Deck 2 Flashcards
Define Asthma
Reversible, obstructive due to exercise/allergens/stress or idiopathic.
Key symptoms are expiratory wheeze, diurnal dyspnoea, chest tightness which VARY
Histologically, bronchial inflammation and eosinophils
Acute asthma phase vs late phase
Early is bronchospasm (histamine, PD2, leukotrienes)
Late phase has cellular infiltrates and oedema (narrows), also hyperreactive
Chronic asthma features
Bronchoconstriction, mucusal oedema, carcot leyden crystals (eosinophil granules), Curschman spirals, pulmonary HTN
Diagnosis of Asthma
If under 5, Tx based on obs/clinical judgement and objective testing ASAP
5-16, use spirometry (look for reversibility), if not then FeNO test
17+ uses spirometry, FeNO, peak flow variability. Also use airway hyperreactivity (histamine or methacholine challenge)
Tx for asthma
SABA
Add ICS
Add LRTA
LABA+ICS+SABA
MART is LABA+steroid as reliever and preventer
Moderate acute asthma
PEFR 50-75%, increasing symptoms, no acute asmtha features
Acute severe asthma
PEF 33-50%, RR>25, HR>110, inability to complete sentences in 1 breath
Life threatening asthma
SpO2 <92%, PEFR <33%, silent chest, poor respiratory effort, cyanosis, altered consciousness
COPD definition
progressive airflow obstruction but not fully reversible.
See mucus hypersecretion, ciliary dysfunction, airflow limitation, hyperinflation, impaired gas exchane and pulmonary HT (hypoxaemia induced vasoconstriction)
COPD RF
Smoking, indoor pollution, occupational toxin, genetic factor, infection, socioeconomic factors
COPD symptoms
Start as asymptomatic apart from exertion, then chronic cough, progressive dyspnoea, regular sputum, whzeeze, fatigue, weight loss, anorexia, cough syncope, depression
Haemoptysis is not common feature, so consider ddx (lung cancer, bronchiectasis, TB)
COPD examination
Hyperinflated chest, wheeze, quiet breath sounds, pursed lip breathing, accessor muscles, paradoxical movement of lower ribs, peripheral oedema, cyanoses, raised JVP, cachexia
COPD spirometry + other investigations
FEV1<80% FVC >80% (although may be reduced) FEV1/FVC <0.7 DLCA reduced in emphysema ECG may show cor pulmonale
COPD management
SABA/SAMA Add LAMA (tiotropium) Steroids can be added Mucolytics Smoking cessation Rescue Abx
Chronic bronchitis
productive sputum on most days for 3 months of at least 2 successive years.
Does not imply airway inflammation.
Caused by chronic irritation stimulating mucus (increase goblet cells).
Sputum increases infection risk.
Proximal airspace disease.
Reid index shows ratio of gland: all thickness (increased)
Typically 40s, mild or late dysponoea, copious sputum, recurrent infection, repeated resp failure and increased airway resistance. on CXR, prominent vessels and large heart
Emphysema
Distal airspace disease with increased terminal bronchiole size and reduced gas exchange.
No fibrosis.
Caused by protease/antiprotease imbalance.
Centrobular is most common (smoking association). Panaacinar is whole lobule, alpha 1 antitrypsin.
Typically 50s-75, severe early dyspnoea, scant sputum, occasional infections. Resp failure at terminal phase. Relatively normal airway resistance but low recoil. Small heart and hyperinflation on CXR.
Lung cancer symptoms
Dry cough (over 3 weeks), haemoptysis, dyspnoea (esp exertional), chest pain (radiating to shoulder?), recurrent infections, clubbing, lymphadenopathy, B symptoms, thrombocytosis, bone pain, hoarseness, fever, dysphagia
Lung cancer investigation
CXR, then staging CT
Bronchoscopy can be used for histology, but only useful up to bronchioles.
Lung cancer types (general)
Small cell (15%) and NSC (85%)
Small cell lung cancer
OAT cell.Rare. Associated with smoking. Grow quickly and metastasise early, so poor prognosis.
Can cause cavitating lesions. Comes from bronchoepithelium but differentiates neuroendocrine. Associated with paraneoplastic syndromes (SIADH, Cushings - > rarely causes MG like syndrome (Eaten Lambert, but symptoms improve with use)
Has pulmonary carcinoid rare subtype which can be benign
Squamous cell lung cancer
NSC. 50% of lung cancers. Heavy smoking association. OFten central, near carina. Tend to have obstructive symptoms and may have overlying infection. Slow growth.
Can diagnose on sputum cytology. May secrete PTH and cause hypercalcaemia
Adenocarcinoma Lung cancer
20% of lung cancers. Equal gender. Less smoking association. Typically peripheral, but can be central. Can arise at scars.
Subtype is bronchoalveolar carcinoma (comes from alveoli and T2 pneumocytes -spreads along alveolar septa. Good prognossi if no mets)
Large cell anaplastic carcinoma (lung)
10% of lung cancers. Need EM to differentiate as often has squamous or adenocarcinoid features.
Metastases to lungs
Breast, kidney, testicular and bladder cancer
Primary lung cancer complications
SVC compression/obstruction, recurrent laryngeal nerve palsy, horner syndrome, distant mets to brain, bone, liver and adrenals
Exudate: Causes Biochemistry Typical precipitating factor Associations
Alteration to formulation or absorption of pleural fluid
>30g/L (or >0.5 effusion:serum protein, effusion:serum LDH >0.6)
Seen in malignancy, infection, pulmonary embolism, pneumonia, TB, mesothelioma, RA, SLE, lymphoma
Often unilateral. If polymorphs in effusion then suggests PE, TB or asbestosis. Lymphocytes in effusion suggests malignancy or TB
Transudate Causes Protein content Typical precipitating factor Associations
Caused by hydrostatic pressure alterations, pleural permeability and oncotic pressure
protein <30g/L, lower protein and lower LDH than exudates
Seen in ‘failures (HF, liver failure, peritoneal dialysis, nephrotic syndrome, (rarely) hypothyroidism or ovarian tumour (Meig’s syndrome)
Often bilateral.
Pleural effusion investigation
CXR (will only see once >250mL),
Chest tap and broncoscopy (esp if no known cause)
Empyema
Can form from stagnant effusion, esp exudate with high protein content
Pneumonia
Pulmonary parenchyma infection plus new shadow on CXR (separate from bronchitis)
In bacterial, inflammatory exudate in alveolar spaces gives consolidation.
In viral infections, alveoli often spared and interstitium affected (pneumonitis/interstitial pneumonia)
Bronchopneumonia
Primary infection around bronchi.
Spreads around lobules and can be multiple lobes. More common at age extremes (immobility and secretion retention.
Tends to affect bases
Lobar pneumonia
Distal airspace affected. Spreads over whole lobe. More common in adults