[Diagnosis of interstitial cystitis].
Interstitial cystitis (IC) represents a rare and complex inflammatory bladder condition in which diagnostics can be challenging. Strict NIH criteria for its diagnosis were designed for research purposes. Their routine application would miss large proportions of IC patients. When IC is suspected, history and physical exam are followed by an evaluation of long-term voiding diaries. Large voided volumes (functional capacity > 250 cc) or longer micturition intervals (> 2 h.), absence of nocturia or symptom-free periods reduce the likelihood of IC. Further exclusion diagnostics include urine tests (infection), cytology (in-situ carcinoma), ultrasound (calculi, bulks, anomalies) and urodynamics in selected cases. Bladder capacity measurements under sedoanalgesia are of limited value, since functional low-volume bladders can be mechanically extendable. Cystoscopy under general anesthesia represents the diagnostic standard procedure for IC during which 90% of IC-patients present with characteristic mucosal glomerulations after bladder distension. Biopsies are recommended for exclusion of malignancy. Potassium-leak testing plays no relevant role in routine diagnostics due to its poor sensitivity. Similarly, complex determinations of novel IC markers (histamine, tryptase, cytokines, growth factors, substance P, nitric oxide) are of no relevance in clinical settings and should be restricted to research projects.