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
Ix: Imaging
- CRX: HF, pneumonia, bronchiectasis or fibrosis (CT modality of choice for fibrosis)
- ECG
Ix: second line Ix and other
Other
• PEFR: used to stratify severely of an asthma attack in chronic asthma
• Spirometry: distinguish between obstructive and restrictive disease
Second line Ix
• Echocardiography: if HF (allows characterisation)
• Coronary angiography: if SOB caused by coronary artery disease
What questions and Ix should you perform in women if they’re young, fit, have no risk factors, atopy, asthma, normal lung examination but feeling increasingly SoB, especially after exercise?
- Period: how heavy?
- Any blood loses anywhere: melena, vomiting
- Ix: FBC - should reveal a micrcytic hypochromic anaemia (compatible with iron deficient anaemia)
What Dx should you suspect in following pt:
• 42 ya pt presenting with SoB
• PC: SoB always present, difficult to type, leg twitching, no enough exercise/poor diet
◦ Ex: CVS, resp, abdo exam unremarkable
◦ Neurological exam: wasting of muscles in both hands, fasciculations over both thighs, reduces power (4/5) on knee flexion and up going plantar reflex
◦ Spirometry: FVC = 60% and FER = 80%
• Dx: should consider MND b/c have fasciculations (LMN pathology) and up going plantar reflex (UMN pathology) —> combination of both is indicative of MND
◦ SoB probably due to diaphragmatic weakness: late sign of disease
What Dx should you suspect in following pt:
• 62 ya pt with 1 month Hx of SoB, now feeling breathless on minimal exertion
◦ No cough, never smoked, HTN (thiazides and ACEi)
◦ No changes in bowel/urine habits but wt loss in last months
◦ Ex: enlarged lymph nodes R-anterior cervical chain + decreased lung expansion on R side & dull to percussion on bases/markedly decreased vocal fremitus on right.
• Dx: right sided pleural effusion
◦ Combination of wt loss, lymphadenopathy and pleural effusion = malignant pleural effusion caused by infiltration of the pleural space by metastatic cancer cells.
