Tuberculosis

Question 1

What is Tuberculosis?

Answer 1

infectious bacterial disease that affects the lungs

Question 2

What bacteria causes Tuberculosis?

Answer 2

Mycobacterium tuberculosis - rod shaped bacillus

Question 3

What stain does Mycobacterium tuberculosis require to be seen?

Answer 3

‘acid-fast’ staining procedure
using Zeihl-Neelsen stain
(stains red against blue background)

Question 4

How is tuberculosis spread?

Answer 4

inhaling saliva droplets

Question 5

5 types of TB infection?

Answer 5

Immediate clearance of the bacteria (in most cases)
Primary active tuberculosis (active infection after exposure)
Latent tuberculosis (presence of the bacteria without being symptomatic or contagious)
Secondary tuberculosis (reactivation of latent tuberculosis to active infection)
Miliary TB - immune system cannot control infection

Question 6

Is a pt with latent TB infectious and why/ why not?

Answer 6

Not infectious as immune system encapsulates bacteria

Pt have no symptoms and cannot pass on

latent TB can reactivate (often due to immunosuppression) = secondary TB

Question 7

Where does TB tend to infect and why?

Answer 7

the lungs due to lots of oxygen for the bacteria

can have extrapulmonary TB

Question 8

Risk factors of TB?

Answer 8

close contact with someone infectious
immunocompromised
Malnutrition, homelessness, drug users, smokers and alcoholics

Question 9

Can TB be vaccinated against?

Answer 9

Yes - BCG vaccine - line attenuated
not a routine vaccine

Question 10

Presentation of tuberculosis?

Answer 10

chronic, gradually worsening symptoms

Cough
Haemoptysis (coughing up blood)
Lethargy
Fever or night sweats
Weight loss
Lymphadenopathy
Erythema nodosum (tender, red nodules on the shins caused by inflammation of the subcutaneous fat)
Spinal pain in spinal tuberculosis (also known as Pott’s disease of the spine)

Question 11

Investigations for tuberculosis?

Answer 11

Mantoux test
Interferon‑gamma release assay (IGRA)
Chest x-ray
Cultures

Question 12

what is the Mantoux test?

Answer 12

test for TB - TB proteins injected under skin. 72 hours - pos test is a 5mm lump

Question 13

what could an CXR show in primary TB?

Answer 13

patchy consolidation
pleural effusions
hilar lymphadenopathy

Question 14

what could reactivated TB show on CXR?

Answer 14

patch or nodular consolidation with cavitation, typically upper zones

Question 15

What could Disseminated miliary tuberculosis show on CXR?

Answer 15

millet seed appearance uniformly across the lungs

Question 16

2 ways to treat latent TB?

Answer 16

Isoniazid and rifampicin for 3 months
Isoniazid for 6 months

Question 17

How to treat active TB?

Answer 17

RIPE

R – Rifampicin for 6 months
I – Isoniazid for 6 months
P – Pyrazinamide for 2 months
E – Ethambutol for 2 months

Question 18

What else must be prescribed alongside RIPE for active TB and why?

Answer 18

pyridoxine or vitamin B6

Isoniazid causes peripheral neuropathy

Question 19

What are the side effects of treatment for active TB?

Answer 19

Rifampicin - red/orange secretions
Isoniazid - peripheral neuropathy
Pyrazinamide - hyperuricaemia
Ethambutol - colour blindness and reduced visual acuity