Reversible right-sided congestive heart failure secondary to primary hyperaldosteronism in a cat.

A 10-year-old male castrated Somali cat presented with neurologic signs, severe systemic hypertension, and hypokalemia. Abdominal ultrasonography demonstrated a left adrenal mass, and the serum aldosterone concentration was increased. Computed tomography and follow-up diagnostic testing confirmed a left adrenal mass consistent with functional adenocarcinoma; additional findings included chronic airway and parenchymal disease. Transthoracic echocardiography revealed biatrial enlargement, with abdominal and pericardial effusion, consistent with right-sided congestive heart failure. The cat was treated for congestive heart failure and adrenalectomy was performed. Cardiac structure and function returned to normal within 6 months postoperatively. This report highlights a case of reversible congestive heart failure secondary to primary hyperaldosteronism.

Selected neurotoxins.

The small animal practitioner is faced with an infinite number of potential toxins in our modern environment. Unapproved usage of drugs and insecticides requires the practitioner to keep informed about the development of new toxic syndromes. Recreational drug toxicosis in animals is still seen with some frequency in clinical practice and should not be overlooked, even when the owner denies the possible exposure. In this article, we have discussed a few of the more common and newer neurotoxicities seen in clinical practice today. Neurologic toxicities are complex, but treatment can be rewarding if early diagnosis is made and aggressive therapy is instituted. The practitioner will find it worthwhile to establish contact with a toxicologist or poison information center for additional support when necessary.

Ophthalmic corticosteroid therapy: systemic effects in the dog.

Degenerative myopathy suggestive of glucocorticoid-induced myopathy was diagnosed in a 10-year-old female Poodle X Pekingese dog with a history of progressive lameness. Electromyography revealed bizarre high-frequency discharges. Evidence of adrenal suppression was obtained in response to exogenous ACTH. The predominant source of corticosteroid was an ophthalmic preparation used in the management of keratoconjunctivitis sicca. Considering the apparent adverse effects of the corticosteroid in this case, a study was undertaken to determine the systemic effects, if any, induced by long-term ophthalmic administration of 0.1% dexamethasone suspension in healthy adult dogs. Dogs in one group (n = 5) were treated 4 times daily for 8 weeks, and dogs in another group (n = 5) were treated 4 times daily for 16 weeks. All dogs remained healthy throughout the study, but dexamethasone-treated dogs developed marked adrenal suppression, beginning the second week of treatment and intensifying throughout the treatment period. Histopathologic changes in the liver of dexamethasone-treated dogs included scattered foci of vacuolated hepatocytes, increased hepatocytic glycogen content, and ballooning degeneration of hepatocytes. Muscle specimens were histologically, histochemically, and electromyographically normal.

Evaluation of evoked-muscle potentials from stimulation of ulnar nerves of the dog.

Evoked muscle potentials were evaluated in 19 anesthetized dogs after stimulation of the ulnar nerve. Subsequently, unilateral dorsal rhizotomy was performed on 6 dogs, and ulnar nerve stimulation was repeated. The evoked muscle potentials were begun at 1 V and increased. Threshold, optimum, and maximum stimuli for the M wave, and the reflex-evoked response (H reflex) were recorded. Threshold voltages for the M wave and the H reflex were 4.4 V and 4.0 V, respectively. The latencies for these stimuli also were recorded for the H reflex from proximal and distal sites. The optimal latency for the proximal and the distal sites were 15.4 +/- 2.5 ms and 18.3 +/- 2.6 ms, respectively (mean +/- SD). The motor nerve conduction velocity was 68 +/- 11 m/s. In addition, a mixed orthodromic sensory-antidromic motor conduction velocity was 75.2 +/- 13.3 m/s. Ratios between thoracic limb length and H reflex latency were 27.5 +/- 3.9 from the proximal site and 23 +/- 2.7 from the distal site. A waveform with a latency less than that of the H reflex, but greater than that of the M wave was observed inconsistently. An additional group of low amplitude waves was observed with a latency greater than the H reflex latency. The H reflex latency/limb length ratio may be clinically useful in evaluation of proximal neuropathies in the dog.

Mucocutaneous subdermal plexus flap from the lip for lower eyelid restoration in the dog.

A mucocutaneous subdermal plexus flap from the lip was transplanted into a defect created by removing the lower eyelid in 17 dogs. The grafts were evaluated from 10 days to 6 months later to assess their survivability, function, and cosmetic appearance. Histology was used in selected cases to examine changes in the grafted tissue. In addition, electromyograms were obtained for 2 grafts at 2 weeks and for 2 grafts at 24 weeks to assess reinnervation of transplanted segments of the orbicularis oris and buccinator muscles. Minor necrosis of the outer flap margin occurred in 4 dogs, but healing by second intention was satisfactory. Results from the histologic and electromyographic analyses suggested reinnervation of the orbicularis oris and buccinator muscle segments occurred from portions of the auriculopalpebral nerve in 2 grafts. The cosmetic and functional results in this procedure were satisfactory. It was concluded that the lip flap is a suitable substitute for the lower eyelid in the dog and can be effectively used for single-stage replacement of major lower eyelid losses, but that an elective second-stage procedure can be done to improve the cosmetic results in selected cases.

Choroid plexus tumors in the dog.

Clinical and necropsy records for nine dogs with tumors of the choroid plexus were reviewed. In seven of the dogs, the tumors were on the left side of the fourth ventricle. All of the dogs were males, ranging in age from 13 months to 9 years. Upper motor neuron tetraparesis and positional nystagmus were the most common neurologic signs. Less frequently recorded were head tilt, vomiting, bradycardia, and signs of cranial nerve dysfunction. Alteration in consciousness was evident in four of the dogs and ranged from personality changes to coma.

Meningiomas in cats: a retrospective clinical study of 36 cases.

Thirty-six cases of meningiomas in cats were reviewed as to the clinical signs and anatomic location. Age, breed, and sex also were noted. It was found that, in general, meningiomas affected older cats, with two thirds of them being greater than or equal to 10 years old. There was no breed predilection, although there was a majority of male cats. In most cases, the anatomic location was supratentorial, with only one case being infratentorial, and no tumors were below the foramen magnum. A number of cats had multiple maningiomas, and this often complicated the anatomic localization by neurologic examination. Tentorial herniation (6 cases) was associated with positional nystagmus or tetraparesis, or both, in addition to the deficits caused by the tumor.