Urodynamics-based evidence for the beneficial effect of imipramine on valve bladders in children

In an era, in which valve bladder is recognised as perhaps the single most important determinant of long-term outcome in patients with posterior urethral valves (PUV), an insight into the etiopathogenesis and management of valve bladders is warranted. The present study was designed to evaluate bladder dysfunction in PUV and to assess the response to imipramine in these patients, both subjectively and objectively, by serial urodynamic studies (UDS).

From 1998-2001, 30 patients with PUV who had documented bladder dysfunction on UDS were studied. Patients with non-compliant or unstable bladders were treated with imipramine (1.5 - 2 mg/kg). All the patients in the present study were 5 years or older and hence old enough to be toilet trained. Assessment of continence and side effects of the drug was done after 3 months and repeat UDS were done at 3-6 months, 1 and 2 years.

On the basis of initial treatment, the patients were divided into 2 groups; a fulguration group (n = 10, 33.3 %) and a vesicostomy group (n = 20, 66.6 %). Symptomatic voiding dysfunction was present in 27 of the 30 patients (90 %). Two patterns of urodynamic abnormalities were noted in the present study; 1) unstable bladders with single or multiple uninhibited contractions (18/30 patients, 60 %), and 2) small capacity, hypocompliant, hypertonic bladder (12/30 patients, 40 %). Post imipramine therapy significant symptomatic improvement was noted in 16/30 patients. On serial UDS, there was a 18-20 % increase in maximum cystometric capacity (MCC) and 30-35 % increase in pressure specific bladder volume (PSBV) following one year of imipramine therapy in 16/30 patients and 11/30 patients, respectively. 4 patients failed to show any improvement in MCC and PSBV with imipramine, they had been initially diverted with vesicostomy and later required augmentation cystoplasty.

Unstable bladders and those with marginal bladder capacity and compliance showed the best response to imipramine therapy. Fibrotic, small capacity, hypertonic bladders are less responsive to imipramine. However, a trial of imipramine therapy is still warranted in these patients, as only 4/12 (33.3 %) patients with fibrotic hypertonic bladders failed to show any response and ultimately required augmentation cystoplasty. Imipramine qualifies as an effective and cheap drug for valve bladders.