Bullous Changes on Bladder
Diagnosis
Bullous changes on the bladder represent catheter-induced bullous cystitis, eosinophilic cystitis, or follicular cystitis—all benign inflammatory conditions that can mimic bladder tumors but require tissue diagnosis via cystoscopy with biopsy to exclude malignancy. 1, 2, 3
Clinical Presentation and Differential Diagnosis
Catheter-induced bullous cystitis is the most common etiology, presenting with thickened bladder mucosa that appears smooth initially and becomes redundant and polypoid with prolonged catheterization, typically localized to the posterior wall 1
Eosinophilic cystitis presents with sessile mass lesions and bullous edema, often accompanied by peripheral eosinophilia on complete blood count, and can cause filling defects on imaging that mimic bladder tumors 3
Follicular cystitis manifests as a chronic inflammatory condition with lymphoid follicles in the bladder mucosa, presenting with irritative voiding symptoms and recurrent urinary tract infections 2
Acute bullous cystitis limited to the trigone can cause acute ureteral obstruction with numerous nodular filling defects on imaging, potentially leading to anuria if untreated 4
Diagnostic Workup
Cystoscopy with biopsy is mandatory to differentiate benign bullous changes from bladder malignancy, as imaging alone cannot reliably distinguish these entities 5, 1, 3
Histopathology reveals acute inflammation, mucosal edema, and lymphangiectasis in catheter-induced cystitis; eosinophilic infiltration in eosinophilic cystitis; and lymphoid follicles with plasma cells in follicular cystitis 1, 2, 3
Complete blood count should be obtained to assess for eosinophilia if eosinophilic cystitis is suspected 3
Upper tract imaging with CT or MRI urography is recommended to evaluate for concurrent pathology and ureteral obstruction 5, 4
Treatment
Catheter-Induced Bullous Cystitis
Remove the indwelling catheter immediately as this is the primary causative factor, with spontaneous resolution expected after catheter removal 1
Sonographic monitoring can track resolution of mucosal thickening without need for repeat cystoscopy in typical cases 1
Eosinophilic Cystitis
Initiate combination therapy with corticosteroids, antimicrobial agents, and antihistamines for symptomatic relief and resolution of inflammatory changes 3
Transurethral resection may be necessary for diagnostic purposes and to relieve obstructive symptoms when mass lesions are present 3
Follicular Cystitis
Treat with ciprofloxacin combined with vitamin A and prednisone for symptom remission in chronic cases 2
Address underlying recurrent urinary tract infections with appropriate antimicrobial therapy 2
Complicated Cases with Obstruction
Acute ureteral obstruction from trigonal bullous edema requires urgent intervention to prevent renal failure, particularly in anuric patients 4
Surgical intervention (ureterolithotomy with ureterovesical neostomy) may be necessary when concurrent ureteral pathology exists or when conservative management fails 6
Critical Pitfalls to Avoid
Never assume bullous bladder changes are benign without tissue diagnosis, as bladder malignancy can present with similar cystoscopic findings requiring complete visual resection when technically feasible 5
Do not perform biopsy of the blister itself in suspected bullous pemphigoid (a dermatologic condition); perilesional skin biopsy is required for that diagnosis 7
Recognize that bullous cystitis findings on imaging (filling defects, mucosal thickening) can simulate bladder tumors on intravenous urography and sonography, making cystoscopy essential rather than optional 1, 3
Monitor for ureteral obstruction in cases of trigonal involvement, as this can progress rapidly to anuria requiring emergent decompression 4