Pneumonia Flashcards
What is pneumonia?
Respiratory infection characterized by inflammation of the alveolar space
What are the different ways pneumonia may be catergorised?
o Community-acquired
o Hospital-acquired/nosocomial
o Aspiration pneumonia:
*On chest x-ray the right lung is most commonly affected, as the right bronchus is wider and more vertical than the left bronchus, making it more likely to facilitate the passage of aspirate.
o Pneumonia in the immunocompromised
o Typical
o Atypical (Mycoplasma, Chlamydia, Legionella)
What are causes of community acquired pneumonia?
- Typical
- Streptococcus Pneumoniae → most common. May have rusty sputum.
- Haemophilus Influenzae → especially in COPD patients. Gram negative coccobacilli.
- Staphylococcus Aureus → IVDU and also occurs after influenza. Causes cavitating lesions (gas filled lesions) on CXR. Gram positive cocci found in clusters.
- Klebsiella Pneumoniae → alcoholics and diabetics. Causes cavitating lesions on CXR (typically upper lobe). Typically causes blood stained sputum (red-currant jelly appearance). Commonly due to aspiration. Commonly causes lung abscess formation and empyema. Gram negative bacillus. - Atypical
- Mycoplasma Pneumoniae → associated with erythema multiforme (ring-shaped rash) and autoimmune haemolytic anaemia (cold agglutins, IgM). Dx with serology and positive cold agglutination test.
- Legionella Pneumophilia → faulty air conditioning, recently returned from holiday. Causes hyponatraemia and abnormal LFTs. (Legionella = Low sodium and Liver derangement). Dx with urinary antigen.
- Chlamydia Psittaci → pet birds
- Pneumocystis Jirovecii → HIV (any immunosuppressed individual). Causes desaturation on exercise. Tx with co-trimoxazole (trimethoprim and sulfamethoxazole).
What are the causes of hospital acquired pneumonia?
The most common organisms are Pseudomonas aeruginosa, Staphylococcal aureus, and Enterobacteria.
- Staphylococcus Aureus → IVDU. Causes cavitating lesions on CXR. (MRSA = tx with Vancomycin)
- Pseudomonas Aeruginosa → CF and bronchiectasis.
(>48 hrs after hospital admission). Tx with Tazocin.
What are risk factors of for pneumonia?
- Age
- Smoking
- Alcohol
- Pre-existing lung disease (e.g. COPD)
- Immunodeficiency
- Contact with patients with pneumonia
Summarise the epidemiology of pneumonia
● 5-11/1000
● Community-acquired pneumonia is responsible for > 60,000 deaths per year in the UK
● High in very young or old
● Mortality: 21% in hospital
What are the presenting symptoms of pneumonia?
● Fever
● Rigors
● Sweating
● Malaise
● Dyspnoea
● Cough
● Purulent Sputum
● Haemoptysis
● Pleuritic chest pain
● Weight loss
● Confusion (in severe cases or in the elderly)
● Atypical Pneumonia Symptoms:
*Headache
*Myalgia
*Diarrhoea/abdominal pain
*DRY cough
What signs of pneumonia can be found on physical examination?
● Pyrexia
● Respiratory distress
● Tachypnoea
● Tachycardia
● Hypotension
● Cyanosis
● Signs of consolidation
*Decreased chest expansion
*Dull to percuss over affected area
*Increased tactile vocal fremitus/vocal resonance over affected area
*Bronchial breathing over affected area
*Coarse crackles on affected side
● Chronic suppurative lung disease (empyema, abscess) –> clubbing
● Confusion and may be hypothermic – elderly
What investigations are used to diagnose/ monitor pneumonia?
- Basic observations
- Sputum culture- MC&S
- Bloods
- FBC - raised WCC
- U&Es
- LFT - deranged LFTs may be seen in legionella pneumobilia
- ABG (assess pulmonary function) to identify type 1 or type 2 respiratory failure - done if O2 sats are low or patient has an underlying respiratory condition
- Blood film -Mycoplasma causes red cell agglutination - CXR
- Lobar or patchy white shadowing
- Bronchopneumonia = patchy shadowing
- Air bronchograms
- Pleural effusion
NOTE: Klebsiella often affects upper lobes
May detect complications (e.g. lung abscess)
Follow up CXRs at around 6 weeks for all CAP patients who have persisting signs or symptoms and those who have risk factors for underlying malignancy
What score is used to access the severity of community- acquired pneumonia?
CURB-65 score is used to assess the severity of community-acquired pneumonia:
- Confusion < 8 AMTS or new disorientation
- Urea > 7 mmol/L
- Respiratory rate ≥30/min
- Blood pressure: systolic < 90 mm Hg or diastolic ≤60 mm Hg
- Age ≥65yrs
*Low risk (0-1) - community-based care
*Intermediate risk (2) - hospital-based care
*High risk (3-5) - consider ITU
How is community acquired pneumonia managed?
- Empirical management:
1. Amoxicillin → typical cover
2. Clarithromycin → atypical cover. If allergic to penicillin. Avoid in patients with long QT syndrome.
3. Erythromycin ⇒ should be used in pregnancy
4. Doxycycline → if allergic to penicillin - Supportive care -advise to stop smoking, rest and remain well-hydrated
- High severity patients with penicillin allergy, give IV levofloxacin
5. add flucloxacillim if staphylococci suspected e.g. in influenza
How is hospital acquired pneumonia managed?
co-amoxiclav or cefuroxime (within 5 days of admission). Piperacillin/tazobactam, sold under the brand name Tazocin or broad spectrum cephalosporin like ceftazidime (after 5 days)
What supportive treatment can be given to a patient with pneumonia?
- CPAP (continuous positive airway pressure), BiPAP (bilevel positive airway pressure) or ITU care for respiratory failure
- Surgical drainage may be needed for lung abscesses and empyema
- Discharge planning
- If TWO OR MORE features of clinical instability are present (e.g. high temperature, tachycardia, tachypnoea, hypotension, low oxygen sats) there is a high risk of re-admission and mortality - Prevention
- Pneumococcal vaccine
- Haemophilus influenzaetype B vaccine
- These are only usually given to high risk groups (e.g. elderly, splenectomy)
What complications may arise following pneumonia?
● Pleural effusion
● Empyema (collection of pus, identified via fluid aspirate sample: pH reading of 7.2 is “almost” diagnostic- treatment involves a chest drain under radiological guidance
● Localised suppuration (e.g. abscess)
Symptoms of abscesses:
*Swinging fever
*Persistent pneumonia
*Copious/foul-smelling sputum
● Septic shock
● ARDS
● Acute renal failure
● Pericarditis
● Myocarditis
Extra complications of Mycoplasma pneumonia
*Erythema multiforme
*Myocarditis
*Haemolytic anaemia
*Meningoencephalitis
*Transverse myelitis
*Guillain-Barre syndrome
Summarise the prognosis for patients with pneumonia
● Most resolve within treatment within 1-3 weeks
● Severe pneumonia has a high mortality
● The CURB-65 score is used to assess the severity of pneumonia:
Confusion < 8 AMTS
Urea > 7 mmol/L
Respiratory rate > 30/min
Blood pressure: systolic < 90 mm Hg or diastolic < 60 mm Hg
Age > 65 yrs
