Feline Lower Urinary Tract Disease

Feline lower urinary tract disease (FLUTD) is a syndrome of varied etiologies. Feline idiopathic cystitis (FIC) is the most common cause in cats < 10 years, accounting for ~60% of cases.

Causes of FLUTD:

• FIC (idiopathic cystitis): 50–60% — diagnosis of exclusion
• Urolithiasis: 20–25% — struvite or calcium oxalate
• UTI: 1–5% in young cats; higher in cats > 10 years
• Neoplasia: Rare — transitional cell carcinoma
• Trauma / congenital: Rare

Clinical signs: Dysuria, pollakiuria, hematuria, periuria (urinating outside box), stranguria, vocalization. Obstructed cats show lethargy, vomiting, abdominal pain, absent urine stream.

Pathophysiology: Urethral plug (mucus + struvite crystals) or urolith → obstruction → post-renal azotemia → hyperkalemia → bradycardia, metabolic acidosis, death.

Immediate workup:

• CBC/Chem/UA (if stable enough)
• ECG — peaked T waves, bradycardia if hyperkalemic
• Assess hydration and cardiovascular status

Treatment:

• IV catheter + fluids: Lactated Ringer's (correct dehydration, promote diuresis)
• Unblocking: Sedation (ketamine/butorphanol or propofol), retrograde flush with sterile saline
• Post-unblock: Indwelling urinary catheter + closed collection system for 24–48h
• Hyperkalemia: Calcium gluconate (cardioprotection), insulin + dextrose, fluid diuresis

Prognosis: Good if treated within 24h; guarded if > 48h or azotemia severe.

FIC is a diagnosis of exclusion. Once stones, UTI, and neoplasia are ruled out, management focuses on stress reduction and environmental modification.

Environmental modification (multimodal):

• Increase water intake (fountains, multiple stations, canned food)
• Litter box management: N+1 boxes, clean daily, multiple locations
• Reduce stress: pheromone diffusers (Feliway), predictable routine, environmental enrichment
• Weight loss if obese

Pharmacologic (limited evidence):

• Amitriptyline: 5–10 mg PO q24h (tricyclic antidepressant; anti-inflammatory)
• Gabapentin: 50–100 mg PO q8-12h (anxiolytic, analgesic)
• Glucosamine/chondroitin: Controversial; may help glycosaminoglycan layer

Diet: Urinary diets (Hill's c/d, Royal Canin Urinary SO) for struvite prevention and stress reduction. Increase moisture content.