Criteria

Tuberculosis (TB)[1]

US Centers for Disease Control and Prevention: 2009 case definition of TB[188]

Clinical criteria (meets all the following criteria):

  • A positive tuberculin skin test or positive interferon gamma release assay for  Mycobacterium tuberculosis

  • Other signs and symptoms compatible with TB (e.g., abnormal chest radiograph, abnormal chest computerised tomography scan or other chest imaging study, or clinical evidence of current TB disease)

  • Treatment with two or more antituberculosis medications

  • A completed diagnostic evaluation.

Laboratory criteria for diagnosis:

  • Isolation of M tuberculosis from a clinical specimen, or

  • Demonstration of M tuberculosis complex from a clinical specimen by nucleic acid amplification test, or

  • Demonstration of acid-fast bacilli (AFB) in a clinical specimen when a culture has not been or cannot be obtained or is falsely negative or contaminated.

Confirmed case:

  • A case that meets the clinical case definition or is laboratory confirmed.

World Health Organization: case definition of TB[189]

Clinically diagnosed TB:

  • A case that does not fulfil the criteria for bacteriological confirmation, but has been diagnosed with active TB by a clinician or other medical practitioner, and a full course of TB treatment is given.

  • This definition includes cases diagnosed on the basis of x-ray abnormalities or suggestive histology, and extrapulmonary cases without laboratory confirmation.

  • Clinically diagnosed cases subsequently found to be bacteriologically positive (before or after starting treatment) should be reclassified as bacteriologically confirmed.

Bacteriologically confirmed TB:

  • Biological specimen is positive by smear microscopy, culture, or World Health Organization-approved rapid diagnostics (such as Xpert MTB/RIF).

Bacteriologically confirmed or clinically diagnosed cases of TB are also classified according to:

  • Anatomical site of disease

  • History of previous treatment

  • Drug resistance

  • HIV status

Mycobacterium avium complex (MAC) disease[1]

Disseminated MAC is typically seen in people with a CD4 count less than 50 cells/microlitre and is often associated with fever, anaemia, weight loss, diarrhoea, and elevated alkaline phosphatase. It is recommended that all such patients have AFB blood cultures done.[146]

Pneumocystis jirovecii pneumonia[190]

Diagnostic criteria

  • A history of dyspnoea on exertion or non-productive cough of recent onset (within the past 3 months); AND

  • Chest x-ray evidence of diffuse bi-lateral interstitial infiltrates or evidence by gallium scan of diffuse bilateral pulmonary disease; AND

  • Arterial blood gas analysis showing an arterial partial pressure of oxygen (pO₂) of less than 70 mmHg or a low respiratory diffusing capacity (<80% of predicted values) or an increase in the alveolar-arterial oxygen tension gradient; AND

  • No evidence of bacterial pneumonia.

Toxoplasmosis of the brain[190]

Diagnostic criteria

  • Recent onset of a focal neurological abnormality consistent with intra-cranial disease or a reduced level of consciousness; AND

  • Evidence by brain imaging (computed tomography or magnetic resonance imaging) of a lesion having a mass effect or the radiographic appearance of which is enhanced by injection of contrast medium; AND

  • Serum antibody to Toxoplasma gondii or successful response to therapy for toxoplasmosis.

Cytomegalovirus[190]

Characteristic appearance on serial ophthalmoscopic examinations (e.g., discrete patches of retinal whitening with distinct borders, spreading in a centrifugal manner along the paths of blood vessels, progressing over several months, and frequently associated with retinal vasculitis, haemorrhage, and necrosis).

Resolution of active disease leaves retinal scarring and atrophy with retinal pigment epithelial mottling.

Cryptococcal meningitis[1]

Sub-acute meningitis or meningoencephalitis with fever, malaise, and headache.

Positive cryptococcal antigen in cerebrospinal fluid and serum.

Oesophageal candidiasis[190]

Diagnostic criteria

  • Recent onset of retrosternal pain on swallowing; AND

  • Oral candidiasis diagnosed by the gross appearance of white patches or plaques on an erythematous base or by the microscopic appearance of fungal mycelial filaments from a non-cultured specimen scraped from the oral mucosa.

Use of this content is subject to our disclaimer