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LEGIONELLA MICDADEI LUNG ABSCESS IN A PATIENT WITH HIV-ASSOCIATED NEPHROPATHY Chike Nzerue, MD, and Anupama Gowda, MD Atlanta, Georgia

A patient with end-stage renal disease due to human immunodeficiency-associated nephropathy developed fever, cough and chest pain over a week's duration. He was diagnosed with lung abscess and started on antibiotic coverage. He underwent bronchoscopy because of progression of his illness and persistent fever and bronchoalveolar lavage culture isolated Legionella micdadei. In spite of appropriate antibiotic therapy, the patient remained febrile for 10 days, necessitating chest tube drainage. After a 6-week course of antibiotics and drainage, the patient made an uneventful recovery. Infections due to L. micdadei may be hard to diagnose because of difficulties in isolating this bacteria. (J Nat/ Med Assoc. 2001 ;93:220-223.)

Key words: Legionella * HIV * abscess * end-stage renal disease Despite substantial progress in defining pathogens and improvements in therapeutic options, lower respiratory infections continue to be major causes of death in the developed and developing world.' The vast majority of human Legionella infections present as community-acquired and/or nosocomial pneumonia with Legionella pneumophila accounting for more than 90% of these cases.2 Pneumonia due to legionella are often described to be "atypical" based on the dogma that chest radiographic findings are neither lobar nor consolidating, as in classic pyogenic pneumonias. Legionella micdadei is the second most common Legionella species causing pneumonia and has a predilection for causing disease in immunosuppressed patients,3 such as those who have received renal transplants.4'5 We present the clinical features and outcome of a © 2001. From the Department of Medicine, Morehouse School of Medicine, Atlanta, GA. Requests for reprints should be addressed to: Chike Magnus Nzerue, MD, FACP, Renal Service, Morehouse School of Medicine, 720 Westview Dr. SW, Atlanta, GA 30310. 220

JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION

case of L. micdadei lung abscess in a patient with human immunodeficiency virus infection-associated nephropathy (HIV-AN).

CASE REPORT A 48-year-old man with end-stage renal disease (ESRD) due to HIV-AN was presented to the emergency room with fever, malaise, chills and cough of a 1-week duration. He denied hemoptysis but did have pleuritic chest pain on the right posterior chest. He had been on hemodialysis for 3 years. He reported an involuntary 10-pound weight loss. The patient was unemployed and had smoked one pack of cigarettes daily for 15 years. He had extensive history of substance abuse and was homosexual. On physical examination, his oral temperature was 40°C, pulse of 92, and respiratory rate was 22/min. His blood pressure was 130/85 mmHg. The patient appeared acutely ill. No rash or lymphademopathy was detected. Breath sounds were diminished on the right lung with dull percussion notes. An AVfistula was present on the left forearm. He had received a course of Isoniazid for a positive tuberculin skin test two years prior to presentation. VOL. 93, NO. 6, JUNE 2001

LEGIONELLA MICDADEI LUNG ABSCESS

Table 1. Laboratory Data Variable Hematocrit (%) Mean corpuscular volume (p.m3) White cell count (/mm3) Differential count (%)

Neutrophils Lymphocytes Monocytes

Eosinophils Basophils Platelet count Prothrombin time (seconds) Partial-thrombo plastin time (seconds) Plasma sodium (mmol/L) Plasma potassium (mmol/L) Blood urea nitrogen (mg/dL) Plasma creatinine

Value 28 94 22,000 84 2 10 2 2 21 8,000 15.8 32.9 130 4.9 48 8.6

Laboratory test revealed leukocytosis of 22,000 and anemia. The rest of the laboratory data are shown in Table 1. A specimen of arterial blood obtained while the patient was breathing intranasal oxygen at 2 L/min revealed a partial pressure of oxygen of 70 mmHG; the partial pressure of carbon dioxide was 39 mmHg, with a pH of 7.34. His CD4D cell count was 14/,uL. An electrocardiogram showed no abnormalities. A chest radiograph revealed a large mass in the right lower lobe (Fig. 1). He was admitted to intensive care and given intravenous ceftriaxone and erythromycin. The temperature ranged daily from 390C to 41°C for the first four days of hospital stay in spite of antibiotics. The patient developed vomiting and diarrhea three days after admission to the hospital. Microscopy of sputum revealed abundant neutrophils, but no organisms were seen and acid-fast bacilli cultures and sputum stains were negative. A urinary direct fluorescent antibody test (DFA) for L. pneumophila was negative. A thoracic computed tomography (CT) scan showed an irregular 10 X 8-cm mass in the right mid-lung anteriorty with central low attenuation suggestive of possible necrosis. Other findings include mediastinal adenopathy and minimal pleural thickening or fluid present posteriorly (Fig. 2). Broncho alveolar lavage specimen cultures grew L. micdadei on the tenth day of hospital stay. The patient's antibiotics were switched to levofloxacan 500 mg i.v. daily, and the patient defervesced after 5 JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION

Figure 1. Antero-posterior (top) and lateral chest (bottom) radiographs depict a large mass in the right lower lobe. days of therapy. He was discharged from the hospital on oral levofloxacin but was readmitted 1 week later with recurrence of fever due to noncompliance with the prescribed antibiotic. He was continVOL. 93, NO. 6, JUNE 2001

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Figure 2. Chest CT scan shows an irregular 10 x 8-cm mass involving the right middle and lower lobes with evidence of necrosis and mediastinal adenopathy. ued on oral levofloxacin but remained febrile for another 10 days. Percutaneous CT-guided drainage of pleural fluid yielded thick purulent material with abundant neutrophils but no organisms. The repeat blood and pleural aspirate cultures continued to be negative. He completed a further 3-week course of antibiotic therapy and was discharged. He was seen by the thoracic surgeon 6 weeks later, at which time the catheter was removed. Chest radiograph on another hospital visit documented near complete resolution of the abscess in the right lung.

DISCUSSION While this patient's presentation with fever, cough, hemoptysis and chest pain may be considered fairly typical for patients with Legionella sepsis,6 there was substantial difficulty in confirming the diagnosis. The clinical suspicion for legionella infection was heightened by the occurrence of diarrhea as well as hyponatremia. However, the negative DFA test, mediastinal adenopathy, and persistent fever with worsening infilterates mandated an investigation to exclude other diagnostic possibilities such as tuberculosis. Some studies suggest that 10% of L. micdadei pneumonias in 222


immunosuppressed patients may cavitate,7,8 but progression to lung abscess is extremely rare. We suspect that the combination of renal disease5'9 and HIVI0 infection led to severe immunosuppression that predisposed this patient to L. micdadei abscess. In 1997, Johnson and Huseby reported the first case of lung abscess in a patient with acquired immunodeficiency syndrome (AIDS) due to L. micdadei."I As does mycobacteria, L. micdadei retains the modified acid-fast stain, and may thus be misidentified as TB."112 This case reports also supports published reports that chest radiographic abnormalities are nonspecific in legionellosis, and these infiltrates may worsen in more than 50% of patients despite appropriate therapy.13 Nosocomial outbreaks of L. micdadei are often traceable to contaminated potable water,'4 so an epidemiologic survey is warranted in nosocomial cases. The organism responds to antibiotics such as macrolides and fluoroquinolones. Erythromycin had been the historical drug of choice, but erythromycin failure has been reported mostly in immunocompromised patients.'5 Because of this, the newer fluoroquinolones and azithromycin are preferred.'5 The optimal duration of therapy is unknown, but it VOL. 93, NO. 6, JUNE 2001


is recommended that immunosuppressed patients be treated for 2-3 weeks. This patient required a 6-week course of antibiotic as well as chest-tube drainage before resolution of the abscess.

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