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Notes: Objective: To measure serum parathyroid hormone (PTH) and 25-hydroxyvitamin D3 concentrations in cats with urethral obstruction.Design: Prospective single cohort study.Setting: University affiliated veterinary teaching hospital.Animals: Male cats with urethral obstruction.Interventions: Routine blood samples drawn from male cats with urethral obstruction.Measurements and main results: Measured variables included blood gas parameters, plasma sodium, potassium, chloride, and ionized calcium concentrations, as well as serum blood urea nitrogen, creatinine, phosphorus, PTH, and 25-hydroxyvitamin D3 concentrations. PTH was inversely correlated with ionized calcium and positively correlated with serum phosphorus. No discernable relationship could be found between 25-hydroxyvitamin D3 and any of the measured parameters.Conclusions: Lack of parathyroid response does not appear to be the underlying mechanism for ionized hypocalcemia in cats with urethral obstruction.

Notes: Objective: To determine the continuous changes in blood volume in response to fluid administration using an in-line hematocrit monitor.Design: Prospective study.Setting: Research laboratory.Animals: Four healthy dogs.Interventions: Each dog received intravenous boluses of 80 mL/kg of 0.9% saline (S), 4 mL/kg of 7.5% saline (HS), 20 mL/kg of dextran 70 (D), 20 mL/kg of hetastarch (HES), or no fluids (control, C) on separate occasions. Fluids were administered at 150 mL/min in the S, D, and HES groups, and at 1 mL/kg/min in the HS group.Measurements and main results: Blood volume changes were measured every 20 seconds for 240 minutes using an in-line hematocrit monitor. There was a rapid rise in blood volume during all infusions. Immediately after the administration of crystalloid fluids, the rapid rise in blood volume ceased. Subsequently, there was a steep decline in blood volume for 10 minutes, and a slower decline thereafter. In contrast, the rise in blood volume continued for at least 10 minutes after the infusion of the colloids was complete, and a plateau was observed for the remainder of the experiment. The blood volume effect, as measured by area under the curve, was significantly greater in the saline group than the other groups during the infusion time and for the 0–240 minutes time period. The areas under the curve for the two colloid solutions were not significantly different from each other during any time periods. The percent increase in blood volume immediately following the infusions was 76.4±10.0 in the S group, 17.1±3.2 in the HS group, 23.0±10.5 in the D group, and 27.2±6.4 in the HES group. At 30 minutes from the start of the infusion, the mean percent increases in blood volumes were 35.2±9.3 in the S group, 12.3±0.9 in the HS group, 35.9±7.3 in the D group, and 36.8±6.5 in the HES group. At 240 h post-infusion, the mean percent increases in blood volume were 18.0±9.7 in the S group, 2.9±6.1 in the HS group, 25.6±16.1 in the D group, and 26.6±8.6 in the HES group. The C group had a mean percent change in blood volume of −3.7±3.4 at the end of the experiment.Conclusions: This study indicates that the rapid administration of saline at clinically relevant doses leads to the largest immediate increase in blood volume, although this change is transient because of rapid redistribution of the fluid. Despite a brief increase in blood volume that was almost 3 times the volume administered, hypertonic saline led to the smallest increase in blood volume post-infusion. The synthetic colloid solutions increased the blood volume by an amount greater than that infused and the effect was sustained for a longer period of time than seen following crystalloid administration, but the maximum increase in blood volume was significantly less than saline. The measurement of continuous changes in blood volume, using an in-line hematocrit monitor, was a useful means of assessing the dynamic effects of fluid administration in dogs in a research setting.

Notes: Objective: To evaluate plasma sodium and glucose concentrations in dogs with congestive heart failure (CHF) prior to treatment and evaluate the differences between survivors and non-survivors.Design: Retrospective study.Animals: Fifty-nine dogs with CHF prior to receiving cardiac medication.Interventions: None.Measurements and main results: The mean plasma sodium concentration in dogs with CHF was below the reference range (144–156 mmol/L) and significantly lower (P=0.009) in non-survivors (141±6 mmol/L) compared with survivors (147±4 mmol/L). The mean plasma glucose concentration was above the reference range (76–117 mg/dL) and significantly higher (P=0.004) in non-survivors (128±52 mg/dL) compared with survivors (100±13 mg/dL). Forty-four percent of non-survivors had concurrent low plasma sodium and high plasma glucose concentrations, whereas no survivors had both abnormalities (P〈0.0001).Conclusions: Lower plasma sodium and higher plasma glucose are associated with a worse outcome in dogs with CHF.

Notes: Objective: The purposes of this study were to characterize the hyperglycemic, hyperosmolar syndrome (HHS), also known as nonketotic hyperosmolar diabetes, in cats; to determine the prevalence of HHS in the diabetic cat population in the emergency room; to document the outcome in cats with HHS; and to identify any predisposing factors or predictors of survival.Design: Retrospective study.Setting: An emergency service at a veterinary teaching hospital located in a major metropolitan area.Animals: The case records of 17 cats with hyperglycemic, hyperosmolar syndrome presenting from 1995 to 2001 were evaluated. An additional 37 cats with diabetic ketoacidosis and 80 cats with diabetes mellitus served as comparison groups.Interventions: None.Measurements and main results: Signalment, history, physical examination findings, clinico-pathologic data, concurrent disease, and outcome were recorded. Hyperglycemic, hyperosmolar syndrome was seen in older cats that were often long-standing diabetics receiving insulin for many months. Client concerns included polydipsia, polyuria, and lethargy. Neurologic and respiratory signs occurred frequently. Evaluation at presentation revealed profound dehydration, lactic acidosis, and azotemia. Serious concurrent diseases that likely contributed to the development of the HHS crisis were diagnosed in 88% (15/17) of the HHS cats. The most common concurrent diseases were renal failure, respiratory compromise, infection, congestive heart failure, neoplasia, and gastrointestinal tract disease. Pancreatitis and hepatic disease did not occur frequently in this diabetic cat population. Sixty-five percent of HHS cats did not survive the initial hospitalization, with most dying or being euthanized within 10 hours of presentation. The long-term survival rate was low (12%).Conclusions: HHS is a serious life-threatening form of diabetic crisis and cats with HHS often have other severe systemic diseases. Cats with diabetes and concurrent disease, especially renal failure and congestive heart failure, are at increased risk of HHS and should be closely monitored for signs of crisis. The mortality rate for HHS cats is high.

Notes: Objective: To compare the incidence of clinically evident post-operative complications, financial cost and length of hospital stay for Dachshunds with acute intervertebral disc disease treated with decompressive surgery with and without the use of methylprednisolone sodium succinate (MPSS). Design: Retrospective clinical study Setting: Veterinary Teaching Hospital Animals: Dachshunds that presented to the Veterinary Hospital of the University of Pennsylvania between January 1994 and December 1999 with acute intervertebral disc disease that were treated with decompressive surgery. Intervention: None Measurements and Main Results: Dogs were divided into 2 groups dependent upon whether they had received MPSS. Medical records were examined for evidence of post-operative complications. Other parameters recorded included details of drugs administered (principally corticosteroids and gastrointestinal protectant drugs), length and cost of hospital stay and neurological status at 24 hours post-operatively and at suture removal. Compared to other corticosteroids, dogs receiving MPSS had a significantly higher incidence of clinically evident post-operative gastrointestinal complications, an increased use of gastrointestinal protectant drugs, and an increased cost for hospital stay (p〈0.01). Conclusions: The use of MPSS inDachshunds with acute intervertebral disc disease is associated with an increased post-operative complication rate and an increased financial cost to the client. The use of MPSS should be carefully evaluated for each patient.

Notes: A four-year old female Rottweiler presented with a 34-hour history of dystocia. Physical examination revealed a purple-black, fluid-filled sac protruding from vulva and suspended by a similar colored stalk. Digital vaginal examination indicated that the stalk of tissue extended up into the cervix and beyond. Due to the grossly necrotic appearance, the stalk of tissue was ligated, and the sac was removed. Three puppies were delivered vaginally, but a subsequent caesarian section was required due to uterine inertia likely secondary to exhaustion. Three more live puppies were delivered via the c-section. Further abdominal exploration revealed a tear in the left vaginal wall, one ligated ureter, and the second ureter free at its distal end and leaking urine into the abdomen. The surgical findings indicated that the bladder, ureters, and urethra had herniated through the vaginal tear and prolapsed through the vulva.

Notes: We report the first case of colonic volvulus in a cat. A 12-year old spayed, female domestic shorthair cat with chronic bowel disease presentated with one-day history of lethargy and anorexia. Physical examination abnormalities included cachexia, poor perfusion, and poor skin turgor. A large, non painful, gas-filled, tubular structure, occupying the majority of the abdominal cavity was noted by palpation. Abdominal radiographs revealed a gas-filled displaced colon. Exploratory laparotomy confirmed a volvulus at the root of the colonic mysetery, along with a partial torsion of the distal colon. The majority of the colon was determined to be necrotic and was surgically resected. Due to persistent hypotension and perceived poor prognosis, the cat was euthanized.

Notes: Objective: To describe the clinical manifestations and treatment of hypermagnesemia and the potential drug errors that can lead to iatrogenic electrolyte toxicities.Summary: We report 2 cases of iatrogenic intravenous (IV) magnesium (Mg) overdose. Both cases developed extreme cardiovascular and neurologic symptoms consisting of vomiting, hypotension, bradycardia, flaccid paralysis, and severe mental depression. Diagnosis was made based upon serum ionized Mg levels (3.47 mmol/L; reference range: 0.43–0.58 mmol/L for Case #1; and 4.64 mmol/L; reference range: 0.42–0.55 mmol/L for Case #2). Each animal was treated with 0.9% NaCl for diuresis and IV calcium gluconate. Within 24 hours, the cardiovascular and neurologic status of both animals, as well as the serum Mg concentration, had normalized. Each animal was discharged with no complications. Both animals had been hospitalized for critical illness and had developed hypomagnesemia that was being treated with Mg sulfate infusions. The cause for the hypermagnesemia was due to miscalculations in treatment orders that led to erroneously administered Mg-containing solutions. Confusing drug labels and varying units of measurement can lead to erroneous miscalculations, especially in critically ill patients that receive multiple IV infusions.New information provided: This is the first case report of iatrogenic Mg overdose in veterinary medicine. These 2 cases had a good clinical outcome with prompt recognition and supportive care.

Notes: Objective: Correlate the necropsy diagnosis with the history, diagnostic findings, and clinical course of dyspneic cats with primary lung parenchymal disease.Design: Retrospective study.Setting: Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania.Animals: Client-owned cats over 6 months of age hospitalized in the Intensive Care Unit (ICU) with a primary problem of respiratory distress that had pulmonary parenchymal disease on thoracic radiographs, and a complete necropsy.Interventions: None.Measurements and main results: Cats included were assigned into 2 groups based on the pulmonary histopathology: inflammatory (n=8) and neoplastic (n=7) disease. No statistical difference was found between the groups with regard to age, body weight, clinical signs, duration of clinical signs, physical examination findings, thoracic radiography, duration of hospitalization, treatment, and outcome. Cats with neoplasia had a statistically higher mean total white blood cell count (26.60 k/μL±10.41) than those with inflammatory lung disease (11.59 k/μL±4.49; P=0.026). Cats with bacterial or viral pulmonary disease had a significantly shorter median duration of illness (5 days, range 1–7 days) than all other cats (30 days, range 7–365 days; P=0.0042). Ultrasound guided pulmonary fine-needle aspiration (FNA) provided an accurate diagnosis in 5/5 cases.Conclusions: Forty-seven percent of cats with pulmonary parenchymal disease had neoplasia. The clinical diagnosis was difficult to obtain ante-mortem; lung FNA appeared to be the most helpful diagnostic tool in these cases.

Notes: Objective: To characterize the clinical characteristics, electrolyte changes, acid–base changes, and renal parameters in a consecutive population of cats with urethral obstruction.Design: Retrospective clinical study.Setting: University Veterinary Teaching Hospital.Animals: Two hundred and twenty-three male cats that presented consecutively with urethral obstruction between 1997 and 1999.Interventions: None.Measurements and main results: The medical records of 223 cats with urethral obstruction were reviewed for signalment, previous medical history, indoor/outdoor status, body weight, clinical signs, physical examination findings, renal function tests (blood urea nitrogen and creatinine), and blood gas and electrolyte analysis. The majority of cats were relatively stable without serious metabolic derangements. Only 12% (24/199) of cats had severe hyperkalemia (〉8.0 mmol/L). Hyperkalemia did not occur in isolation; the majority of these cats had concurrent acidemia and low ionized calcium concentrations. Potassium was significantly inversely correlated with pH, bicarbonate, pCO2, sodium, chloride, and ionized calcium, but positively correlated with blood urea nitrogen and creatinine. Ionized calcium was positively correlated with pH and bicarbonate. Of the animals with a potassium concentration greater than 8.0 mmol/L, 75% (18/24) had an ionized calcium concentration of less than 1.0 mmol/L. Seventy-nine percent (19/24) of cats with a potassium concentration greater than 8.0 mmol/L had a blood pH〈7.20. Similarly, 74% (23/31) of cats with a pH〈7.20 had an ionized calcium concentration 〈1.00 mmol/L.Conclusions: The majority of cats with urethral obstruction presented with mild electrolyte and blood gas changes and were relatively stable, although 12% of cats had multiple, life-threatening metabolic derangements. Of 219 cats in this study, 205 (93.6%), where it could be determined, survived to discharge from the hospital, supporting the fact that most cats with urethral obstruction survive the acute episode with emergency treatment.