08 February 2010
Response Protocol For NSW Public Health Units
Public Health Priority
Routine. Follow up rests primarily with Area Tuberculosis staff.
PHU response Time
Enter confirmed cases on NDD within 3 working days. Enter updated information, including outcomes on NDD within 8 months of diagnosis (and again, if necessary, on completion of therapy).
By chest Clinic staff
PHUs should assist Area Tuberculosis staff in planning contact investigations involving > 25 contacts
1. Reason for surveillance
- To identify and treat infectious cases
- To monitor the epidemiology of tuberculosis
- To identify infected contacts and reduce their risk of developing active tuberculosis.
2. Case definition
A confirmed case requires a diagnosis accepted by the Public Health Unit Director based on:
- Laboratory definitive evidence, or
- Clinical evidence.
Laboratory definitive evidence
- Isolation of Mycobacterium tuberculosis complex (M. tuberculosis, M. bovis or M. africanum) from a clinical specimen by culture, or
- Detection of M.tuberculosis complex by nucleic acid testing EXCEPT where this is likely to be due to previously treated or inactive disease.
A clinician experienced in tuberculosis makes a clinical diagnosis of tuberculosis including clinical follow-up assessment to ensure a consistent clinical course.
3. Notification criteria and procedure
Tuberculosis is to be notified by:
- Laboratories on diagnosis (ideal reporting to the TB service/Chest Clinic by telephone on diagnosis)
- Medical practitioners on diagnosis (ideal reporting to the TB service/Chest Clinic by telephone on diagnosis)
- Hospital CEOs (or delegates) on diagnosis (ideal reporting to the TB service/Chest Clinic by telephone on diagnosis).
Only cases that meet the case definition should be entered onto NDD.
4. The disease
Tuberculosis is almost always caused by the bacterium Mycobacterium tuberculosis. Rarely, the bacteria Mycobacterium bovis and Mycobacterium africanum cause disease in humans.
Mode of transmission
Tuberculosis is transmitted by airborne droplets from cases of pulmonary or laryngeal disease produced by expiratory efforts such as coughing, singing or sneezing. Bovine tuberculosis may also be transmitted by ingestion of raw milk.
The typical incubation period from infection to demonstrable primary lesion or significant tuberculin reaction is 2 to 10 weeks.
The risk of infection is higher in people who have had close contact with a case of pulmonary or laryngeal tuberculosis as they may have inhaled expelled TB bacteria. Such people include:
- household contacts of cases,
- persons born in countries with a high prevalence of TB, and
- persons living in close proximity to others, particularly in congregate settings.
Infection can be detected by demonstration of a positive Tuberculin skin test. After infection with M.tuberculosis, most people will have no symptoms.
Newly infected people have about a 10% chance of developing active tuberculosis in their lifetime; about half those who develop tuberculosis do so within 2 years of infection. The risk of progressing to disease is higher in persons who are:
- immunocompromised (eg, with HIV infection),
- injecting drug users, or
- renal failure,
- some hematological disorders,
- other specific malignancies,
- previous gastric surgery, or
- are underweight.
The degree of infectiousness is determined from clinical, radiological, bacteriological and nucleic acid detection findings, and categorised as follows:
- Sputum smear positive (bacteria of TB detected in sputum), or
- laryngeal involvement,
- Chest x-ray cavitation, or
- evidence of transmission to other contacts
- Sputum smear negative, but sputum culture positive or nucleic acid test positive, or
- pleural disease (without pulmonary involvement), or
- bronchial washing smear positive.
- Sputum culture and smear negative, or
- smear positive and clinically unlikely to be TB disease
Patients may present with a range of symptoms depending on the site of disease. The majority of cases involve a pulmonary site of disease. Common symptoms include:
- A chronic cough
- Weight loss
- Night sweats
Because TB is an uncommon cause of these symptoms in Australia, the diagnosis is often not made on initial presentation.
5. Managing single notifications
Within 1 working day of notification of a confirmed case, report the case to the local Area TB Coordinator by phone.
Within 3 working days of notification, enter confirmed cases onto NDD. Within 8 months of the initial notification, (and if necessary again at the end of treatment) in collaboration with the Chest Clinic managing the case, update NDD information relating to treatment and its outcome.
Chest Clinics undertake contact screening and other relevant investigations, and forward details of the case to the PHU for entry onto NDD, using the Tuberculosis Investigation Form.
Managed by TB service/Chest Clinic staff. The PHU Director should ensure that the public health issues are effectively managed where the AHS TB Co-ordinator considers that the patient may be exposing other people to a risk of infection (see PD 2005_068 Tuberculosis Management of People Knowingly Placing Others at Risk of Infection).
TB/Chest Clinic staff will interview the patient to obtain a list of contacts and to initiate appropriate public health action. All patients should receive directly observed therapy (DOT) throughout treatment to ensure compliance. DOT should be provided by TB service/Chest Clinic staff, except in special circumstances where an alternative health care worker or other trusted person trained by the TB service/chest clinic who is familiar with compliance issues agrees to observe the patient swallow all medications.
Investigation and treatment
All isolates of Mycobacterium species should be referred to the Mycobacterium Reference Laboratory at ICPMR for confirmation and susceptibility testing.
Hospitalisation of tuberculosis patients
Generally patients with tuberculosis should be admitted to hospital if:
- Essential investigations are required that can only be carried out on an in-patient basis
- There is a need to assess the patient's tolerance to medication and/or stabilize the patient on treatment
- The patient requires isolation to prevent further spread of the disease.
When to hospitalise
A longer time in hospital may be required if there is:
- Concern for continued infectivity due to severe disease with cavitation, or
- previous medication failures, or
- social situations that may lead to non-compliance and disease transmission.
When to discharge
Patients with tuberculosis may be discharged from hospital before confirmation of decreased infectivity (three negative sputum smears). The decision to cease isolation and airborne precautions should always be undertaken in consultation with the specialist TB physician, the Area TB Co-ordinator and local infection control staff.
Each case must be assessed for risk of disease transmission before discharge from hospital. TB service/Chest Clinic staff should counsel the patient about infection control at home and in the community.
Care at home
Patients who are sputum smear positive who do not need hospital admission may be managed at home with counselling about the disease, its transmission and prevention (including advice to cover the mouth and nose when coughing or sneezing).
Multi-drug resistant tuberculosis (MDR TB) and other difficult to manage cases
All cases of MDR TB (i.e. persons with TB resistant to at least rifampicin and isoniazid) should be referred to the NSW Health MDR TB Expert Panel. The Panel will help the managing physicians and the TB service/Chest Clinic develop a case management plan.
In addition, clinicians can refer difficult to manage cases of active tuberculosis to the panel for peer review.
Referral to the Panel can be made via the NSW Tuberculosis Program Manager.
The recommended composition of the panel includes:
- Attending physician and Area Tuberculosis Coordinator
- Infectious diseases physician
- ICPMR representative
- Director of Public Health Unit
- Physicians nominated be the Cheif Health Officer
- NSW Health Department representative
- Other relevant persons as defined by the chair of the panel.
Cases should be counselled about the nature of the disease and its mode of transmission, the need to adhere to treatment, to cover their mouth and nose when coughing and sneezing, and if infectious, to avoid contact with any new persons. If treated at home, they must be instructed to remain there for ≥2 weeks after the commencement of anti-TB treatment or until they are assessed as not being infectious.
Isolation and restriction
When a patient with suspected infectious TB is admitted to hospital the patient must be isolated in a single room, ideally with negative pressure. Airborne precautions must be taken.
All patients admitted with suspected infectous multi drug resistant TB must be isolated with airborne precautions in a single negative pressure room. Where a hospital does not have a room with negative pressure ventilation arrangements should be made to relocate the patient to a hospital with this facility as agreed by the treating physician, Area TB Co-ordinator and the patient. airborne precautions must be implemented during transit.
A P2 (N95) mask should be worn by all health care workers and other entering the room.
- Infectious patients are to wear a surgical mask when leaving their rooms to walk in the hospital grounds or during transport.
Children should be discouraged from visiting infectious cases. People with infectious TB must be isolated from immunocompromised persons, until sputum is negative for acid fast bacilli (AFB) or until no sputum is being produced. Immune compromised staff members should not work on wards where there are cases of infectious TB.
Standard precautions should be followed in the disposal of sharps, contaminated waste and linen and all body fluids. Soiled tissues should be isposed of in a sealed bag. Sputum must be collected in a disposable container, with a lid that can be secured. Laboratory specimens should be well sealed with no contamination of the outside of the container and transported immediately to the laboratory in a sealed bag.
The case may be confined if behaving in a way that is endangering, or is likely to endanger the health of the public because the person is suffering from tuberculosis (Public Health Act 1991, Section 23). Consult with the NSW TB Program Manager and see Controlling TB in NSW.
There are no restrictions on the movement of patients with non-respiratory disease, or those on treatment with negative sputum smears.
To assist in the identification of contacts at risk of infection, an environmental assessment should be undertaken of the settings that the patient has been spending >8 hours in whilst infectious. Factors to consider include:
- Room size
- Proximity to the case
- Duration of contact.
Managed by the TB service/Chest Clinic. The PHU Director should provide advice to the AHS TB Co-ordinator when a large number of potential contactcs have been identified (e.g. involving >25 contacts).
Contact tracing should be managed by the TB service/Chest Clinic according to NSW Health's Controlling TB in NSW.
The aims of contact tracing are to identify further cases of TB among those in contact with the disease, identify people who may have been infected following contact with a person found to have TB, counsel people found to have latent TB infection (LTBI) and offer them treatment for LTBI.
The estimated risk of transmission should guide the priority, rapidity and thoroughness of the contact investigation.
The following steps should be undertaken:
- Categorise the case according to the likely degree of infectiousness (see section 4)
- Obtain a list of contacts and categorise the contacts according to their estimated risks of exposure to TB
- Assess all high-risk contactcs of suspected or confirmed pulmonary and laryngeal TB cases first
- Consider examination of medium risk contacts (see below) of pulmonary or laryngeal TB cases if there is evidence of transmission in high-risk contacts
- Consult with the NSW TB Program Manager, if:
- the case works in a hospital, school, day care, prison, any other institution or long term care facility
- screening may be indicated for >25 contacts, or
- there is doubt about the priority/ extent of contact screening required.
Identification of contacts
A list of close contacts, including names and addresses, should be compiled first. Contacts should be categorised into:
- Frequent, prolonged and close contact in an enclosed environment during the infectious period.
This group may include:
- All people living in the same dwelling
- Relatives and friends who have frequent, prolonged and close contact
- Close work colleagues who share the same indoor small work area on a daily basis.
- Frequent but less intense contact.
This group may include:
- Other close relatives
- Work colleagues
- Relatives and neighbours who frequently visit the case and are not included in the high-risk group.
- Includes other contacts at school or in the workplace or social environments not included in the high or medium risk groups.
- Obtaining details of low risk contacts is not necessary initially and need only be pursued if there is evidence of transmission in the high risk and medium risk groups.
- It is different to be prescriptive about the overllap between groups, and each screening activity needs to be developed and evaluated on an individual basis. After contact tracing has been carried out i each risk group, an evaluation of the results should be carried out to determine if transmission has occurred.
Investigation and treatment
Contacts under investigation should be initially assessed using symptom review and a Tuberculin Skin Test (TST). Contacts who are TST positive or symptomatic at any visit should have a chest x-ray, and be referred to a physician for assessment for treatment. Symptomatic contacts should have sputum collected for assessment.
If the first screening occurs <10 weeks after last exposure to the infectious case, TST negative contacts should have a repeat TST 10 weeks after the last exposure.
Children < 5 years old who are high risk contacts of highly infectious cases should be referred to a physician and considered for preventive therapy until the 10 week TST is shown to be negative.
- High-risk contacts of highly infectious cases should be assessed within 7 days of diagnosis
- High-risk contacts of cases of medium or low infectiousness should be assessed within 14 days of notification of diagnosis.
- Contacts of cases with negligible infectiousness need not be examined
- Only if there is evidence of transmission in the highrisk contacts group, should screening progress to the medium risk group
- Only if there is evidence of transmission in the medium risk group, should screening progress to the low risk group.
As a guide, if 10 or more of the closest contacts have been tested and all are TST negative, testing of more remote contacts is usually unnecessary. If < 10 contacts have been tested, and all are TST negative, careful consideration should be given to the theoretical risk of infection before stopping the contact investigation.
All contact tracing is carried out free of charge at NSW Chest Clinics.
Isolation and restriction
Contacts of cases are not restricted unless that contact is suspected to have infectious TB.
Additional information, resources and TB program materials can be found at the following web address: http://www.health.nsw.gov.au/PublicHealth/Infectious/TB/index.asp