When identifying the causes of breathlessness the checklist of possibilities cover most of the biology of the respiratory and cardiac systems, mental health, and haematological and renal factors. Breathlessness might occur at any point on the continuum from oxygen supply to the lungs to its consumption by the tissues. For the clinician trying to sort out a predominant cardiac cause of breathlessness from a respiratory one going through Table 1 may help – it contains a non-exhaustive list of possible mechanisms.
Table 1. Causes of breathlessness
|Peripheral muscle oxygen extraction abnormality or inefficiency|
|Anaemia, iron deficiency*|
∗ Common and potentially reversible factors that contribute to breathlessness; AF=atrial fibrillation, HFpEF= heart failure with preserved ejection fraction; HFrEF= heart failure with reduced ejection fraction.
Evaluation of a patient presenting with breathlessness will vary dependent on clinical situation such as acuity, age of the patient and their prior medical history.
The case history should determine the duration and severity – based on the New York Heart Association functional classification – of breathlessness and whether there are predisposing factors (e.g. effort and emotion).
If heart failure is suspected, the GP should enquire as to whether the patient has orthopnoea, paroxysmal nocturnal dyspnoea or associated symptoms such as chest pain, palpitations, dizziness, syncope, swollen ankles and abdominal bloating. Physical examination should include assessment of vital signs (heart rate and rhythm, blood pressure, respiratory rate and temperature), peripheral perfusion, volume status (JVP, peripheral and sacral oedema, ascites and hepatic congestion), cardiac palpitation and auscultation (apex beat, gallop rhythm and murmurs) and auscultation of lung fields (air entry, crackles and wheeze).
Basic investigations include non-invasive measurement of oxygen saturation, 12-lead ECG, chest X-ray, serum biochemistry (electrolytes, renal function and liver function) and full blood count. Further investigations will depend on clinical circumstances and findings from the initial clinical workup.
Requirement for more urgent evaluation or referral
Table 2. When to consider early referral (red flags)
BP=blood pressure, ECG=electrocardiogram, Both tables Reproduced from National Heart Foundation of Australia and Cardiac Society of Australia and New Zealand: Guidelines for the Prevention, Detection, and Management of Heart Failure in Australia 2018.
To assist identifying patients with Heart Failure and then to focus on how to manage worsening symptoms refer to the updated national guidelines. www.heartfoundation.org.au/for-professionals/clinical-information/heart-failure. For the full text see https://www.heartlungcirc.org/article/S1443-9506(18)31777-3/fulltext
Acknowledgement: The author wishes to acknowledge the assistance provided by Assoc/Prof Tom Briffa, Director, Centre for Health Services & Cardiovascular Research Groups, Perth, in preparing this article.
References available on request.
Questions? Contact the editor.
Author competing interests: nil relevant disclosures.
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