TB

Question 1

Approximately what percentage of the worlds population carry the causative bacteria, mycobacterium tuberculosis

Answer 1

1/3

Question 2

Travel to which countries would raise suspicion of TB?

Answer 2

India, China, Indonesia, Pakistan, Bangladesh (essentially any asian country)

Question 3

What is the causative bacteria?

Answer 3

Mycobacterium tuberculosis

Question 4

When should TB be considered infectious?

Answer 4

When tested positive for ziehl-neelson sputum test showing alcohol fast and acid fast bacteria

Question 5

When in children under 12 does it tend to be infectious or not?

Answer 5

Unlikely to be infectious

Question 6

What are the symptoms of primary infection of adults?

Answer 6

No, patients are almost always asymptomatic

Question 7

Children may suffer symptoms on primary infection which are?

Answer 7

Local pulmonary hilum lymphadenopathy which can cause bronchial narrowing and pleural effusion

Question 8

Clinical features of reactivation and primary infection (occurs when there is hypersensitivity to TB or bacilli spread before immunity can contain them)

Answer 8

Weight loss, fever, night sweats, malaise, anorexia, cough, purulent sputum and haemoptysis

Question 9

Post primary and non pulmonary TB can effect a large number of different areas such as?

Answer 9

Kidneys, joints, abdomen (ascites), female genitals and CNS (TB meningitis)

Question 10

What are he two key tests for confirming diagnosis of TB?

Answer 10

Auramine and ziehl-neelson sputum screening and culturing to find mycobacterium tuberculosis

Question 11

What other test can confirm TB?

Answer 11

PCR (can confirm before full sputum sample can be achieved). Very poor sensitivity if non-pulmonary TB and in some cases biopsy and culture are required

Question 12

What might CXR reveal?

Answer 12

Consolidation, cavitation, calcification

Question 13

Cavitation is less likely in which group of patients?

Answer 13

In those who are co-infected with HIV (10% of TB infections)

Question 14

If sputum sample and PCR cannot be done and TB is suspected what must be done?

Answer 14

Bronchoscopy and culturing of bronchial Washington to ensure it is mycobacterium tuberculosis

Question 15

Which patients with TB are not infective?

Answer 15

Those who have non-pulmonary TB

Question 16

Name 5 risk factors for getting TB

Answer 16

First gen immigrants from high incidence countries, overcrowded housing, homelessness, primary infection less than a year previously, smoking, corticosteroid therapy, HIV, malignancy (esp leukaemia and lymphoma), diabetes, silicosis

Question 17

What are the manifestations of TB 3-8 weeks post infection?

Answer 17

Primary complex forms and tuberculin skin test positive

Question 18

What are the manifestations 3-6 months post infection

Answer 18

Meningeal, milary, pleural disease

Question 19

Up to 3 years what can manifest?

Answer 19

Gi, bone, joint, lymph node disease

Question 20

By 8 years what can develop?

Answer 20

Renal tract disease

Question 21

What happens in most patients post initial infection?

Answer 21

M. tuberculosis is contained in a lesion in the apices of the lung and it calcifies (visible on x ray) and usually doesn’t reactivate

Question 22

What might cause reactivation of TB?

Answer 22

Diabetes, malnutrition, HIV, immunosupression or corticosteroid therapy

Question 23

What happens to normal tissue once infected?

Answer 23

It is replaced by macrophages which transform into langerhans and epithelial cells to form a tuberculous granuloma

Question 24

What is milary TB

Answer 24

It is when M. tuberculosis disseminates I to the blood and affects other areas of the body and multiple disperse lung areas. Anaemia and leukopenia may occur with bone marrow involvement

Question 25

What preventative action can be taken?

Answer 25

Give BCG vaccine

Question 26

Management of patients with TB

Answer 26

Isolate for 2 weeks, notify, HRZE treatment (h=isoniazid R=rifampicin Z=pyrazinamide E=ethambutol) given once daily for 2 months while drug sensitivities and diagnosis confirmation is awaited, after it is simplified into two drugs for a further 4 months to make a total treatment time of 6 months

Question 27

What disease has played a large role in allowing TB to persist into he 21st century?

Answer 27

HIV