Shortness of Breath Flashcards
Outline the 4 main categories for causes of dyspnea
- Insufficient oxygen into lungs
- V/Q mismatch: insufficient O2 going from air into blood
- Insufficient O2 distribution throughout body
- Increased respiratory drive per se
Causes of dyspnea: insufficient oxygen into lungs- causes
- Obstructed airways (asthma, COPD, lung cancer) or upper airway obstruction (anaphylaxis)
- Decreased lung compliance: restrictive lung diseas (pulmonary fibrosis)
- Decreased lung space: pneumothorax/lung collapse
- Weak diaphragm: Guillain-Barré syndrome, myasthenia gravis
- Chest wall cannot inflate properly: kyphosis spine/obesity
Causes of dyspnea: causes of V/Q mismatch
- Pulmonary oedema: HF, liver failure, nephrotic syndrome
- Pneumonia
- Pulmonary embolism
- Pulmonary fibrosis
Causes of dyspnea: causes of insufficient O2 distribution throughout body
- Reduced CO: HF, aortic stenosis
- Anaemia
- Shock: sepsis/haemorrhage
Hx taking - questions about SOB
- Timing of onset: PE/pneumothorax can occur very quickly vs cancer/pulmonary fibrosis take months before cause dyspnea
- Alleviating/exacerbating factors: exertion (most SOB worse), HF worse lying flat, asthma worse seasonally/diurnally, psychogenic hyperventilation worse at times of anxiety/stress
Hx taking: questions about risk factors
- Smoking: 1 pack = 20 cigarettes
- Pets? May be allergic
- Occupational Hx: asbestos, silica dust and coal particles (at risk of pneumoconiosis)
- Medications: drugs that cause pulmonary fibrosis: amiodarone, methotrexate, cyclophosphamide, bleomycin, hydralazine, bisulphate
- Nutritional status: tea and toast diet, alcoholism —> pts may be anaemic
Hx taking: questions about associated symptoms
• Cough: productive, colour of sputum, any blood, when does it occur
◦ Persistent productive cough 3/7 suggests pneumonia
◦ Chronic cough: chronic bronchitis
◦ Blood stained: PE/burst vessel from coughing
• Chest pain:
◦ Pleuritic? Suggests PE or pneumothorax vs non pleuritic cough suggest a cardiac cause
• Muscular weakness or fatigue: neuromuscular diseases (Guillain-Barré), myasthenia gravis, Lambert-Eaton syndrome, polymyositis, MND
• Tender limbs: DVT can occur anywhere
• Wt loss/night sweats/anorexia: suggest highly metabolic systemic inflammatory process
• Loss of blood from anywhere
Differential for SOB - seconds to minutes
- Acute asthma attack
- Anaphylaxis
- Laryngeal oedema
- PE
- Pneumothorax
- Flash pulmonary oedema
- Laryngotracheobronchitis
- Hysterical hyperventilation
- Inhaled foreign body
- Tension Pneumothorax
- Acute epiglottitis/supraglottitis
Differential for SOB: hours-days
- Pneumonia
- Bronchitis
- Heart failure
- Pleural effusion
- Post-operative atelectasis
- Chronic/multiple Pulmonary emboli
- Altitude sickness
- Myasthenia Gravis/GB syndrome
- ARDS
- Lung collapse: secondary to other cause
Differential for SOB: weeks-months
- COPD
- Chronic asthma
- Heart failure
- Pulmonary fibrosis
- Anaemia
- Bronchiectasis
- Physical deconditioning/obesity
- Pulmonary hypertension
- Mesothelioma
- Others: pulmonary TB, ankylosing spondylitis, MND
Give 6 differentials for post op SOB
- Atelectasis (alveolar collapse): pain leads to inadequate expectoration, leading to mucus plugs in bronchioles. These areas collapse as air gets trapped and air is gradually absorbed into surrounding tissues. Will give a ‘rattling cough’
- Pneumonia: common post op, poor mucus clearance due to pain, gastric aspiration, weak immune system due to physiological stress of surgery.
- Pulmonary oedema: HF or excessive fluids peri-op
- PE: V common
- Anaemia: if significant blood loss during surgery
- Pneumothorax: esp if pt has interventions near the chest
Patient from Africa
Symptoms: dry cough, SoB, low O2 sats/de-saturation with exercise and diffuse interstitial shadowing through lungs on CXR
What organism?
If you suspect this particular organism, what else should you do?
• Organisms: Pneumocystis jiroveci pneumonia
◦ Opportunistic organism that cause pneumonia in immunosuppressed pts (esp AIDS)
◦ Dx: microscopy + silver staining and culture on sputum + bronchi-alveolar lovage samples
• If suspect Pneumocystis jiroveci should also do:
◦ HIV testing + CD4+ lymphocyte levels
◦ TB testing: microscopy (Ziehl-Neelsen staining) and culture of sputum and broncho-alveolar lovage samples.
Pt with pulmonary fibrosis: outline examination findings
- lungs expand symmetrically and show normal resonance to percussion
- Very fine crackles heard all over lung fields
Pt with pulmonary fibrosis: give 7 possible causes
What Ix is modality of choice?
◦ Congenital: neurofibromatosis, Gaucher disease
◦ Systemic inflammatory disease: RA, ankylosing spondylitis, sarcoidosis
◦ Chemical irritation: silica, asbestos, coal dust, chlorine
◦ Drugs: methotrexate, amiodarone
◦ Allergic reactions: bird-funcier’s lung
◦ Radiation
◦ Unknown: cryptogenic fibrosising alveolitis/usual interstitial pneumonitis
• Best Ix: CT scan
Ix: bloods for pt with SOB?
- FBC: anaemia
- Blood: cholesterol (<5mM total), glucose (<11.1 random and <7mM) and HBA1C (<6.5%)
- Thyroid function test: hyperthyroidism can cause a tachy arrhythmia and high output cardiac failure
- U+Es: if think pt is overloaded good to have baseline before starting diuretics
