Introduction
Tuberculosis can present in different ways which may pose difficulties in diagnosis. Extra pulmonary tuberculosis infections often lack typical clinical symptoms and imaging features. It can potentially be easily misdiagnosed leading to a delay in treatment.
Case Presentation
A 72-year-old female, with no known comorbidities, presented with complaints of 8kg weight loss in the last two months, loss of appetite, generalised fatigue and a recent onset of altered sensorium which lasted for one week. The patient did not report fever, cough, shortness of breath, haemoptysis, swelling of legs or abdominal symptoms. On clinical examination, the patient was confused (Mini mental state examination score of 14; normal score 24-30), but haemodynamically stable. A respiratory system examination revealed dull note and decreased breath sounds in both lung bases.
Initial investigations showed total leukocyte count 5.7K/ul (normal range 4-10K/ul), raised ESR of 100 mm/hr (normal range 20-35mm/hr), raised serum protein 9.2g/dl (normal range 6.4-8.3g/dl), hypoalbuminemia of 2.8g/dl (normal range 3.6-5.1 g/dl ), hyperglobulinemia of 6.0g/dl (normal range 2-3.5 g/dl) with albumin/globulin (A/G) ration reversal of 0.5. Serum Lactate dehydrogenase of 162 U/L (normal range 135-214 U/L). Serum Calcium was elevated at 13.5 mg/dl (normal range 8.6 -10.2mg/dl) and CT Thorax shows bilateral pleural effusion (Figure 1). A diagnostic thoracentesis and pleural fluid analysis showed protein 5.7g/dl (normal range 1-2 g/dl), sugar 104 mg/dl (normally similar to plasma), Lactate dehydrogenase 167.3 U/L (normally less than 50% of serum LDH). Pleural fluid adenosine deaminase level (ADA) level was of 20.8 U/L (normal range 0-40U/L). Cytology revealed 85% lymphocytes (normal less than 50%). This low ADA was inconclusive to consider the possibility of tuberculosis despite being a lymphocytic exudative effusion. Thus further evaluation was carried out.
Figure 1 CT thorax (axial plane) showing bilateral pleural effusion (black arrows)
As serum intact PTH was low at 7.3pg/ml (normal range 14.0-72pg/ml), hyperparathyroidism was ruled out. Her hypercalcaemia was managed with intravenous hydration and Zoledronic acid. Serum electrophoresis showed polyclonal gammaglobulinemia but no paraproteins. Multiple myeloma panel (by FISH technique) was negative for any chromosomal abnormalities. Bone marrow biopsy showed trilineage haematopoiesis with few scattered plasma cells. Urine Bence Jones proteins was negative. Serum free kappa/lambda ratio was normal. The patient underwent a whole body PET scan which revealed FDG avid multiple supra and infra-diaphragmatic, paracardiac lymph nodes and diffuse peritoneal uptake with multiple pericolic necrotic lymph nodes with circumferential wall thickening and luminal narrowing of terminal ileum (Figure 2). CT guided biopsy from PET avid lesion from juxtaphrenic lymph nodes was performed. Examination of biopsy specimen showed features of granulomatous inflammation with extensive necrosis (Figure 3). Rapid molecular test for tuberculosis, Xpert MTB/RIF assay of lymph node biopsy also detected mycobacterium tubercle bacillus which was sensitive to rifampicin. We initiated anti-tubercular treatment (two months of intensive phase with Isoniazid 300mg, Rifampicin 450mg, Pyrizinamide 1200mg, Ethambutol 800mg and four months of continuation phase with Isoniazid 300mg, Rifampicin 450mg and Ethambutol 800mg).
Figure 2 PET scan showing uptake in diaphragmatic nodes (green arrow), terminal ileum (red arrow)
After six weeks, AFB culture of the biopsy specimen by Mycobacterial Growth Indicator Tube (MGIT) liquid culture technique also showed the growth of Mycobacterium Tuberculosis. The patient showed good clinical response to antitubercular treatment. Her altered sensorium can be attributed to hypercalcaemic status, which showed improvement in two weeks with correction of serum calcium. Her appetite improved in four weeks with a weight gain of 6kg with six months of antitubercular treatment.
Figure 3 Histopathologic examination of lymph node showing granulomatous inflammation (yellow arrow) with necrosis (black arrows).
