Pneumonia and Aspergillus Flashcards
(36 cards)
Pneumonia - definition
An acute lower respiratory tract infection associated with fever, symptoms, clinical signs in the chest and abnormalities on chest x-ray. The mortality rate is 10% in hospital and 30% if transferred to ITU.
Pneumonia - community acquired
May be 1°or 2° to underlying disease – the most common cause is Streptococcus pneumoniae then Haemophilus influenza and Mycoplasma pneumonia. Less common causes are Staph aureus, Legionella, Moraxella catarrhalis and Chlamydia and viruses account for 15%.
Pneumonia - hospital acquired
By definition pneumonia that occurs >48 hours after hospital admission. It is most commonly caused by negative enterobacteria e.g. Salmonella or E coli or Staphylococcus aureus. Less commonly it is caused by Pseudomonas, Klebsiella, Bacteroides and Clostridia.
Pneumonia - aspiration
Stroke, myasthenia, bulbar palsies, decreased consciousness, oesophageal disease (e.g. reflux) or with poor dental hygiene increase risk of aspirating oropharyngeal anaerobes.
Pneumonia - immunocompromised
The community acquired organisms above plus gram negative bacilli, Pneumocystitis jiroveci (formely P carinii) and other funghi and viruses (CMV or HSV).
Pneumonia - clinical features
- Symptoms – fever, rigors, malaise, anorexia, dyspnoea, cough, purulent sputum, haemoptysis and pleuritic pain.
- Signs – fever, cyanosis, confusion (especially in the elderly), tachypnoea, tachycardia, hypotension, pleural rub and signs of consolidation – reduced expansion, dull percussion note, increased tactile vocal fremitus or vocal resonance and bronchial breathing.
Pneumonia - investigations
Aim to establish the diagnosis, identify the pathogen and assess severity.
- Oxygen saturation – if SaO2 is <92% or severe pneumonia do an ABG.
- Bloods – FBC for WCC, Us and Es for hydration status, LFTs, CRP and blood cultures.
- Imaging – chest x-ray to look for lobar or multilobar infiltrates, cavitation or pleural effusion.
- Culture – sputum, pleural fluid or bronchoalveolar lavage are used for culture and sensitivity.
Pneumonia - severity
Use CURB65:
- Confusion (abbreviated mental test) <8 Urea >7mmol/L, Respiratory rate >30 per min, Blood pressure systolic <90 or diastolic <60 or age >65 years.
- If 0-1 features present treat at home, if 2 the patient requires hospital treatment and >3 indicates severe pneumonia so consider ITU.
Pneumonia - management
- Oxygen – do not give to all patients but aim for a Sa02 >8.0 and/or saturations of >94%.
- IV fluids – after clinical examination but likely to be dehydrated due to anorexia and shock.
- Analgesia – if there is pleurisy then can give 1g paracetamol QDS.
- Antibiotics – can be given orally in most cases but in severe cases they should be given IV.
Pneumonia - community acquired antibiotics
- Mild - 500mg-1g Amoxicillin PO TDS or 500mg Clirithromycin PO BD or 100mg Doxycycline PO BD.
- Moderate - oral antibiotics as above or 500mg Amoxicillin IV TDS or 500mg Clirithromycin IV BD.
- Severe - 1.2g Co-amoxiclav IV TDS or 1.5g Cefuroxime IV TDS and 500mg Clarithromycin IV BD.
- Legionella pneumophilia - add Rifampicin for 14-21 days.
- Chlamydophilia species - tetracycline.
- Pneumocystis jiroveci - high dose Co-trimoxazole.
Pneumonia - hospital acquired and neutropenic antibiotics
IV aminoglycoside (the -mycins) and IV penicillin or IV 3rd generation cephalosporin (ceftriaxone).
Pneumonia - aspiration pneumonia antibiotics
1.5g Cefuroxime IV TDS and 500mg Metronidazole IV TDS.
Pneumonia complications - respiratory failure
Type 1 failure (PaO2 oxygen. The patients should be transferred to ITU if hypoxia does not improve with O2 therapy or if PaCO2 rises to >6 kPa. Be careful with oxygen therapy in COPD patients – check ABGs regularly and consider elective ventilation if rising PaCO2 or worsening acidosis.
Pneumonia complications - Hypotension
Due to a combination of dehydration and vasodilation due to sepsis. If systolic BP is fluid challenge of 250mL colloid or crystalloid over 15 minutes. If the BP does not rise insert a central line and give IV fluids to maintain systolic BP >90 mmHg. If there is still no improvement iontropic support (adrenaline or noradrenaline) may be needed.
Pneumonia complications - pleural effusion
Inflammation of the pleura may cause fluid exudation into the pleural space. If it accumulates and becomes large or infected (empyema) then drainage is required.
Pneumonia complications - empyema
Pus in pleural space – chest drain should be inserted under radiological guidance.
Pneumonia complications - lung abscess
A cavitating area of localised, suppurative (pus forming) infection within lungs.
- Causes – inadequately treated pneumonia, aspiration, bronchial obstruction, pulmonary infarction and septic emboli (in sepsis, endocarditis or IV drug use).
- Clinical features – swinging fever, cough, purulent and foul smelling sputum, pleuritic chest pain, haemoptysis, malaise, weight loss, finger clubbing and anaemia.
- Investigations – FBC for anaemia and neutrophils, CRP, blood cultures, sputum microscopy, culture and cytology and CXR will show a walled cavity with a fluid level.
- Management – antibiotics as indicated by sensitivities and continue for 4-6 weeks.
Pneumonia complications - others
- Atrial fibrillation – quite common particularly in elderly and usually resolves with treatment.
- Septicaemia – as a result of bacterial spread from the lung parenchyma into the bloodstream - may cause metastatic infection e.g. endocarditis. Treat according the antibiotic sensitivities.
- Pericarditis and myocarditis – may complicate the pneumonia.
- Jaundice – usually cholestatic due to sepsis or secondary to antibiotic use e.g. flucloxacillin.
Pneumonia - prevention
The pneumococcal vaccine e.g. 0.5mL Pneumovax II SC should be given to over 65’s and:
- Chronic patients – heart, liver (cirrhosis), renal (post-transplant) or lung conditions or diabetes.
- Immunocompromised – impaired spleen function, AIDs or on chemotherapy or prednisolone.
Pneumococcal pneumonia
Can affect any age but more common in the elderly, alcoholics, post-splenectomy, immunosuppressed and patients with chronic heart failure or pre-existing lung disease. Clinical features include fever, pleurisy and herpes labialis (oral). The CXR shows lobar consolidation.
Staphylococcal pneumonia
May complicate influenza infection or occur in the young, elderly, intravenous drug users or patients with underlying disease e.g. leukaemia, lymphoma or cystic fibrosis. It causes a bilateral cavitating bronchopneumonia.
Klebsiella pneumonia
Rare but occurs In the elderly, diabetics and alcoholics. It causes cavitating pneumonia particularly of the upper lobes and can be drug resistant –needs cefotaxime or imipenem.
Pseudomonas
A common pathogen in cystic fibrosis and bronchiectasis and can also cause hospital acquired infection, particularly in ITU or following surgery.
Mycoplasma pneumonia
Occurs in epidemics approx every 4 years and presents with flu like symptoms - headache, myalgia and arthralgia followed by a dry cough. The chest x-ray shows reticular nodular shadowing or patchy consolidation often of 1 lower lobe and worse than the signs suggest. Complications – cold agglutinins causing autoimmune haemolytic anaemia, erythema multiforme, Stevens-Johnson syndrome, Meningoencephalitis, myelitis or Guillian-Barre syndrome.
