OVERVIEW

What is renal tuberculosis?

Renal tuberculosis refers to a tuberculosis infection occurring in the kidneys and is one of the common extrapulmonary forms of tuberculosis. This disease mostly affects young adults aged 20–40, with males slightly outnumbering females.

The pathogenic bacteria of renal tuberculosis primarily originate from pulmonary tuberculosis. The tuberculosis bacteria spread to the kidneys via the bloodstream, eventually causing renal tuberculosis. The onset of renal tuberculosis is slow, and early stages often show no clinical symptoms.

As the disease progresses, patients may experience symptoms such as frequent urination, urgency, painful urination, hematuria, pyuria, and lower back pain. Without active treatment, renal tuberculosis can ultimately lead to kidney failure and, in severe cases, become life-threatening. Treatment for renal tuberculosis includes systemic therapy, medication, and surgical intervention.

Generally, the prognosis for early-stage renal tuberculosis is favorable, while late-stage cases have a poorer prognosis. Advanced renal tuberculosis can severely impact a patient's quality of life, especially after secondary bladder contracture, where lower urinary tract symptoms like frequent urination, urgency, and painful urination cause significant distress.

Is renal tuberculosis common?

Yes, it is common. Pulmonary tuberculosis is the most prevalent form of tuberculosis, but extrapulmonary tuberculosis also includes peripheral lymph node tuberculosis, renal tuberculosis, intestinal tuberculosis, and bone tuberculosis, among others. Renal tuberculosis is one of the common extrapulmonary forms.

What are the types of renal tuberculosis?

Based on clinical manifestations, renal tuberculosis can be classified into pathological renal tuberculosis and clinical renal tuberculosis.

Pathological renal tuberculosis often occurs in the early stages of the disease, where patients show no clinical symptoms, and tuberculosis bacteria can only be detected in their urine. When the patient's systemic or local immunity declines, pathological renal tuberculosis may progress to clinical renal tuberculosis, leading to a series of clinical symptoms.

Generally, the progression from pathological renal tuberculosis to clinical renal tuberculosis takes 2–20 years.

Is renal tuberculosis contagious?

As a form of tuberculosis, renal tuberculosis is contagious. However, the tuberculosis bacteria in renal tuberculosis are primarily excreted through urine, meaning transmission requires contact with urine, making its contagiousness far lower than that of pulmonary tuberculosis. Nevertheless, if a renal tuberculosis patient also has active pulmonary tuberculosis, their contagiousness should be managed according to pulmonary tuberculosis protocols.

SYMPTOMS

What are the common manifestations of renal tuberculosis?

• In the early stages, renal tuberculosis often presents no clinical symptoms and may only be detected through abnormal urine tests during physical examinations. For example, the urine pH may be acidic, with small amounts of protein, red blood cells, or white blood cells. Tubercle bacilli can be detected in the urine at this stage.
• As the disease progresses, the initial symptom for most patients is frequent urination, followed by varying degrees of urgency, burning sensation during urination, pain, increased nocturia, and hematuria. The frequency of urination may gradually increase from 3–5 times a day to 10–20 or more times, and in severe cases, even over a hundred times, significantly affecting the patient's quality of life.
• Patients with renal tuberculosis may also experience varying degrees of pyuria, with severe cases presenting as rice-water-like urine. If renal tuberculosis further develops into tuberculous pyonephrosis, leading to hydronephrosis or pyonephrosis, or if blood clots or pus block the ureter, symptoms such as back pain or discomfort may occur. Additionally, systemic symptoms of tuberculosis, such as loss of appetite, weight loss, fatigue, night sweats, and low-grade fever, may also appear in renal tuberculosis patients.
• If renal tuberculosis continues to progress, it may lead to kidney failure, which can be life-threatening in severe cases.

What other diseases can renal tuberculosis cause?

Renal tuberculosis can lead to tuberculosis throughout the genitourinary system, such as contralateral renal tuberculosis, ureteral tuberculosis, bladder tuberculosis, urethral tuberculosis, prostatic tuberculosis, epididymal tuberculosis, and testicular tuberculosis. Additionally, hydronephrosis, pyonephrosis, hydroureter, bladder contracture, and kidney failure are common complications of renal tuberculosis.

CAUSES

What are the causes of renal tuberculosis?

The tuberculosis bacteria in renal tuberculosis mainly originate from pulmonary tuberculosis, with a small number coming from other organ tuberculosis such as bone and joint tuberculosis or intestinal tuberculosis. There are four routes of transmission for tuberculosis bacteria to reach the kidneys:

• Hematogenous spread: Tuberculosis bacteria enter the bloodstream and colonize the kidneys through blood circulation, which is the primary route of infection;
• Direct extension: Tuberculosis in nearby organs (such as spinal tuberculosis or intestinal tuberculosis) directly spreads and involves the kidneys;
• Retrograde infection: Tuberculosis bacteria reach the kidneys through retrograde urine flow, causing infection, such as when renal tuberculosis in one kidney leads to secondary renal tuberculosis in the contralateral healthy kidney;
• Lymphatic spread: Tuberculosis bacteria spread to the kidneys through the lymphatic system.

Which groups are most susceptible to renal tuberculosis?

Patients with pulmonary tuberculosis are most prone to developing renal tuberculosis. Studies have shown that the incidence of renal tuberculosis in pulmonary tuberculosis patients is as high as 15%–20%. Additionally, the prevalence of renal tuberculosis is significantly higher in patients with HIV/AIDS, diabetes, hemodialysis, or kidney transplants compared to the general population.

DIAGNOSIS

What tests are needed for renal tuberculosis? Why are these tests necessary?

Typical renal tuberculosis is not difficult to diagnose, but in recent years, atypical cases have become increasingly common. The diagnosis of renal tuberculosis requires combining multiple test results to reach a clinical conclusion.

• Physical examination: Can preliminarily assess whether there are other tuberculosis lesions in the body, such as nodules in the prostate, vas deferens, or epididymis.
• Tuberculin test: Determines whether the patient has been infected with tuberculosis and provides a preliminary assessment of the current infection status.
• Urinalysis and urine sediment acid-fast staining: A preliminary search for Mycobacterium tuberculosis.
• Urine tuberculosis culture: Confirms whether Mycobacterium tuberculosis is present in the urine.
• Urine tuberculosis DNA test: Confirms whether Mycobacterium tuberculosis is present in the urine.
• Urinary tract ultrasound: Evaluates whether hydronephrosis or hydroureter is present and checks for nodules in the prostate, vas deferens, epididymis, or testicles.
• Abdominal plain film and intravenous pyelography: Determines the extent of renal tuberculosis damage.
• Chest and spine X-rays: Preliminary screening for pulmonary or spinal tuberculosis.
• Retrograde pyelography: Determines the extent of renal tuberculosis damage.
• Ultrasound-guided percutaneous nephrostomy and pyelography: Determines the extent of renal tuberculosis damage.
• Abdominal CT: The gold standard for diagnosing renal tuberculosis.
• Cystoscopy: Confirms whether bladder tuberculosis is present and assists in diagnosing renal tuberculosis.
• Renal function tests: Assess whether renal insufficiency is present.

What precautions should be taken for the tuberculin test in renal tuberculosis?

• Avoid scratching or rubbing the tuberculin injection site, and do not apply any medications, perfumes, essential oils, soap, etc., to prevent affecting the test results.
• Avoid spicy, seafood, or other irritating foods for three days after the test.
• Rest for 15–20 minutes after the test and leave only if no discomfort occurs to monitor for allergic reactions.
• Have a doctor measure the results 72 hours after the test.
• Generally, there are no significant adverse reactions during the test. Some patients may develop blisters or ulcers at the injection site, which usually resolve on their own. If high fever or other abnormal reactions occur, seek medical attention immediately.

How to distinguish between renal tuberculosis and acute cystitis?

Although both conditions present with bladder irritation symptoms such as frequent urination, urgency, and dysuria, acute cystitis typically does not cause systemic symptoms like fever, night sweats, weight loss, or loss of appetite. Additionally, symptoms of acute cystitis usually resolve quickly with antibiotic treatment. In contrast, renal tuberculosis does not respond to antibiotics.

TREATMENT

Which department should I go to for renal tuberculosis?

Urology, Nephrology, or Tuberculosis Department.

What are the treatment options for renal tuberculosis?

• Systemic therapy: Adequate rest, proper nutrition, suitable physical exercise, and necessary medication (for other conditions).
• Drug therapy: Anti-tuberculosis treatment, commonly using drugs such as isoniazid, rifampin, streptomycin, ethambutol, and pyrazinamide. Combination therapy is generally recommended, with a standard course of 6 months. Common side effects include liver and kidney damage, vision impairment, hearing loss, etc.
• Surgical treatment: Such as nephrectomy.

What are the common risks of nephrectomy for renal tuberculosis?

• Intraoperative and postoperative bleeding, which in severe cases may lead to hemorrhagic shock and endanger life;
• Wound infection, affecting wound healing;
• Lung infections, urinary tract infections, bloodstream infections, etc.;
• Damage to surrounding vital tissues and organs;
• Postoperative wound pain;
• Renal insufficiency, etc.

Are there any sequelae after nephrectomy for renal tuberculosis?

Generally, if the contralateral kidney is normal, nephrectomy for renal tuberculosis has no significant impact on daily life. A few patients may develop renal insufficiency postoperatively, leading to renal failure, requiring dialysis or kidney transplantation. Additionally, some patients may experience long-term chronic lower back pain and abnormal sensations in the lower abdomen after nephrectomy.

Do renal tuberculosis patients need follow-up examinations after surgery? How?

Yes.

• After nephrectomy, renal tuberculosis patients still require 6–9 months of anti-tuberculosis treatment. During this period, monthly tests such as urinalysis, urine tuberculosis bacilli, ESR, urinary system ultrasound, and liver/kidney function are needed. Close monitoring of the contralateral kidney's function and morphology is also necessary to observe improvements in tuberculous cystitis.
• Patients receiving drug therapy alone should undergo intravenous pyelography every 3–6 months.
• After stopping medication, long-term follow-up is required, with check-ups every 6 months to 1 year for at least 3–5 years.

Can renal tuberculosis be completely cured?

Yes. With early and standardized treatment, most early- to mid-stage renal tuberculosis patients can achieve clinical cure.

Can renal tuberculosis recur?

Yes. Factors such as drug-resistant tuberculosis bacteria, irregular medication, or weakened immunity can lead to recurrence.

DIET & LIFESTYLE

What should kidney tuberculosis patients pay attention to in daily life?

• Taking medication on time and in the correct dosage is crucial as it directly affects treatment efficacy;
• Get adequate rest, maintain proper nutrition, engage in suitable physical exercise, and receive necessary medical treatment (for other conditions);
• Attend regular follow-up examinations to promptly detect and address any abnormalities.

Does kidney tuberculosis affect fertility?

When kidney tuberculosis is complicated by reproductive system tuberculosis (such as fallopian tube tuberculosis, vas deferens tuberculosis, epididymis tuberculosis, or testicular tuberculosis), it may lead to infertility.

PREVENTION

Can renal tuberculosis be prevented? How to prevent it?

Yes, it can be prevented. First, actively get vaccinated against tuberculosis. Second, avoid contact with tuberculosis patients. Finally, strengthen physical exercise to enhance your own resistance.

How to detect renal tuberculosis early?

• Get regular check-ups, and if there are any abnormalities, actively investigate the cause;
• If you experience discomfort such as frequent urination, urgency, painful urination, or hematuria, seek medical attention promptly to determine the cause.