Bladder contractility and idiopathic detrusor instability in males.

Thirty males (mean age 54 +/- 13 years) with an "idiopathic" detrusor instability and fully compensated bladders (no post-micturition residuals) were assessed urodynamically at a short distance of time (3 months, on average) from the beginning of clinical symptoms. Thirty age-matched controls were also investigated. Detrusor shortening velocity was found to be increased in the unstable patients (P < 0.001), which seemed to derive from enhanced contractile capability in the presence of normal urethral resistance. Such data confirm the results of previous investigations in males with obstructive detrusor instability as well as in women with idiopathic unstable bladders. The significance of these findings was discussed. In particular, it was suggested that detrusor instability may involve changes leading both to more excitable bladder smooth muscle cells and to an easier electrical coupling between the same cells, thus, to enhanced contractile capability. It was also suggested that if an impaired contractile function in unstable bladders may be the final result of a process of detrusor collagenosis, increased bladder contractility would rather characterize an initial phase in the natural history of detrusor instability.