Table 2.

Different clinical syndromes associated with tuberculosis in children

Pathological classification	Disease phase (time period)	Clinical syndromes	Risk groups	Pathogenesis	Imaging manifestations
Primary Mtb infection	Incubation(0–6 wk)	Asymptomatic	All ages	No adaptive immunity TST(−); IGRA(−)	None
	Infection(1–3 mo)	Self-limiting symptoms (mild, viral-like)		Adaptive immunity IGRA(+); TST(+) No test to register reinfection	Transient hilar or mediastinal lymphadenopathy (50%–70% of cases), rarely visible transient Ghon focus
		Hypersensitivity reactions (fever; erythema nodosum; phlyctenular conjunctivitis)
Early disease progression >90% of disease occur within 12 months of primary infection	Very early(2–6 mo)	Uncomplicated lymph node (LN) disease	<10 years	Inadequate innate and/or adaptive immunity TST(+); IGRA(+) May be negative with immune compromise or extensive disease, cannot be used as “rule out” tests	Hilar or mediastinal lymphadenopathy without airway or parenchymal involvement
		Progressive Ghon focus	<1 yr		Ghon focus with visible cavitation
		Disseminated disease: – Miliary disease – TB meningitis	<3 yr		– Discrete lung nodules (1–2 mm) on CXR; hepatosplenomegaly – Hydrocephalus; basal enhancement; brain infarcts and/or tuberculomas
	Early(4–12 mo)	Complicated LN disease – Airway compression – Expansile caseating pneumonia – Infiltration of adjacent anatomic structures (esophagus, phrenic nerve, pericardium)	<5 yr		– Hyperinflation or atelectasis/collapse – Expansile consolidation of a segment or lobe – Tracheo-/bronchoesophageal fistula; pericardial effusion; hemidiaphragmatic palsy
		Pleural disease – Exudative effusion (rarely empyema; or chylothorax)	>3 yr		Effusion usually unilateral; some pleural thickening and loculations (attributable to fibrinous strands)
		Lymphadenitis – Most common extra-thoracic manifestation; usually cervical	1–10 yr		Usually not needed, matting and edema of adjacent soft tissue
Late disease progression Generally rare apart from adult-type disease in adolescents	Late(1–3 yr)	Adult-type pulmonary disease – Difficult to differentiate primary infection; reactivation and reinfection disease	≥8 yr	“Overagressive” innate and/or adaptive immunity	Apical cavities; may be bilateral; minimal or no LN enlargement (previously referred to as postprimary TB)
		Osteoarticular disease: – Spondylitis/Arthritis/Osteomyelitis	≥5 yr	Inadequate local control; usually local manifestations only, but can disseminate from any active focus	Periarticular osteopenia, subchondral cystic erosions, joint space narrowing
	Very late(>3 yr)	Urinary tract (renal, ureter, bladder) disease	>5 yr		Renal calcifications; hydronephrosis, calyceal dilation and/or ureter stricture

Data adapted from Perez-Velez and Marais 2012 and based on detailed disease descriptions provided by Wallgren 1948 and Lincoln and Sewell 1963.

Age ranges, risk groups, and time lines specified provide general guidance only. HIV-infected children are particularly vulnerable and may present with atypical features.