Pneumonia Flashcards

1
Q

Who does pneumonia most commonly affect

A
  • Young children
  • Elderly
  • Immunocompromised
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2
Q

Which bacteria cause pneumonia

A
  • Most commonly streptococcus pneumoniae
  • Haemophilus influenzae
  • Mycoplasma pneumoniae
  • RSV,influenza,staphyloccous aureus, klebsiella pneumoniae, pneumocystis jirovecii

-The following cause atypical/walking pneumonia chlamydophilia pneumoniae,legionella pneumonia

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3
Q

How is pneumonia spread?

A
  • Nasopharyngeal aspiration
  • droplet spread
  • Inhalation of airborne microorganisms
  • Haematogenous spread
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4
Q

Describe the components of the respiratory immune system

A
  1. ) Mucociliary clearance: entrapment in mucus, ciliary escalator
  2. )Alveolar macrophages: phagocytosis, inflammation
  3. ) Neutrophils: phagocytosis
  4. )Complement&antibodies: opsonisation, agglutination
  5. )Lymphocytes: inflammation, activation of other immune cells
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5
Q

Describe the pathophysiology of pneumonia

A
  • Alveoli with pus
  • Impaired gas exchange
  • SIRS
  • Bacteraemia
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6
Q

What makes up the pus that fills the alveoli?

A
  • Pathogen
  • Congestion: vascular engorgement, intra-alveolar fluid
  • Red hepatisation: exudation of RBCs, neutrophils, fibrin
  • Grey hepatisation-Disintegration of RBC,persisting inflammatory cells
  • Resolution
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7
Q

What is red hepatisation?

A

-Red cells,neutrophils &fibrin present in the alveoli

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8
Q

What is grey hepatisation?

A
  • Follows red hepatisation

- The red cells have been broken down leaving a fibrinosuppurative exudate

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9
Q

How does the lung appear in pneumonia?

A

-Large & heavy

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10
Q

What are the symptoms of infection?

A
  • Dyspnoea
  • Cough
  • Sputum+/- purulence
  • Fever
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11
Q

What are the clinical signs of infection?

A
  • Tachypnoea
  • Tachycardia
  • Hypotension
  • Pyrexia
  • Crackles
  • Whispering pectoriloquy,increased tactile fremitus and vocal resonance
  • Cental cyanosis
  • Altered mental status
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12
Q

What investigations can we use when trying to diagnose pneumonia?

A
  • Arterial blood gas( ABG)
  • Chest X ray (CXR)
  • Full blood count (FBG)
  • U&E, CRP, liver function test (LFT)
  • Blood & sputum cultures
  • Viral PCR
  • Atypical serology
  • Urine Ag for Legionella & S.pneumoniae
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13
Q

What is systemic inflammatory response syndrome?

A
  • Serious condition related to systemic inflmmation, organ dysfunction and organ failure
  • Subset of cytokine storm in which there’s abnormal regulation of various cytokines
  • Closely related to sepsis, in which patients satisfy criteria for SIRS and have a suspected or proven infection
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14
Q

What are the 4 SIRS criteria?

A
  • Tachycardia(HR>90bpm)
  • Tachypnea(RR>20 Breaths/min)
  • Fever
  • Hypothermia (temp>38 or <36)

3 additional criteria…

  • Leukocytosis
  • Leukopenia
  • Bandemia
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15
Q

What are the 4 stages of pneumonia?

A

1.) Congestion days 1-2
2.)Red hepatisation dqays 3-4
3.) grey hepatisation days 5-7
4.)Resolution day 8-3 weeks
NB hepatisation refers to the lung taking on a lung like appearance

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16
Q

Outline the use of antibiotics in pneumonia

A
  • Should be used within 4 hours
  • Empirical (& broad spectrum if patient unwell) at intitiation, then narrow if specific organism cultured
  • OP- Penicillin derivative
  • IP moderate severity- penicillin derivative+ macrolide
  • IP severe- iv Blactamase resistant Abx + macrolide
17
Q

What is the role of S.pneumoniae in pneumonia?

A
  • Most common pathogen
  • Especially post influenza
  • More common with splenic dysfunction
  • Capsule that inhibits phagocytosis
  • Pneumolysin-cytotoxic toxin
  • Culture and urine Ag
  • Usually very sensitive to penicillin
18
Q

How is pneumonia managed according to the ABCDE method?

A

A-Ensure patent airway
B-Oxygen to maintain desired saturation range (mechanical ventilation)
C-IV fluids if required (inotropes, haemofiltration)
D-GCS
E-Analgesia, antipyretics, antibiotics

19
Q

How do we diagnose pneumonia?

A
  • Cytology- intranuclear or cytoplamic inclusion bodies
  • Viral culture
  • PCR
  • Rapid Ag detection
  • Serology
20
Q

How are infections of the lung managed?

A
  • Largely supportive
  • Influenza-amantadine
  • RSV-ribavirin
  • HSV,VZV-aciclovir
21
Q

What is the role of S.aureus in pneumonia?

A
  • More common post influenza
  • Common in IVDU-likely haematogenous spread
  • increased risk of rapidly progressing necrosis and cavitation
  • often associated GI Sx
  • Has a variety of toxins-rarely develop toxic shock syndrome( superantigens that cause widespread T cell activation and cytokine release)
  • Flucloxicillin
22
Q

What is Legionnaire’s disease?

A
  • A serious pneumonia caused by the legionnaire bacteria
  • Contaminated water supply often seen in endemic outbreaks
  • Resist intracellular killing by alveolar macrophages unless activated by Th cells
  • Neuro Sx-confusion,agitation,ataxia, lethargy
  • Gi Sx- watery diarrhoea, abdominal pain,
  • other systems- myo/peri-carditis, cellulitis, pancreatitis
  • Pontiac fever-flu-like, self limiting
23
Q

Outline atypical pneumonia

A
  • More systemic Sx( myalgia,fatigue,headache, often non-productive cough)
  • CXR- often multilobar
  • Mycoplasma pneumoniae
  • Chlamydophila pneumoniae
24
Q

Outline aspiration pneumonia

A
  • Alcohol excess

- Dysphagia/GORD

25
Q

What is CURB-65?

A

A scale for calculating the severity of pneumonia. Can be used to calculate mortality

26
Q

Which factors are included in the CURB-65 scale

A
  • Confusion, AMTS< OR =8
  • Serum urea>7 mmol/L
  • RR> OR = 30
  • Systolic BP>90 or diastolic BP< OR= 60mmHg
  • Age > OR =65
27
Q

What are the different types of acquired pneumonia?

A
  • Community acquired pneumonia
  • Hospital acquired pneumonia
  • Viral pneumonia
  • Atypical pneumonia
  • Aspiration pneumonia
28
Q

What is the role of S.pneumoniae in pneumonia?

A
  • Most common pathogen
  • Especially post influenza
  • More common with splenic dysfunction
  • Capsule that inhibits phagocytosis
  • Pneumolysin-cytolytic toxin
  • Culture and urine Ag
  • Usually very sensitive to penicillin
29
Q

Outline hospital acquired pneumonia.

A
  • Inhalation/aspiration/haematogenous
  • More gram -ve organisms e.g Ecoli
  • Increased risk of drug resistance
  • Broader spectrum antbiotics e.g antipseudomonal penicillins, aminoglycosides, MRSA cover
30
Q

Pneumonia may take advantage of an immunocompromised host; how may this host be brought about?

A
  • Neutrophil defect: post chemo, AML, bacteria,filamentous fungi
  • Antibody defect
  • T cell defect
  • High dose steroids
31
Q

How can aspergillus cause pneumonia?

A
  • Ubiquitous mould, inhaled
  • Has toxic metabolites that inhibit macrophage and neutrophil function
  • Immunosuppressed, allowing haematogenous spread
32
Q

What is the role of nocardia in pneumonia?

A
  • genus of bacteria
  • Often affects patient with T cell dysfunction
  • pneumonia with cavitation & abscesses, empyema or inflammatory endobronchial lesions
  • Often concurrent non tender erythrmatous nodules that may drain purulent material
33
Q

How can HIV make someone more prone to developing pneumonia?

A
  • Increased risk of bacterial pneumonia
  • Increased risk of infection with endemic mycoses. and more likely to be disseminated
  • With low CD4 high risk of diseminated mycobacterium avium/ intracellulare
  • cryptococcal pneumonia more likely to be symptomatic
34
Q

How may a person become immunosuppressed ( thus making them more prone to pneumonia)?

A
  • Malignancy
  • Steroids
  • Asplenia
  • Diabetes mellitus
  • CKD
35
Q

List some of the differential diagnoses of pneumonia

A
  • Malignancy
  • vasculitides
  • infarcted lung, PE
  • Pulmonary oedema
36
Q

What complications may arise from pneumonia?

A
  • Septic shock
  • Adult respiratory distress syndrome
  • Parapneumonic effusion & empyema
  • Cavitation &abscess
  • MI
37
Q

What is Legionnaire’s disease

A

-Contaminated water supply often seen in endemic
outbreaks – cooling towers, humidifiers, portable
water distribution
-Resist intracellular killing by alveolar macrophages
unless activated by Th cells
- Neuro Sx – confusion, agitation, ataxia, lethargy
-GI Sx – watery diarrhoea, abdominal pain, N,V
-Other systems – myo/peri –carditis, cellulitis,
pancreatitis
-Pontiac fever – flu-like, self limiting

38
Q

How can we use a chest c-ray to diagnose different types of pneumonia

A
  1. ) bronchopneumonia- patchy areas spread throughout
  2. )lobar pneumonia- fluid localised to a single lobe
  3. ) atypical pneumonia- spread throughout the lung but concentrated in the peri-hilar region& reticular pattern (there will be more lined shape opacities in the chest c-ray_
39
Q

which examinations will help in the diagnosis of pneumonia

A
  • Dullness to percussion: indicates lung consolidation
  • Tactile vocal fremitus:more vibrations from pts back on repeating certain phrases cos sound travels better through the fluid filled consolidated tissue than the air filled healthy tissue
  • bronchophony &egophony may be heard