# Renal and Genitourinary Tuberculosis > Renal and genitourinary tuberculosis for NEET-PG Medicine: sterile pyuria, calyceal destruction, autonephrectomy, early morning urine tests and NTEP treatment. - Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/renal-and-genitourinary-tuberculosis - Exam / course: NEET-PG · Subject: Medicine - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-14 - Last updated: 2026-10-14 - Reference basis: Harrison's Principles of Internal Medicine; Campbell-Walsh Urology; National Tuberculosis Elimination Programme Guidelines - How to cite: "Renal and Genitourinary Tuberculosis", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/renal-and-genitourinary-tuberculosis ## Direct answer Renal tuberculosis is infection of the kidney by Mycobacterium tuberculosis, usually spread haematogenously from a primary focus, and it typically presents as sterile pyuria with haematuria. Destruction of the calyces and ureteric strictures can leave a shrunken, non-functioning kidney, a state called autonephrectomy. Diagnosis rests on early morning urine examined for acid-fast bacilli, culture or nucleic acid testing, and treatment follows the standard six-month national regimen. ## What you must remember - **Sterile pyuria:** white cells in the urine with a negative routine bacterial culture is the classic early clue. - **Spread:** haematogenous from a primary pulmonary focus, with the kidney usually involved first and the lesion later reaching the ureter, bladder and prostate. - **Early morning urine:** three specimens are sent for acid-fast bacilli smear, culture and nucleic acid amplification, since a single sample often misses the organism. - **Culture:** the reference standard for diagnosis, with drug susceptibility testing sent on positive cultures. - **Imaging:** calyceal irregularity, strictures, a contracted small-capacity bladder and calcification on urography or CT. - **Autonephrectomy:** a shrunken, non-functioning kidney left by destructive disease, often unilateral. - **Putty kidney:** an end-stage, shrunken and calcified tuberculous kidney that is non-functioning. - **Treatment:** the standard NTEP first-line regimen for at least six months, with surgery for strictures or nephrectomy only when required. ## A diagnostic approach to suspected renal tuberculosis Renal tuberculosis is often diagnosed late because it looks like recurrent bacterial infection that fails to respond to antibiotics. The approach below targets the specimen and the imaging that confirm the diagnosis early. 1. **Think of tuberculosis:** Sterile pyuria with haematuria, frequency and flank pain, especially with a history of tuberculosis or contact, points to genitourinary disease. 2. **Collect the urine correctly:** Three early morning samples are sent for smear, culture and nucleic acid testing, because one specimen often misses the organism. 3. **Image the tract:** Urography or CT may show calyceal irregularity, strictures and calcification, and ultrasound shows hydronephrosis or a small contracted bladder. 4. **Confirm the diagnosis:** Culture is the reference standard, while nucleic acid testing gives a rapid result, and drug susceptibility testing is sent. 5. **Treat for at least six months:** The standard national first-line regimen is given, and urine is monitored for conversion of sterile pyuria. 6. **Plan the late complications:** Ureteric strictures may need stenting or surgery, and a shrunken non-functioning kidney may need nephrectomy once drug therapy is complete. Early recognition prevents the destructive stage. Many patients who are treated late are left with a non-functioning kidney that cannot be salvaged. ## Where the examiner tries to catch you Genitourinary tuberculosis is a favourite viva topic because the clues run against the instinct to treat pyuria with antibiotics. - **Trap:** treating sterile pyuria with repeated antibiotics. — **Correct:** a negative routine culture with pyuria points to tuberculosis, and antibiotics for bacterial infection will not cure it. - **Trap:** taking a single negative urine smear as proof of absence. — **Correct:** the smear is insensitive, so multiple early morning samples with culture or nucleic acid testing are needed. - **Trap:** choosing nephrectomy as first-line management of a non-functioning kidney. — **Correct:** drug therapy comes first, and nephrectomy is considered later for a shrunken kidney that causes symptoms or hypertension. ## Frequently asked questions ### Why is renal tuberculosis usually unilateral? Renal tuberculosis is usually unilateral, and it typically arises from haematogenous spread from a primary focus, often in the lung. The unilateral pattern together with sterile pyuria makes tuberculosis more likely than an ordinary bacterial infection. ### How many urine samples are needed to diagnose genitourinary tuberculosis? Three early morning urine samples are usually collected for acid-fast bacilli smear, culture and nucleic acid testing in suspected genitourinary tuberculosis. Culture is the reference standard, and a single negative smear does not exclude the disease. ### What does autonephrectomy mean in renal tuberculosis? Autonephrectomy is the spontaneous functional loss of a kidney due to tuberculous destruction, leaving a small, shrunken, non-functioning organ. Nephrectomy may be considered later if the kidney causes symptoms or hypertension, after drug therapy has been completed. ### What is putty kidney? Putty kidney is an end-stage tuberculous kidney that is shrunken, calcified and non-functioning, and it is named for the putty-like calcified caseous material in its cut surface. It reflects long-standing caseation and fibrosis, and nephrectomy may be considered when the kidney causes symptoms. ### Which urinary finding suggests genitourinary tuberculosis rather than bacterial infection? Sterile pyuria, meaning white cells in the urine with a negative routine bacterial culture, suggests genitourinary tuberculosis. Haematuria, frequency and flank pain may accompany it, and early morning urine is examined for acid-fast bacilli.