Tuberculosis

Question 1

Cause of Tuberculosis

Answer 1

Mycobacterium tuberculosis

Question 2

Transmission of Tuberculosis

Answer 2

• spread person to person by droplet nuclei through the air
• produced when a person coughs, sneezes, speaks, or sings

MUST HAVE PULMONARY OR LARYNGEAL TUBERCULOSIS TO SPREAD

Question 3

Key Points

Answer 3

• you cannot get TB from eating or drinking after someone
• you cannot get TB from dishes, utensils, clothing, or linens
• you do not need to wear gloves, caps, gowns
• there is not much more risk with flying

Question 4

Pathogenesis

Answer 4

tubercle bacilli is inhaled through the nose or mouth –> carried down the trachea into the lung by droplet nucleus –> once reaching alveoli, they multiply freely for 2 to 10 weeks –> bacilli can then spread unopposed from the initial location (lung) to the lymph nodes in the chest –> from the lymphatic system, the bacilli can spread to other parts of the body through the blood stream

Question 5

Susceptible Areas to TB Downstream

Answer 5

upper portions of lungs
kidneys
spine
brain
bone

Question 6

Latent TB

Answer 6

• bacilli in the body
• positive skin test/TGRA
• normal chest xray
• no symptoms
• negative sputum
• infected: yes
• infectious: no

5-10% of patients will develop active TB

Question 7

Active TB

Answer 7

• bacilli in the body
• positive skin test/IGRA
• abnormal chest xray
• symptoms present
• positive sputum
• infected: yes
• infectious: yes

Question 8

Epidemiology

Answer 8

• second leading cause of death due to infectious disease in the world
• Hot spots: sub-saharan Africa, India, South Asia
• in 2019, the 30 high TB burden countries accounted for 87% of new TB cases

Question 9

Resistant Strains

Answer 9

• becoming resistant to almost all standard treatment
• the multidrug and extreme resistant cases must be treated by TB experts

Question 10

Countries leading TB Cases

Answer 10

1. India
2. Indonesia
3. China
4. Philippines
5. Pakistan
6. Nigeria
7. Bangladesh
8. South Africa

Question 11

Clinical Presentation

Answer 11

• 70-80% of the infections involve the lungs
• cough, fever, hemoptysis, weight loss (anorexia), night sweats

HEMOPTYSIS DISTINGUISHES SYMPTOMS OF TB FROM THE FLU

Question 12

Drug Therapy

Answer 12

Latent:
- Isoniazid x 9 months
- Isoniazid + Rifapentine x 12 weeks
- Rifampin x 4 months

Active:
- Isoniazid + Rifampin + Ethambutol + Pyrazinamide x 2 months then Isoniazid + Rifampin x 4-7 months

FOR ACTIVE TB, DIRECT OBSERVED THERAPY FOR 6-9 MONTHS

Question 13

Cost of Treatment

Answer 13

Drug Sensitive: $49,000

MDR-TB: $393,000

XDR-TB: $758,000

Question 14

Rifampin ADR & Monitoring Parameters

Answer 14

ADR:
- hepatotoxicity
- lupus like syndrome
- peripheral neuropathy
- monoamine toxicity

Monitoring:
- LFT
- flushing & tingling in hands/feet

Question 15

Isoniazid ADR & Monitoring Parameters

Answer 15

ADR:
- hepatotoxicity
- flu like syndrome
- GI upset
- hemolytic anemia
- thrombocytopenia
- renal failure
- orange/discoloration of body fluids

Monitoring:
- LFT, CBC, SCr

Question 16

Pyrazinamide ADR & Monitoring Parameters

Answer 16

ADR:
- hepatotoxicity
- hyperuricemia
- arthralgia
- rash
- GI upset

Monitoring:
- LFT, SCr, uric acid

Question 17

Ethambutol

Answer 17

ADR:
- optic neuritis (blurred vision)
- hyperuricemia

Monitoring:
- SCr, visual acuity/colored vision

Question 18

Prevention

Answer 18

• adequate ventilation
• cough etiquette
• avoidance of crowded environments
• protective gear
• screening
• vaccination

Question 19

Vaccine

Answer 19

Bacille Calmette-Guerin (BCG)
- most foreign born people have been vaccinated
- used in high prevalence of TB countries to prevent childhood TB
- not commended in US

Question 20

Why is BCG Vaccine not recommended in US

Answer 20

• low risk of infection
• variable effectiveness of vaccine
• vaccines potential interference with TB skin tests