Operational Handbooks

EPTB refers to any bacteriologically confirmed or clinically diagnosed case of TB involving organs other than the lungs (e.g. pleura, peripheral lymph nodes, abdomen, genitourinary tract, skin, joints and bones, meninges) (71). The classification of intrathoracic lymphadenopathy in children was updated following an expert consultation in September 2021 as PTB. EPTB is common in young children and in children and adolescents living with HIV.

In children with presumptive PTB attending health care facilities, integrated treatment decision algorithms may be used to diagnose PTB. This is an interim conditional recommendation valid until 2024, after which new evidence will be reviewed (see Box 4.6).

CXR remains an important tool in the diagnosis of TB in children, especially those with negative bacteriological tests or where bacteriological testing is not available or not feasible. Most children with PTB have radiographic changes suggestive of TB. If possible, anteroposterior and lateral films should be obtained in children aged under 5 years, and posteroanterior films in older children and adolescents.

Abnormalities on CXR suggestive of PTB include:

In children with signs and symptoms of PTB in settings with a pre-test probability of 5% or higher (prevalence of confirmed TB of 5% or above in this specific population), repeat testing with Xpert MTB/RIF or Ultra may be considered after an initial negative Xpert MTB/RIF or Ultra test if the clinician has a high index of suspicion that the child has TB, using any of the recommended specimen types.

The urine lateral flow lipoarabinomannan (LF-LAM) assay is an immunocapture assay based on the detection of the mycobacterial lipoarabinomannan antigen in urine. For specific populations, LF-LAM may be used together with other approved TB diagnostics tests and affords a distinct advantage as a point-of-care test. Although the assay lacks sensitivity, it can be used as a fast bedside rule-in test for people living with HIV, especially in urgent cases where a rapid TB diagnosis is critical for the person’s survival.

Depending on the availability, resources and capacity, appropriate specimens from suspected sites of involvement should be collected for rapid testing using mWRDs or culture, and histopathological examination should be done for children with EPTB whenever possible. WHO recommends that NTPs replace microscopy as the initial diagnostic test for TB with mWRDs, which can be used on various respiratory and non-respiratory specimens (Table 4.4) (76).

WHO-recommended clinical samples for the diagnosis of PTB in children and adolescents using Xpert MTB/RIF or Ultra include sputum (expectorated or induced), gastric or nasopharyngeal aspirates, and stool. Other mWRDs using respiratory samples have only been validated on sputum samples. Each of these specimen types has distinct advantages and disadvantages (Table 4.1). Annex 3 summarizes the types of respiratory and non-respiratory specimens.

Although there are no findings on clinical examination that can confirm TB, some clinical signs are highly suggestive. In addition, a variety of nonspecific signs should raise clinical suspicion and prompt an evaluation for TB disease. The following clinical features can alert care providers that the child may have TB (6, 72):

TB may present in atypical ways, such as acute severe pneumonia (more common in children aged under 2 years and children living with HIV) or fixed airway wheezing (more common in young children aged under 5 years) (72).

Signs of severe pneumonia include:

In most cases, children with TB disease develop chronic unremitting symptoms that persist for more than 2 weeks without sustained improvement or resolution following treatment for alternative diagnoses (e.g. antibiotics for pneumonia, antimalarials for fever, nutritional rehabilitation for failure to thrive or malnutrition). The most common clinical presentation of PTB in children is persistent cough and poor weight gain.