Traumatic brain injury in horses: 34 cases (1994-2004)

OBJECTIVE: To investigate the clinical, clinicopathologic, and diagnostic characteristics; treatment; and outcome associated with acute traumatic brain injury (TBI) in horses and assess risk factors for nonsurvival in TBI-affected horses. DESIGN: Retrospective case series. ANIMALS: 34 horses with TBI. Procedures-Medical records of horses that had sustained trauma to the head and developed neurologic signs were reviewed. Data that included signalment, clinicopathologic findings, diagnosis, treatment, and outcome were analyzed. Clinicopathologic variables among horses in survivor and nonsurvivor groups were compared, and risk factors for nonsurvival were determined. RESULTS: Median age of affected horses was 12 months. Findings of conventional survey radiography of the head alone failed to identify all horses with fractures of the calvarium. Horses with basilar bone fractures were 7.5 times as likely not to survive as horses without this type of fracture. Depending on clinical signs, horses received supportive care, osmotic or diuretic treatments, antimicrobials, anti-inflammatory drugs, analgesics, or anticonvulsants. Twenty-one (62%) horses survived to discharge from the hospital. In the nonsurvivor group, mean PCV was significantly higher, compared with the value in the survivor group (40% vs 33%). Risk factors associated with nonsurvival included recumbency of more than 4 hours' duration after initial evaluation (odds ratio, 18) and fracture of the basilar bone (odds ratio, 7.5). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that prognosis for survival in horses with acute TBI may be more favorable than previously reported. Among horses with TBI, persistent recumbency and fractures involving the basilar bones were associated with a poor prognosis.     

Bone marrow necrosis in dogs: 34 cases (1996-2004)

OBJECTIVE: To identify the incidence, potential causes, and clinical and clinicopathologic features of bone marrow necrosis in dogs. DESIGN: Retrospective study. ANIMALS: 34 client-owned dogs. PROCEDURES: Reports of cytologic examinations of bone marrow specimens performed between 1996 and 2004 were reviewed. All reports that indicated the presence of necrosis, stromal disruption, phagocytic macrophages, individual cell necrosis, or myelofibrosis were evaluated further. RESULTS: Of 609 reports of bone marrow evaluations performed during the study period, 34 (5.6%) had evidence of bone marrow necrosis. Nine dogs had no evidence of associated diseases or drug or toxin exposure, and 25 dogs had associated disease conditions or drug exposures. All 9 dogs with idiopathic bone marrow necrosis were anemic (mean Hct, 14%), but only 3 had neutropenia, and 3 had thrombocytopenia. All 9 had myelofibrosis. Of the 25 dogs with associated disease conditions or drug exposures, only 14 (56%) had anemia (mean Hct, 33%). In addition, 14 (56%) had neutropenia and 18 (72%) had thrombocytopenia. Only 10 (40%) had myelofibrosis. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that bone marrow necrosis may be common in dogs with hematologic disorders. In most dogs, bone marrow necrosis was associated with an underlying disease condition or drug exposure, but idiopathic bone marrow necrosis was also identified. Disease conditions that should increase suspicion of possible bone marrow necrosis include sepsis, lymphosarcoma, and systemic lupus erythematosus; drug exposures that should increase suspicion of possible bone marrow necrosis include chemotherapeutic agents, phenobarbital, carprofen, metronidazole, and mitotane.     

Variables associated with outcome in dogs undergoing extrahepatic biliary surgery: 60 cases (1988-2002)

OBJECTIVE: To report clinical findings and define clinical variables associated with outcome in dogs undergoing extrahepatic biliary surgery. STUDY DESIGN: Retrospective study. ANIMALS: Sixty dogs that had extrahepatic biliary tract surgery. RESULTS: Primary diagnoses included necrotizing cholecystitis (36 dogs, 60%), pancreatitis (12 dogs, 20%), neoplasia (5 dogs, 8%), trauma (4 dogs, 7%), and gallbladder rupture from cholelithiasis without necrotizing cholecystitis (3 dogs, 5%). Bile peritonitis occurred in 19 (53%) dogs with necrotizing cholecystitis, 4 dogs with trauma, and 3 dogs with cholelithiasis without evidence of necrotizing cholecystitis. Cholecystectomy (37 dogs, 62%) and cholecystoduodenostomy (14 dogs, 23%) were the 2 most commonly performed procedures. Median hospitalization for survivors was 5 days (range, 1-15 days). There were 43 surviving dogs (72%) and 17 nonsurvivors (28%, 4 died, 13 euthanatized). Presence of septic bile peritonitis (P=.038), elevation in serum creatinine concentration (P=.003), prolonged partial thromboplastin times (PTTs; P=.003), and lower postoperative mean arterial pressures (P=.0001) were significantly associated with mortality. CONCLUSIONS: Extrahepatic biliary surgery is associated with high mortality and a relatively long hospitalization time for survivors. Cholecystectomy and cholecystoduodenostomy were the most common surgical procedures to treat the 4 major biliary problems (necrotizing cholecystitis, pancreatitis, neoplasia, and trauma) observed in this cohort of dogs. The relatively high mortality rate likely reflects the underlying diseases and their effects on the animal (septic bile peritonitis, higher serum creatinine, prolonged PTT, and lower postoperative mean arterial pressure) rather than complications of surgery. CLINICAL RELEVANCE: Septic bile peritonitis, preoperative elevated creatinine concentration, and immediate postoperative hypotension in dogs undergoing extrahepatic biliary tract surgery are associated with a poor clinical outcome. Adequate supportive care and monitoring in the perioperative period is critical to improve survival of dogs with extrahepatic biliary disease.     

Cardiac lymphoma and pericardial effusion in dogs: 12 cases (1994-2004)

OBJECTIVE: To determine clinical characteristics and clinicopathologic findings, including results of pericardial fluid analysis, and determine the outcome associated with pericardial effusion caused by cardiac lymphoma in dogs. DESIGN: Retrospective case series. ANIMALS: 12 dogs. PROCEDURE: Medical records of affected dogs were reviewed for echocardiographic findings, radiographic findings, results of pericardial fluid analysis, clinicopathologic findings, treatment protocols, and outcomes. RESULTS: Pericardial effusion was detected by echocardiography in all 12 dogs, and lymphoma was detected by cytologic examination of the effusion (11/12 dogs) or histologic examination of pericardium (3/12). Large-breed dogs were overrepresented; median weight was 40.5 kg (89.1 lb). Most hematologic and biochemical changes were mild and non-specific. Survival time for dogs treated with combination chemotherapeutic agents was 157 days and for dogs that did not receive chemotherapy survival time was 22 days. This difference was not significant, but several dogs had long-term survival. CONCLUSIONS AND CLINICAL RELEVANCE: Cardiac lymphoma is an uncommon cause of pericardial effusion, and results suggest that cardiac lymphoma does not always warrant the poor prognosis of other stage V, substage b lymphomas.     

Prognostic factors associated with survival two years after surgery in dogs with malignant mammary tumors: 79 cases (1998-2002)

OBJECTIVE: To identify prognostic factors for female dogs that have undergone surgical removal of malignant mammary tumors. DESIGN: Retrospective case series. ANIMALS: 79 female dogs with malignant mammary tumors. PROCEDURE: Information obtained from the medical records included breed, age, sex, tumor size (maximum diameter), number and location of affected mammary glands, time between tumor identification and surgical removal, radiographic evidence of distant metastasis, surgical procedure, ovariohysterectomy (OHE) status, histologic classification of the tumor, and survival time. RESULTS: Results of univariate analyses indicated that clinical stage, tumor size, OHE status, metastasis to adjacent lymph nodes or distant sites, and histologic classification of the tumor were significantly associated with survival 2 years after surgery. Tumors > or = 5 cm in diameter and tumors that had been identified > 6 months before surgery were more likely to metastasize to adjacent lymph nodes. Ovariohysterectomy was more beneficial in dogs with complex carcinomas than in dogs with simple carcinomas. In multivariate analyses, clinical stage, tumor size, and OHE status were significantly associated with survival 2 years after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that tumor stage, tumor size, and OHE status were significant prognostic factors associated with survival 2 years after surgery in dogs with malignant mammary tumors. Further, either dogs with tumors > or = 5 cm in diameter or dogs with tumors present for > 6 months prior to surgery had a higher risk of having lymph node metastases.     

Survival and factors affecting survival in small ruminants and camelids attacked by dogs: 62 cases (1994–2004)

Objective: To determine the survival rates and factors affecting survival in small ruminants and camelids attacked by dogs. Design: Retrospective study. Setting: Two university teaching hospitals. Animals: Thirty goats, 28 sheep, 3 alpacas, and 1 llama. Measurements and main results: Medical records were reviewed to obtain signalment, time between injury and admission, hospitalization length, lesion site, treatment, complications, survival rate, and cost. Follow‐up information was obtained by telephone conversation with the owner. Sixty‐two patients met the inclusion criteria. Six animals were euthanized at admission and thus excluded. Of the 56 animals that were treated, 43 (77%) were discharged, 5 (9%) died, and 8 (14%) were euthanized. Animals that had thoracic or abdominal injuries, required surgery, or received more potent analgesic therapy were less likely to survive to discharge from hospital compared with animals that did not. Complications developed in 50 (82%) animals. Animals with respiratory complications were also less likely to survive to discharge from hospital than animals that did not. Long‐term follow up was available on 38/43 (88%) animals that were discharged. Thirty‐five of 38 (92%) animals were discharged and recovered from their injuries and 5 animals had long‐term complications. Conclusions: Small ruminants and camelids that are attacked by dogs have a good prognosis for short‐term survival. Short‐term survival is affected by lesion location and complications.     

Evaluation of factors associated with survival in dogs with untreated nasal carcinomas: 139 cases (1993-2003)

OBJECTIVE: To evaluate factors associated with survival in dogs with nasal carcinomas that did not receive treatment or received only palliative treatment. DESIGN: Retrospective case series. ANIMALS: 139 dogs with histologically confirmed nasal carcinomas. PROCEDURES: Medical records, computed tomography images, and biopsy specimens of nasal carcinomas were reviewed. Only dogs that were not treated with radiation, surgery, chemotherapy, or immunotherapy and that survived > or = 7 days from the date of diagnosis were included. The Kaplan-Meier method was used to estimate survival time. Factors potentially associated with survival were compared by use of log-rank and Wilcoxon rank sum tests. Multivariable survival analysis was performed by use of the Cox proportional hazards regression model. RESULTS: Overall median survival time was 95 days (95% confidence interval [CI], 73 to 113 days; range, 7 to 1,114 days). In dogs with epistaxis, the hazard of dying was 2.3 times that of dogs that did not have epistaxis. Median survival time of 107 dogs with epistaxis was 88 days (95% CI, 65 to 106 days) and that of 32 dogs without epistaxis was 224 days (95% CI, 54 to 467 days). CONCLUSIONS AND CLINICAL RELEVANCE: The prognosis of dogs with untreated nasal carcinomas is poor. Treatment strategies to improve outcome should be pursued.     

Correlation between leukocytosis and necropsy findings in dogs with immune-mediated hemolytic anemia: 34 cases (1994-1999)

OBJECTIVE: To determine whether severity of leukocytosis correlates with severity of postmortem lesions in dogs with immune-mediated hemolytic anemia (IMHA). DESIGN: Retrospective study. ANIMALS: 34 dogs with IMHA that had CBC performed within 48 hours prior to death and complete necropsy examinations. PROCEDURE: Dogs were independently assigned to 4 leukocytosis groups (within reference range; mild leukocytosis, moderate leukocytosis, marked leukocytosis) and 3 lesion severity groups (mild lesions, moderate lesions, severe lesions). RESULTS: Moderate to marked leukocytosis correlated with moderate to severe postmortem lesions. Ischemic necrosis within liver, kidney, heart, lung, and spleen attributable to thromboembolic disease or anemic hypoxia were the most common important lesions found at necropsy. None of the dogs with mild lesions had moderate or marked leukocytosis. Four of 14 severely affected dogs had WBC counts within reference range, but all 4 had neutrophilic left shifts. Three of these 4 dogs had toxic change in neutrophils. CONCLUSION AND CLINICAL RELEVANCE: Moderate to marked leukocytosis, neutrophilic left shift, and toxic change in neutrophils in dogs with IMHA should alert clinicians to the potential for moderate to severe tissue injury, which could complicate treatment and worsen prognosis. Lesions appear to be secondary to anemic hypoxia, thromboembolic disease, or both; therefore, treatment objectives should focus on improving blood oxygen-carrying capacity and monitoring for thromboembolic disease.     

Evaluation of risk factors for development of secondary glaucoma in dogs: 156 cases (1999-2004)

OBJECTIVE: To determine the immediately antecedent cause of secondary glaucoma and the prevalence of secondary glaucoma with anterior uveitis or lens dislocation in dogs. DESIGN: Retrospective case series. ANIMALS: 156 dogs with secondary glaucoma. PROCEDURES: Cause of glaucoma was determined from records. Breed, age, sex, and neuter status of all dogs with secondary glaucoma were compared with the general hospital population. The prevalence of secondary glaucoma in dogs with a primary diagnosis of lens dislocation or anterior uveitis during the same period was determined. RESULTS: Secondary glaucoma was diagnosed in 156 of 2,257 (6.9%) dogs examined because of ophthalmic disease and was bilateral in 33 (21.2%) of those dogs. In 31 (94%) bilaterally affected dogs, the antecedent cause was the same in both eyes. Common causes of secondary glaucoma were non-surgical anterior uveitis (44.9%), anterior uveitis associated with prior phacoemulsification (15.8%), and lens dislocation (15.2%). Parson Russell Terriers, Poodles, Boston Terriers, Cocker Spaniels, Rhodesian Ridgebacks, and Australian Cattle Dogs had diagnoses of secondary glaucoma more often than expected, compared with the reference population. Age, sex, neuter status, and laterality were not associated with secondary glaucoma. The prevalence of secondary glaucoma in dogs with lens dislocation or uveitis was 15% or 17%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Glaucoma develops secondary to many intraocular diseases, particularly uveitis and lens dislocation. Diagnosis of these diseases should prompt frequent monitoring of intraocular pressure, regardless of signalment.     

Outcome and complications associated with treatment of pemphigus foliaceus in dogs: 43 cases (1994-2000)

OBJECTIVE: To identify factors affecting prognosis, outcome, and complications associated with pemphigus foliaceus in dogs. DESIGN: Retrospective study. ANIMALS: 43 dogs with pemphigus foliaceus. PROCEDURE: Medical records were reviewed for signalment, age at diagnosis, duration to diagnosis, body area affected, initial immunosuppressive regimens and concurrent use of antimicrobials and sucralfate or histamine receptor 2 blocking agent, adverse effects of treatment, duration of treatment, number of visits for follow-up care, cause of death, and credentials of the veterinarians responsible for continued care. RESULTS: The case fatality rate was 60.5%. Factors significantly correlated with survival time included concurrent use of antimicrobials during initiation of immunosuppressive treatment and a lower number of adverse effects to treatment. Treatment times lasting more than 10 months from diagnosis correlated significantly with survival. CONCLUSIONS AND CLINICAL RELEVANCE: Treatment with or prophylactic use of antimicrobials may be warranted during initial immunosuppressive treatment. The inverse correlation between survival time and number of adverse treatment effects was not unexpected because it was reflective of the owners' decision to euthanatize their dogs and of corticosteroid-related secondary diseases. Survival beyond the tenth month of treatment predicted long-term survival, which suggests that dogs require careful management during the early months of treatment.     

Risk factors for recurrence of clinical signs associated with thoracolumbar intervertebral disk herniation in dogs: 229 cases (1994-2000)

OBJECTIVE: To assess risk factors for recurrence of clinical signs associated with thoracolumbar intervertebral disk disease (IVDD) in dogs that had decompressive laminectomy without attempted prophylactic treatment of other disk spaces. DESIGN: Retrospective study. ANIMALS: 229 dogs. PROCEDURE: Medical records of dogs that had decompressive laminectomy without prophylactic fenestration for a first episode of IVDD and were available for follow-up were reviewed. Information on 7 clinical and 8 radiographic potential risk factors were recorded. RESULTS: Clinical signs associated with recurrence of IVDD developed in 44 (19.2%) dogs. Ninety-six percent of recurrences developed within 3 years after surgery. Recurrence developed in 25% of Dachshunds and 15% of dogs of other breeds combined. Number of opacified disks was a significant risk factor for recurrence. Risk increased with number of opacified disks in an almost linear manner; each opacified disk increased risk by 1.4 times. Dogs with 5 or 6 opacified disks at the time of first surgery had a recurrence rate of 50%. CONCLUSIONS AND CLINICAL RELEVANCE: When all likely episodes of recurrence are considered and a long follow-up period is achieved, true rate of recurrence of IVDD appears to be higher than in many previous reports. Dogs with multiple opacified disks at the time of first surgery should be considered a high-risk subpopulation.     

Diagnostic use of cytologic examination of bone marrow from dogs with thrombocytopenia: 58 cases (1994-2004)

OBJECTIVE: To determine the diagnostic use of cytologic examination of bone marrow from dogs with thrombocytopenia. DESIGN: Retrospective case series. ANIMALS: 58 dogs with thrombocytopenia. PROCEDURES: Medical records were searched and reviewed for dogs with thrombocytopenia. Dogs that had thrombocytopenia and cytologic examination of bone marrow were included in the study. Dogs with other hematologic abnormalities, with a previous diagnosis of hematopoietic neoplasia, or that had previous treatment with cytotoxic drugs were excluded. Bone marrow cytologic findings were reviewed. Results were compared between dogs with severe thrombocytopenia (< 20,000 platelets/microL) and dogs with mild to moderate thrombocytopenia (20,000 to 200,000 platelets/microL). RESULTS: 58 dogs met the inclusion criteria. Of 55 dogs with diagnostic bone marrow aspirates, 36 had severe thrombocytopenia. Cytologic evaluation of bone marrow did not reveal substantial nonmegakaryocytic bone marrow abnormalities or result in a definitive diagnosis in any of these dogs. Nineteen dogs with mild to moderate thrombocytopenia had diagnostic bone marrow aspirates. Bone marrow cytologic findings revealed nonmegakaryocytic abnormalities in 4 of these dogs. Significantly fewer dogs with severe thrombocytopenia had abnormalities identified on cytologic examination of bone marrow, compared with dogs with mild to moderate thrombocytopenia. CONCLUSIONS AND CLINICAL RELEVANCE: Cytologic examination of bone marrow is unlikely to provide specific diagnostic or prognostic information in dogs with severe thrombocytopenia.     

Risk factors associated with outcome in dogs with tetanus: 38 cases (1987-2005)

OBJECTIVE: To assess the clinical course of disease and risk factors associated with outcome in dogs with tetanus. DESIGN: Retrospective case series. ANIMALS: 38 dogs with tetanus. PROCEDURES: Data were collected from medical records of dogs with tetanus, including signalment; wound characteristics; initial clinical signs; severity of worst clinical signs; time to wound management, antimicrobial treatment, and antitoxin administration; and 28-day survival rate. Statistical analyses were performed to evaluate relationships between the potentially predictive variables and disease progression and outcome. RESULTS: The 28-day survival rate was 77% (among 35 uncensored dogs). The most common initial clinical signs in affected dogs were ocular (n = 18) and facial (11) abnormalities. Nineteen dogs progressed to recumbency with severe muscle spasms, and 14 dogs had high or low heart rate or blood pressure values. Eight dogs died or were euthanized because of complications of tetanus. There was a significant association between younger age and development of more severe clinical signs. Furthermore, a significant inverse relationship between development of severe clinical signs and survival was identified. There was no association between earlier initiation of wound management, antimicrobial administration, or antitoxin administration and either progression of signs or 28-day survival rate. Wound type was not associated with 28-day survival rate. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that younger dogs with tetanus may be more likely to develop severe clinical signs. The prognosis for survival in dogs with tetanus is good if abnormalities in heart rate or blood pressure values do not develop.     

Evaluation of prognostic factors associated with outcome in dogs with multiple cutaneous mast cell tumors treated with surgery with and without adjuvant treatment: 54 cases (1998-2004)

OBJECTIVE: To evaluate prognostic factors associated with outcome of dogs with multiple cutaneous mast cell tumors (MCTs) treated with surgery with or without adjuvant treatment. DESIGN: Retrospective case series. ANIMALS: 54 dogs with a minimum of 2 simultaneous, histologically confirmed cutaneous MCTs that had been excised and had adequate staging and follow-up data. PROCEDURE: Medical records from 1998 to 2004 were examined. Outcome was assessed with the Kaplan-Meier product-limit method and log-rank analysis. Prognostic factors evaluated included signalment; number, histologic grade, location, size, local recurrence, and de novo development of MCTs; quality of surgical margins; clinical signs at the time of diagnosis; and use of adjuvant treatment. RESULTS: Medical records of 54 dogs with 153 tumors were included. Median follow-up time was 658 days. Median disease-free interval (1,917 days; range, 11 to 1,917 days) and median survival time (1,917 days; range, 14 to 1,917 days) were not yet reached. The 1- year and 2- to 5-year survival rates were 87% and 85%, respectively. The overall rate of metastasis was 15%. Factors that negatively influenced survival time in the univariate analysis included incomplete excision, local recurrence, size > 3 cm, clinical signs at the time of diagnosis, and use of adjuvant treatment. Presence of clinical signs at the time of diagnosis was the only negative prognostic factor for disease-free interval detected in the multivariate analysis. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that multiple cutaneous MCTs in dogs are associated with a low rate of metastasis and a good prognosis for long-term survival with adequate excision of all MCTs.     

Characteristics of cisternal cerebrospinal fluid associated with intracranial meningiomas in dogs: 56 cases (1985-2004)

OBJECTIVE: To determine CSF characteristics associated with intracranial meningiomas in dogs. DESIGN: Retrospective case series. ANIMALS: 56 dogs with intracranial meningiomas. PROCEDURES: Medical records of dogs with a histopathologic diagnosis of intracranial meningioma, in which CSF analysis had been performed, were reviewed. Information concerning total nucleated cell counts (TNCCs) and differential nucleated cell counts, RBC counts, and total protein concentration in CSF; seizure history and glucocorticoid administration; and location of meningiomas was recorded. RESULTS: TNCCs < 5 cells/microL were detected in 41 of 56 (73%) dogs; 5 of 56 (9%) dogs had TNCCs > 50 cells/microL. Analysis of CSF revealed predominantly neutrophilic pleocytosis in < 20% of dogs. There was a significant association between meningioma location (caudal portion of the cranial fossa or middle and rostral portion of the cranial fossae) and increased TNCCs (> or = 5 cells/microL). CONCLUSIONS AND CLINICAL RELEVANCE: Results were significantly different from those routinely reported in the veterinary literature. Neutrophilic pleocytosis, especially with TNCCs > 50 cells/microL, was not typical in CSF samples from dogs with intracranial meningiomas. Neutrophilic pleocytosis may not be detected in CSF samples from dogs with meningiomas located within the middle or rostral portion of the cranial fossae.     

Palmar carpal osteochondral fragments in racehorses: 31 cases (1994-2004)

OBJECTIVE: To evaluate records of racehorses with palmar carpal osteochondral fragments and determine whether the fragments were indicators of the severity of pathologic joint changes or prognosis. DESIGN: Retrospective case series. ANIMALS: 31 racehorses. PROCEDURES: Medical records, radiographs, and videos of arthroscopic procedures were reviewed. Information gathered included signalment; location, number, and size of the primary lesion; number and size of palmar carpal fragments; and details pertaining to surgical procedures. Outcome variables were obtained from race records. RESULTS: 31 horses met the selection criteria. Multiple palmar fragments were diagnosed in 58% of horses; small fragments (< 3 mm in diameter) were most common (52% of horses). Fifty-two percent of the horses returned to racing, 48% returned to racing and earned money, and 32% had at least 5 more starts. Horses with multiple fragments had significantly less earnings per start and lower performance index values after surgery than those with 1 fragment. Horses with palmar fragments < 3 mm in diameter were significantly less likely to return to racing and have 5 starts or to win money after surgery than horses with larger fragments. CONCLUSIONS AND CLINICAL RELEVANCE: Palmar carpal osteochondral fragments can be used as an indicator of clinically important joint pathology and as a prognostic indicator in racehorses. Horses with multiple small fragments were less likely to successfully return to racing than horses with only dorsally located carpal fragments or horses with 1 or 2 large palmar fragments. When possible, removal of palmar carpal osteochondral fragments should be considered.     

Heat stroke in dogs: A retrospective study of 54 cases (1999-2004) and analysis of risk factors for death

The medical records of 54 dogs presented to the Hebrew University Veterinary Teaching Hospital and diagnosed with heat stroke were retrospectively reviewed. Data abstracted included history, clinical and clinicopathological signs at admission, treatment, disease progression, and outcome. Exertional and environmental heat stroke were present in 63% (34 of 54) and 37% (20 of 54) of the dogs, respectively, and 78% (42 of 54) were examined between June and August. The mean temperature and heat discomfort index in the particular days of heat stroke were significantly increased (P < .001, P < .001, respectively) compared with their corresponding average daily values. In 27 dogs the body temperature was > or = 41 degrees C (105.8 degrees F). Belgian Malinois (15%, odds ratio [OR] = 24, 95% confidence interval [CI95%] 8.2-64.5), Golden and Labrador Retrievers (21%, OR = 2.08, CI95% 0.95-4.2), and brachycephalic breeds (25%, OR = 1.7, CI95%], 0.81-3.21) were overrepresented, whereas small breeds (<8 kg) were underrepresented (2%, OR = 0.08, CI95%, 0.002-0.48). Thrombocytopenia (45 of 54 dogs) and prolongation of the prothrombin (PT) and activated thromboplastin (aPTT) times (27 of 47 dogs) were recorded during hospitalization. Disseminated intravascular coagulation (P = .013) and acute renal failure (P = .008), diagnosed in 28 of 54 and 18 of 54 of the cases, respectively, were risk factors for death. The overall mortality rate was 50%. Hypoglycemia (<47 mg/dL, P = .003), prolonged PT (>18 seconds, P = .05), and aPTT (>30 sec, P < .001) at admission were associated with death. Serum creatinine >1.5 mg/dL (P = .003) after 24 hours, delayed admission (>90 minutes, P = .032), seizures (P = .02), and obesity (P = .04) were also risk factors for death. Heat stroke in dogs results in serious complications and high fatality rate despite appropriate treatment.