimal transdermal absorption of lidocaine, with lidocaine concentrations below the sensitivity of the assay at all but 1 or 2 time points. In the other 4 cats, the median maximum plasma concentration was 149.5 ng/ml, the median time to maximum plasma concentration was 2 hours, and the median area under the concentration versus time curve from zero to infinity was 1014.5 ng.h/ml. CONCLUSIONS AND CLINICAL RELEVANCE: Maximum plasma concentrations of lidocaine remained substantially below toxic plasma concentrations for cats. On the basis of these data, topical administration of a liposome-encapsulated lidocaine formulation at a dose of 15 mg/kg appears to be safe for use in healthy adult cats.     

Use of a condylar screw plate for repair of a Salter-Harris type-III fracture of the femur in a 2-year-old horse

A 2-year-old sexually intact male Paint horse weighing 427 kg (940 lb) was admitted for examination and treatment of intermittent non-weight-bearing lameness of the right hind limb of 1 week's duration. Radiography revealed a displaced Salter-Harris type-III fracture of the right femoral condyle with the sagittal component of the fracture line located in the intercondylar space and the transverse component exiting on the medial aspect of the femur. The fracture was repaired with a condylar screw plate designed for repair of femoral condylar fractures in humans. The owner reported by telephone 9 months after surgery that the horse was sound. To our knowledge, use of this particular implant system for fixation of a Salter-Harris type-III fracture on the medial side of the femur in a horse has not been described. Results in this horse suggest that this implant can be successfully used for repair of femoral condylar fractures in selected adult horses.