Australian Doctor 16th May 2025 | Page 45

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New cases

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cases

Pulmonary only

700

45

2

Pulmonary plus other sites

171

5

2

Pulmonary cases— total

871

50

4

Extrapulmonary only Pleural

59

2

0

Lymph nodes

256

5

0

Bone / joint

28

1

0

Genitourinary

30

0

0

Miliary / disseminated

14

0

0

Meningeal

13

1

0

Peritoneal

30

1

0

Other

97

3

1

Extrapulmonary cases— total

498

14

1

Unknown site of disease— total

2

1

0

Total anatomical sites

1609

69

7

Isoniazid

Pyrazinamide

Rifampicin

Ethambutol

( very rare)

arrange supervision of therapy( often daily, with direct observed therapy), as well as evaluation of contacts to identify and manage those at risk of contracting M. tb.

can be considered in patients with tuberculous pericarditis.

Although intermittent treatment regimens( usually thrice weekly) have been used for consolidation

Vintage engraving of Victorian nurses caring for a dying man with tuberculosis.

limit transmission. In most cases of extrapulmonary TB, transmission is unlikely, with the exception of direct contact with an infectious source. Most patients with isolated extrapul-

Hepatitis— cholestatic

Upper gastrointestinal tract symptoms

Rifampicin

Rifampicin Pyrazinamide Isoniazid Ethambutol

Isoniazid( drug-induced lupus)

Ethambutol

Fully susceptible pulmonary tuberculosis In Australia, around 90 % of TB cases are fully susceptible, demonstrating no evidence of resistance to standard first-line antituberculous agents. 2 In these patients, standard short-

therapy in the past, daily therapy is now recommended in most cases. Daily treatment is especially important for the initial two-month intensive treatment phase. In patients who may face challenges adhering to prescribed therapy, directly observed

monary TB therefore require standard infection control measures only. Exceptions to this include patients with oropharyngeal or laryngeal disease, or who have a discharging tuberculous abscess. When patients are managed in the community, it is

Hypersensitivity( fever plus rash plus other)

Isoniazid Rifampicin Pyrazinamide Ethambutol

Adapted from Queensland Clinical Guidelines, Treatment of tuberculosis in adults and children, Queensland Health 2023 11

course therapy for a total duration

therapy can facilitate optimal adher-

critical that adequate social support

Australian guidelines suggest either

undertaken in specialist TB clinics,

of six months has a high likelihood

ence. Adequate adherence is crucial

is in place to allow patients to main-

test is reasonable as a first-line

where access to multidisciplinary

of cure in fully compliant patients.

to maximising treatment success.

tain home isolation. 8

investigation. False-positive TST

support teams can assist patients in

This regimen comprises a twomonth intensive phase of isoniazid, rifampicin and pyrazinamide with ethambutol, pending confirmation of drug susceptibilities. This is fol-

New, shorter course regimens are emerging, that will likely be included in future Australian guidelines for treatment of fully susceptible pulmonary TB. 6

Latent tuberculosis

When to test

Latent TB is the most common form of infection with M. tb, affecting an

can be seen in those with a history of recent BCG vaccination( particularly within the previous 15 years) and with exposure to environmental NTM organisms. IGRA testing

monitoring therapy and maintaining adherence. 11

Major drug side effects

Many of the agents used to treat TB

lowed by a four-month continuation phase with isoniazid and rifampicin. In those who have more extensive disease with cavitation, or who fail to convert their sputum cultures to negative after two months of therapy, the continuation phase can be

Drug-resistant tuberculosis The most common pattern of drug resistance is isoniazid monoresistance, seen in approximately 5 % of cases in Australia. 2 Treatment of rifampicin-resistant TB and multi-

estimated 25 % of the world’ s population. 9 Of those diagnosed with latent TB, approximately 10-15 % will reactivate to develop active TB. 10 Testing for latent TB should be undertaken when there is an intention to offer treatment to prevent reactivation to

has greater specificity and does not cross-react with the BCG vaccine or the majority of environmental NTM. Neither test distinguishes active from latent TB, so should not be used to help diagnose active infection. Nonetheless, a positive result

have overlapping side effects, which can lead to challenges in identifying the offending agent. Table 3 lists the most likely causative medication for each common side effect. 11

In addition to the side effects listed in table 3, it is important to

extended to seven months( complet-

drug-resistant TB is individualised,

active TB, if the test is positive. The

on either test requires evaluation to

recognise the potential for ocular

ing a total of nine months duration).

and should be managed with spe-

decision to treat latent TB is com-

exclude active disease, including a

toxicity with ethambutol. This man-

Co-administration of pyridoxine

cialist TB clinicians associated with

plex, and is based on the likelihood

clinical assessment and chest X-ray

ifests as bilateral painless loss of

( vitamin B6) can reduce the risk of

a regional TB control unit.

of reactivation( highest in those with

at a minimum, with consideration

central visual acuity, central visual

neuropathy associated with isonia-

impaired immunity, including chil-

of sputum sampling if there is con-

field changes, and dyschromatopsia.

zid but should be reserved for those

Infection control precautions

dren under two years of age), time

cern for active pulmonary TB. It is

Colour vision( Ishihara) and visual

with other risk factors for peripheral

The primary mode of transmission

since exposure, and the anticipated

important to note that IGRA and TST

acuity should be checked prior to

neuropathy( such as HIV infection,

of M. tb is by the respiratory route,

remaining life span of the patient.

may be negative in cases of active TB

commencement of therapy and then

diabetes mellitus, malnutrition). 6

following the inhalation of infec-

The highest risk for reactivation is

and so should not be relied upon to

monthly, with immediate ophthal-

Standard short-course therapy

tious aerosols from an index case. In

seen in those who have confirmed

exclude active disease.

mological review if any changes are

is appropriate for treatment of iso-

patients with proven or suspected

latent TB within the first two years

identified. It is important to warn

lated lymph node, pleural, bone,

pulmonary TB, airborne precau-

of exposure to an infectious case.

How to treat

patients of the orange discoloura-

joint, or pericardial TB, with longer

tions are necessary in the healthcare

Treatment of latent TB is aimed

tion of body fluids from rifampicin

course treatment indicated for those

setting, including isolation of the

How to test

at reducing the risk of reactiva-

— which is harmless, be mindful of

with disseminated, miliary, or CNS

patient in a negative pressure room,

Two diagnostic tests are availa-

tion. Acceptable regimens include

the potential for drug interactions

TB, usually for a total duration of

with high-grade respiratory protec-

ble in Australia, including tubercu-

four months of monotherapy with

( mostly with rifampicin), and mon-

12 months of treatment. Oral corti-

tive equipment( such as N95 masks)

lin skin testing( TST) and the more

rifampicin, six months of isonia-

itor for hepatotoxicity.

costeroid may be used with CNS TB at initiation of treatment to reduce morbidity from cerebral oedema and

worn by those in direct contact with the patient. A properly fitted surgical mask to an index case can

recently developed IGRA, which in most Australian jurisdictions is the QuantiFERON-TB Gold test. Current

zid, or three months of dual therapy with rifampicin and isoniazid. The decision to treat is generally

References on request from kate. kelso @ adg. com. au