Garosi LS, Dennis R, Platt SR, et al.
A7-year-old male neutered mixed breed dog was pre- sented to the Neurology Unit at the Animal Health Trust, Newmarket, UK, for investigation of a 3-day history of lethargy, vomiting, and progressive neurological signs. Before onset of neurological signs, the dog had been show- ing signs of recurrent vomiting and weight loss (approxi- mately 20% of body weight) for 5 weeks. Investigations performed at that time by the referring veterinarian (com- plete blood count. serum biochemistry, thoracic and abdom- inal radiographs) were all within normal limits. Symptom- atic treatment 2 weeks before presentation (metoclopramide 0.5 mglkg PO ql2h and amoxicillin with clavulanic acid 10 mgkg PO ql2h for 1 week) failed to resolve the vom- iting. At the onset of the neurological signs, the owners noticed propulsive walking and hypermetria of the thoracic limbs, blindness, head tremor and hyperesthesia when the dog was touched around the head or neck region, and in- termittent loss of awareness. Over the 12 hours that pre- ceded the initial examination, generalized ataxia had pro- gressed to an inability to walk, occasional recumbency with opisthotonus, and generalized seizures. Abnormalities noted on physical examination included tachycardia (heart rate of 170 bpm), weak femoral pulses, and congested mucous membranes. The dog had been fed a commercial dog diet. Routine vaccinations were current and the owners did not report any previous medical history. The owners considered the possibility of exposure to toxins very unlikely. Neuro- logical examination identified severely depressed mental status, intermittent opisthotonus with increased extensor tone of all 4 limbs and nonambulatory tetraparesis. Severe postural reaction deficits were present in all 4 limbs. Ab- normalities on cranial nerve examination included absent bilateral menace responses, dilated and unresponsive pupils in both eyes, and positional vertical nystagmus. Segmental spinal cord reflexes were intact in all 4 limbs. The dog had several generalized seizures shortly after the initial evalu- ation. The neuroanatomic diagnosis was a diffuse or mul- tifocal (forebrain and brainstem) lesion localization. Inflam- matory or infectious central nervous system diseases, a multifocal neoplastic process, metabolic disease, and tox- icity were considered as the most likely differential diag- noses for this neurolocalization and clinical history.
On presentation, the dog was severely dehydrated (8 to 10% of body weight), and fluid resuscitation was performed with 900 mL lactate Ringer’s solutiona and 100 mL of Gel- ofusinbadministered IV over 2 h until the dog was consid- ered sufficiently stable, as indicated by normal heart rate (100 bpm), central venous pressure of 6 mm Hg, urine out- put >1 mLIkglh, and mean blood pressure >70 mm Hg. Lactate Ringer’s solution administration was continued at 10 mLkg1h for the next 5 h and then decreased to twice maintenance with potassium supplementation of 20 mEq/L. IV boluses of diazepam (0.5 mglkg) were administered at 15-minute intervals to control seizures.