Urolithiasis in guinea pigs is caused by uroliths. Stones are common in middle-aged and older animals — solid mineral masses crystallised from urine. They may occur anywhere in the urinary tract: kidneys, ureters, bladder, urethra.
Stones are most often found in bladder and urethra. Lodging in urethra or ureters may cause obstruction — a life-threatening emergency.
Cause
The exact cause of stone formation is unclear; risk factors include diets high in calcium (e.g. alfalfa hay), chronic dehydration, genetic predisposition, urinary tract infection, obesity, lack of exercise, poor hygiene, neurological disease.
Unlike many mammals, guinea pigs excrete excess calcium in urine; urine is concentrated and alkaline pH may increase stone risk together with the factors above.
Clinical signs
Signs vary with stone size and location; some animals show none. Common signs: haematuria, straining to urinate (often mistaken for constipation). Pain and discomfort: loud tooth grinding, hunched posture, vocalisation when urinating. Reduced or absent urine output, anorexia, weight loss, depression, reduced activity.
Diagnosis
Diagnosis uses history, examination, and imaging — radiographs confirm diagnosis and localisation. Urinalysis may show crystalluria and UTI. Blood CBC and biochemistry are useful. Ultrasound is recommended.
Treatment
Surgical removal of calculi and supportive care (analgesia, fluids, antibiotics per urine culture, assisted feeding if anorexic).
Female guinea pigs have a short, wide urethra — stones may be removed instrumentally from distal urethra or endoscopically.
Prognosis
Generally favourable; without prevention stones often recur.
With ureteric or urethral obstruction prognosis is guarded — speed of referral and appropriate veterinary care matter greatly.
Prevention
Nothing guarantees prevention. Measures below reduce risk, especially after prior stones — recurrence is common.
Diet
Avoid high-calcium items: alfalfa hay, cabbage, dandelion greens, spinach. Ideally offer unlimited timothy hay (lower calcium), limited timothy-based pellets, and fresh vegetables.
Water
Chronic dehydration is a risk factor — ensure constant access to fresh water; multiple sources in the enclosure. Keep housing clean to reduce infection risk.
If you are unsure about your pet’s diagnosis and want a second opinion, you can request a veterinary consultation via messengers, phone, or the form on this page.