Disseminated tuberculosis with Evans syndrome: an uncommon presentation

Introduction

Tuberculosis (TB) has a wide spectrum of haematological manifestations and can closely mimic many unrelated diseases. We describe this case of a woman who appeared to have concomitant systemic lupus erythematosus (SLE) but later turned out to have Evans syndrome as a part of disseminated TB.

Case report

A 30-year-old woman presented with a history of fever for eight months, mucocutaneous bleeding (epistaxis, menorrhagia and gum bleeds) for ten days, and significant weight loss. She had no other significant present, past or family history. On admission, she was pale, febrile with petechiae and non-palpable, non-tender purpura present all over the body. Lymphadenopathy and sternal tenderness were absent. There was no organomegaly and no other remarkable signs on general examination. Possible differential diagnosis considered at initial presentation were acute haematological malignancy, disseminated infections with bone marrow involvement such as TB or histoplasmosis (the patient being a resident in an endemic zone for these infections) or retrovirus infection.

Initial investigations revealed anaemia (Hb, 48 g/dL) with severe thrombocytopaenia (platelet count, 5000/mm³). Peripheral smear showed normocytic normochromic anaemia with polychromasia, giant platelets with no blasts. Urine examination was normal. Chest radiography showed infiltrates in bilateral middle zones. There was a strongly positive direct Coombs test, with increased serum lactate dehydrogenase levels suggestive of immune mediated haemolytic anaemia. A contrast-enhanced thoraco-abdominal computer tomography (CECT) scan showed bilateral lung consolidation with necrotic mediastinal and mesenteric nodes (Figure 1). Induced sputum with 3% saline revealed 3+ acid fast bacilli. Consequently, a diagnosis of disseminated TB (pulmonary, mediastinal and abdominal) with Evans syndrome (immune mediated haemolytic anaemia and thrombocytopenia) was made. Her HIV tests were negative. Another possibility was concomitant SLE with haematological involvement being unmasked by the presence of infection. Antinuclear antibodies (ANA) effected by immunofluorescence revealed an end titre of 1:80 (speckled pattern); antidsDNA and complement levels (C3, C4) were normal. OPEN IN VIEWER

Our patient was started on Category 1 antitubercular therapy (ATT), hydroxychloroquine along with 500 mg methylprednisolone pulse for three days followed by oral corticosteroids (1 mg/kg) in view of her severe thrombocytopenia. The therapeutic option of intravenous immunoglobulin (IvIg) was offered but was too expensive for her to contemplate. On the fourth day of treatment, she developed hepatitis; ATT was therefore modified. However, despite being on a high dose of steroids for 10 days, her haematological parameters did not show any improvement. Possible explanations were dissemination of TB to the bone marrow, myelofibrosis secondary to TB, an autoimmune disease or steroid-resistant Evans syndrome. The bone marrow biopsy revealed a hypercellular marrow with erythrocytic and megakaryocytic hyperplasia with neither granuloma nor myelofibrosis. Thus, Evans syndrome was presumed secondary to disseminated TB or SLE. First line ATT was reintroduced as the hepatitis had resolved. Within five days, the haematological parameters showed a significant improvement with resolution of petechial eruptions (Figure 2). On the 29th day of admission, our patient was discharged on ATT and corticosteroids (1 mg/kg/day) with a plan to taper off steroids over six weeks. OPEN IN VIEWER

Discussion

TB is often regarded as a great masquerader owing to its closely mimicking unrelated illnesses. A wide array of haematological changes has been described in TB. Normocytic normochromic anaemia is common. Thrombocytopaenia and pancytopenia are more commonly observed in patients with disseminated TB. ¹ Immune mediated thrombocytopaenia associated with TB has been described in many case reports. ² The possible mechanism of this may be generation of antiplatelet antibodies by lymphocytes owing to a host response to the pathogen itself or through molecular mimicry by yet unidentified antigens present on the bacillary surface and the platelet surface antigen. ³ Evans syndrome and TB is a rare association previously described in isolated case reports.^4,5