7 December 2020
Globally in 2019 there were an estimated 10 million cases of tuberculosis (TB). TB is uncommon in Australia with most cases imported by people travelling from high burden countries. In South Australia (SA) 73, cases of TB have been notified year to date in 2020, compared to a total of 76 cases in 2019.
TB must be considered as a differential diagnosis in patients who are in at risk groups and present with compatible symptoms. A delayed diagnosis may result in increased morbidity and mortality in TB cases, and increase the risk of TB transmission within the South Australian community.
Multidrug-resistant TB (resistance to at least rifampicin and isoniazid) is an increasing global concern but presently uncommon in SA (1-2% of all cases). It invariably reflects reactivation of “imported” infection. Extensively drug-resistant TB which involves further amplification of resistance to key second line agents has also been detected. Early detection of such cases is paramount to minimise transmission of infection. Management is significantly more complex requiring prolonged durations of more toxic treatment.
All inpatient and outpatient services (including pathology, radiology and pharmaceuticals) related to the screening, care and management of people with suspected, active or latent TB are available at no charge to any patient within the South Australian public health system.
Medical practitioners are advised to be aware of the following groups at increased risk of TB:
People with increased risk of exposure to TB
- Migrants, refugees or students from high burden countries
- Close contacts of an infectious TB case
- Aboriginal and Torres Strait Islander people
- People born in Australia prior to the 1960s
- Health care workers who have worked in high burden countries
People with increased risk of progression from latent TB infection to active TB disease
- Infants and children under 5 years with a positive tuberculin skin test (TST)
- People with “old healed” TB on chest X ray (CXR)
- People with immunosuppressive disorders (e.g. HIV, malignancy) or those requiring prolonged use of corticosteroids or other immunosuppressive agents
- People with solid organ transplants
- People with medical disorders such as diabetes, kidney disease requiring dialysis, or silicosis
Medical practitioners should consider TB in these risk groups when:
- Cough or persistent chest infection is present for more than 2 weeks that does not respond to a standard course of antibiotics and/or,
- Other respiratory symptoms are present – dyspnoea, chest pain, haemoptysis and/or,
- Constitutional symptoms are present – loss of appetite, weight loss, fever, night sweats, fatigue, lymphadenopathy.
Medical practitioners should investigate and manage suspected pulmonary TB
- Request radiology. Atypical CXR findings are common in the immune suppressed and elderly – consider a CT chest if clinical suspicion remains.
- Request sputum TB culture and acid-fast bacilli (AFB) smear testing – request 3 sputum specimens collected at least 8 hours apart (e.g. early morning) for AFBs.
- Send sputum to SA Pathology for faster result turnaround time.
- Seek urgent advice from SA TB Services or nearest tertiary hospital if sputum is smear positive.
- Recognise that smear negative sputum results does not exclude TB as culture confirmation can take 3-6 weeks. Seek specialist advice if there is high suspicion of TB.
- Note that TST and interferon gamma release assay (IGRA) are NOT recommended for the initial investigation of active TB. A negative result does not exclude the possibility of TB.
- Telephone SA TB Services at the Royal Adelaide Hospital on 7117 2967, if advice is required.
- Notify SA TB Services of suspected or confirmed cases on 7117 2967.
Dr Louise Flood – Director, Communicable Disease Control Branch