DIAGNOSTIC APPROACH OF RECURRENT /PERSISTANT PNUEMONIA IN CHILDREN

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This month we are going discuss something about the diagnostic approach in recurrent pneumonia in children.

In hospital practice recurrent and persistent pneumonia is a relatively common problem in children and there is very few literature available on this subject. Even though a number of conditions are known to cause recurrent and persistent pneumonia in children, little is known about these groups of cases. Recurrent pneumonia is defined as two episodes of pneumonia in one year, or more than three episodes at any time with radiographic clearance between two episodes. Persistent pneumonia is characterized by persistence of symptoms and roentgenographic abnormalities of more than a month. It is often difficult to determine whether pneumonia is persistent or recurrent, unless there has been a symptom-free interval during which chest radiographs have documented clearing of the pneumonia infiltrations. Bacterial pneumonia may appear to be a recurrent infection, if infection is persistent because therapy was inappropriate for the underlying pathogen; or else, because the duration was inadequate as a result of non-compliance. Even when chest radiographs are available, there may be problems in distinguishing between persistent and recurrent pneumonia. Variability in the technical quality and positioning of chest radiographs may result in misinterpretation of resolution of the pulmonary pathologic process. Reappearance of radiological densities in the same area on subsequent films may be attributed to recurrence, whereas the densities actually represent persistence of previous pulmonary lesions.

Clinical Evaluation:
A careful history, through physical examination and review of chest radiograph helps clinicians for further evaluation. The age of onset of pneumonia is important factor in the evaluation of underlying etiological agents. The possibility of associated congenital anomaly or hereditary disorder is greater soon after birth. Particular attention should be paid to the sequence of events leading to diagnosis of pneumonia, such as nature and pattern of cough, presence and duration of fever; physical finding is such as crackles or wheeze. Nature and pattern of cough is helpful in the evaluation. E.g., A brassy cough is suggestive of tracheal irritation; a croupy cough implies involvement of glottis or subglottis; Paroxysmal cough is associated with foreign body in the respiratory tract. The history of cough and its relationship to feeding or swallowing is important for detecting swallowing dysfunction or defects, GER or poor feeding techniques. It is important to inquire about any family history of asthma, allergic disease, cystic fibrosis, congenital anomalies or recurrent infection suggesting immunnological disorders. Infants below 1 year of age are vulnerable to persistent or recurrent pneumonia due to the bad child rearing practices like oil bath, blowing into the nose and throat clearing maneuvers by the attendants who are routinely giving bath to children. CBC and Mantoux test are done routinely in all cases. Leucocytosis with toxic granules in leucocytes is suggestive of bacterial pneumonia. A positive Montoux test should warrant further work up of tuberculosis. It is important to document specific area of pulmonary infiltrates on all chest radiography and classify the pulmonary infiltrates into those that are unilobar or involve multiple lobes.

Evaluation of recurrent / persistent unilobar / pneumonia:
The differential diagnosis of a child with persistent or recurrent pneumonia involving a single lobe of the lung may be due to intra-luminal obstruction, extra-luminal bronchial obstruction and structural malformation of the bronchus, the intraluminal obstruction being the commonest. In children, the most often cause of intraluminal obstruction is a foreign body. First step in diagnostic workup is the Flexible Fiber-optic Bronchoscopy (FFBS). It is useful both in diagnosis and therapy. Broncho Alveolar Lavage (BAL) or biopsy is performed in other cases of intralobar obstructions (I.e. bronchial adenoma or lipoma). A tracheal bronchus can be diagnosed by FFBS. If bronchoscopy is normal or not revealing any abnormality, CT scan is performed to identify the extraluminal cause of bronchial obstruction. When there is a space occupying lesion in CT Scan, a bronchogenic cyst or sequestered lobe is suspected; an aortogram will be helpful to confirm the diagnosis of sequestered lobe.

Evaluation of recurrent persistent pneumonia involving multiple lobes:
The diagnostic considerations for multilobar-infiltrates are broadly classified into aspiration syndromes, asthma, immunodeficiency states, mucociliary dysfunction, structural abnormalities, alpha-1 antitrypsin deficiency, hypersensitivity pneumonitis and pulmonary hemosideoris should be considered. When aspiration is suspected, a barium study or cineesophagogram is performed to study any defect in swallowing disorders or esophageal pathology. If gastro esophageal reflux is present, it is further confirmed by esophageal pH monitor, technetium milk scan, esophagoscopy and biopsy. If Gastro-Esophageal reflux is absent, FFBS is performed and the Broncho alveolar lavage (BAL) may yield lipid laden alveolar macrophages, which is suggestive of lipoid aspiration. A child presenting with wheeze and mutilobar pulmonary infiltrates often pose problem in the management. If there is PEFR variation of more than 20% with good response to the bronchodilator therapy - asthma is confirmed. The pulmonary infiltrates are secondary to the multiple atelectasis from mucus plugging. If there is a poor response to bronchodilator therapy, the other underlying conditions can be considered based on the following factors. To detect the structural abnormalities of tracheo-bronchial tree, a CT Scan and bronchogram will be done. A careful cardiac evaluation with an echocardiography can identify a congenital heart disease. Evaluation of immunodeficiency state includes quantitative estimation of immunoglobulins and for phagocyte disorder- total and differential white blood cell count are performed in addition to nitroblue tetrazolim (NBT), to evaluate mechanism of intracellular killing. Cystic fibrosis can be diagnosed by sweat chloride estimation be quantitative pilocarpineiontophoresis method. The ciliary dyskinesia can be identified by saccharin clearance, a simple test to assess the ciliary beat frequency. The simplest screening test to study ciliary defects is the measurement of the ciliary beat frequency by studying under electron microscopy the nasal brush biopsy or scrapping the nasal mucosa. By doing serum electrophoresis the absence of alpha globulin can be detected and further confirmation by gene analysis to confirm alpha-1 antitipsin deficiency.
The hypersensitivity pneumonitis can be diagnosed by doing lung biopsy. The patients will show gradual improvement in hospital atmosphere and relapse on return to home when exposed to the offending antigens in the environment. BAL is performed when a child presents with anemia and recurrent pneumonia, which may show alveolar macrophages filled with hemosiderin pigments which is suggestive of pulmonary hemosiderosis.

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