TB Case definition
Possible tuberculous meningitis (TBM)
Clinical entry criteria consistent with tuberculous meningitis plus exclusion of alternative diagnoses.
Paradoxical tuberculosis-associated IRIS (immune reconstitution inflammatory syndrome)
Recurrent, new, or worsening symptoms or signs of tuberculosis following initiation of antiretroviral therapy (ART) in people living with HIV, diagnosed with tuberculosis, and started on anti-tuberculosis treatment before ART. These signs or symptoms typically occur within the first few weeks and up to 3 months after ART is initiated.
Extrapulmonary tuberculosis (EPTB)
Any bacteriologically confirmed or clinically diagnosed case of tuberculosis involving organs other than the lungs (e.g. pleura, peripheral lymph nodes, abdomen, genitourinary tract, skin, joints and bones, meninges).
Incipient tuberculosis
Individuals with M. tuberculosis infection in whom progression to tuberculosis has started and who have no symptoms, no radiographic abnormalities suggestive of tuberculosis, and negative microbiological investigations.
Disseminated tuberculosis
Simultaneous involvement of at least two non-contiguous organ sites of the body resulting from the hematogenous spread of M. tuberculosis.
Clinically diagnosed tuberculosis (case definition)
Tuberculosis in a person who does not fulfil the criteria for bacteriological confirmation and has been diagnosed with tuberculosis by a medical practitioner who has decided to initiate anti-tuberculosis treatment.
Bacteriologically confirmed tuberculosis (case definition)
Tuberculosis occurring in a patient from whom a biological specimen tests positive by smear microscopy, culture or WHO-recommended rapid diagnostic. Also known as laboratory or microbiologically confirmed tuberculosis case.
Active tuberculosis
Symptomatic disease that occurs in someone infected with M. tuberculosis or other mycobacteria from M. tuberculosis complex. This term is broadly used but is outdated. The preferred term is ‘tuberculosis’.
Unlikely tuberculosis (for intrathoracic tuberculosis in children)
Condition in which a person does not have M. tuberculosis bacteriological confirmation and the criteria for “unconfirmed tuberculosis” is not met – With M. tuberculosis infection; Immunological evidence of M. tuberculosis infection (TST and/or IGRA positive) – Without M. tuberculosis infection; No immunological evidence of M. tuberculosis infection. This term was developed for diagnostic research purposes.
Unmasking tuberculosis-associated IRIS
Type of immune reconstitution inflammatory syndrome that occurs when a patient is not receiving treatment for tuberculosis when ART is initiated and then presents with tuberculosis within 3 months of starting ART. One of the following criteria must be met: Heightened intensity of clinical manifestations, presentation with pulmonary tuberculosis that is complicated by respiratory failure due to adult respiratory distress syndrome, or those who present with a marked systemic inflammatory syndrome related to tuberculosis.
