Tuberculosis

Question 1

MDR TB is resistant to?

Answer 1

Isoniazid, Rifampicin

Question 2

XDR TB is resistant to

Answer 2

= extensively drug resistnat TB
MDR TB: ISoniazid, Rifampicin + resistance to fluroquinolones and one of the three injectable second line drugs (capreomycin, kanamycin or amikacin)

Question 3

describe the microbiological properties of tuberculosis

Answer 3

mycobacterium tuberculosis is a n aerobic non spore forming non motile slightly curved or straight rodded bacteria which stains weakly gram positive. detectable by 3 weeks.. it is acid fast.

Question 4

Transmission of TB

Answer 4

REspiratory route.

Question 5

Describe the pathogenesis of tuberculosis

Answer 5

• first few weeks the bacteria multiply freely within alveolar macrophages, and spread lymphatogenously.
• unrestricted replication leads to both intiial focus and metastatic foci.
• develop some immunity; macrophages and lymphocytes arrive and resultant granuloma known as the Ghon Focus is formed.. Ranke complex can develop after this.
• Positive mantoux test 3-9 weeks post initial infection
• TB may be associated with erythema and keratoconjunctivitis.
• In most cases infection is controlled and the only sign is a positive skin test.
• In a minority you get hte ranke complex.
• latent TB infection is lifelong

Question 6

What are some of the risk factors for reactivation of latent TB?

Answer 6

Greatest risk is in first two years after infection

Risk factor associated: immunosuppressed, HIV, old age, cigarette smoking

Question 7

What are some symptoms of the primary tuberculosis infection

Answer 7

Usually asymptomatic, although in the immunocompromised, may show signs

• allergic phenomena (EN, fever, arthralgia, conjunctivitis)
• Bronchial compression due to hilar lymph node enlargement causing brassy cough or distal lung collapse
• Pneumonia
• Pleural effusion
• Dissemination or miliary TB

Question 8

What would an X ray of a primary tuberculoid infection show?

Answer 8

Patchy infitrate, pneumonia, bronchial compression

Question 9

name some extrapulmonary tB sites

Answer 9

TB lymphadenitis - young women, supraclavicular LN- most common
Pleural TB
TB meningitis
Disseminated TB
Bone and joint TB
Genitourinary TB
Abdominal TB

Question 10

TB HIV coinfection

Answer 10

Risk of active TB increases soon after infection with HIV. depending on CD4 count, can expect to see different forms.

Question 11

What are some CXR findings you would expect to see in TB?

Answer 11

Patchy or nodular infiltrate
Air fluid levels
Fibrotic scars
Pneumonia associated with hilar adenopathy suggestive of primary TB

Question 12

Diagnosis of TB

Answer 12

CXR, positive sputum specimen (3) + PCR

if it is latent TB- use tuberculin skin test or IGRA

Question 13

Treatment for TB

Answer 13

Respiratory isolation, 4 drugs + contact tracing + HIV testing
Drugs: rifampicin, isoniazid, ethambutol, pyrazinamide

4 drugs for 2 months, followed by two drugs for four months,