小儿肾结核

　　一、发病原因

　　1、常见的病原体本病最常见的病原体是人型结核分枝杆菌。

　　2、少见的病原体其他少见病原体包括牛型结核杆菌及未定型分枝杆菌等。

　　二、发病机制

　　肾结核的主要原发病灶为肺结核，少数来自于骨，关节，肠，淋巴结的结核病灶，偶有从生殖道蔓延到肾脏，肾脏结核的基本病理改变为结核结节或结核性肉芽肿形成，结核结节的中心为干酪样坏死组织，周围为类上皮细胞及laugharis巨细胞，外围为淋巴细胞及纤维组织，结核杆菌经血路侵入双肾，先在双侧肾脏的肾小球毛细血管丛中形成微结核病灶（病理性肾结核），在机体抵抗力正常的情况下，微结核病灶可痊愈或长期处于静止状态，不出现临床症状，但未痊愈的微结核病灶可引起结核菌尿，初起病变是一个肾小球结核结节，以后可发生坏死性损害，并且蔓延到小管，大多数病例从隐匿到再活动10～40年，一旦形成干酪样坏死损害，极少能自愈，发生坏死性乳头炎到肾实质空洞形成，钙沉积；感染继续播散，肾盂炎症到纤维化，影响集合系统，形成狭窄和肾盂积水，如果实质纤维化进展，肾内血管狭窄，致纤维化，最终肾结构破坏，若“种植”到尿，可发生尿道炎，膀胱炎（伴有溃疡形成，纤维化及壁增厚）。

　　It may be complicated by urinary incontinence, secondary bacterial infection, cold abscesses, uremia, etc. In addition, 5% to 10% of patients may develop hypertension, and there may be prostatitis, epididymitis. 10% to 25% of patients may experience renal function decline.

　　1. Urinary tract irritation symptoms:Frequent urination, urgency, and dysuria are typical and prominent clinical symptoms of renal tuberculosis. Frequent urination often appears first, and in the early stages of the disease, frequent urination may not be accompanied by dysuria. Treatment with general antibiotics is ineffective, and severe patients may experience urinary incontinence, difficulty in urination, and nocturia, which is related to the involvement of the bladder.

　　2. Hematuria:Tuberculosis lesions in the kidney, ureter, or bladder can all lead to hematuria. The one caused by tuberculous ulcers in the bladder trigone area is usually terminal hematuria, while hematuria throughout the day is often due to vascular injury in the urinary tract above the bladder.

　　3. Pyuria:Microscopically, there are a large number of pus cells, and sometimes necrotic tissue can be found. In severe cases, the urine may appear 'rice gruel-like'.

　　4. Pain and mass in the renal area:Local symptoms of renal tuberculosis are not prominent, tenderness and renal mass (hydrocele) are rare. When secondary infection occurs in tuberculous pyelonephritis (most often caused by Escherichia coli), or when there is a cold abscess around the kidney, local percussion tenderness may occur, and even lumbar sinus tracts may appear. Urinary colic may be caused by stones, clots, or debris.

　　5. General symptoms:Serious patients or those with tuberculosis in other organs may experience weight loss, fatigue, feverishness, night sweats, decreased appetite, which are common symptoms. In severe cases with severe renal dysfunction, uremia may occur.

　　1. Vaccination with BCG vaccine is the fundamental measure to prevent tuberculosis for those who have not been infected with tuberculosis.

　　2. Treat actively to prevent the spread. If tuberculosis infection occurs, it should be treated actively to prevent the spread of the disease.

　　3. Strengthen nutrition and avoid overwork.

　　4. Prevention of renal tuberculosis: Renal tuberculosis often originates from pulmonary tuberculosis. If pulmonary tuberculosis has been cured, although the tuberculosis bacteria are not transmitted through the respiratory tract, they can still be transmitted through urine.

　　1. Laboratory examination

　　1. Urinalysis examination:About 90% of patients with renal tuberculosis have proteinuria, pyuria, and hematuria. Aspyric pyuria should be highly suspected of renal tuberculosis. In addition to routine urine tests, repeated 24-hour concentrated urine direct smears for acid-fast bacilli can be performed to detect, and the positive rate in a standardized laboratory is up to 70%. However, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Mycobacterium phlei are also acid-fast bacilli, therefore: (1) When collecting urine, attention should be paid to the cleanliness of the surrounding area of the urethral orifice to avoid contamination. (2) A positive acid-fast bacilli does not necessarily mean tuberculosis.

　　2. Urine culture examination:About 90% of patients have positive urinary culture for Mycobacterium tuberculosis. If the urine culture for Mycobacterium tuberculosis is positive, it can confirm urinary system tuberculosis. Stop using antibiotics for one week before urine culture for Mycobacterium tuberculosis to increase the positive rate. The presence of bacterial growth in a routine urine culture does not exclude the possibility of tuberculosis infection.

　　3. Blood tests:Part of the patients have decreased renal function.

　　2. Other auxiliary examinations

　　1. X-ray examination:90% of patients have abnormal renal enlargement with IVP, abnormal calyces, and 'worm-eaten' ulcers that initially start as small ulcers and later develop into feather-like shapes, eventually connecting with the collecting duct system. A funnel-like fibrous stricture can be seen, and scarring at the ureteric-renal pelvis junction leads to 'cutting off' the calyces, causing hydronephrosis and spontaneous nephrectomy. The ureter appears as a rigid, bead-like or spiral-like cork-like plug. Calcification in the renal pelvis, calyces, and bladder wall of the ureter suggests tuberculosis, mainly manifested as renal calcification and changes in kidney size. This disease is often unilateral, with irregular scattered calcification in the renal cortex and medulla. At the time of renal autolysis, the whole kidney is calcified. When diagnosing, attention should be paid to distinguishing from bilateral renal papillary calcification caused by hyperparathyroidism and positive calculi located in the renal pelvis and calyces. The kidney can expand and appear lobulated, unlike hydronephrosis, which expands uniformly. Venous or retrograde urography: Changes only appear when there is significant renal parenchymal destruction, and early manifestations can include blurred cup-shaped calyces, uneven, worm-eaten-like edges. Later, the calyces may become irregularly expanded and deformed. Scar contraction can cause the shrinkage of one or more small calyces, resulting in calyceal defects. In the late stage, most calyces are destroyed, and multiple irregularly shaped, unevenly sized cavities can be seen. If renal function is lost, the affected kidney does not appear in the venous urography. Retrograde cystoureterography may sometimes show multiple cavity shadows in the kidney, but it is not easy to succeed in retrograde imaging when there is severe bladder tuberculosis or ureteral stenosis. The X-ray manifestation of ureteral tuberculosis is multiple narrowings or unevenly thickened bead-like stricture, with a rigid lumen. When renal tuberculosis is accompanied by significant renal function impairment, the contrast in general dose venous urography is often not satisfactory. After using high-dose venous urography,空洞 lesions and ureteral stenosis can be clearly displayed, and dynamic changes at the renal pelvis-ureter or ureterovesical junction can be observed under closed-circuit television. Therefore, retrograde pyelography has been greatly reduced and is only used when there is stenosis at the lower ureter and when collecting urine from both renal pelvises separately.

　　2. CT examination:CT can display X-ray images of each cross-section of the kidney, which is very helpful for detecting renal tuberculosis and also aids in monitoring.

　　3. Ultrasound examination:It can help diagnose tuberculosis cavities, hydronephrosis, or calcification in the kidney.

　　4. Cystoscopy examination:In the early stage, bladder mucosal edema, congestion, and ulcers may be observed; in the late stage, granulomas and scar formation and other lesions may be seen, with the lesions near the ureteral orifice on the affected side and the bladder trigone being particularly prominent. The ureteral orifice is narrowed and cave-like. Bladder capacity less than 100ml makes cystoscopy difficult, and less than 50ml makes it impossible to perform cystoscopy. When inflammation is severe and cannot be distinguished from primary bladder cancer, a biopsy is required. If there is a suspicion of tuberculosis, a biopsy pathological section examination can be performed to confirm the diagnosis.

　　It is advisable to consume more high-fiber foods as well as fresh vegetables and fruits, maintaining a balanced diet that includes essential nutrients such as proteins, sugars, fats, vitamins, trace elements, and dietary fibers.

　　1. Treatment

　　1. Treatment principles

　　Renal tuberculosis is a systemic disease, and the following 4 principles must be emphasized in treatment:

　　(1) Combination of systemic treatment and local treatment: that is, while treating renal tuberculosis, attention should also be paid to the condition of the primary lesion causing renal tuberculosis;

　　(2) Combination of antituberculosis treatment and supportive therapy: Pay attention to strengthen nutrition, improve the patient's immunity and tissue repair capacity;

　　(3) Combination of medical and surgical treatment: For severe and complex renal tuberculosis patients, especially those with closed renal abscesses, urinary tract obstruction that cannot be relieved by medical treatment, or those with severe bladder contraction, a combination of medical and surgical treatment should be considered;

　　(4) The treatment course for male patients should be appropriately prolonged: because male patients are prone to concomitant reproductive system tuberculosis, the treatment course for male patients with drug therapy should be appropriately prolonged compared to female patients.

　　2. General treatment

　　Strengthen nutrition, improve living environment, adequate rest, reasonable exercise, maintain a good mental state.

　　3. Medication treatment

　　Regardless of whether surgical treatment is needed, all patients must first use antituberculosis drugs to control the spread of tuberculosis. The use of medication is guided by precise bacteriological diagnosis, and it is not recommended to use monotherapy. The typical triple-drug regimen is isoniazid (300mg/d), ethambutol (15 to 20mg/kg per day), and cycloserine (250mg, twice a day, for adults), with a course of 2 years. In recent years, the combination of rifampicin, isoniazid, ethambutol, or pyrazinamide has been used, with a course of 6 months, with no recurrences. Short-course therapy can reduce treatment reactions (such as jaundice, decreased appetite, nausea, vomiting, increased transaminase levels, etc.).

　　Common antituberculosis drugs: Antituberculosis drugs are divided into two major categories: bactericidal agents and bacteriostatic agents. Bactericidal agents can kill a large number of rapidly multiplying or semi-resting tuberculosis bacteria in a short period of time. Common bactericidal agents include:

　　(1) Isoniazid: It is currently the most effective tuberculosis bactericidal agent. It can kill Mycobacterium tuberculosis both inside and outside the cells, and can penetrate into caseous foci. It is the basic medication for various chemotherapy regimens. 70% is excreted through the kidneys, some of which are unchanged. Due to the concentration of urine, the actual effective component can be several times higher than the plasma concentration. The general dosage is 0.3g per day for adults, taken orally once. For severe tuberculosis, 0.1 to 0.6g can be added to 20 to 40ml of 5% glucose or isotonic saline and administered slowly by intravenous push. Alternatively, it can be added to 250 to 500ml of 5% glucose or isotonic saline for intravenous infusion. The main side effects include: mental excitement, paresthesia, peripheral neuritis, etc. Elderly patients should be given a small dose of vitamin B6 concurrently to prevent optic neuritis leading to blindness. Long-term use can lead to an increase in serum transaminase levels, which are generally mild and can be restored after discontinuation of the drug.

　　(2) Rifampicin: It has a killing effect on Mycobacterium tuberculosis in both the intracellular and extracellular reproductive and stationary phases. It has a synergistic antituberculosis effect with isoniazid, and can be affected by aminosalicylic acid and gastrointestinal contents, so it is generally taken on an empty stomach in the morning, and it is best to avoid concurrent use with aminosalicylic acid. 30% is excreted through the kidneys, so it can reach an effective therapeutic concentration in the urine. Rifampicin has no accumulation effect in the body in cases of renal insufficiency, and it can occasionally cause rashes, drug fever, and liver damage. For patients with liver disease, the elderly, and those taking isoniazid or aminosalicylic acid concurrently, the hepatotoxic effect is enhanced. The recommended dose for adults is 0.45 to 0.6g, taken orally once a day.

　　(3) Pyrazinamide: Pyrazinamide is effective against intracellular tubercle bacilli, and tubercle bacilli are prone to develop drug resistance to it. It must be used in combination with other anti-tuberculosis drugs. It has liver toxicity and can occasionally cause an acute gout attack. The general dose is 35mg/(kg·d), with a total daily dose of ≤2.0g, taken in 3-4 divided doses orally. It is contraindicated in pregnant women.

　　(4) Streptomycin: Can kill tubercle bacilli inside or outside the cavity, the intensity of anti-tuberculosis action is similar to that of isoniazid, and it is better in an alkaline environment. When the pH is below 6.0, the efficacy significantly decreases. The normal urine pH is about 6.0, so it is best to add sodium bicarbonate when treating renal tuberculosis with streptomycin to alkalinize the urine. The most important adverse reaction is the toxic effect on the 8th cranial nerve. Long-term use can cause vestibular dysfunction and permanent deafness. The dose for adults in the first month is 0.75～1.00g/d, once a day, intramuscular injection, and then 3 times a week intramuscular injection.

　　Second, prognosis

　　Depends on the following several factors:

　　1. General condition and status of tuberculosis outside the urinary system (because male patients often have concomitant reproductive system tuberculosis, so female patients generally have a better prognosis than male patients).

　　2. Severity of bladder tuberculosis lesions.

　　3. Lesion and functional status of the contralateral kidney.

　　4. Timing of treatment and the correctness of treatment. Before the advent of anti-tuberculosis drugs, the treatment of renal tuberculosis mainly involved the removal of the infected kidney. After the widespread application of anti-tuberculosis drugs in renal tuberculosis, not only can early and middle-stage patients be cured, but also the prognosis of severe and advanced renal tuberculosis patients (such as bilateral renal tuberculosis, solitary kidney renal tuberculosis, renal tuberculosis with contralateral hydronephrosis, bladder stricture, tuberculous vesicovaginal fistula, tuberculous vesicorectal fistula, tuberculous urethral fistula, etc.) has been significantly improved, greatly reducing the number of patients requiring surgical treatment, and greatly protecting renal function. The overall mortality rate reported in recent years is 2% to 50%, with significant early treatment effects and poor prognosis in late treatment.