DISORDERS OF THE RESPIRATORY SYSTEM PART 3.3 (based on T)

Question 1

What is the global ranking of TB as a cause of death?

Answer 1

TB is the 13th leading cause of death worldwide and the second leading infectious killer after COVID-19.

Question 2

How many people were estimated to have TB worldwide in 2021?

Answer 2

10.6 million people.

Question 3

What is the estimated number of men, women, and children affected by TB in 2021?

Answer 3

6 million men, 3.4 million women, and 1.2 million children.

Question 4

How many people died from TB in 2021?

Answer 4

1.6 million people.

Question 5

Why is multidrug-resistant TB (MDR-TB) a public health crisis?

Answer 5

Because it remains a health security threat and only about 1 in 3 people with MDR-TB accessed treatment in 2021.

Question 6

What is the ranking of the Philippines in terms of TB cases worldwide?

Answer 6

The Philippines ranks 4th worldwide in TB cases.

Question 7

How many Filipinos have active TB?

Answer 7

About 1 million Filipinos.

Question 8

How many Filipinos die from TB daily?

Answer 8

Nearly 70 Filipinos die every day from TB.

Question 9

What is the morphology of Mycobacterium tuberculosis?

Answer 9

(ANSS)
Aerobic,
nonmotile, and
slightly curved or straight bacilli.

Question 10

What staining method is used to identify Mycobacterium tuberculosis?

Answer 10

Ziehl-Neelsen method (acid-fast staining).

Question 11

What component in the cell wall of Mycobacterium tuberculosis makes it unique?

Answer 11

Mycolic acid, a long fatty acid that gives the bacterium its characteristic resistance.

Question 12

What are the two classifications of mycobacteria?

Answer 12

M. tuberculosis complex and
Non-tuberculous mycobacteria (MOTT).

Question 13

What are the members of the Mycobacterium tuberculosis complex?

Answer 13

(TBAM)
M. tuberculosis,
M. bovis,
M. africanum, and
M. microti.

Question 14

What is the primary mode of transmission of TB?

Answer 14

Airborne transmission through inhalation of infectious droplets from a person with pulmonary or laryngeal TB.

Question 15

How many infectious droplets can a single cough or talking for 5 minutes produce?

Answer 15

3,000 infectious droplets.

Question 16

What is a rare mode of TB transmission?

Answer 16

Ingestion of contaminated unpasteurized dairy products from infected cattle or skin inoculation from an abrasion.

Question 17

Why are fomites not considered important in TB transmission?

Answer 17

TB is not transmitted through contaminated objects, so special handling of utensils and bed linens is unnecessary.

Question 18

Who are the most common sources of TB infection in children?

Answer 18

Infectious adolescents or adults, usually household contacts.

Question 19

Why is TB transmission from children under 10 years old uncommon?

Answer 19

Most children cannot expectorate sputum, and their sputum has a lower bacilli load than adults.

Question 20

What is the risk of untreated childhood TB infection?

Answer 20

It can remain dormant and reactivate as adult pulmonary TB.

Question 21

What factors influence the risk of TB infection in child contacts?

Answer 21

Proximity and duration of contact, degree of lung involvement, and sputum smear positivity of the index case.

Question 22

Why is the first week of TB treatment critical for adults?

Answer 22

Adults remain contagious until two weeks after starting anti-TB drugs.

Question 23

Which age group is at the highest risk for disseminated TB disease?

Answer 23

Children under four years old and infants with TB infection.

Question 24

What percentage of untreated latent TB infections progress to active TB?

Answer 24

5-10%.

Question 25

What factors increase the risk of TB infection?

Answer 25

Close contact with an infectious TB patient, overcrowding, and institutional settings like hospitals, prisons, and shelters.

Question 26

What factors influence the progression of TB infection to active disease?

Answer 26

Age, time after exposure, nutritional status, intercurrent diseases, immunosuppression, and lifestyle factors.

Question 27

What medical conditions increase the risk of TB reactivation?

Answer 27

HIV/AIDS, diabetes mellitus, silicosis, severe kidney disease, low body weight, organ transplants, and immunosuppressive treatments.

Question 28

What are the effects of chemotherapy on TB transmission?

Answer 28

Success or failure in treatment adherence impacts the spread and control of TB.

Question 29

What are common environmental factors that increase TB transmission risk?

Answer 29

Overcrowding and poor ventilation.

Question 30

How is TB transmitted and what is the portal of entry?

Answer 30

Through inhalation of infectious droplet nuclei, which are deposited in the alveoli.

Question 31

How many bacilli are generally required for successful TB infection?

Answer 31

Approximately 5-200 inhaled bacilli.

Question 32

What is the incubation period of TB?

Answer 32

3 weeks to 3 months, but can be shorter with a large inoculum.

Question 33

What is the first stage of TB pulmonary pathology?

Answer 33

Scavenging by non-activated alveolar macrophages that ingest the tubercle bacillus.

Question 34

What is the second stage of TB pulmonary pathology?

Answer 34

Symbiosis stage where macrophages fail to destroy bacilli, leading to uncontrolled replication.

Question 35

What happens in the third stage of TB pathology?

Answer 35

Cell-mediated immunity develops, inhibiting the logarithmic increase in bacilli.

Question 36

What are the two possible outcomes in the fourth stage of TB pathology?

Answer 36

4A: Weak immunity leads to widespread dissemination; 4B: Strong immunity leads to stabilization or regression of the tubercle.

Question 37

What characterizes the fifth stage of TB pathology?

Answer 37

Caseous liquefaction, extracellular bacillary growth, cavity formation, and bronchial dissemination.

Question 38

What is the primary lung lesion in primary TB called?

Answer 38

Ghon focus.

Question 39

Where is the Ghon focus typically located?

Answer 39

Subpleural area of the upper segment of the lower lobe or lower segment of the upper lobe.

Question 40

What is the Ghon complex?

Answer 40

A combination of the primary pulmonary focus, infected lymph nodes, and associated lymphangitis.

Question 41

What is the significance of lymphohematogenous spread in TB?

Answer 41

It is usually asymptomatic but can cause extrapulmonary lesions years later.

Question 42

What are the different clinical forms of tuberculosis (TB)?

Answer 42

TB can be pulmonary or extrapulmonary, including TB of the pancreas, bones, and other organs.

Question 43

What is latent TB infection?

Answer 43

Latent TB infection is asymptomatic, with the only clue being a positive tuberculin skin test (PPD).

Question 44

How is PPD (tuberculin skin test) administered?

Answer 44

PPD is done intradermally.

Question 45

What are the characteristics of latent TB?

Answer 45

Infection associated with tuberculin hypersensitivity and a positive tuberculin test, but no clinical or radiographic manifestations.

Question 46

What is the primary disease form of intrathoracic TB?

Answer 46

It occurs mostly in infants, with a higher risk of disease progression until age 5, and is also referred to as Primary TB.

Question 47

What is progressive primary TB disease?

Answer 47

A complication where the primary pulmonary focus enlarges, develops a caseous center, and leads to pneumonia, persistent cough, fever, malaise, and weight loss.

Question 48

What are common radiographic findings in primary TB?

Answer 48

Primary complex: primary focus, lymphangitis, and regional lymphadenitis, with or without pleural effusion.

Question 49

What is the significance of pleural effusion in TB?

Answer 49

Pleural effusion may be part of the Ghon complex or a complication of primary TB.

Question 50

What is endobronchial tuberculosis?

Answer 50

TB involving the bronchi due to peribronchial lymph node enlargement or direct nodal extension, leading to airway obstruction.

Question 51

What are potential complications of endobronchial TB?

Answer 51

Asphyxia, obstructive emphysema, atelectasis, and lobar hyperaeration.

Question 52

What symptoms are associated with endobronchial TB?

Answer 52

Moderate fever, anorexia, night sweats, weight loss, paroxysmal cough, cyanosis, and expiratory wheezes.

Question 53

What is pericardial TB?

Answer 53

TB involving the pericardium, often due to direct invasion or lymphatic spread from caseous subcarinal nodes.

Question 54

What are the clinical signs of pericardial TB?

Answer 54

Low-grade fever, anorexia, poor weight gain, chest pain, pericardial friction rub, distant heart sounds, tachycardia, and narrow pulse pressure.

Question 55

What are the diagnostic findings for pericardial TB?

Answer 55

CXR: Cardiomegaly; ECG: Low QRS amplitude, ST segment and T wave abnormalities; Pericardial fluid: Sanguinous with lymphocytic reaction.

Question 56

What is chronic pulmonary TB?

Answer 56

A more common form in adolescents with prior TB infection, presenting as chronic cough, fever, chest pain, and hemoptysis.

Question 57

What is miliary TB?

Answer 57

A generalized hematogenous TB with massive bloodstream invasion, often occurring within 3-6 months post-infection, primarily affecting infants and young children.

Question 58

What are the clinical features of miliary TB?

Answer 58

High fever, dyspnea, cough, prostration, and symptoms from systemic organ involvement.

Question 59

What is the characteristic radiographic finding in miliary TB?

Answer 59

Chest X-ray shows millet seed-like densities over the lung fields.

Question 60

What is tuberculoma?

Answer 60

A rounded lesion that develops as a residual of parenchymal TB, often containing caseous or granulomatous tissue with fibrous encapsulation and sometimes calcification.

Question 61

Why is tuberculoma often confused with malignancy?

Answer 61

Because it appears as a solid mass-like lesion on imaging.