Abacterial cystitis (Alkylating Agent Cystitis)

Abacterial Cystitis (Alkylating Agent–Induced Cystitis)

Overview

Abacterial cystitis refers to bladder inflammation without bacterial infection, commonly associated with alkylating chemotherapeutic agents such as cyclophosphamide and ifosfamide. These drugs produce toxic metabolites (notably acrolein) that concentrate in urine, causing direct urothelial irritation and leading to dysuria, frequency, urgency, suprapubic pain, and hematuria.

This condition is distinct from infectious cystitis because urine cultures are sterile.

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Treatment Options

1. Uroprotective Agent

• Mesna (2-mercaptoethanesulfonate)

  • Mechanism: Binds and detoxifies acrolein in the urinary tract.

  • Dose (for prevention with cyclophosphamide/ifosfamide):

    • IV/PO: Typically 60–100% of the alkylating agent dose, divided into multiple doses (e.g., 20% given immediately before chemotherapy, 20% at 4 hours, 20% at 8 hours).

  • Example: If ifosfamide 1 g/m², then mesna 200 mg/m² IV/PO at 0, 4, and 8 hours.

2. Hydration and Diuresis

• Aggressive IV fluids: Maintain urine output > 100 mL/hr.

• Forced diuresis with furosemide (20–40 mg IV) may be used if hydration alone is insufficient.

3. Symptomatic Relief

• Analgesics:

  • Paracetamol (acetaminophen): 500–1000 mg PO every 6–8 hours (max 4 g/day).

  • NSAIDs (e.g., ibuprofen 400 mg PO q8h) if not contraindicated.

• Antispasmodics:

  • Oxybutynin: 2.5–5 mg PO 2–3 times daily for bladder spasms.

• Phenazopyridine (urinary analgesic): 200 mg PO TID after meals, up to 2 days (for short-term relief).

4. Severe Hemorrhagic Cystitis Management

• Continuous bladder irrigation with saline for clot prevention.

• Intravesical instillations: alum, prostaglandins, or formalin (specialist use only).

• Hyperbaric oxygen therapy may be considered in refractory cases.

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Supportive Care

• Monitor urine output and color (for hematuria).

• Avoid unnecessary antibiotics (sterile urine).

• Nutritional support to maintain hydration and prevent bladder irritation (avoid caffeine, alcohol, acidic foods).

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Key Notes

• Risk is higher with ifosfamide > 1.5 g/m²/day or high-dose cyclophosphamide.

• Mesna prophylaxis is the standard of care in preventing alkylating agent–induced cystitis.

• Condition is preventable with proper hydration, mesna, and bladder monitoring.

• Long-term cases may lead to fibrosis and reduced bladder capacity.