Migrating Porcupine Quills: Sudden Death of a Yearling American Black Bear (Ursus americanus) at a Wildlife Rehabilitation Center

A yearling, intact, apparently healthy male American black bear (Ursus americanus) died peracutely at a rehabilitation facility in Ontario, Canada while overwintering, after recovery from porcupine quilling a few months previously. The postmortem examination findings support that porcupine quill migration should be a differential for cause of sudden death in wildlife.

Sudden death caused by Aeromonas hydrophila in a Crab-eating Macaque (Macaca fascicularis) associated with captivity stress

Aeromonas hydrophila is a facultative anaerobic gram-negative bacterium regarded as an opportunistic pathogen in animals. A 17-year-old female crab-eating macaque (Macaca fascicularis) died after experiencing anorexia and depression for several days. The carcass was severely emaciated, and the sternum was exposed under subcutaneous lesions in the thorax. Many abnormal pathological lesions were found, including tracheal inflammation, pulmonary inflammatory emphysema, yellowish discoloration of the liver, enlargement of the gall bladder, necrosis of the heart, congested bilateral kidneys, and enlargement of the adrenal glands. The stomach was empty, mucosal ulcerations were found, and the duodenum was congested. Giemsa staining revealed rod-shaped organisms in the whole blood smear and major organs, which were identified as A. hydrophila. The animal had experienced stress, and decreased immune system function possibly contributed to the infection.

Should we be screening cats for cardiomyopathy? If so, how?

Occult feline hypertrophic cardiomyopathy (HCM) can result in unexpected sudden death or congestive heart failure (CHF) following routine interventions such as anesthesia, fluid administration, or, potentially, administration of corticosteroids. Consequently, clinicians would like to be able to screen at-risk cats to detect occult HCM and either avoid the risky intervention or attempt to reduce the risk of death or CHF. Currently, the feline N-terminal-proBrain natriuretic peptide test is the only potential screening test for detecting occult HCM. However, some cardiologists have pointed out the poor sensitivity of the test precludes its use as a screening test. This interpretation appears somewhat flawed. Using the current rapid test will allow clinicians to correctly identify half of the cats with moderate-to-severe occult HCM. A small number of cats without HCM will also test positive, necessitating an ultimately needless echocardiographic evaluation to demonstrate their disease-free status. However, the low prevalence of HCM in the general cat population and the apparently much lower rate of adverse events than would be predicted brings into question whether clinicians should bother screening. Therefore, until a more sensitive and accurate screening test becomes available, clinicians will have to decide for themselves whether identifying half of the at-risk cats of sudden death and CHF with this test is better than identifying none of them.

Sudden death due to acute hemoabdomen and hypovolemia from a ruptured splenic hemangiosarcoma in a German shepherd dog

A 12-year-old neutered male German shepherd dog was evaluated after dying suddenly at home. A few hours prior to the unexpected death the dog displayed anorexia and lethargy. Post-mortem examination and histopathology led to a diagnosis of marked hemoabdomen and hypovolemia due to a single ruptured splenic hemangiosarcoma.

Blackleg without skeletal muscle involvement as a cause of sudden death in unvaccinated calves

Nine, 5-month-old unvaccinated black Angus calves died in less than 48 hours of each other. The calves expressed minimal or no clinical signs prior to death. On-farm post-mortem examinations were carried out on 3 of the deceased calves, and findings included: necrotizing and fibrinosuppurative myositis of the diaphragm muscle, and fibrinosuppurative pleuritis and epicarditis. Fluorescent antibody testing for pathogenic clostridia identified Clostridium chauvoei and a diagnosis of blackleg was made. The remainder of the herd were then vaccinated.

Accidental selenium toxicosis in lambs

Acute selenium toxicosis occurred in 3-week-old lambs after accidental over-supplementation by intramuscular injection and caused dyspnea, cyanosis, and sudden death. Pathological lesions included myocardial necrosis, skeletal muscle necrosis, pulmonary edema, hydrothorax, and hydropericardium.

Postmortem findings in Ontario racehorses, 2003-2015

Postmortem lesions and cause of death were evaluated retrospectively for 963 horses examined as part of the Ontario Racing Commission Death Registry over a 13-y period. The Death Registry was established in 2003 to identify factors leading to death or euthanasia of racehorses in this Canadian province. Postmortem examination was carried out on 56% of horses reported to the Death Registry and included Standardbred, Thoroughbred, and American Quarter Horses. Musculoskeletal injury was the most common reason for death associated with racing or training among all racehorses and involved 68% of horses. A history of sudden death during or immediately following exercise was described for 31% of racing- or training-associated deaths, and in 16% of all horses in the study. Sudden death occurred in horses of all breeds, and our report describes lesions associated with sudden death in a series of Standardbreds. The cause of death in these cases was most frequently attributed to cardiopulmonary lesions. The cause of death was undetermined in 20% of sudden death cases, and it is speculated that cardiac arrhythmia may have contributed to these deaths. Injection-associated death was documented in 4% of the study population. Lesions among horses whose death was not associated with exercise were similar to those in other equine populations, and lesions involving the gastrointestinal system were most common. Standardization of pathology reporting of pulmonary and other lesions in racehorse postmortem cases would allow direct comparison of results among racehorse populations.

Ventricular arrhythmias in Rhodesian Ridgebacks with a family history of sudden death and results of a pedigree analysis for potential inheritance patterns

OBJECTIVE To evaluate a group of related Rhodesian Ridgebacks with a family history of sudden death for the presence of arrhythmia and to identify possible patterns of disease inheritance among these dogs. DESIGN Prospective case series and pedigree investigation. ANIMALS 25 Rhodesian Ridgebacks with shared bloodlines. PROCEDURES Pedigrees of 4 young dogs (1 female and 3 males; age, 7 to 12 months) that died suddenly were evaluated, and owners of closely related dogs were asked to participate in the study. Dogs were evaluated by 24-hour Holter monitoring, standard ECG, echocardiography, or some combination of these to assess cardiac status. Necropsy reports, if available, were reviewed. RESULTS 31 close relatives of the 4 deceased dogs were identified. Of 21 dogs available for examination, 8 (2 males and 6 females) had ventricular tachyarrhythmias (90 to 8,700 ventricular premature complexes [VPCs]/24 h). No dogs had clinical signs of cardiac disease reported. Echocardiographic or necropsy evaluation for 7 of 12 dogs deemed affected (ie, with frequent or complex VPCs or sudden death) did not identify structural lesions. Five of 6 screened parents of affected dogs had 0 to 5 VPCs/24 h (all singlets), consistent with a normal reading. Pedigree evaluation suggested an autosomal recessive pattern of inheritance, but autosomal dominant inheritance with incomplete penetrance could not be ruled out. CONCLUSIONS AND CLINICAL RELEVANCE Holter monitoring of Rhodesian Ridgebacks with a family history of an arrhythmia or sudden death is recommended for early diagnosis of disease. An autosomal recessive pattern of inheritance in the studied dogs was likely, and inbreeding should be strongly discouraged.

[Sudden death of outdoor housed pigs caused by Clostridium novyi. A case report]

In an outdoor pig-breeding unit of the Tierpark Arche Warder e. V. (Germany), 16 pigs of different age and sex died in October 2011. Necropsy findings revealed tympany, liver emphysema, subcutaneous oedema, haemopericardium, haemothorax, and intense gas bubble infiltrations in muscles. The stomachs were filled. The initial anaerobic bacteriological investigations gave negative results. In further analyses of tissue samples, the flagellin gene of C. novyi types A and B was detected using PCR. Based on the anatomical-pathological and bacteriological findings as well as PCR testing, a C. novyi infection was assumed to be the cause of the pig mortality.

Endpoints in myelin-deficient (MD) rats

Health problems in some animal models remain unexplained, rendering in vivo studies ethically challenging, especially when experimental animals are prone to sudden death. Over the last 3 decades, the myelin-deficient (md) rat, a strain with severe dysmyelination due to mutant proteolipid protein, has been key to important discoveries in mechanisms of myelination and glial cell biology. The usefulness of this mutant rat, however, has been limited by sudden death during the fourth week of life. Timely euthanasia has been difficult because the cause of these mortalities remains unexplained and the endpoint not determined. In this clinicopathologic study, we determined that sudden onset of hindlimb paralysis inevitably leads to paralysis of the urinary bladder and then breathing difficulties because of severe injury to the spinal cord in the midthoracic region with concurrent narrowing of the vertebral canal due to fracture of a vertebral body. Sudden onset of hindlimb paralysis likely is related to seizures and severe muscle spasms that begin to occur at the end of the third week of life. Once seizure activity begins, we recommend frequent monitoring of md rats for hindlimb paralysis and distention of the urinary bladder as indication of endpoints mandating prompt euthanasia.

Sudden death associated with hypertrophic cardiomyopathy in an alpaca (Llama pacos)

A healthy, 3-year-old, intact male alpaca (Llama pacos) died suddenly and unexpectedly and had an unusual pattern of hypertrophic cardiomyopathy that was restricted to the interventricular septal and right ventricular myocardium. Grossly pale areas in the affected myocardium corresponded histologically to thickened and disorganized myofibers with excessive branching and marked nuclear pleomorphism. Mitoses were absent. Inflammation and fibrosis were minimal. A few thickened muscular arteries were scattered in the affected myocardium.

Peracute selenium toxicosis followed by sudden death in growing and finishing pigs

Fattening pigs (n = 751) showed progressive apathy, paralysis, and sudden death after accidental ingestion of excessive concentrations of selenium in mineral feed. Selenium concentrations of 1.09 to 1.32 mg/L in the serum confirmed the diagnosis. Within 3 d all pigs had died spontaneously or were euthanized due to the grave prognosis and on welfare grounds.

Excessive sulfate and poor water quality as a cause of sudden deaths and an outbreak of diarrhea in horses

Sudden deaths and an outbreak of diarrhea in horses occurred in southern Saskatchewan in 2006. Five horses died while survivors presented with diarrhea and, in 1 case, acute neurologic signs attributed to hyponatremia. Diagnostic testing of affected horses and environmental testing suggested poor water quality, specifically high salinity and high sulfate concentration as the cause.

Staphylococcus aureus isolated from a horse in a sudden death condition in Kassala state, eastern Sudan

In this study, Staphylococcus aureus was isolated from a draught horse presented to Kassala Veterinary Research Laboratory (KVRL) for investigation and diagnosis. The affected animal was previously treated with Gentamycin and Tetracycline before submitted to this laboratory, but the animal was not cure. Thereafter, the animal was attended to the laboratory; it was suffering from inguinal abscess and some clinical signs. Clinical and laboratory examinations were carried out however, the animal was suddenly fallen and died immediately. Then post-mortem, bacteriological and histopathological examinations were done. S. aureus was isolated as pure culture from the lungs and peritoneum of the necropsied animal. This isolate showed highly sensitivity to Erythromycin and Clindamycin and it was resistant to Penicillin, Cloxacillin, Cefotaxime, Co-Trimoxazole, Cephalexin and Tetracycline. It was concluded from this study, the shock resulted from S. aureus was the causative agent of the death in this case.

A study on pathogenesis of sudden death syndrome in broiler chickens

Sudden death syndrome (SDS) in fast growing broiler chickens has been recognized as a patho-physiological entity for four decades, but its pathogenesis still remains unknown. More recent investigations provided evidence that link SDS to cardiac arrhythmia, but the mechanism triggering arrhythmogenesis and factors responsible for fatal outcome are poorly understood. In order to understand the chain of events leading to SDS in broilers, the present study focused on putative mechanisms that trigger arrhythmia and mechanisms that predispose the myocardium to fatal arrhythmia. Susceptibility of broilers to cardiac arrhythmia under stress conditions was evaluated using a simulated stress test with epinephrine. Detailed histopathological evaluation of the broiler heart was undertaken to identify structural features that may predispose the myocardium to fatal arrhythmia. The simulated stress challenge revealed that many broilers are highly susceptible to stress induced cardiac arrhythmia. In some broilers the stress challenge induced severe ventricular arrhythmia, and the life threatening nature of this arrhythmia was evidenced by the fact that several birds showing the most severe arrhythmic responses, died suddenly within several days after the stress challenge. Examination of hearts of broilers that died of SDS revealed microscopic lesions in the cardiomyocytes, and widespread changes in the sub-endocardial and mural His-Purkinje system (HPS). Immune staining for Caspase-3 confirmed that numerous Purkinje cells in the left ventricular myocardium from broiler chickens that died of SDS were undergoing apoptosis. The observed lesions suggest that the electrical stability of the myocardium was compromised. Taken together, our findings indicate that stress is a most likely trigger of cardiac arrhythmia in broilers, whereas the pathological changes seen in the myocardium and in the HPS in fast growing broilers provide a very conducive milieu for sustained ventricular arrhythmia. In cases where the electrical stability of the myocardium is compromised, even an episodic arrhythmic event may readily degenerate to catastrophic ventricular fibrillation and sudden death. We conclude that the combination of stress and changes in the cardiomyocytes and HPS are the key requisite features in the pathogenesis of SDS.

Atrial myocarditis as a cause of sinus arrest in a dog

A 10-year-old male cairn terrier cross was presented with a history of myxomatous mitral valve disease diagnosed six months previously and with a four-week history of intermittent collapse. On 24 hour electrocardiograph (Holter) analysis, periods of no discernable electrical cardiac activity, which coincided with three collapsing episodes, were identified. Unfortunately, on re-presentation for removal of the Holter monitor, the dog collapsed and died. A post-mortem examination was conducted, and histology of the right and left atrium showed evidence of myocarditis. This is the first reported case, to our knowledge, of collapse because of electrical asystole in a dog with atrial myocarditis.

Signalment, clinical signs, and prognostic indicators associated with high-grade second- or third-degree atrioventricular block in dogs: 124 cases (January 1, 1997-December 31, 1997)

OBJECTIVE

To evaluate signalment, clinical signs, and prognosis associated with high-grade second- or third-degree atrioventricular block (AVB) in dogs.

DESIGN

Retrospective case series.

ANIMALS

124 dogs.

PROCEDURES

Data were gathered from ECGs, veterinarian questionnaires, echocardiograms, and radiographs submitted for review; compared with data from a large control group; and examined for association between variables and duration of survival. A new classification system for AVB was evaluated.

RESULTS

Afghan, Catahoula Leopard Dog, Chow Chow, Cocker Spaniel, German Wirehaired Pointer, and Labrador Retriever breeds were predisposed to high-grade second- or third-degree AVB. Heavier, older, and sexually intact female dogs were overrepresented in the study group. Weakness, lethargy, exercise intolerance, and syncope were the most common clinical signs. The presence of clinical signs was not associated with duration of survival. Dogs with high-grade second-degree AVB had a duration of survival similar to that of dogs with third-degree AVB. Dogs with high-grade second- or third-degree AVB were at high risk for sudden death in the first 6 months after diagnosis. High ventricular escape rhythm rate and narrow escape-complex QRS width were negatively associated with duration of survival. Pacemaker implantation had a significant positive association with survival.

CONCLUSIONS AND CLINICAL RELEVANCE

Pacemaker implantation should be strongly considered in all dogs with high-grade second- or third-degree AVB regardless of whether clinical signs are evident. If medical treatment is warranted, vagolytic medications may be the best choice. A new classification system for AVB may merit further investigation.

PHEOCHROMOCYTOMA IN AN AGED FEMALE AFRICAN ELEPHANT (LOXODONTA AFRICANA)

A 43 yr-old female African elephant (Loxodonta africana) collapsed acutely and died. Necropsy revealed an enlarged right adrenal medulla. Histologic appearance was typical of pheochromocytoma. Special stains and electron microscopy demonstrated chromaffin granules, suggesting that the tumor was derived from catecholamine secreting cells of the adrenal medulla, and may have been functionally secretory. Serum levels of both norepinephrine and epinephrine were elevated at time of death, supporting the functional nature of the tumor. Histologic findings of arteriolar sclerosis and smooth muscle hyperplasia suggested that the animal may have suffered from chronic systemic hypertension. Pheochromocytoma should be considered as a differential diagnosis in cases of suspected hypertension and acute death in elephants.

Investigation of a syndrome of sudden death, splenomegaly, and small intestinal hemorrhage in farmed deer

A newly recognized syndrome, characterized by sudden death of farmed deer that are in good to excellent nutritional condition, with lesions of small intestinal mucosal hemorrhage and splenomegaly, is described. Other frequently observed lesions were small intestinal mucosal necrosis, abomasal hemorrhage, random hepatic necrosis, and multifocal hepatic congestion. Clostridium perfringens type A was isolated in high numbers from the intestines of many of the deer affected by the syndrome; however, the numbers were not significantly different from those of control deer. The syndrome did not appear to be related to dietary or any other specific management factors and a definitive cause of the syndrome was not identified.

Sudden death due to thoracic lymphoma in a standardbred racing horse

During training, a 6-year-old standardbred gelding collapsed, exhibiting severe epistaxis and agonal breathing and was euthanized. The horse had a recent history of poor performance, lethargy, and unilateral eyelid swelling with serous ocular discharge. Postmortem and histopathologic examination findings revealed thoracic lymphosarcoma and concurrent exercise-induced pulmonary hemorrhage.

Mechanisms of alpha-adrenergic potentiation of ventricular arrhythmias in dogs with inherited arrhythmic sudden death

OBJECTIVE

In German shepherd dogs having inherited arrhythmias and sudden death, pause-dependent arrhythmias are triggered by early afterdepolarizations (EADs) originating from left ventricular (LV) Purkinje fibers (PF). Heterogeneity of LV repolarization provides the arrhythmogenic substrate. To elucidate the mechanisms whereby alpha-adrenergic stimulation exacerbates these arrhythmias we tested the effects of phenylephrine on both arrhythmogenic trigger and substrate.

METHODS AND RESULTS

We used microelectrode techniques to record action potentials from LV and right ventricular (RV) PF and from midmyocardial sections of anteroseptal, anterobasal and posterobasal LV wall of unafflicted and afflicted dogs. EADs occurred spontaneously in 8 of 12 LV PF and in no RV PF from afflicted dogs and in no PF from unafflicted dogs. In LV PF from afflicted dogs, phenylephrine (10(-9)-10(-5) M) concentration-dependently decreased membrane potential, induced abnormal automaticity at membrane potentials from -65 to -45 mV in 6 LV PF and potentiated EADs in another 6. To determine the mechanisms of membrane depolarization we studied phenylephrine effects on IK1 in voltage-clamped single LV and RV PF cells from afflicted dogs. In LV PF, phenylephrine (10(-5) M) reduced IK1 over the range of -120 to -40 mV and had no effects on RV PF. Regional heterogeneity of LV repolarization was observed in afflicted dogs only. Phenylephrine had no effects on repolarization in either group.

CONCLUSION(S)

Alpha-adrenergic stimulation exacerbates arrhythmias in afflicted dogs by increasing the arrhythmogenic trigger while leaving the substrate unchanged. Decrease in IK1 contributes importantly to alpha-adrenergic effects on LV PF.

Cardiac Rhabdomyoma in a Juvenile Fallow Deer (Dama dama)

A cardiac rhabdomyoma is described in a 6-wk-old captive fallow deer (Dama dama) that died suddenly without previous clinical signs. The tumor was characterized by multiple nodules composed of large atypical vacuolated myoblastic cells. As previously reported in humans and other animal species, there is compelling evidence that the cardiac rhabdomyoma is a congenital developmental anomaly rather than a true neoplasm. To our knowledge, this is the first report of a cardiac tumor and a rhabdomyoma in a cervid species.

Monensin toxicity in preruminant dairy heifers

Four-to six-week-old calves from a seasonal dairy herd in North Western Tasmania were presented for veterinary attention due to the occurrence of sudden deaths. Necropsy examination of one of the calves revealed several small pale foci of 1 cm diameter on the epicardium. Mortalities were found to be caused by monensin that was added to the milk diet as part of a vitamin/mineral commercial premix that also controlled coccidiosis. No cases of monensin toxicity in preruminant calves have been previously documented, although there have been numerous reports in older cattle and other species.

Use of neostigmine in massive ivermectin toxicity in cats

Over-the-counter availability of drugs in developing countries poses the risk of their abuse and overdosing in animals by the owners. This report describes ivermectin toxicosis and its treatment with neostigmine methylsulfate in 2 kittens and an adult cat that had been massively overdosed by their owners. Of two 4-w-old 300 g kittens, one was injected with 1.5 ml ivermectin (15 mg; corresponding to 250 times the recommended dose) by the owner and became comatose, started salivation and died after 2 1/2 h. The other kitten was treated with about 0.75 ml ivermectin (7.5 mg; corresponding to 125 times the recommended dose) by the same owner and developed ataxia and salivation after 2 h, went into coma the next morning and was presented for treatment with mydriasis, coma, slight fever (102.4 F), tachypnea (48/min) and severe tachycardia. This kitten was treated twice at a half hourly interval with neostigmine methylsulfate (25 microg) and 5% dextrose (20 ml) iv showed a transient improvement but died 12 h later. A 2-y-old, 4.5 kg male cat was treated s.c. with 1.5 ml ivermectin (15 mg; corresponding to 16.6 times the recommended dose) by its owner and developed slight salivation, lacrimation. mydriasis, protrusion of third eye-lid, tachypnea (42 breaths/min), tachycardia (128 beats/min) and ataxia. The patient was treated with neostigmine methylsulfate (150 microg) and 5% dextrose (100 ml) i.v., and 200 ml of Heartmann's solution i.v. Treatment was repeated after 6 h Follow up treatment over next 2 d was with daily i.v. administration of neostigmine and dextrose. The patient completely recovered 5 d after initiation of treatment.

Outbreak of dysautonomia (Key-Gaskell syndrome) in a closed colony of pet cats

Six of eight pet cats in a closed colony developed overt signs of dysautonomia over a period of seven days; two of them died and one was euthanased. Dysautonomia was confirmed histopathologically in two of these cats, and in the others the diagnosis was based on the characteristic clinical and radiographic findings. In the two apparently unaffected cats abnormal oesophageal motility was demonstrated by fluoroscopy, suggesting that there may be a subclinical form of the disease. The surviving cats had higher and more variable heart rates (mean 165 bpm) than the non-survivors (mean 121 bpm).

Equine Viral Arteritis in a Newborn Foal: Parallel Detection of the Virus by Immunohistochemistry, Polymerase Chain Reaction and Virus Isolation

A 4-days-old foal died after a short course of respiratory syndrome and fever. Large areas of the alveoli, bronchioles and bronchi were partly or completely filled by hyaline membranes. Pronounced oedema and mild interstitial pneumonia were present and, in the small muscular arteries, fibrinoid necrosis and vasculitis or perivasculitis could be seen. Vasculitis was found in several other organs, and it was most severe in the thymus. The virus was detected in the lung, kidney and spleen using virus isolation and in the lung and spleen using polymerase chain reaction. The virus was also detected in several organs and cell types using both N protein-specific monoclonal antibody and horseradish peroxidase-labelled equine arteritis virus-specific equine IgG.

Postanesthesia death and suspected peracute endotoxic shock due to Pseudomonas putida in a cynomolgous macaque (Macaca fascicularis)

An adult male cynomolgous macaque (Macaca fascicularis) died suddenly after anesthesia for a positron emission tomography scan. Bacteriologic culture of the mucopurulent secretions recovered from the endotracheal tube yielded heavy growth of Pseudomonas putida, a known endotoxin producer. Histologically, the lungs had severe, diffuse perivascular edema and neutrophils marginating to the endothelium. The sudden death and the pathologic findings were consistent with peracute endotoxic shock. Numerous environmental swab specimens of the surgical suite and equipment were submitted for bacteriologic culture, as were swab specimens of endotracheal secretions from a control animal; however, Pseudomonas putida was not isolated from any specimen. The animal in this report may have carried Pseudomonas putida as a commensal in the oropharynx, and the stress of anesthesia may have resulted in increased sensitivity to the endotoxin.