Surgical Management of an Infant with Nonresolving Pneumonia

ABSTRACT

We describe a 3-month-old baby who presented with a nonresolving pneumonia which failed to respond to antibiotic therapy. An underlying congenital pulmonary adenomatous malformation was suspected. On thoracotomy, she was found to have a tuberculous mediastinal abscess which was drained. Mediastinal abscess is a rare occurrence in childhood tuberculosis.

INTRODUCTION

Nonresolving pneumonia (NRP) is defined as the persistence of symptoms and radiological signs of pneumonia for more than 1 month despite an adequate course of antibiotics. About 16% of children with pneumonia have NRP and require further evaluation.[1] Tuberculosis and aspiration syndromes are among the most common causes for NRP. Isolated case reports have described tuberculous mediastinal abscess in older children.[2,3] We describe a young infant with a NRP who was diagnosed to have a tuberculous mediastinal abscess only after she underwent thoracotomy.

CASE REPORT

A 3-month-old adopted baby girl weighing 4.3 kg was brought with a 2-week history of cough and fast breathing. She had no history of fever, lethargy, or poor feeding. She was adopted in the 1^st week of life and details of her biological family were not known. She was born by full-term normal delivery, weighed 2.75 kg, and received routine vaccination. She was formula fed and was thriving well so far. At presentation, she had mild tachypnea with subcostal retractions and bilateral wheeze. Cardiovascular, abdominal, and general examination were normal. Bacille Calmette-Guerin (BCG) vaccination scar was absent.

Chest radiography showed right upper zone air space disease [Figure 1a]. Total leukocyte count was 13.8 × 10⁹/L (42% neutrophils, 49% lymphocytes, 6% monocytes, and 3% eosinophils). C-reactive protein was 7.0 mg/L. Human immunodeficiency virus (HIV) I and II antibodies were negative. A provisional diagnosis of community-acquired pneumonia was made and ceftriaxone started empirically. As the degree of radiological lung involvement seemed out of proportion to her clinical status, a computed tomography (CT) of the thorax was ordered. This showed: (1) consolidation of the apical and posterior segments of the right upper lobe and superior segment of the right lower lobe with postcontrast inhomogeneous enhancement and multiple cystic nonenhancing areas in the right upper lobe and (2) a peripherally enhancing lobulated lesion in the right paratracheal region contiguous with the involved lung segments with extension along the posterior mediastinum and causing lower tracheal compression and mild left mediastinal shift [Figure 2]. A differential diagnosis of congenital pulmonary adenomatoid malformation (CPAM) with secondary infection was considered.

Figure 1.

Chest radiograph showing air space disease in right upper and middle lobe (a). Chest radiograph after 1 year of anti-tubercular therapy showing resolution of disease (b)

Figure 2.

Contrast-enhanced computed tomography of the thorax showing consolidated segments in the right upper and middle lobes on coronal (a) and sagittal (b) sections

Despite a 3-week antibiotic regime her symptoms, clinical findings, and radiological picture remained unchanged. Mantoux test and gastric lavage for Acid-Fast Bacilli (AFB) were negative. CPAM was reconsidered and elective surgery was planned. Intraoperatively (right posterolateral thoracotomy), she had right upper and middle lobe consolidation with a posterior mediastinal abscess. No malformed lung tissue or lymphadenopathy was found. The abscess was drained and the right upper lobe was biopsied.

The mediastinal pus was positive for AFB. Cartridge-based nucleic acid amplification test was positive and showed sensitivity to rifampicin. Bacterial and fungal cultures were negative. Histopathology of the lung showed caseating epithelioid granulomas and was AFB positive. Abdominal ultrasonography and cerebrospinal fluid analysis were normal.

The baby was started on anti-tubercular therapy (ATT) with rifampicin, isoniazid, pyrazinamide, and ethambutol as per the Revised National Tuberculosis Control Program guidelines. Ofloxacin was added to the intensive phase as BCG disease could not be ruled out at this stage. Contact screening on her adoptive family was negative.

With 2 weeks of therapy, her symptoms had reduced considerably and at 1-month, she had no symptoms. Her respiratory examination was normal. Gastric lavage was negative for AFB at the end of the intensive phase. Pus culture grew Mycobacterium tuberculosis and ofloxacin was stopped.

Investigations for primary immunodeficiency disorders (Lymphocyte subset analysis, immunoglobulin profile, nitroblue tetrazolium test, and complement H50) and genetic studies for Mendelian susceptibility to mycobacterial disease (MSMD) were normal.

The continuation phase of ATT was extended by another 6 months providing a 12-month regime in all. The child was asymptomatic at the end of therapy. Physical examination, chest radiograph, growth parameters, and milestones were normal [Figure 1b].

DISCUSSION

Mediastinal abscesses are fairly uncommon in children and are generally secondary to chest trauma, esophageal perforation, and thoracic surgery.[4] Nontraumatic mediastinal abscesses are rare and usually follow infection at a contiguous anatomical site (such as buccopharyngeal spaces, lungs, pleura, ribs, and vertebrae) or from a distant site by hematogenous spread.[2,3,5,6] Staphylococcus aureus and Streptococcus pneumoniae have been the most frequent isolates.[6] TB mediastinal abscesses have been reported in adolescents and adults following lymph node disease and vertebral osteomyelitis.[2,3]

A few diagnostic challenges with our patient are worth mentioning. From the initial clinical and laboratory picture, the suspicion of tuberculosis was not very strong. The limited birth and family history provided little evidence to support the diagnosis. A lung malformation appeared more likely due to the discrepancy in the clinical severity and the radiological findings.

The microbiological diagnosis of pulmonary tuberculosis in infants remains challenging as sputum sampling is difficult and gastric aspirates have limited diagnostic value.[7] In retrospect, it appears that a bronchoalveolar lavage or a transthoracic biopsy would have been sufficient to make a diagnosis and start ATT. However, considering the age and available regional expertise, a thoracotomy was considered the most appropriate option. Besides, given the location of the abscess, we feel that a thoracotomy would be necessary regardless of BAL/biopsy findings.

We chose to treat her for 1 year (rather than 6 months as per guidelines), since data on the natural history of TB mediastinal abscesses in infants are scarce.

Primary immunodeficiency disorders such as chronic granulomatous disease, common variable immunodeficiency, and MSMD are often associated with unusual presentations of TB.[8] Investigating on these lines is important in young infants with extensive disease, especially with no BCG reaction and negative Mantoux test.

BCG disease, a tuberculosis-like disease caused by live bacilli from the BCG vaccine (Mycobacterium bovis), is known to occur in severe combined immunodeficiency, HIV, and MSMD and can present in a spectrum ranging from isolated local BCGitis to disseminated BCGosis.[9,10] BCG being inherently resistant to pyrazinamide and partially to isoniazid warrants the use of ofloxacin. We started this empirically while awaiting culture results.

Mediastinal abscess is a rare possibility in young infants with tuberculosis. CT imaging is advisable when radiological findings are inconsistent with their clinical picture. With appropriate surgical drainage and prolonged ATT, the outcome of a mediastinal tuberculous abscess appears good.

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Conflicts of interest

There are no conflicts of interest.