Tuberculosis: a case of miliary hepatosplenic involvement

A 12-month old female infant was referred to our hospital’s Emergency Department presenting with enlarged cervical lymph nodes. There was a history of close contact with a family member with confirmed active pulmonary tuberculosis (TB). The patient showed no fever and had no cough. A chest x-ray showed evenly distributed diffuse small nodules (2-3mm), suspicious of miliary TB. An abdominal ultrasound (US) was performed to exclude intra-abdominal involvement.

Abdominal US showed multiple millimetric hyperechoic nodules scattered diffusely throughout the splenic parenchyma. (Fig.1) The spleen had otherwise an adequate size and morphology. Some hyperechoic well defined millimetric hepatic nodules were also noted. (Fig. 2) The rest of the abdominal examination was unremarkable.

The following day, a thoracic computed tomography (CT) scan was carried out showing innumerable micronodules distributed randomly throughout both lungs. The lung parenchyma also presented areas of ill-defined, slightly nodular densifications with air bronchogram. (Fig. 3) Multiple mediastinal and hilar enlarged lymph nodes were also found. (Fig. 4) No cavitated lesions or pleural effusion were noted.

These findings were highly suspicious of miliary TB with hepatosplenic involvement.

Primary TB is seen in patients not previously exposed to Mycobacterium tuberculosis. It is most common in infants with a higher prevalence in children under 5 years of age.[1]

Clinically significant miliary disease results from massive lymphohematogenous dissemination of Mycobacterium tuberculosis bacilli, and affects 1 – 7% of patients with all forms of TB, usually the elderly, infants, or immunocompromised patients.[1,2]

The clinical manifestations of miliary TB are non-specific, and constitutional symptoms such as fever, anorexia, weight loss and cough are frequent.[2]

Peripheral lymphadenopathy and hepatosplenomegaly are more common in children compared with adults.[2]

The classic pulmonary radiographic findings include randomly distributed diffuse small 2–3-mm lung nodules, with a slight lower lobe predominance, as was demonstrated in this case.[1] High-resolution CT is more sensitive than conventional radiography and is usually the imaging modality of choice.[2]

US, CT, and magnetic resonance imaging are useful in discerning the extent of extrapulmonary organ involvement by miliary TB.[2]

Hepatosplenic involvement is common and is either micronodular (more frequently) or macronodular (rare).[3,4]  The liver and spleen usually appear hyperechoic at US and lesions generally appear hypo to isoechoic relative to the background parenchyma, however, in some cases, a hyperechoic nodule pattern can be demonstrated, as was shown. [2,3,4]  Calcification of these nodules is frequent in long-standing chronic disease and these lesions are actually better discernible at this stage, when they manifest as small nodular foci of calcifications.[3,4]

Histopathological examination of tissue biopsy specimens, and rapid culture methods for isolation of Mycobacterium tuberculosis in sputum, body fluids, and other body tissues aid in confirming the diagnosis.[2]

It is important to be aware of the radiologic appearance of miliary TB as its clinical presentation is so vague and rapid diagnosis is required to limit disease transmission.[2]

Written informed patient consent for publication has been obtained.