Prevalence of renal tuberculosis among patients presenting with active pulmonary tuberculosis in Ilorin - Nigeria

Abstract

Tuberculosis (TB) is a major health problem world-wide, especially in tropical developing countries involving major organs in the body. The kidney is usually affected through haematogenous spread from a primary focus. Renal tuberculosis is the commonest form of extrapulmonary TB particularly among the Caucasians but thought to be rare in Blacks. Due to the paucity of data on the prevalence of renal TB. A prospective study was undertaken to investigate the prevalence ofrenal TB in cases of active pulmonary TB (PTB) in llorin - Nigeria.

Confirmed cases of active PTB patients were consecutively recruited from the Pulmonary Clinic and the PTB Ward over a one year period. The inclusion criteria were sputum acid fast baccili (AFB) positivity on two or more occasions and radiological evidence of PTB. Patients fullfilling the above criteria were investigated by urine analysis for sterile acid pyuria, Z-N stain, plain abdominal x-rays, renal ultrasound, intravenous urogram and renal biopsy.

A total of 148 active PTB patients were studied (91males, 57 females). Male to female ratio was 3:2.The mean age of the males and females with renal TB was 40 and 29 years respectively. The prevalence rates of AFB in urine and sterile acid pyuria were 9.5% and 8.8% respectively. Only 2.7% had both AFB in urine and sterile pyuria. Renal histology was abnormal in 70% of the biopsied kidneys with sterile pyuria. The combination of AFB in urine and histologic evidence of renal TB increased the prevalence of renal TB to 14% in the study.

The study shows that renal TB in active PTB may be similar in Black and White populations. The diagnosis is difficult and a high index of clinical suspicion with combined diagnostic tools are required to identify the lesion.