A 45-year-old female resident in Ireland, originally from the Philippines, was transferred to our institution for further management of acute renal failure. She initially presented to the referring hospital with generalized malaise and fatigue over the preceding month associated with a small, painless swelling on the left side of the neck. She denied any fevers, chills, rigors, night sweats, photosensitive rash, joint pains, weight loss, or urinary tract symptoms. She did not suffer from any upper respiratory tract symptoms, sinusitis, or rash. She was not taking any medications or herbal remedies. Her past medical history was unremarkable except for lumpectomy for a benign breast cyst several years ago. Her menstrual cycles were normal and there was no history of miscarriages in the past. Her serum creatinine on admission was 205 mumol/L with an active urine sediment.
On examination, she appeared unwell, was afebrile, with a blood pressure 130/80 mmHg, and weighed 57 kgs. A bedside urine dipstick was positive for blood (+) and protein (+++). There was no evidence of oral ulceration, rashes, or joint swelling. Her neck was supple to palpation except for a solitary 1 cm nontender, mobile lymph node in the left anterior triangle of neck. The thyroid gland was not enlarged. The remainder of her cardiovascular, respiratory, and abdominal examination was unremarkable.
Biochemical investigations revealed a serum creatinine which had risen to 568 mumol/L and urea of 23.4 mmol/L. Haematological parameters showed a normal haemoglobin level of 13 g/dL with a serum C-reactive protein of 74 mg/L (normal < 10). No prior biochemical parameters were available for comparison. A full vasculitic screen was performed; antinuclear factor (ANF) was positive with a homogenous pattern, antidouble-stranded DNA antibodies were raised (anti-dsDNA titre 59, >30 positive) and antineutrophil cytoplasmic (ANCA) and antiglomerular basement membrane antibodies were negative. Antistreptolysin O titres were also within normal limits. Serum complement levels showed depletion of C4 and normal C3 levels. Serology was negative for human immunodeficiency virus (HIV), toxoplasmosis, and brucellosis. A 24-hour urine collection quantified the proteinuria at 1.2 g/24 hrs.
Her admission chest radiograph was normal. Renal ultrasonography revealed normal sized kidneys with good corticomedullary differentiation and no evidence of hydronephrosis. Fine needle aspiration biopsy of the neck lump showed mature lymphocytes admixed with neutrophils, with 90% of the cells showing positivity for CD45:strongly suggestive of nonspecific inflammatory changes. In view of the presentation of acute renal failure, haematuria, and proteinuria with serological evidence suggestive of lupus, a renal biopsy was performed to clarify the diagnosis. Histopathology results, however, showed widespread caseating granulomata with Langerhan's cells (Figure 1) consistent with renal tuberculosis. No acid fast bacilli (AFB) were seen on light microscopy.
On further review, our patient had been vaccinated with BCG in her childhood. She could not recall any contact with tuberculosis carriers nor was there any history of recent travel abroad. A mantoux test was subsequently performed and was positive at 12 mm. Sputum microscopy was negative for AFB. Serial early morning urine samples were also examined and cultured for the presence of AFB but were negative. In view of the renal biopsy findings, a CT of the thorax, abdomen, and pelvis was performed which revealed enlarged retrogastric lymph nodes measuring up to 2.8 x 1.2 cm and further subcentimetre mediastinal and retroperitoneal lymph nodes.
She was commenced on standard combination antituberculous chemotherapy consisting of isoniazid, rifampicin, ethambutol, and pyrazinamide. She subsequently developed deranged liver enzymes which normalized following withdrawal of rifampicin. Our patient completed 18 months of treatment for renal tuberculosis, but failed to recover renal function and is now dialysis dependent, awaiting renal transplantation. A repeat renal biopsy was performed following completion of anti-tuberculous therapy. This confirmed significant tubulointerstitial fibrosis in the absence of any caseating granulomas (Figure 2). A follow-up CT scan showed resolution of the previously detected lymphadenopathy.