[Scrotal vasculitis simulating recurrent epididymitis]

We present a case of scrotal vasculitis, of difficult diagnosis despite the patient's history, where it was necessary to resort to surgery in order to establish definitely its diagnostic differentiation with a specific epididymitis. Taking advantage of this uncommon form of presentation of scrotal vasculitis, in this case an evolved Schonlein-Henoch syndrome in a 35-year-old patient, we analyse the different forms of gonad, epididymis and scrotal affectation recognised in cases of vasculitis, with special reference to the forms of acute presentation, simulating testicle torsion.

[Psoas abscess: considerations on 6 cases]

We present six cases of psoas abscess, three primary and three secondary. The etiologic, pathogenic and therapeutic considerations are outlined. Staphylococcal infections prevail in the primary abscesses. The diagnostic difficulties are considerable but nowadays are facilitated by echography and TAC. In the secondary ones, the psoas abscess is an epiphenomenon of a more easily recognised clinical syndrome. It is surprising how these septic processes are increasingly placed in the hands of urologists in recognition of their mastery of retroperitoneal surgery.

[Spontaneous rupture of the ureter caused by an impacted stone]

We report a case of spontaneous rupture of the ureter from an impacted calculus, paradigm of diagnostic and therapeutic difficulties of these uncommon pathologic conditions. Spontaneous rupture of the ureter from an impacted calculus should be considered in cases of persistent renal colic and atypical presentation. Diagnosis is based on urographic evidence of urinary extravasation. This should be differentiated from nephric colic from urinary extravasation arising from the renal fornices which is relatively common in nephric colic. Treatment must always include drainage of the urinoma, ureteroraphy, and urinary diversion. However, a controversy exists on the advantages and disadvantages of nephrostomy versus ureteral splinting.

Population pharmacokinetic study of gentamicin and a Bayesian approach in patients with renal impairment

A population pharmacokinetic study was conducted on a total of 70 patients receiving gentamicin therapy. The patients included those with normal renal function and those with varying degrees of renal impairment. The parameters studied were the apparent volume of distribution and the plasma clearance of gentamicin. The interindividual variability and the residual variability of those parameters in the different subpopulations were studied according to a statistical model that assumed log normal distribution. Use of the one-way ANOVA test revealed statistically significant differences (P = 0.004) in the population plasma clearance of gentamicin in patients below and above 50 years of age. A linear relationship was established between the plasma clearance of gentamicin and the creatinine clearance in those patients. At the same time, the coefficient of variation of the Clp increased progressively in patients with renal impairment, varying between 28.98% in patients with a ClCR greater than 100 ml/min and 76.53% in patients with a ClCR between 20 and 60 ml/min. The results obtained in the population study were later applied to drug monitoring in 23 patients with varying degrees of renal function and who received gentamicin therapy with different doses. The residual variability of the population allowed us to calculate a weighting factor (FF) between the experimental and the population data using Bayesian fitting. The weighting factor was 0.89 in patients with normal renal function and 0.80 in patients with renal impairment. Statistical comparison of the pharmacokinetic parameters obtained from the populational data, non-linear regression and the Bayesian method using revealed differences in the values for the apparent volume of distribution obtained with the two methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathology of equine phycomycosis

The pathological findings in three cases of equine phycomycosis in Costa Rica are described. Two cutaneous (Pythium sp) and one nasal lesion (Conidiobolus) were observed.