LUNG ABSCESS
Lung abscesses in children is usually due to: (a) incomplete clearance of acute pneumonia,, though may also develop due to (b) aspiration of infected material in debilitated children,
(c) bronchial obstruction with poor mucus clearance, e.g.
foreign body, tumors, sequestration etc., (d) hematogenous spread from distant septic foci, or (e) direct spread from surrounding tissues, e.g. amebic abscess from liver.Post-aspiration abscesses are common in dependent parts, i.e. right lower lobe in older children and right apical region in infants/bed-ridden children.
Etiology: Staph. aureus and Klebsiella are two most common pathogens in lung abscess, though anaerobic infection from oral flora, e.g. bacteroides, fusobacterium, etc. are also common. Abscesses due E. histolytica, Actinomyces, Nocardia, etc. are rare in childhood. Staphylococcal abscesses are usually multiple, while those following aspirations are usually solitary.
Clinically, lung abscesses usually present with insidious onset of: (a) wet-cough with copious, purulent and foul-smelling expectoration, (b) persistent fever and constitutional signs, (c) clubbing and growth failure.
Common lung signs include localized dullness, bronchial (amphoric or cavernous) breathing and coarse crepitations.
Complications may be local, e.g. empyema, pneumothorax, bronchiectasis or bronchopneumonia or distant, i.e. metastatic abscesses in other tissues.
Diagnosis depends on: (a) X-ray chest, showing a cavity with/without fluid level (Fig. 16.13), (b) CT chest, and (c) gram-staining/culture of sputum. USG/CT guided percutaneous drainage of abscess for staining and culture is indicated in non-responders.
Treatment: Empirical antibiotic therapy must include an anti-staphylococcal agent, e.g. cloxacillin or vancomycin, along with an antibiotic against anaerobes, e.g. clindamycin, Ticarcillin or metronidazole; for at least 3-6 weeks, which needs to be modified after culture reports.
Fig. 16.13: Lung abscess.
Percutaneous CT-guided or thoracoscopic drainage is indicated only in severely sick and non-responding cases or those with associated empyema. Gradual resolution of abscess must be demonstrated on serial skiagrams.
16.10.3