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Flashcards in Chest Medicine Deck (36)
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1
Q

Pneumonia - definition

A

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.

2
Q

Pneumonia - community acquired

A

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%.

3
Q

Pneumonia - hospital acquired

A

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.

4
Q

Pneumonia - aspiration

A

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

5
Q

Pneumonia - immunocompromised

A

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

6
Q

Pneumonia - clinical features

A
  • 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.
7
Q

Pneumonia - investigations

A

Aim to establish the diagnosis, identify the pathogen and assess severity.

  • Oxygen saturation – if SaO2 is <92% of pneumonia is severe perform arterial blood gas.
  • 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.
8
Q

Pneumonia - severity

A

Use CURB65:

  • Confusion (abbreviated mental test) <8, Urea >7mmol/L, Respiratory rate >30 per min, Blood pressure <90 systolic or <60 diastolic and 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.
9
Q

Pneumonia - management

A
  • 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.
10
Q

Pneumonia - community acquired antibiotics

A
  • 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.
11
Q

Pneumonia - hospital acquired and neutropenic antibiotics

A

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

12
Q

Pneumonia - aspiration pneumonia antibiotics

A

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

13
Q

Pneumonia complications - respiratory failure

A

Type 1 failure (PaO2 <8 kPa) is quite common and should be treated with high flow 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.

14
Q

Pneumonia complications - Hypotension

A

Due to a combination of dehydration and vasodilation due to sepsis. If systolic BP is <90 mmHg give an IV 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.

15
Q

Pneumonia complications - pleural effusion

A

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.

16
Q

Pneumonia complications - empyema

A

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

17
Q

Pneumonia complications - lung abscess

A

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.
18
Q

Pneumonia complications - others

A
  • 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.
19
Q

Pneumonia - prevention

A

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.
20
Q

Pneumococcal pneumonia

A

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.

21
Q

Staphylococcal pneumonia

A

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.

22
Q

Klebsiella pneumonia

A

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.

23
Q

Pseudomonas

A

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

24
Q

Mycoplasma pneumonia

A

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.

25
Q

Legionella pneumonia

A

Colonises water tanks kept at <60°C 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.
26
Q

Chlamydiophilia pneumonia

A

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.

27
Q

Chlamydiophilia psittaci

A

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.

28
Q

Pneumocystis pneumonia (PCP)

A

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.
  • DiagnosisCXR 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 x 106/L.
29
Q

Avian influenza

A

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.
30
Q

SARS

A

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 >30°C, child, 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.
31
Q

Aspergillus

A

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.
32
Q

Allergic bronchopulmonary aspergillus (ABPA)

A

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.
33
Q

Aspergilloma

A

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.
34
Q

Invasive aspergillosis

A

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%.
35
Q

Extrinsic allergic alvelolitis

A

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

36
Q

Amphotericin B

A

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.