ARDS as a complication during the course of MLTB though rare has been reported.It usually occurs several weeks after the onset of symptoms of TB.We describe a patient in whom ARDS was the presenting manifestation of MLTB.Familiarity with this rare presentation is necessary in order to consider tuberculosis in the setting of ARDS even in the abscence of prior symptoms suggestive of tuberculosis especially as MLTB is one of the few treatable causes of ARDS.
A 42 year old Asian male presented with fever,cough and increasing dyspnea of 3 days duration.Prior to this he was well and had immigrated to the United States 1 month ago.He was febrile and found to be in severe respiratory distress with bilateral rales heard on lung auscultation.The chest x-ray revealed bilateral diffuse air space disease.The patient was severly hypoxic and on assist mode ventilation with 500cc tidal volume and rate of 12/min,PEEP 7.5 cm of H2O the plateau pressure was 38 cm of H2O and ABG on fio2 0.6 revealed PH7.48,PCO2 24, PO2 56. WBC was 2300 with 18% lymphocytes,hemoglobin 11g/dl and platelets 100K.Sodium was126,bicarbonate 18 and anion gap 14 while renal function was normal.There was no evidence of congestive heart failure. Bronchoalveolar lavage done on day 2 grew mycobacterium tuberculosis on day 10 when parenteral rifampin,quinolone,capreomycin and enteral ethambutol,pyrazinamide, isoniazid via nasogastric tube was started along with methylprednisolone at 1mg/kg.HIV test was negative.In 10 days fever decreased,oxygenation and ARDS improved but the subsequent course was complicated by DIC, bilateral pneumothoraces and ventilator assosiated pneumonia leading to the patient’s demise 7 days later.Autopsy revealed poorly formed granuloma with AFB scattered through out both lungs,liver,spleen and adrenal glands.Hyaline membrane formation and areas of pyogenic consolidation were noted in both lungs.DISCUSSION: Though uncommon ARDS has been described with MLTB and to a lesser extent with TB pneumonia.Upto 1995,71 cases have been described world wide.In Canada 13 cases of ARDS due to TB have been reported,7 due to MLTB of a total of 37 cases(18.9%) and 6 of a total of 722(.08%)due to TB pneumonia.Mortality was 68% in MLTB and ARDS and 46% in TB pneumonia and ARDS. Mean duration of symptoms was 2 – 4 weeks unlike 3 days in our patient.Pathogenesis of ARDS in TB include cell wall lipoarabinonimomine causing machrophage activation and tumor necrosis factor (TNF) and interlukin lB production leading to alveolar capillary injury. Prognosis is poor in spite of treatment.Therapeutic delay and difficulty in drug administration in the critically ill may be one reason.Diagnostic clues include pancytopenia, DIC and hyponatremia.Fiberoptic bronchoscopy,bone marrow examination and liver biopsy have the highest diagnostic yield.
ARDS due to TB is uncommon and therefore may lead to delay in diagnosis.ARDS is usually not an early complication of the disease and thereby provides time for timely diagnosis if it is recognised that TB can lead to ARDS.The case we describe draws attention to the fact that ARDS may be the presenting manifestation of TB disease.Familiarity with this fact will allow for timely recognition and treatment of TB in patients with ARDS.
L. Kasirajan, None.