Pneumonia Flashcards

1
Q

How can pneumonia be classified?

A
  • Anatomic distribution e.g bronchopneumonia/lobar pneumonia
  • Etiology e.g primary/secondary
  • Clinical setting e.g community acquired/healthcare associated
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2
Q

Describe lobar pneumonia

A
  • Usually involves an entire lung - entire lobe affected
  • Usually caused by Strep. pneumoniae
  • Congestion, red and gray hepatization and resolution are present
  • Opacification of entire lobe present on CXR
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3
Q

Describe bronchopneumonia.

A
  • Patchy consolidation in lobe of lung
  • Gravitation of secretions means can be bilateral basal in location
  • Affects extremes of ages i.e infants and elderly
  • CXR shows patchy opacification of lobe
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4
Q

Describe typical pneumonia

A
  • Caused by extracellular organisms e.g bacteria
  • Characterised by neutrophilic infiltration and presence of intra-alveolar exudates (causing consolidation)
  • Acute onset of high graded fever and mucopurulent cough
  • May be associated with pleuritic pain
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5
Q

Describe atypical pneumonia

A
  • Caused by intracellular organisms e.g Chalmyida pneumoniae and viruses e.g rhinovirus and influenza
  • Associated with lymphocytic infiltration and alveolar septal and interstitial inflammation
  • Absence of alveolar exudates
  • CLINICAL FEATURES - fever, dry cough, headache, myalgia
  • PRODUCTIVE COUGH, PLEURAL INVOLVEMENT - UNCOMMON
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6
Q

Give examples of community acquired and hospital acquired infections.

A
  • COMMUNITY - Strep, pneumoniae, Staph. aureus, Mycoplasma/Chlamydia pneumoniae
  • HOSPITAL - E. coli, Pseudomonas, MRSA
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7
Q

What are some predisposing factors for lobar pneumonia?

A

Patients with the following
- Immunosuppression
- Neurological impairment of cough reflex
- Secretion retention
- Pulmonary oedema
- Impaired mucociliary clearance
- Respiratory tract infection (viral)
- Antibiotics/cytotoxics
- Tracheal instrumentation
- Impaired alveolar macrophages
- Other/Neoplasia
ACRONYM - INSPIRATION

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8
Q

Describe characteristics of lobar pneumonia.

A
  • Common in adults (vagrants and alcoholics)
  • Microorganisms gain entry to distal air spaces
  • If treated promptly, recover
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9
Q

Describe the natural evolution of bacterial lobar pneumonia.

A
  • RED HEPATISATION - Acute pneumonia
  • GREY HEPATISATION - Sub-acute pneumonia
  • RESOLUTION - Organising pneumonia
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10
Q

What are the pathological stages of lobar pneumonia? PART 1

A
  • CONGESTION - outpouring of protein-rich exudate into alveoli
  • RED HEPATISATION - accumulation of RBCs and polymorphs in alveolar spaces - appears like the alveoli
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11
Q

What are the pathological stages of lobar pneumonia? PART 2

A
  • GREY HEPATISATION - accumulation of fibrin in lung spaces with red cell disintegration
  • RESOLUTION - recover - lungs return to normal structure and function
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12
Q

What causes pleuritic chest pain in pneumonia?

A
  • Pleurisy - inflammation of the pleura
  • Pleura become red and inflamed
  • Rub against one another when lungs expand to breathe in air
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13
Q

What causes dullness to percussion?

A
  • Usually resonates due to presence of air
  • Appears dull due to solid appearance of lung
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14
Q

What does C-reactive protein indicate?

A
  • Activated during the immune response
  • High CRP count indicates bacterial infection
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15
Q

When a patient is diagnosed with community-acquired pneumonia, what further tests might be sent to find out the cause of infection?

A
  • SPUTUM - Gram stain and culture
  • BLOOD - culture
  • Nasal swabs - test for influenza and COVID
  • Urine - test for legionella and pneumococcal antigens
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16
Q

What does pneumonia diagnosis in the hospital rely on?

A
  • Symptoms and signs of acute lower respiratory tract infections
  • Opacities on CXR not due to other causes
17
Q

What are the key diagnostic factors for community-acquired pneumonia?

A
  • Cough with increasing sputum production
  • Dyspnoea
  • Pleuritic chest pain
  • Rigors/night sweats
18
Q

What are some other diagnostic factors considered in community-acquired pneumonia?

A
  • Myalgia
  • Malaise
  • Anorexia
  • Lethargy
19
Q

Describe the CURB-65 test.

A
  • Higher CURB score, greater risk of mortality
  • CONFUSION
  • UREA > 7 mmol per litre
  • Respiratory rate > 30
  • BP - Systolic < 90 OR Diastolic < 60 mmHg
  • Age > 65
20
Q

What is the most common cause of community acquired pneumonia?

A

Strep. pneumoniae

21
Q

What is bronchopneumonia characterised by?

A
  • Patchy distribution affecting one or more lobes
  • Inflammatory infiltrate extending from bronchioles into adjacent alveoli
22
Q

What are the main characteristics of bronchopneumonia?

A
  • Common in infancy and old age
  • Pre-disposing conditions are debility and immobility
  • Primary infection centred at bronchi can spread to adjacent alveoli
  • Involvement of pleura - pleurisy common
23
Q

What cases is bronchopneumonia particularly frequent in?

A
  • Terminal event in chronic debilitating disease
  • In infancy and old age
  • Secondary infection to viral conditions
24
Q

What are the pathological features of bronchopneumonia?

A
  • Inflammation spreads from terminal bronchioles to related alveoli
  • Lesions initially focal - involve one or more lobules
  • Red to grey to bronchiole containing pus
25
Q

Describe the macroscopic features of bronchopneumonia.

A
  • Slightly elevated, dry, granular, grey-red to yellow areas with poorly defined margins
26
Q

Describe the microscopic features of bronchopneumonia.

A
  • Neutrophil-rich exudate filling bronchi, bronchioles and adjacent alveolar spaces
27
Q

Name four types of acute pneumonias based on clinical setting.

A
  • Community-acquired
  • Hospital-acquired (nosocomial)
  • Immunocompromised
  • Aspiration
28
Q

Describe nosocomial pneumonia. PART 1

A
  • Pulmonary infections acquired in course of hospital stay
  • Patients at risk - patients on ventilation, on immunosuppression, with severe underlying diseases and prolonged antibiotic regimens
29
Q

Describe nosocomial pneumonia. PART 2

A
  • Most common agents - Gram-negative rods e.g Pseudomonas, Enterobacteria and Staph. aureus
  • Adverse impact on clinical course of ill patients and heightened cost of care
30
Q

What are the risk factors for hospital acquired pneumonia?

A
  • Advanced age
  • Chronic underlying disease
  • Immunosuppression
  • Obesity and malnutrition
  • Smoking, drug abuse and alcohol abuse
  • Altered levels of consciousness
31
Q

What are the risk factors for lobar pneumonia?

A
  • Prolonged hospital/nursing home stay
  • Chronic illness
  • Prior antibiotic exposure
  • Home infusion therpay/wound care
  • Recent hospital admission
  • Immunosuppression
  • Haemodialysis
32
Q

Describe what can cause pneumonia in immunocompromised hosts.

A
  • Diseases such as AIDS
  • Immunosuppressive drugs
  • Therapeutic irradiation
  • Opportunistic pathogens - bacteria e.g Pseudomonas aerguinosa, Legionella pneumophila, viruses e.g herpesvirus and fungi
  • Splenectomy, chemotherapy-induced neutropenia and abnormal T-lymphocyte function
33
Q

When does aspiration pneumonia occur?

A
  • When fluid or food aspirated into lung
  • Causes secondary inflammation and consolidation
34
Q

Describe the characteristics of aspiration pneumonia. PART 1

A
  • POPULATION AT RISK - debilitated patients or those aspirate gastric contents whilst unconscious or during repeated vomiting
  • Can be caused chemically or bacterially
  • Most common agents are anaerobic oral flora and aerobic bacteria
35
Q

Describe the characteristics of aspiration pneumonia. PART 2

A
  • Often necrotising
  • Fulminant evolution
  • COMPLICATIONS - Death and abscess formation
36
Q

What are the complications of pneumonia? PART 1

A
  • LUNG FIBROSIS - inflammatory exudate not fully absorbed - organised with residual fibrous scarring - causes lung dysfunction
  • BACTERAEMIA - leading to septicaemia with meningitis, arthritis, enddocarditis
  • LUNG ABSCESSES - single/multiple areas of suppuration
37
Q

What are the complications of pneumonia? PART 2

A
  • EMPYEMA - pus in pleural cavity due to extension of infection into pleural cavity
  • PLEURAL EFFUSION
  • DEATH