[The usefulness of clinical history for the diagnosis of lower urinary tract obstruction in patients with acute urinary retention].

Objectives: To determine the diagnostic usefulness of data provided by clinical history for the diagnosis of lower urinary tract obstruction in patients with acute urinary retention.

Methods: We performed a transversal study in a series of 70 patients (19 women and 51 men) with a mean age of 61.5 years (typical deviation 20.7 years), who underwent urodynamic study due to acute urinary retention. Past medical history was recorded in all patients. Physical exam was also carried out, evaluating prostate size in males, presence of genital prolapse in females, and neurourological examination. Urodynamic tests consisted on flowmetry, pressure/flow studies with simultaneous perineal electromyography, and voiding cystourethrogram or videocystogram. Student's t mean comparison and chi-square tests were used for the statistical analysis.

Results: The only clinical data that showed a statistically significant relationship with obstruction of the lower urinary tract were: age, sex, prostate size, and existence of infrasacral neurological lesion (absence of bulbocavernous reflex). Age > 74 years showed a sensitivity of 71 % for lower urinary tract obstruction and a specificity of 60%. Male sex showed a sensitivity of 88% and specificity of 36%. Prostate size > or ='3d grade II sensitivity was 58% and specificity 82%; and absence of infrasacral lesion a sensitivity of 77% and specificity of 48%.

Conclusions: Provided that a negative result in a test with high sensitivity makes the likelihood of disease low, in women the presence of infrasacral neurogenic dysfunction or age < or ='3d74 years diminish the probability of obstruction in patients with acute urinary retention. On the other side, if a negative result of a test with high specificity increases the probability of having the disease, a prostate size > or ='3d grade II and age > 74 years favour the likelihood of having urinary tract obstruction for a patient with acute urinary retention.