Shortness of Breath Flashcards
What could the 4 broad causes of SOB be?
- Insufficient O2 getting into lungs
- Insufficient O2 getting into blood
- Insufficient O2 getting around the body
- Increased respiratory drive
What may cause insufficient O2 to get into the lungs?
- Obstructed airways - COPD, airway oedema (anaphylaxis), obstructing tumour
- Decreased lung volume - intrathoracic (pneumothorax, pleural effusion) or extra thoracic (kyphoscoliosis)
- Decreased volume of functioning lung - bullous disease, fibroses lungs in interstitial disease)
- Inability to inflate lungs - due to increased work to do (obesity/increased lung stiffness), weak respiratory muscles (e.g. Guillain-barre / myasthenia gravis), or already hyper inflated (COPD)
What may cause insufficient oxygen getting into bloodstream?
- Damage to alveolar membrane - e.g. emphysema / fibrosis (ILD)
- Fluid between alveolar wall and capillary - oedema (HF) / inflammatory (pneumonia)
- Disrupted blood supply (e.g. pulmonary embolus)
What may cause insufficient oxygen getting around the body?
- Shock
- Reduced cardiac output (e.g. HF, aortic stenosis)
- Anaemia
What may cause increased respiratory drive?
- Hysterical hyperventilation
2. Acidaemia (e.g. DKA)
Why does the timing of onset of SOB matter?
Vascular (PE, etc) and mechanical (pneumothorax, foreign body, etc) - present suddenly
Lung cancer / pulmonary fibrosis = present over weeks/months
What alleviating / exacerbating factors regarding shortness of breath must you ask?
- Worse on exertion? - (?HF)
- Worse when lying flat? (HF)
- Time of year - if allergy/asthma?
- Anxiety/stress related? - psychogenic hyperventilation
What risk factors must you ask about for SOB?
- Smoking
- Occupational history - asbestos? silica? dust/coal? Puts them at risk of pneumoconioses
- Medications? - drugs like nitrofuarantoin, amiodarone, methotrexate, bleomycin can cause hypersensitivity pneumonitis (a type of ILD)
- PMH - autoimmune conditions e.g. rheumatoid arthritis/SLE can cause ILD and Pleural effusions
- Pets
What associated symptoms must you enquire about?
- Cough - indicates respiratory pathology
- Chest pain - pleuritic (PE/pneumonia/pneumothorax) vs non-pleuritic (CVS pathology)
- Muscular weakness / fatigue - ?neuromuscular diseases
- Tender limbs - ?PE. Patients will notice DVT as inflammation is present
- FLAWS - red flag symptoms - ?metabolic pathology e.g. cancer
- Blood loss - ?anaemia. Ask about menstrual bleeding / rectal bleeding / melaena
Describe the information that can be gathered by asking the patient about their cough in relation to SOB
Cough - indicates respiratory pathology.
Persistent productive cough over past few days = ?pneumonia.
Persistent, productive cough over past 3 months over a few years = ?chronic bronchitis.
Dry cough w/ SOB or at night time = ?Asthma/LVF.
Why may pleuritic chest pain indicate PE/pneumothorax/pneumonia?
Because these conditions often involve parietal pleura
If SOB presents within seconds to minutes, what Ddx must you exclude?
- Bronchospasm (acute asthma/COPD)
- Anaphylaxis
- Laryngeal oedema
- PE
- Pneumothorax
- Inhaled foreign body
- Tension pneumothorax
- Acute epiglottitis/supraglottitis
If SOB presents within hours to days, what ddx must you exclude?
- Pneumonia
- HF
- Pleural effusion
- ARDS (Acute Respiratory Distress Syndrome)
If SOB presents within weeks to months, what ddx must you exclude?
- COPD
- Chronic asthma
- HF
- Pulmonary fibrosis
- Anaemia
- Bronchiectasis
Which 2 conditions does COPD encompass
Emphysema and chronic bronchitis
What may be the risk factors for COPD
- Smoking (usually >20 pack years)
- Occupational exposure
- a1 - antitrypsin deficiency
What are the signs of COPD?
- Hyperexpanded chest
- Hyperresonant percussion
- Breathing through pursed lips
- Reduced air entry/chest expansion
- Prolonged expiratory phase
In chronic asthma, what may a typical history include?
History of wheeze (audible on lung auscultation), breathlessness, chest tightness/cough. Often worse at night / early morning, during exercise, or when exposed to cold/allergens
Family hx - presence of atopic conditions in the family e.g. eczema, hay fever, allergies, nasal polyps
Which drugs may exacerbate symptoms of asthma?
NSAIDS, aspirin, B-blockers
What may be a typical history of ILD?
Exposure to asbestos, silica, coal: all 3 are pneumoconioses that cause ILD
Exposure to drugs (e.g. methotrexate, amiodarone)
What signs on examination may be present in someone with ILD?
Clubbing
Reduced air entry/chest expansion
Late inspiratory fine crackles
What may a typical history of someone with HF be?
History of SOB on exertion, orthopnoea, PND (waking up short of breath), swollen ankles
NB swollen ankles if RHF as well as LHF
What RFs can cause HF?
IHD (smoking, DM, hypercholesterolaemia, HTN, south asian, family history)
Atherosclerotic disease e.g. Stroke, TIA, limb claudication
HTN on its own can cause HF
Valvular diseases (Eg Aortic stenosis)
Cardiomyopathy
What signs may be present on examination in someone with HF
- Displaced apex beat
- HS 3 + 4
- Crackles in both lung bases
- Raised JVP, hepatomegaly, peripheral oedema (ankles, sacrum)
What may a typical history of someone with anaemia be?
History of bleeding (Eg menorrhagia, melaena), fatigue and SOB on exertion
What signs may be present on examination in someone with anaemia
Peripheral (fingers) / central (tongue) cyanosis
Koilonychia, glossitis, angular stomatitis.
Check for conjunctival pallor but it is unreliable
What history may suggest chronic bronchiectasis is occurring?
History of productive cough and recurrent chest infections
Name 3 conditions that cause SOB that can be excluded on inspection
Obesity, kyphoscoliosis, ankylosing spondylitis