Teaching Case

A 10-month-old girl presented with fever, productive cough, and otorrhoea. She had been hospitalized for 5 days in Angola, with a diagnosis of left bronchopneumonia and acute otitis media, and treated with antibiotics. After 1 week she was re-hospitalized with persistent cough. There was contact with family members with active tuberculosis.

A chest radiograph showed an extensive left-sided lung opacity.
An ultrasound revealed an enlarged spleen with multiple scattered granulomas.
A computed tomography (CT) depicted a hypodense mass-like consolidation in the upper left lobe and lingula, with inhomogeneous enhancement, and scattered calcifications. This mass led to compressive atelectasis of the adjacent pulmonary parenchyma, and right-sided deviation of the mediastinum. In the left and right lower lobes two smaller similar lesions were observed. Several calcified lymph nodes were present in the mediastinum and pulmonary hila.
Although a mass-like consolidation is not the most typical finding and previous gastric aspirates were negative for Mycobacterium tuberculosis, a diagnosis of tuberculosis was suggested.
The diagnosis was confirmed by a positive polymerase chain reaction (PCR) for Mycobacterium tuberculosis and a positive interferon gamma release assay (IGRA).
Tuberculosis treatment with isoniazid, rifampicin, pyrazinamide and ethambutol (HRZE) was initiated.
Significant clinical improvement occurred and she was discharged without cough.

The Mycobacterium tuberculosis bacterium causes tuberculosis (TB). It is one of the most common infectious diseases and the main cause of infection-related death in the world [1, 2].
5-15% of all TB cases occur in children. In children the most common form is pulmonary TB and most cases are primary infections [1].

65-95% are asymptomatic [2]. The most common symptoms are cough and low grade fever [1].
In children bacteriologic confirmation of TB is difficult. In infants under 3 months the tuberculin skin test is frequently negative [3, 4]. In children under 6 years, gastric aspirates are used instead of sputum [1].
Young age is the most significant risk factor for the occurrence of disseminated TB or severe disease [4].

History of a direct contact with a contagious source and chest radiographs play an essential role in the diagnosis.
CT has some advantages over conventional radiographs and is indicated when TB or its complications are suspected and the radiographic findings are inconclusive or normal [3, 5].
The hallmark of pulmonary TB in children is mediastinal lymphadenopathy with or without parenchymal abnormalities. Younger children (0-3 years) have a higher prevalence of lymphadenopathy and a lower prevalence of parenchymal changes, compared with those 4-15 years of age [3].
CT may show mediastinal and hilar lymphadenopathy, as enlarged nodes with low-attenuation centres (caseation necrosis) and peripheral rim enhancement (inflammatory hypervascularity) [3]. Calcified lymphadenopathy may be a clue for TB [5]. The most frequently involved lymph node stations are lower paratracheal, upper paratracheal, hilar and subcarinal [2]. Air-space consolidation is the most common parenchymal lesion [3]. A mass-like consolidation, defined as an enhancing, volume-preserving or expanding mass, with no air-bronchogram within it, can be found [3]. Low-attenuation areas (caseation necrosis) and calcifications may be seen within it [5]. The parenchymal lesions are often seen in areas of greatest ventilation: middle, lower and anterior segments of the upper lobe [5]. Cavitation is rare in children with primary TB [3]. Other less common forms of presentation are bronchogenic nodules, miliary nodules, bronchial narrowing and pleural effusion [3].

Children with suspected or confirmed pulmonary tuberculosis or peripheral lymphadenitis should be treated with a four-drug regimen (HRZE) for 2 months followed by a two-drug regimen (HR) for 4 months [6]. After treatment radiographs may be performed to evaluate for non-progression or complications [3]. Radiographic regression of primary pulmonary TB is a slow process and a normal radiograph is not mandatory to discontinue treatment [3].

TB must be a consideration in children with lung and mediastinal masses and when unresponsive to pneumonia treatment [7, 8].