Respiratory Flashcards
Define Aspergillus Lung Disease
Lung disease associated with Aspergillus fungal infection
Explain the aetiology/risk factors for Aspergillus lung disease
Inhalation of Aspergillus spores can produce THREE different clinical pictures:
* Aspergilloma
o Growth of an A. fumigates mycetoma ball in a pre-existing lung cavity (e.g. post-TB, old infarct or abscess)
* Allergic Bronchopulmonary Aspergillosis (ABPA)
o Colonisation of the airways by Aspergillus leads to IgE and IgG-mediated immune responses
o Usually occurs in asthmatics
o The release of proteolytic enzymes, mycotoxins and antibodies leads to airway damage and central bronchiectasis
* Invasive Aspergillosis
o Invasion of Aspergillus into lung tissue and fungal dissemination
o This occurs in immunosuppressed patients (e.g. neutropenia, steroids, AIDS)
Summarise the epidemiology of Aspergillus lung diseas
- UNCOMMON
* Mainly occurs in the ELDERLY and IMMUNOCOMPROMISE
Recognise the presenting symptoms of Aspergillus lung disease
* Aspergilloma o ASYMPTOMATIC o Haemoptysis (potentially massive) * ABPA o Difficult to control asthma o Recurrent episodes of pneumonia with wheeze, cough, fever and malaise * Invasive Aspergillosis o Dyspnoea o Rapid deterioration o Septic picture
Recognise the signs of Aspergillus lung disease on physical examination
- Tracheal deviation (only with very large aspergillomas)
- Dullness in affected lung
- Reduced breath sounds
- Wheeze (in ABPA)
- Cyanosis (possible in invasive aspergillosis)
Identify appropriate investigations for Aspergillus lung disease
- Aspergilloma
o CXR - May show a round mass with a crescent of air around it
- Usually found in the upper lobes
o CT or MRI - may be used if CXR is unclear
o NOTE: sputum cultures may be negative if there is no communication between the cavity colonised by Aspergillus and the bronchial tree
* ABPA o Immediate skin test reactivity to Aspergillus antigens o Eosinophilia o Raised total serum IgE o Raised specific serum IgE and IgG to A. fumigatus o CXR * Transient patchy shadows * Collapse * Distended mucous-filled bronchi * Signs of complications: * Fibrosis in upper lobes * Bronchiectasis o CT * Lung infiltrates * Central bronchiectasis o Lung Function Tests * Reversible airflow limitation * Reduced lung volumes/gas transfer
- Invasive Aspergillosis
o Aspergillus is detected in cultures or by histological examination
o Bronchoalveolar lavage fluid or sputum may be used diagnostically
o Chest CT - Nodules surrounded by a ground-glass appearance (halo sign)
- This is caused by haemorrhage into the tissue surrounding the fungal invasion
Define asthma
- Chronic inflammatory airway disease characterised by variable reversible airway obstruction, airway hyper-responsiveness and bronchial inflammation
Explain the aetiology/risk factors for asthma
* Genetic Factors o Family history o Atopy (tendency for T lymphocytes to drive production of IgE on exposure to allergens) * Environmental Factors o House dust mites o Pollen o Pets o Cigarette smoke o Viral respiratory tract infections o Aspergillus fumigatus spores o Occupational allergens
Summarise the epidemiology of asthma
- Affects 10% of children
- Affects 5% of adults
- Prevalence appears to be increasing
Recognise the presenting symptoms of asthma
- Episodic history
- Wheeze
- Breathlessness
- Cough (worse in the morning and at night)
- IMPORTANT: ask about previous hospitalisation due to acute attacks - this gives an indication of the severity of the asthma
- Precipitating Factors
o Cold
o Viral infection
o Drugs (e.g. beta-blockers, NSAIDs)
o Exercise
o Emotions - Check for history of atopic disease (e.g. allergic rhinitis, urticaria, eczema)
Recognise the signs of asthma on physical examination
- Tachypnoea
- Use of accessory muscles
- Prolonged expiratory phase
- Polyphonic wheeze
- Hyperinflated chest
- Severe Attack
o PEFR < 50% predicted
o Pulse > 110/min
o RR > 25/min
o Inability to complete sentences - Life-Threatening Attack
o PEFR < 33% predicted
o Silent chest
o Cyanosis
o Bradycardia
o Hypotension
o Confusion
o Coma
Identify appropriate investigations for asthma
* ACUTE o Peak flow o Pulse oximetry o ABG o CXR - to exclude other diagnoses (e.g. pneumonia, pneumothorax) o FBC - raised WCC if infective exacerbation o CRP o U&Es o Blood and sputum cultures * CHRONIC o Peak flow monitoring - often shows diurnal variation with a dip in the morning o Pulmonary function test o Bloods - check: (* Eosinophilia * IgE level * Aspergillus antibody titres ) o Skin prick tests - helps identify allergens
Generate a management plan for acute asthma attacks
o ABCDE
o Resuscitate
o Monitor O2 sats, ABG and PEFR
o High-flow oxygen
o Salbutamol nebulizer (5 mg, initially continuously, then 2-4 hourly)
o Ipratropium bromide (0.5 mg QDS)
o Steroid therapy
* 100-200 mg IV hydrocortisone
* Followed by, 40 mg oral prednisolone for 5-7 days
o If no improvement –> IV magnesium sulphate
o Consider IV aminophylline infusion
o Consider IV salbutamol
o Anaesthetic help may be needed if the patient is getting exhausted
o IMPORANT: a normal PCO2 is a BAD SIGN in a patient having an asthma attack
* This is because during an asthma attack they should be hyperventilating and blowing off their CO2, so PCO2 should be low
* A normal PCO2 suggests that the patient is fatiguing
o Treat underlying cause (e.g. infection)
o Give antibiotics if it is an infective exacerbation
o Monitor electrolytes closely because bronchodilators and aminophylline causes a drop in K+
o Invasive ventilation may be needed in severe attacks
o DISCHARGE when:
* PEF > 75% predicted
* Diurnal variation < 25%
* Inhaler technique checked
* Stable on discharge medication for 24 hours
* Patient owns a PEF meter
* Patient has steroid and bronchodilator therapy
* Arrange follow-up
Generate a management plan for chronic asthma therapy
o Start on the step that matches the severity of the patient’s asthma
o STEP 1
* Inhaled short-acting beta-2 agonist used as needed
* If needed > 1/day then move onto step 2
o STEP 2
* Step 1 + regular inhaled low-dose steroids (400 mcg/day)
o STEP 3
* Step 2 + inhaled long-acting beta-2 agonist (LABA)
* If inadequate control with LABA, increase steroid dose (800 mcg/day)
* If no response to LABA, stop LABA and increase steroid dose (800 mcg/day)
o STEP 4
* Increase inhaled steroid dose (2000 mcg/day)
* Add 4th drug (e.g. leukotriene antagonist, slow-release theophylline or beta-2 agonist tablet)
o STEP 5
* Add regular oral steroids
* Maintain high-dose oral steroids
* Refer to specialist care
* Advice
o Teach proper inhaler technique
o Explain important of PEFR monitoring
o Avoid provoking factors
Identify the possible complications of asthma
- Growth retardation
- Chest wall deformity (e.g. pigeon chest)
- Recurrent infections
- Pneumothorax
- Respiratory failure
- Death
