• Cause: unclear, sterile cystitis of unknown cause, interstitial cystitis is a diagnosis of exclusion. Infectious causes, neoplasia such as transitional cell carcinomas and uroliths or urinary sludge should be excluded first. In the author’s experience female guinea pigs are affected more often.
• Signs: hematuria, stranguria, vocalizing during urination, polydipsia, polyuria, dysuria, weight loss, hyporexia, anorexia, lethargy. In prey species signs are often non-specific and may go undetected particularly if animals are housed outdoors.
• Diagnosis: interstitial cystitis is a diagnosis of exclusion as bacterial cystitis, uroliths and neoplasia are more common. Extensive diagnostics such as diagnostic imaging, culture and sensitivity, hematobiochemistry and a bladder wall culture are needed. It is important the clinician does not overlook infectious causes which if left untreated may lead to nephritis and septicemia. Other causes such as urinary sludge secondary to hypercalcemia or reduced activity seen with osteoarthritis need to be excluded as well but are often present.
• Treatment: long-term husbandry adjustments concentrating on diuresis, increasing voluntary water intake and activity as well as analgesia.
• Prognosis: good if a holistic approach is taken.

• Hematuria.
• Stranguria.
• Vocalizing during urination.
• Polydipsia.
• Polyuria.
• Dysuria.
• Lethargy.
• Hyporexia.
• Anorexia.
• Weight loss.

• Hematuria.
• Stranguria.
• Vocalizing during urination.
• Polydipsia.
• Polyuria.
• Dysuria.
• Lethargy.
• Hyporexia.
• Anorexia.

• Worldwide.

• In the author’s experience females are more commonly affected.

• Cost of initial diagnostics should be discussed with the owner. This includes:
  • Potential anesthesia for blood collection.
  • Hospitalization for diagnostics to be performed.
  • Diagnostic imaging.
  • Urinalysis.
  • Cystocentesis.
  • Culture and sensitivity.
• As interstitial cystitis is often well managed, but rarely curable, cost of repeat visits should also be discussed with the clients as well as cost of long-term medication such as analgesics.

• The risk of general anesthesia which may be required for diagnostics should always be discussed with the owner.

• Largely unknown, interstitial cystitis is a diagnosis of exclusion.

General

• Previous urolithiasis, particularly when requiring cystotomy, may predispose to chronic scarring and thickening of the bladder wall. This may reduce the elasticity of the bladder and lead to discomfort during voiding.
• Systemic amyloidosis may lead to hyaline AA deposition within the urinary bladder. This is typically seen with chronic bacterial infections such as pododermatitis.
• Recurrent bacterial infections may lead to thickening and scarring of the urinary bladder wall. Reproductive disease in females such as endometritis may lead to ascending urinary disease as well.
• Animal suffering with other primary conditions such as osteoarthritis leading to reduced mobility, may  have reduced voiding frequency. This may predispose to urinary sludge resulting in chronic inflammation.

• Largely unknown, idiopathic cystitis is a diagnosis of exclusion.

• Months to years.
• Patients are usually seen with recurrent urinary symptoms which respond to symptomatic management but recur for no obvious cause.

• Largely unknown.

Refereed papers

• Recent references from PubMed and VetMedResource.
• Reaveill D R & Lennox A M (2020) Disease overview of the urinary tract in exotic companion mammals and tips on clinical management. Vet Clin North Am Exotic Anim Pract 23 (1), 169-193 PubMed.

Other sources of information

• Pignon C & Mayer J (2020) Guinea Pigs. In: Ferrets, Rabbits and Rodents: Clinical Medicine and Surgery. Eds: Quesenberry K, Mans C, Orcutt C & Carpenter J W. Elsevier, USA.