A n indoor, 2-year-old, spayed female domestic cat was referred to the University of Missouri Veterinary Medical Teaching Hospital (UMC-VMTH) for evaluation of weight loss and polyphagia of 1-year duration, with recent episodes of generalized weakness and lethargy. These episodes occurred approximately once per month over the past 4 months. The cat produced frequent stools, which were occasionally poorly formed. A CBC and serum biochemistry were performed 1 and 5 months before referral, and leukopenia (1,200/L; reference interval, 3,500-16,000/L; no differential provided), hypocholesterolemia (64 mg/dL and 46 mg/dL; reference interval, 75-220 mg/ dL), and hypotriglyceridemia (22 mg/dL and 16 mg/dL; reference interval, 26-160 mg/dL) were identified. The most recent serum biochemistry results disclosed mild hypercalcemia (11.3 mg/dL; reference interval, 8.2-10.8 mg/ dL) and hypernatremia (163 mg/dL; reference interval, 145-158 mg/dL). Antibody titers for Toxoplasma were consistent with past exposure (immunoglobulin M [IgM] negative; IgG 1:256).The cat did not improve with clindamycin therapy (11 mg/kg PO q12h), prednisone (2 mg/kg q24h), and vitamin supplements (dosage unknown). During recent episodes of severe weakness, supportive care with IV lactated Ringer's solution, 5% dextrose, vitamin B complex, penicillin G benzathine, and dexamethasone (dosages unknown) improved the generalized weakness, but did not affect appetite or weight loss. The cat was referred to the UMC-VMTH for further diagnostic testing 12 days after the last episode.The cat was emaciated (body condition score, 2 out of 9; weight, 2.85 kg), and had an unkempt hair coat. Vital signs and hydration were normal. Mentation appeared normal at admission, but gait showed subtle evidence of weakness and ataxia with occasional crossing-over of the paws in all 4 limbs. Incomplete closure of the palpebral fissure
