MICRO: LRTIs

Question 1

pneumonia
- how does the organism reach the lungs
- size of particles that can reach alveoli
- onset
- Sx

Answer 1

• inhalation, aspiration, blood (uncommon)
• particles < 5um reach the alveoli
• sudden onset
• Sx: high fever and chills, productive cough, purulent (infected) sputum, pleurisy (pleuritis), SOB, crackles

Question 2

ATYPICAL pneumonia
- aetiology
- Sx
- Tx

Answer 2

• M. pneumoniae, viruses (RSV, influenza, CMV), fungal - pathogens that lack a typical cell wall
• Sx: gradual onset, low-grade fever, dry cough, minimal or absent pleural pain
• Tx: penicillin not effective but certain antibiotics (e.g. macrolides, tetracyclines and fluoroquinolones) can be used

Question 3

Dx of atypical pneumonia

Answer 3

• serology, PCR - bc no typical cell wall

Question 4

what is pneumonia

Answer 4

• infection of the lungs causing inflammation > brings water into lungs causing dyspnoea and hypoxia
• can be community acquired or nosocomial

Question 5

pneumonia
- aetiology

Answer 5

• viral: influenza
• bacterial: S. pneumoniae (most common), H. influenzae, S. aureus, M. tuberculosis
• can also be fungal but rare

Question 6

3 types of pneumonia

Answer 6

• bronchopneumonia: throughout bronchioles and alveoli
• atypical/interstitial
• lobar: whole lobe of the lung filled with fluid (usually bacterial)

Question 7

pneumonia Dx + Tx

Answer 7

• Dx: nasal swabs, sputum culture, urinary, bloods, CXR, bronchoscopy
• Tx: antibiotics

Question 8

influenza
- virus type
- pathogenesis
- antigenic shift and drift

Answer 8

• -ve sense ssRNA virus
• infects ciliated epithelium > cytokine storm
• antigenic drift: uses haemagglutinin to enter cell and neuraminidase to exit cells > these can mutate
• antigenic shift: has 8 pieces of RNA which can recombine w/ other viruses to make a whole new virus

Question 9

influenza
- Sx
- Dx
- Tx and prevention

Answer 9

• Sx: fever, cough, sore throat
• Dx: clinical, could do PCR
• Tx: symptomatic, antivirals if hospitalised or if risk of complications (prevention = vaccination)

Question 10

tuberculosis
- aetiology
- transmission
- Sx

Answer 10

• aetiology: M. tuberculosis
• transmission: inhalation of airborne respiratory droplets
• Sx: majority asymptomatic - haemoptysis, cachexia, malaise, fever + chills, cough, night sweats

Question 11

tuberculosis pathogenesis

Answer 11

• persists inside alveolar macrophages = inflammatory response
• infected macrophages clump together into a granuloma and can remain latent and persist for decades
• healthy person = will likely be eliminated or permanently latent
• immunocompromised ppl = granuloma can burst, reactivate and spread to other parts of the body via lymphatics

Question 12

tuberculosis Dx

Answer 12

• acid fast stain

Question 13

whooping cough
- aetiology
- pathogenesis
- transmission
- Sx

Answer 13

• B. pertussis
• toxins kill cilia = decreased mucus clearance
• transmission: severe, contagious childhood disease spread via droplets
• Sx: apnoea, persistent whooping cough followed by vomiting

Question 14

stages of B. pertussis infection

Answer 14

• catarrhal: low-grade fever, mild cough
• paroxysmal: numerous rapid coughs, long inspiratory effort accompanied by whoop, cyanosis, vomiting, exhaustion
• convalescent: gradual reduction in cough frequency and severity

Question 15

acute bronchitis:
- aetiology
- pathogenesis
- Sx

Answer 15

• viral: rhinovirus, coronavirus, adenovirus
• pathogenesis: acute inflammation of bronchial wall = increased mucus production + oedema
• Sx: productive cough, fever

Question 16

Dx and Tx of acute bronchitis

Answer 16

• Dx: clinical, may do X-ray to exclude pneumonia
• Tx: symptomatic e.g. bronchodilators or anti-cough

Question 17

acute bronchiolitis:
- aetiology
- pathogenesis
- Dx

Answer 17

• viral: RSV, rhinovirus, adenovirus, human bocavirus
• infection of bronchiole epithelium = necrosis, inflammation, oedema
• Dx: oximetry

Question 18

Sx and Tx for bronchiolitis

Answer 18

• Sx: cough, tachypnoea, wheezing, fever, crackling sounds, fluctuating clinical findings
• Tx: oxygene, hydration, ribavirin (if RSV)

Question 19

tuberculosis
- aetiology
- pathogenesis
- Sx

Answer 19

• M. tuberculosis
• deposits and multiplies in alveolar macrophages - can become latent or more severe
• Sx: cough, fever, night sweats, cachexia

Question 20

empyema
- aetiology
- pathogenesis
- Sx
- Tx

Answer 20

• results from bacterial pneumonia, usually polymicrobial
• end-stage pleural inflammation - lungs fill with pus = fibrosis of pleura
• Sx: pyrexia, dull percussion, reduced breath sounds, vocal resonance
• Tx: empirical antibiotics + fluid drainage