Differential Diagnosis: Proteinuria in Cats

Following are differential diagnoses for cats presented with proteinuria.

Prerenal

• Hemoglobinuria

• Myoglobinuria 

• Light chain immunoglobulins (multiple myeloma, lymphoma)

Renal

• Functional or physiologic

  • Congestive heart failure

  • Strenuous exercise

  • Fever

  • Seizure

  • Exposure to extreme temperatures

• Glomerular

  • Infectious

    • Bacterial (eg, chronic bacterial infection, mycoplasmal polyarthritis, endocarditis)

    • Viral (eg, FIV, feline infectious peritonitis, FeLV)

    • Protozoal (eg, toxoplasmosis) 

    • Fungal (eg, cryptococcosis, other systemic fungal infection)

  • Inflammatory

    • Acute pancreatitis

    • Cholangiohepatitis

    • Chronic progressive polyarthritis

    • Systemic lupus erythematosus

    • Other immune-mediated diseases

  • Neoplastic

    • Leukemia

    • Lymphoma

    • Mastocytosis

  • Miscellaneous

    • Acromegaly

    • Drug reactions

    • Diabetes mellitus

    • Corticosteroids (endogenous/spontaneous hyperadrenocorticism and exogenous)

    • Hyperthyroidism

    • Systemic hypertension

  • Familial

    • Membranous nephropathy

    • Amyloidosis (Abyssinian, Siamese)

• Tubulointerstitial

  • Chronic kidney disease

  • Acute kidney injury

    • Toxins (eg, NSAIDs, acetaminophen, ethylene glycol, lilies [Lilium and Hemerocallis spp], heavy metal ingestion [eg, lead, mercury, arsenic, thallium], insect or snake bite)

    • Hypotension

Postrenal

• Bacterial cystitis

• Idiopathic cystitis/FLUTD

• Urolithiasis

• Neoplasia (eg, urothelial carcinoma, other)

• Prostatitis (rare in cats)

• Vaginitis

• Pyometra