Respiratory Flashcards
Asthma
Chronic, inflammatory condition causing episodes of REVERSIBLE airway OBSTRUCTION due to bronchoconstriction and excessive secretion production
Aetiology of asthma
Hypersensitivity of the airways triggered by:
Cold air Exercise Cigarette smoke Air pollution Allergens e.g. pollen, animals, mould Time of day: early morning and night
Presentation of asthma
Episodes of wheeze (widespread, polyphonic)
Breathlessness
Chest tightness
Dry cough (often nocturnal)
Hyper resonant percussion (too much air)
Atopy (family or personal history)
Diurnal variability
Investigations for asthma
Spirometry:
- bronchodilator reversible testing (>5 years)
- obstructive pattern: FEV1 <80% predicted, FEV1/FVC ratio <0.7
Peak flow measurement (monitoring, not used for diagnosis)
Skin prick test + IgE
FEV1
Forced expiratory volume in one second
Obstructive: DECREASED
Restrictive: minimally decreased or normal
FVC
Forced vital capacity measures the amount of air you can breath out forcefully after taking a deep breath
Obstructive: decreased or normal
Restrictive: decreased
FEV1/FVC
Amount of air a person can forcefully exhale in ONE SECOND compared to the TOTAL amount they can exhale
= FEV1%
Normal: 85%
Obstructive: <80% (DECREASED: EXHALE disorder)
Restrictive: 85% (EQUALLY REDUCED)
Obstructive lung diseases
Difficulty EXHALING
Asthma
COPD
Wheezing, mucus production
Restrictive lung diseases
Difficulty INHALING
Pulmonary fibrosis
TLC
Total lung capacity = volume of air left in the lungs after exhalation (residual volume) + FVC
Obstructive: normal
Restrictive: DECREASED (INHALE disorder)
FEV1% predicted
FEV1% of the patient divided by the average FEV1% in the population for any person of similar age, sex, and body composition
Treatment of asthma
Avoid triggers
NICE guidelines: CHECK ADHERANCE AND INHALER TECHNIQUE BEFORE INCREASING DOSE OR ADDING NEW DRUG
1) SABA (salbutamol)
2) Add Low dose Inhaled corticosteroids (ICS; e.g. budesonide)
3) Add Leukotriene receptor antagonist (LRTA; e.g. montelukast)
4) Add LABA (salmeterol) (and stop LRTA)
5) Increase ICS dose
Indication for localised wheeze
Foreign body (not asthma)
COPD definition
NON-REVERSIBLE (i.e with bronchodilators) OBSTRUCTION in air flow through the lungs, caused by damage to lung tissue (almost always due to SMOKING)
Two main types of COPD
Chronic bronchitis: chronic inflammation of the bronchial wall > mucus hypersecretion > progressive narrowing
Emphysema: loss of elastic recoil of alveoli > keeps airways open during expiration
COPD presentation
Long term smoker Chronic shortness of breath Cough Sputum production (clear, white) Wheeze Recurrent respiratory infections (particularly in winter)
NO finger clubbing
Differential diagnosis in COPD
Lung cancer
Fibrosis
Heart failure
COPD does NOT cause Finger clubbing
Unusual:
Haemoptysis
Chest pain
MRC Dyspnoea scale
COPD risk factors
SMOKING
Age (usually presents between 40-60)
Secondhand smoke exposure
Occupational therapy exposure (mining, dust, asbestos)
Pollution
Genetics (alpha-1-antitrypsin deficiency can lead to earlier onset and increased severity as A1AT is protective)
COPD diagnosis
Clinical presentation and spirometry
LFT/Spirometry:
- FEV1/FVC ratio <0.7
- reversibility testing: no response
CXR: hyperinflated lungs
Severity of airflow obstruction using FEV1
Stage 1: FEV1 >80% predicted
Stage 2: FEV1 50-79% predicted
Stage 3: FEV1 30-49% predicted
Stage 4: FEV1 <30% predicted
Other investigations to support the diagnosis of COPD
Just know a few
Chest X-ray: exclude other pathology e.g. lung cancer
Full blood count: polycythaemia (high Hb; response to chronic hypoxia) or anaemia (low Hb)
BMI: weight monitoring for loss (cancer or severe COPD) or gain (steroids)
Sputum: chronic infection e.g. pseudomonas
ECG: cardiac function
Serum A1AT
Emphysema symptoms
‘PINK PUFFERS’
Dyspnoea/tachypnoea Minimal cough Pink skin, pursed-lip breathing Accessory muscle use Cachexia (muscle wasting, weight loss) Hyperinflation (barrel chest)
Complication: pneumothorax (in bullous emphysema/vanishing lung syndrome)
Chronic bronchitis symptoms
‘BLUE BLOATERS’
Chronic productive cough (purulent sputum)
Dyspnoea
Cyanosis (hypoxaemia): secondary polycythaemia, pulmonary HT (reactive vasoconstriction)
Peripheral oedema
Obesity
Haemoptysis
Management of COPD
General:
SMOKING CESSATION
Vaccine regime (pneumococcal, annual flu)
Step 1 (stable): SABA or SAMA
Step 2 (no asthmatic responsive features): LABA plus LAMA
Step 2: (asthmatic response): LABA plus ICS
Severe COPD: long term oxygen therapy (note: chronic COPD causes CO2 insensitivity so the system is dependent on hypoxia, 100% oxygen removes the respiratory drive)
SAMA
Short acting muscarinic antagonist
Ipratropium bromide
LAMA
Long acting muscarinic antagonist
Tiotropium
ICS
Inhaled corticosteroid
Budesonide
Management of exacerbated COPD (IE)
Usually triggered by infection (IE)
Acute worsening of symptoms i.e. SoB, sputum, wheeze
ABG:
- Co2 retention = acidosis
- normal pCO2 + low pO2 = T1RF
- high pCO2 + low pO2 = T2RF
CXR, sputum culture + sensitivities for AB therapy, FBC, U&Es
Steroids (hydrocortisone/prednisolone) + nebulised bronchodilators (salbutamol/ipratropium bromide) + ABs
Alpha 1 antitrypsin deficiency
A1AT is a protease inhibitor produced by the liver which acts protectively by inhibiting neutrophil elastase (an enzyme that digests connective tissue)
An autosomal recessive defect causes a deficiency in this enzyme causes:
- EARLY ONSET COPD (emphysema) and bronchiectasis (after 30 years old)
- cirrhosis of the liver (after 50 years old)
A1AT deficiency presentation (specific to liver pathology)
Fatigue Loss of appetite Weight loss Oedema Jaundice Haematemesis/blood in stools
A1AT deficiency presentation (specific to lung pathology)
Shortness of breath Excessive cough with sputum production Wheeze Decreased exercise capacity, persistent fatigue Chest pain (worse on inhalation)
Diagnosis of A1AT deficiency
Gold standard: low serum A1AT
Liver biopsy: cirrhosis, acid-Schiff-positive staining globules (mutant A1AT proteins) in hepatocytes
Genetic testing: A1AT gene
CT thorax: diagnose bronchiectasis and emphysema
Management of A1AT deficiency
Smoking cessation
Supportive treatment: inhalers, oxygen therapy
Organ transplant for end stage liver/lung disease
Monitoring: hepatocellular carcinoma
Interstitial lung disease
Umbrella term to describe conditions that affect the lung parenchyma causing inflammation and fibrosis
Types of interstitial lung disease
Idiopathic pulmonary fibrosis (IPF)
Occupational: silicosis, asbestosis, hypersensitivity pneumonitis
Systemic: granulomatosis with polyangiitis, Goodpasture’s
Idiopathic pulmonary fibrosis
Formation of scar tissue in the lungs with no known cause
IPF epidemiology
The most common interstitial lung disease
2/3 of patients are >60 at presentation
M > F
Presentation of IPF
Ds!!
Dyspnoea
Dry cough (> 3 months)
Diffuse bibasal inspirations crackles
Digits (Finger clubbing)
Diagnosis of IPF
High resolution CT thorax: ground glass appearance
Bloods: increased CRP
Treatment of IPF
No real cure
Pharmacological:
- Pirdenidone (antifibrotic)
- Nintedanib (monoclonal)
Non-pharmacological:
Smoking cessation, physiotherapy, vaccination schedule
Poor prognosis
Asbestosis presentation
Dyspnoea on exertion
Dry cough
Onset >10 years after initial exposure
Bibasal inspiration crackles
Investigations of asbestosis and silicosis
CXR
Spirometry (restrictive)
HRCT
Treatment of asbestosis and silicosis
Remove exposure
Smoking cessation
Symptom treatment
Complications of asbestosis
Mesothelioma
Adenocarcinoma
Pleural thickening
Symptoms: Acute renal failure and Haemoptysis
Differential diagnosis?
Goodpasture syndrome: anti-GBM antibodies
Granulomatosis with polyangiitis: c-ANCA antibodies, saddle-shaped nose
Goodpastures syndrome
Autoimmune anti-glomerular basement membrane (anti-GBM) disease
Anti-GMB antibodies attack glomerulus and alveoli basement membranes (Type IV collagen)
Glomerulonephritis and pulmonary haemorrhage
Presentation of Goodpasture syndrome
Haemoptysis Haematuria Dyspnoea Glomerulonephritis Oedema Reduced urine output Chest pain Fever Fatigue
Investigations for Goodpasture syndrome
Anti-GBM antibodies
Lung and kidney biopsy
Treatment for Goodpasture syndrome
Supportive
Corticosteroids (prednisolone)
Immunosuppressant (cyclophosphamide)
Plasmapheresis (removal of plasma)
Hypersensitivity pneumonitis
“Extrinsic allergic alveolitis”
Type 3 Hypersensitivity reaction to an inhaled allergen
Causes alveolar and bronchial inflammation
Examples of specific causes of hypersensitivity pneumonitis
Bird-fanciers lung: bird droppings
Farmers lung: mouldy spores in hay
Mushroom workers lung: specific mushroom antigens
Presentation of hypersensitivity pneumonitis
Dyspnoea Cough Fever Malaise Weight loss
Investigations for hypersensitivity pneumonitis
Bronchoalveolar lavage during bronchoscopy:
- raised lymphocytes
- mast cells
CXR
- acute: patchy reticulonodular infiltrates
- chronic: fibrosis
Treatment for hypersensitivity pneumonitis
Remove allergen
Steroids
Granulomatosis with polyangiitis
Wegener’s granulomatosis
Systemic vasculitis involving small and medium vessels
ENT, lung and kidney involvement (ELK)
Associated with c-ANCA antibodies
Presentation of granulomatosis with polyangiitis
ENT: Epistaxis Crusty nasal secretions Hearing loss Sinusitis Saddle shaped nose (perforated septum)
Lungs: Cough, wheeze, haemoptysis
Kidneys: Rapidly progressing glomerulonephritis (haematuria)
Investigations for granulomatosis polyangiitis
c-ANCA (anti-neutrophil cytoplasmic antibodies)
Urinalysis
CT chest
Treatment for granulomatosis polyangiitis
Corticosteroids (methylprednisolone, prednisolone)
Immunosuppression (rituximab, methotrexate)
Prophylactic ABx
Clinical presentation of lung cancer
Local disease: Persistent cough Shortness of breath Haemoptysis Weight loss Chest pain, wheeze, recurrent infections
Metastatic disease: Bone pain Horners syndrome (ptosis, anhydrosis, miosis) Headache, seizures, neurological deficit Abdominal pain
Paraneoplastic changes: Increased PTH (hyperparathyroidism) Increased ADH (SIADH) Increased ACTH (Cushing’s)
Two main types of lung cancer
Small cell lung carcinoma (SCLC) - 20%
Non-small cell carcinoma - 80%
Types of non-small cell carcinoma
Adenocarcinoma (40%)
Squamous cell carcinoma (20%)
Large cell and differentiated carcinoma (10%)
Other including carcinoid tumours (10%)
Risk factors for lung cancer
Cigarette smoking (biggest cause) Asbestos Coal Radon exposure Pulmonary fibrosis HIV Genetic factors
Why is small cell lung cancer responsible for paraneoplastic syndromes
SCLC cells contain neurosecretory granules that can release neuroendocrine hormones
Investigations for lung cancer
First line: Chest X-ray (central mass, hilar lymphadenopathy, pleural effusion) but a negative CXR doesn’t rule out cancer
CT thorax: staging of cancer
Sputum cytology: malignant cells (high specificity, low sensitivity)
Diagnosis: biopsy + histology
SCLC
Strongly associated with cigarette smoking
Arises from ENDOCRINE cells (kulchitsky cells) typically in the central bronchus
Secretes polypeptide hormones which act as hormones and neurotransmitters
Treatment: chemotherapy
Squamous cell carcinoma
Most strongly associated with cigarette smoking
Arises from EPITHELIAL cells (cells that line the airways) typically in the central bronchus
Adenocarcinoma lung cancer
Most common cell type in non-smokers
Strongest association with asbestos exposure
Originate from mucus-secreting glandular cells
Metastasises to: pleura, lymph nodes, brain, bone, adrenal glands
Sites of metastatic spread TO lung
Breast Colon Prostate Sarcoma Bladder
Cancer metastasising from elsewhere is more common than a primary lung tumour!
Tuberculosis epidemiology
Majority of cases in Africa and Asia (India and China)
Cause of death for most people with HIV
Pathophysiology of TB
Mycobacterium TB spreads via respiratory droplets (airborne)
1) alveolar macrophages ingest bacteria and the rods proliferate inside
2) hilar lymph nodes > present antigen to T-cells > cellular immune response
3) delayed hypersensitivity reaction > tissue necrosis and CASEATING granuloma formation (central necrosis and cheese like) - primary TB
4) necrotic zone disintegrates (e.g. in immunocompromised) and TB spreads (secondary TB)
Systemic symptoms of TB
WEIGHT LOSS Low grade fever Anorexia Drenching NIGHT SWEATS Malaise
Pulmonary symptoms of TB
Productive cough HAEMOPTYSIS Cough >3 weeks (dry or productive) Breathlessness Chest pain (sometimes)
Signs of TB
Bronchial breathing Dullness on percussion Decreased breathing FEVER Cackles
RECENT TRAVEL
TB investigations
CXR:
- Ghon complex (primary TB lesion alongside ipsilateral mediastinal lymphadenopathy) - dense homogenous fibronodular opacities on upper lobes (caseating granuloma)
- hilar lymphadenopathy
Sputum culture (3 x samples): Ziehl-Neelsen stain on Lowenstein-Jensen agar = acid-fast bacilli
Lymph node aspiration or biopsy: caseating granuloma
Diagnosing latent TB
Mantoux skin test: TB injected intradermally; 72 hours later, positive test = induration of >5mm (offered to young people in close contact with TB and new entrants to UK from TB prevalent countries)
Positive Mantoux test but no features of active TB:
Interferon gamma release assay: sample of blood mixed with TB antigens; previous TB contact = WBCs will be sensitised and release IFN-y = positive for latent TB
Treatment for ACUTE active TB
RIPE
Rifampicin
Isoniazid
Pyrazinamide
Ethambutol
Rifampicin
Course, MOA, side effects
6 months
MOA: Bactericidal (blocks protein synthesis)
SE: red urine, sweats, hepatitis