Be alert to tuberculosis-mediated glomerulonephritis: a retrospective study

Mesangiocapillary glomerulonephritis complicating pulmonary tuberculosis

Glomerulonephritis in tuberculosis may be a direct manifestation of renal infection or a result of immune-complex deposition complicating extra-renal infection, such as in pulmonary tuberculosis. A 17-year-old adolescent boy from Somalia was found to have pulmonary tuberculosis during routine health screening performed on entering Malta, with computed tomography of the chest showing scarring and calcification of the left upper lobe, left lower lobe consolidation, and a small left-sided pleural effusion. Five days after starting anti-tuberculous therapy, he developed lower limb and sacral oedema: urinary albumin: creatinine ratio was > 400 µg albumin/mg creatinine, and 24-h urinary protein showed nephrotic-range proteinuria of 4.963 g/day. In view of worsening lower limb, sacral and periorbital oedema and ascites, he was started on oral prednisolone, omeprazole and penicillin V prophylaxis. As heavy proteinuria persisted, a renal biopsy was performed after 8 days of prednisolone treatment, which confirmed the presence of mesangiocapillary glomerulonephritis (MCGN), with electron microscopy showing effacement of the podocytes, with hypercellularity and subendothelial immune deposits, confirming an immune-mediated pathophysiology. Ziehl-Neelsen staining did not reveal acid-fast organisms. The patient received a total of 3 weeks of oral prednisolone with subsequent tailing doses, 2 months of pyrazinamide and ethambutol and 6 months of rifampicin and isoniazid with complete resolution of his clinical and radiological signs, though heavy proteinuria persisted, so he was commenced on oral enalapril. This case highlights the potential association of MCGN with tuberculosis in adolescence. Timely recognition and treatment can prevent progression to chronic kidney disease.

Curious case of fever of unknown origin

A 58-year-old immunocompetent woman presented with fever and significant weight loss of 4-month duration. She had mild pallor; rest of the examination was unremarkable. Investigations revealed anaemia with raised inflammatory markers. Cultures, serologies, routine urine examination, bone marrow examination, contrast enhanced CT and two-dimensional echocardiography examination were unremarkable. An 18F-fluorodeoxyglucose positron emission tomography with CT (18F-FDG-PET/CT) scan was performed which revealed atypical heterogenous uptake in bilateral renal cortex. Subsequently, urine GeneXpert came positive for Mycobacterium tuberculosis with sensitivity to rifampicin. She responded to category 1 antitubercular therapy. The challenges in diagnosis of genitourinary tuberculosis, low sensitivity of conventional diagnostic tests and potential role of GeneXpert and 18F-FDG-PET/CT scan are discussed in this report.

Tuberculosis-associated IgA nephropathy

Immunoglobulin A nephropathy (IgAN) is the most frequent pathological diagnosis of tuberculosis (TB)-associated glomerulonephritis. Diagnosing TB-associated IgAN (TB-IgAN) is difficult because of its non-specific and insidious symptoms. An inaccurate diagnosis of TB-IgAN could result in the spread of TB and reduced renal function. Haematuria and proteinuria in conjunction with TB should be assessed because of the potential for diagnosis of IgAN. Renal biopsy is important in securing an accurate diagnosis prior to initiating treatment. Detection of Mycobacterium tuberculosis DNA and assessment of early secreted antigenic target of 6 kDa in renal biopsy tissues may have great potential diagnostic value in patients with TB-IgAN. Anti-TB therapy can effectively alleviate TB and TB-IgAN.

Clinical Features and Drug-Resistance Profile of Urinary Tuberculosis in South-Western China: A Cross-sectional Study

To investigate the epidemiology, clinical features, and drug-resistance profile of urinary tuberculosis (UTB) in south-western China to improve UTB diagnostics.After the screening of 1036 cases of suspected UTB, 193 patients with UTB were enrolled during 2009 to 2014. Urine samples were collected for routine urinalysis, smear, tuberculosis DNA (TB-DNA) detection, and drug-resistant analysis, whereas blood samples were collected for erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and renal function evaluation. Clinical features (such as symptoms and outcome) and imageology results (such as B ultrasonic, computerized tomography, intravenous pyelography, and renography) were also collected and analyzed to investigate the epidemiology, clinical features, and drug-resistance profile.The most common presenting symptoms were urinary irritation (61.1%) and lumbago (49.2%). High proportions of microscopic hematuria (63.2%) and microscopic proteinuria (45.6%) were also observed. The positive rate for TB-DNA was 66.3%. The positive rate for culture was 13.1% and for smear it was 9.8%. The abnormal outcome rates of the computerized tomography, ultrasonography, intravenous pyelography, and the nephrogram were 76.9%, 70.1%, 29.8%, and 37.0%, respectively. The total rate of drug-resistant TB (resistant to at least 1 drug) was 39.7%, of which 20.7% was multidrug-resistance TB. The most prevalent mutation sites were katG S315T1, rpoB S531L, and gyrA D94G.We observed a serious epidemic of drug-resistant UTB and a substantial number of new UTB cases with multidrug resistance TB. Molecular diagnostics is crucial in the definite diagnosis of UTB, and our finding is a supplement and further confirmation of polymerase chain reaction usage for TB diagnosis. We recommend real-time polymerase chain reaction for TB-DNA identification instead of culture, and GenoType tests (MTBDRplus and MTBDRsl assay) for drug resistance as routine assays for patients with suspected UTB.