Pneumonia and Aspergillus

Question 2

Pneumonia - definition

Answer 2

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.

Question 3

Pneumonia - community acquired

Answer 3

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%.

Question 4

Pneumonia - hospital acquired

Answer 4

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.

Question 5

Pneumonia - aspiration

Answer 5

Stroke, myasthenia, bulbar palsies, decreased consciousness, oesophageal disease (e.g. reflux) or with poor dental hygiene increase risk of aspirating oropharyngeal anaerobes.

Question 6

Pneumonia - immunocompromised

Answer 6

The community acquired organisms above plus gram negative bacilli, Pneumocystitis jiroveci (formely P carinii) and other funghi and viruses (CMV or HSV).

Question 7

Pneumonia - clinical features

Answer 7

• 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.

Question 8

Pneumonia - investigations

Answer 8

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.

Question 9

Pneumonia - severity

Answer 9

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.

Question 10

Pneumonia - management

Answer 10

• 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.

Question 11

Pneumonia - community acquired antibiotics

Answer 11

• 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.

Question 12

Pneumonia - hospital acquired and neutropenic antibiotics

Answer 12

IV aminoglycoside (the -mycins) and IV penicillin or IV 3rd generation cephalosporin (ceftriaxone).

Question 13

Pneumonia - aspiration pneumonia antibiotics

Answer 13

1.5g Cefuroxime IV TDS and 500mg Metronidazole IV TDS.

Question 14

Pneumonia complications - respiratory failure

Answer 14

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.

Question 15

Pneumonia complications - Hypotension

Answer 15

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.

Question 16

Pneumonia complications - pleural effusion

Answer 16

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.

Question 17

Pneumonia complications - empyema

Answer 17

Pus in pleural space – chest drain should be inserted under radiological guidance.

Question 18

Pneumonia complications - lung abscess

Answer 18

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.

Question 19

Pneumonia complications - others

Answer 19

• 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.

Question 20

Pneumonia - prevention

Answer 20

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.

Question 21

Pneumococcal pneumonia

Answer 21

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.

Question 22

Staphylococcal pneumonia

Answer 22

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.

Question 23

Klebsiella pneumonia

Answer 23

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.

Question 24

Pseudomonas

Answer 24

A common pathogen in cystic fibrosis and bronchiectasis and can also cause hospital acquired infection, particularly in ITU or following surgery.

Question 25

Mycoplasma pneumonia

Answer 25

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.

Question 26

Legionella pneumonia

Answer 26

Colonises water tanks kept at e.g. hotel air conditioning and hot water systems causing outbreaks of Legionnaire’s disease:

• Clinical features - flu-like fever, malaise or myalgia followed by dry cough and dyspnoea. Extra-pulmonary features - anorexia, diarrhoea and vomiting, hepatitis, renal failure and confusion.
• Investigations – blood tests will show lymphopenia, hyponatraemia and deranged LFTs and urinalysis will show haematuria.
• Diagnosis - made using Legionella serology or urine antigen.

Question 27

Chlamydiophilia pneumonia

Answer 27

The most common chlamydial infection – person to person spread occurs causing a biphasic illness – pharyngitis, hoarseness or otitis is followed by pneumonia. Diagnosis is with Chlamydophilia serology and management is with tetracycline and clarithromycin.

Question 28

Chlamydiophilia psittaci

Answer 28

Causes psittacosis acquired from infected birds, typically parrots. Symptoms – headache, fever, dry cough, lethargy, arthralgia, anorexia, diarrhoea and vomiting. Extra-pulmonary features – meningo-encephalitis, infective endocarditis, hepatitis, nephritis, rash or splenomegaly. CXR shows patchy consolidation and management is with tetracycline and clarithromycin.

Question 29

Pneumocystis pneumonia (PCP)

Answer 29

Causes pneumonia in immunosuppressed e.g. in HIV. The organism responsible was previously called Pneumocystis carinii and is now called Pneumocystis jiroveci.

• Clinical features – dry cough, exertional dyspnoea, fever and bilateral crepitations on exam.
• Diagnosis – CXR is normal or may show bilateral peri-hilar interstitial shadowing and visualisation of organism in induced sputum, bronchoalveolar lavage or lung biopsy specimen.
• Management – high dose co-trimoxazole, steroids and prophylaxis if CD4 is <200.

Question 30

Avian influenza

Answer 30

Avian to human transmission of the H5N1 strain of influenza A causes serious infection with a >50% mortality rate often from a rapidly progressive pneumonia. Human to human transmission is possible but is unusual. Oseltamivir (Tamiflu) can reduce morbidity by 1-2 days.

• Diagnosis – viral culture ± reverse transcription PCR with H5 and N1 specific primers.
• Management – contain the outbreak, give oxygen and ventilatory support and antivirals.

Question 31

SARS

Answer 31

Severe acute respiratory syndrome is caused by a coronavirus and is transmitted by close contact with an index case. The major features are persistent fever >38°C, chills, rigors, myalgia, dry cough, headache, diarrhoea and dyspnoea. The CXR will be abnormal and the WCC will be low.

• Complications – respiratory failure is the major complication – 50% require supplementary oxygen and 20% will develop acute respiratory distress syndrome requiring invasive ventilation.
• Management – only supportive as no drugs have convincing efficacy. Rapid diagnosis, early isolation and good infection control measures are vital to prevent spread.

Question 32

Aspergillus

Answer 32

A group of fungi that can affect the lungs in 5 ways:

1. Asthma – caused by a type 1 hypersensitivity (atopic) reaction to fungal spores.

Question 33

Allergic bronchopulmonary aspergillus (ABPA)

Answer 33

Results from a type 1 and 3 hypersensitivity reaction to Aspergillus fumigatus. In the early stages an allergic response causes bronchoconstriction but as inflammation persists permanent damage leads bronchiectasis.

• Clinical features – wheeze, cough, sputum, dyspnoea and recurrent pneumonia.
• Investigations – CXR shows transient segmental collapse or consolidation or bronchiectasis. Aspergillus in sputum, positive skin test and Aspergillus specific RAST.
• Management – 30-40mg Prednisolone for acute attacks and 5-10mg for maintenance.

Question 34

Aspergilloma

Answer 34

A fungus ball within a pre-existing cavity e.g. caused by TB or sarcoidosis. It is usually asymptomatic but may cause cough, haemoptysis, lethargy ± weight loss.

• Investigations – CXR shows round opacity in a cavity and positive Aspergillus skin test.
• Management – consider surgical excision for solitary symptomatic lesions or severe haemoptysis. An alternative is local instillation of amphotericin B under CT guidance.

Question 35

Invasive aspergillosis

Answer 35

Risk factors are immunocompromised e.g. HIV, leukaemia, burns, SLE, Wegener’s or following broad spectrum antibiotics.

• Investigations – sputum culture, broncho-alveolar lavage, biopsy, CXR showing consolidation, chest CT and serum galactamannan (an Aspergillus antigen).
• Management – IV amphotericin B and mortality rate is 30%.

Question 36

Extrinsic allergic alvelolitis

Answer 36

May be caused by sensitivity to Aspergillus – malt workers lung.

Question 37

Amphotericin B

Answer 37

An antifungal – give a test dose of 1mg in 20mL 5% dextrose IV over 20-30 mins and monitor for the next half an hour for signs of anaphylaxis e.g. shock, swelling, wheeze etc.