Pneumonia Flashcards
Pneumonia definition
Pneumonia is an acute inflammation of the terminal bronchioles and the area surrounding the alveoli.
Epidemiology of pneumonia
0.5-1% of people develop CAP in the UK every year, with mortality between 5-14%
Bacteria that cause pneumonia
- MRSA
- TB
- Streptococcus pneumoniae
- Haemophilus influenzae
- Staphylococcus aureus
- Klebsiella pneumonia
- Pseudomonas aeruginosa
What viruses cause Pneumonia?
- Respiratory syncytial virus (RSV)
- Influenza
What fungi cause pneumonia?
Pneumocystic jirovicii
What are idiopathic intersitial pneumonias?
group of non-infective causes e.g. cryptogenic organising pneumonia which may occur as a complication of rheumatoid arthritis or amiodarone use.
RFs for Pneumonia
- Extremes of age: young children and the elderly are particularly at risk
- Preceding viral infection
- Immunosuppressed: e.g. due to steroid use
- Intravenous drug abuse:Staphylococcus aureus
- Respiratory conditions: asthma, COPD, malignancy, cystic fibrosis
Pneumonia is secondary to inflamamtion, what does inflammation do in the lungs?
brings water into the lung tissue, which makes it harder to breathe.
What do microbes do in pneumonia?
- Enter and evade body defences
- Multiply and cross over from airways into lung tissue > inflammatory respionse
What happens to lung tissue as it inflammed?
tissue fills with white blood cells as well as proteins, fluid, and red blood cells if a nearby capillary is damaged in the process.
Pneumonias categorised by how its acquired - what are the 2 types of pneumonia?
- Community acquired pneumonia (CAP): pneumonia acquired outside a hospital setting
- Hospital-acquired pneumonia (HAP): pneumonia that develops more than 48h after hospital admission
What is aspiration pneumonia?
- due to foreign material lodging in the lungs.
- Microbes on the foreign material can cause infection.
- Aspiration pneumonia can also happen with drinks, or vomiting of gastric contents.
What is atypical pneumonia?
pneumonia caused by an organism that cannot be cultured in the normal way or detected using a gram stain.
They don’t respond to penicillins and can be treated with macrolides (e.g. clarithomycin), fluoroquinolones (e.g. levofloxacin) or tetracyclines (e.g. doxycycline).
What is bronchopneumonia?
infection can be throughout the lungs involving the bronchioles as well as the alveoli.
What is atypical/interstitial pneumonia?
infection is mainly just outside the alveoli in the interstitium.
What is lobar pneumonia?
infection causes complete consolidation of a whole lobe of the lung.
S + S of Pneumonia
Pyrexia
Tachycardia
Hypoxia
Dyspnoea
Fever
Pleuritic chest pain
Productive cough
Primary investigations for pneumonia
- CXR
- FBC:leukocytosis
- U&Es:deranged in severe disease
- CRP:raised
- ABG:perform if hypoxic to assess for respiratory failure
- Sputum culture:allows assessment of organism and antibiotic sensitivities
What is CURB-65?
Criteria for pneumonia - nazias note good explanation
Initial management for Pneumonia
- O2, if needed
- Analgesia
- Antibiotics: will vary by trust
Management for Community acquired pneumonia
- Low severity (CURB ≤ 1):oral amoxicillinORdoxycycline/clarithromycin if penicillin-allergic or an atypical pathogen is suspected; usually a 5 day course
- Moderate severity (CURB 2): amoxicillin;addclarithromycin if an atypical pathogen is suspected; usually a 5 day course
- High severity (CURB ≥ 3):IV co-amoxiclavandclarithromycin are often used
Treatment for Hospital acquired pneumonia
Severity is determined clinically
- Low severity:oral co-amoxiclav
- High severity:a**broad-spectrum antibiotic, such as IV tazocin or ceftriaxone
- Suspected or confirmed MRSA:add vancomycin
When should you not discharge a patient with CAP?
if in the last 24 hours they have had 2 or more of the following:
- Temperature > 37.5°C
- RR ≥ 24
- HR ≥ 100
- SBP ≤ 90 mmHg
- SpO2≤ 90% on room air
- Abnormal mental status
- Inability to eat without assistance
Complications of Pneumonia
- Acute respiratory distress syndrome:associated with a 30-50% mortality rate and usually requires mechanical ventilation
- Sepsis:complicates severe CAP and may be fatal, particularly in immunocompromised patients
- Lung abscess:may require prolonged antibiotic therapy and drainage; can occur due toKlebsiellaorStaphylococcalpneumonia
- Pleural effusion:parapneumonic effusions can either be sterile or infected (empyema
Most common community acquired pneumonia bacteria
Streptococcus pneumonia - 80% of pneumonia
Haemophilus influenza - COPD assosciate
SA - causes secondary bacterial infection
Common bacteria for HAP
Gram negative bacteria and SA
Aspirational pneumoniae bacteria
Klebsiella pneuomniae
Streptococcus pneumoniae
SA
What is pneumocystis pneumonia?
Pneumocystis pneumonia (PCP) is an opportunistic respiratory infection caused by the fungus, Pneumocystis jirovecii.
PCP epidemiology
- PCP is the most common opportunistic infection in patients with AIDS.
- 40% of people with PCP have HIV/AIDS, whilst the remaining people are typically immunosuppressed due to conditions such as leukaemia, inflammatory diseases and solid organ transplantation.
RFs for PCP
- HIV/AIDS: PCP is associated with a CD4 count < 200/mm^3
- Primary immunodeficiency conditions
- Secondary immunodeficiency: e.g. steroids
- Other causes of immunosuppression: e.g. haematological malignancies
S + S of PCP
CXR often normal
Lymphadenopathy
Hepatosplenomegaly
Dyspnoea
Pyrexia
Cough
Fever
Primary investigations for PCP
- Oxygen saturation:patients with PCP characteristically desaturate onexertion
- Arterial blood gas:type 1 respiratory failure
- Chest X-ray:may reveal bilateral interstitial infiltrates but can be normal
- Induced sputum:silver staining to identify PCP
Other investigation for PCP
Broncho-alveolar lavage
High res CT chest
HIV serology and CD4 count
Treatment for PCP
- Trimethoprim/sulfamethoxazole (co-trimoxazole):first-line therapy
- Prednisolone:indicated if hypoxic with pO2< 9.3 kPa, to reduce the risk of respiratory failure (< 50% risk) and death
- ## IV/ nebulised pentamidine:this is reserved for severe cases where co-trimoxazole is contraindicated or has failed
Prophylaxis for PCP
Trimethoprim/sulfamethoxazole (co-trimoxazole): primary prophylaxis is recommended in all patients with a CD4 < 200/mm3 or a history of an AIDS-defining illness
