Suspected toxoplasma-associated myocarditis in a cat

Clinical toxoplasmosis is commonly reported in the cat, with the most consistent findings being ocular, pulmonic, hepatic, neurological, gastrointestinal and muscular abnormalities. Myocarditis, whilst frequently identified at post-mortem examination, has not been identified ante-mortem. In immunocompromised humans, myocarditis associated with toxoplasmosis is not an uncommon complication. In such cases, lymphocytic myocardial infiltration can lead to depressed myocardial function, which can be associated with congestive heart failure, rhythm disturbances and pericardial effusions. In addition, myocardial failure has been reported in immunocompetent humans associated with active toxoplasmosis [Chandenier J, Jarry G, Nassif D, Douadi Y, Paris L, Thulliez P, Bourges-Petit E, Raccurt C (2000) Congestive heart failure and myocarditis after seroconversion for toxoplasmosis in two immunocompetent patients. European Journal of Clinical Microbiological Infectious Disease 19, 375-379]. Here we describe a cat with echocardiographic changes consistent with infiltrative or inflammatory disease, and elevated IgG and IgM titres to Toxoplasma gondii. There was resolution of these myocardial changes once the toxoplasmosis was treated.     

Suspected fibrocartilaginous embolism in a cat

A 12-year-old cat was presented to the University of Queensland's Small Animal Teaching Hospital with a 1-day history of left hemiparesis of acute onset, with no evidence of trauma or toxin exposure. Neurological examination findings were consistent with a lesion in the caudal left cervical spinal cord (C6 to C8), which was non-painful and had not progressed since the onset of clinical signs. No other abnormalities were found, although myelography showed a mild swelling involving the caudal cervical and cranial thoracic spinal segments. A diagnosis of suspected fibrocartilaginous embolism was made on the basis of the history, clinical presentation and diagnostic tests results, making this case the first report of a suspected fibrocartilaginous embolism in a cat that returned to normal function.     

Food hypersensitivity in a cat

Food hypersensitivity was diagnosed in a 4-year-old Siamese cat. Clinical signs included intense erythema, with alopecia, excoriations, erosions, and crusts involving the ventral portion of the abdomen, inguinal region, medial aspect of each thigh, and cranial and lateral aspects of all 4 limbs. The cat was intensely pruritic. Histologically, there was cutaneous mast cell hyperplasia and diffuse infiltration of eosinophils in the dermis. Blood eosinophilia also was found. Clinical signs resolved after exclusive feeding of a hypoallergenic diet.     

Suspected mechanobullous skin disease in a cat

This report describes a three-year-old male domestic longhaired cat which was presented with generalised pruritus, alopecia and ulcerative dermatitis. All four feet showed evidence of nail shedding and there was widespread scarring of the skin of the back. Clinicopathological investigations suggested a mechanobullous disease. The condition was unresponsive to attempted medical therapy which included antibiotics, glucocorticoids and vitamin E supplementation.     

Suspected clostridial myositis in a domestic cat

Extract

Sir:- A long-haired domestic cat. aged two years, appeared normal when fed by the owner, at 9.00am. At 3.00pm the cat arrived home walking on three legs. The other leg appeared very painful. The owner brought the cat to the clinic immediately as she thought it has been hit by a car.     

Suspected iatrogenic paradoxical embolization in a cat

A cat was evaluated for a 5-year history of progressive, episodic, exercise-induced cyanosis and panting. Diagnostic testing demonstrated tetralogy of Fallot with predominant right-to-left shunting and right-sided heart failure. Following diagnostic catheterization, the cat developed clinical signs consistent with systemic arterial thromboembolization and was euthanized. Necropsy findings included multiple thrombi within the right atrium and ventricle, and thromboemboli within the terminal aorta and right common carotid artery, a condition most consistent with iatrogenic paradoxical embolization secondary to diagnostic catheterization. Paradoxical embolization and thromboembolic complications of diagnostic catheterization are discussed.     

Pseudolymphoma in a cat on phenobarbital treatment

A two‐year‐old female spayed domestic shorthair cat was presented with apathy, inappetence and generalised lymphadenomegaly. Anamnestic data included a generalised seizure disorder and phenobarbital treatment started one month before presentation. Routine blood analysis revealed only mild abnormalities and FeLV and FIV tests were negative. Both popliteal lymph nodes were aspirated and cytology was consistent with reactive lymph node hyperplasia. PCR for antigen receptor rearrangement testing diagnosed a polyclonal cell population. In the absence of another cause, lymphadenomegaly was attributed to an adverse drug reaction and phenobarbital was discontinued. The cat's condition improved and lymph node size normalised over the next 10 days. The retrospective diagnosis was phenobarbital‐induced pseudolymphoma.     

Suspected relative adrenal insufficiency in a critically ill cat

Objective: To describe a case of likely relative adrenal insufficiency (RAI) in a cat with critical illness. Case summary: A cat recovering from polytrauma developed hypotension unresponsive to intravenous fluid support and vasopressor therapy. An adrenocorticotropin hormone stimulation test documented insufficient adrenal function. Treatment with exogenous low‐dose glucocorticoids in addition to standard therapies resulted in rapid hemodynamic and clinical improvement. The cat ultimately recovered and was weaned from supplemental glucocorticoids. New or unique information provided: This is the first report of changes consistent with acquired RAI in a cat with critical illness.     

Suspected brainstem anesthesia following retrobulbar block in a cat

A 10‐year‐old, male, neutered, domestic shorthair cat was anesthetised for enucleation of a perforated left globe. A retrobulbar injection of local anesthetic (lidocaine/bupivacaine) was performed prior to surgery to provide intra‐ and postoperative analgesia. Following administration of the injection, the cat developed apnea and heart rate increased. Mechanical ventilation was initiated and surgery went ahead as planned. At the conclusion of surgery, the cat remained apnoeic requiring positive pressure ventilation until spontaneous ventilatory effort resumed. Upon recovery, the cat demonstrated neurological signs including tremors, nystagmus and absent dazzle reflex. These signs were attributed to brainstem anesthesia from the retrobulbar block and fully resolved within 3 h. This is the first report of suspected intrathecal spread of local anesthetic following retrobulbar block in a cat to the authors’ knowledge.     

Suspected malignant hyperthermia after halothane anesthesia in a cat

A 6 month old domestic shorthaired cat died of suspected malignant hyperthermia. Anesthesia was induced and maintained with halothane vaporized in oxygen and nitrous oxide, after acepromazine premedication. Before an incision was made, the cat's heart rate dropped from 140 to 90 beats/min concomitant with a drop in blood pressure. Glycopyrrolate administration resulted in severe ventricular tachycardia (340 beats/min). Halothane and nitrous oxide were discontinued and the surgery was abandoned. Lidocaine administration resulted in a normal sinus rhythm. In recovery, the cat was tachypneic and struggling, with a rectal temperature of 40.1 degrees C that quickly increased to 41.4 degrees C. While the cat was being cooled, cardiac dysrhythmias progressed to ventricular fibrillation that was not responsive to cardiorespiratory resuscitation. Blood specimens obtained while the cat was being cooled showed hyperkalemia (10.0 mEq/L) and increased serum creatine kinase activity (780 IU/L). There was extreme extensor rigidity (rigor mortis) within 5 min of cardiac arrest. Results of microscopic and electron microscopic examination of muscle showed occasional perivascular infiltrates of lymphocytes with infrequent perimysial and epimysial neutrophils and a few sarcomeres with streaming of Z-bands (suggesting a contracted state). Histochemical evaluation of skeletal muscle showed no significant difference between type I and type II fibers.     

Suspected necrolytic migratory erythema associated with chronic hepatopathy in a cat

A cat presenting with generalised hypotrichosis and crusts on the feet and tail was found to have an unusual chronic hepatopathy. There was also evidence of a chronic small intestinal disease which went undiagnosed. Necrolytic migratory erythema was suspected based on clinical findings and dermatohistopathology, and an association with the chronic hepatopathy was suggested. This is the first report of such an association in a cat. Serum zinc, amino acids and essential fatty acids were analysed, and medical treatment was given with equivocal efficacy.     

Suspected Bartonella-associated myocarditis and supraventricular tachycardia in a cat

A 4-year old female spayed domestic short hair cat presented for evaluation of a tachyarrhythmia identified on routine physical examination. Supraventricular tachycardia (SVT) was identified on electrocardiogram (ECG). Echocardiogram failed to identify any structural heart disease. A positive Bartonella antibody titer was identified on serological evaluation. The cat received anti-arrhythmics for control of the SVT and azithromycin for Bartonella. After completion of antibiotic therapy, a four-fold decrease in the Bartonella antibody titer was measured and the cat was eventually weaned off anti-arrhythmic medications. At 1 week, 1 month and 3 month re-checks off all therapy, no SVT was identified.     

Carbimazole‐associated hypersensitivity vasculitis in a cat

Feline hyperthyroidism can be treated medically, surgically or with radioactive iodine. Carbimazole inhibits both triiodothyronine and thyroxine synthesis in the thyroid gland and reported side effects include mild eosinophilia, leucopenia and lymphocytosis, thrombocytopenia, elevated liver enzyme activities, gastrointestinal signs and skin abnormalities. This case report describes a cat with carbimazole‐associated apparent hypersensitivity vasculitis causing digital and tail necrosis, with multiple renal infarcts. Withdrawal of carbimazole resulted in stable disease .     

Chemically-induced delayed hypersensitivity in the cat

A technique to evaluate the cell mediated immune response in cats by the induction of delayed-type hypersensitivity to the strong contact sensitizer, 1-chloro, 2–4 dinitrobenzene is described. Following topical sensitization with this agent, challenge was done on the cats ear. Ear thickness measurements, the kinetics of the response and histopathologic examination of the tissue were used to assess this delayed-type hypersensitivity reaction. Based on the results it is shown that allergic contact dermatitis can be experimentally induced in the cat.