A, 67 year old male, with no previously known comorbidities presented to our hospital with fever, cough, generalized weakness and low back ache since 1month. He gave a history of receiving oral antibiotic treatment during the past month, but his symptoms did not resolve. He was febrile, had tachycardia (108 beats/min), blood pressure was normal (120/80 mm of Hg), and maintained oxygen saturation of 96% in room air. A routine random blood sugar (RBS) testing revealed very high blood glucose level (RBS- 704.2 mg/dl).
He was admitted for further investigation and management. His blood sample was sent for analysis and he was started on a broad spectrum antibiotic (intravenous ceftriaxone). His blood glucose levels were controlled with insulin and oral anti-hyperglycemic agents. He was also symptomatically treated with antipyretics, bronchodilators and expectorants.
Upon investigation his chest radiograph showed bilateral multiple thick walled air filled cavities [Image 1]. High resolution computed tomography (HRCT) of his lungs revealed multiple evolving thick walled cavities in both lungs suggestive of Koch's [Image 2, Image 3]. Based on the nature and duration of symptoms, relentless course, diabetic status and classical radiographic findings a clinical diagnosis of pulmonary tuberculosis was made. His sputum samples were sent for acid fast bacilli (AFB) smear and he was started on standard anti tubercular treatment (ATT) (Rifampicin 600 mg, INH 300 mg, Ethambutol 1 gm, and Pyrazinamide 1.5 gm, along with Pyridoxine). Two consecutive sputum samples (early morning and evening of the same day) did not show any AFB on smear. So the next day a further sample was sent for AFB smear, bacterial culture and sensitivity, and PCR assay (GeneXpert-MTb/Rif) for Mycobacterium tuberculosis.
His blood sugars were controlled with insulin, and oral anti-hyperglycemic agents. He was also symptomatically treated with antipyretics, bronchodilators and expectorants. His renal and liver functions were evaluated and found to be normal.
Meanwhile the blood counts showed an elevated total count (12,440) with relative neutrophilia (85.6%). His erythrocyte sedimentation rate (ESR) was 62 mm/hr. The sputum culture grew Escherichia coli (E. coli), resistant to most first line antibiotics including ceftriaxone. It was sensitive to gentamicin, amikacin, meropenem and piperacillin/tazobactam. The GeneXpert-Rif report was negative for Mycobacterium tuberculosis. His blood culture was sterile and no growth was noticed after 72 hours of incubation. He continued to be febrile with fever spikes (between 100 and 102 deg F).
In view of the conflicting evidences the scope of investigations were broadened. A bronchoscopy was performed and bronchoalveolar lavage (BAL) fluid was obtained. The BAL fluid sample was analyzed for AFB smear and culture, gram's stain, bacterial culture & sensitivity, fungal stain and fungal culture along with study for presence of malignant cells. Ceftriaxone was stopped and he was started on piperacillin/tazobactam. The BAL sample studied did not show the presence of any AFB, fungal elements or malignant cells on smear. On bacterial culture the BAL sample grew E. coli with a colony count of 104 cfu/ml, resistant to most first line antibiotics including ceftriaxone, cefuroxime and cefixime, with in-vitro sensitivity to levofloxacin, gentamycin, amikacin, meropenem and piperacillin/tazobactam. Over the next 1 week the patient improved clinically. His cough decreased and he became afebrile. A diagnosis of necrotizing pneumonia due to E. coli was made and ATT was stopped. His blood sugars were well controlled and dose of his oral anti-hyperglycemic drugs titrated and he was discharged from the hospital.
He continued to receive parenteral piperacillin/tazobactam on an out-patient basis for 10 days and he was followed up regularly. His cough steadily decreased and serial chest radiographs on follow up, over the next 4 months showed gradually resolving cavities. During follow up, the BAL culture reports were received and they did not grow any fungus and the culture was negative for AFB. The cavities completely resolved at 4 months [Image 4].