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Heat syncope
From WikEM
Contents
Background
- Variant of postural hypotension[1]
- Results from combination of volume depletion, decreased vasomotor tone and peripheral vasodilatation
- Often precipitated by rapid change in position during exercise
- Occurs in nonacclimatized patients during early stages of heat exposure (especially elderly)
Clinical Features
- Syncope in the setting of environmental heat exposure
Differential Diagnosis
Environmental heat diagnoses
Syncope Causes
- Cardiovascular-mediated syncope
- Dysrhythmias:
- WPW (pre-excitation)
- Long QT Syndrome
- Brugada Syndrome
- 2nd/3rd AV Block
- Afib/aflutter
- Vtach/torsades
- Sick sinus syndrome
- Arrhythmogenic right ventricular dysplasia
- Short QT syndrome
- Cardiovascular disease
- Valvular Disease (AS, MS, tricuspid stenosis)
- Aortic Dissection
- Myocardial Infarction
- CHF
- Hypertrophic Cardiomyopathy
- PE
- Pericardial Tamponade
- Myxoma
- Pulmonary Hypertension
- Pacemaker malfunction
- Dysrhythmias:
- Neurally mediated syncope
- Vasovagal:
- Fear, pain, emotion, valsalva, breath-holding spell
- Situational (associated with):
- Coughing, micturition, defecation, vomiting
- Carotid sinus stimulation
- Vasovagal:
- Orthostatic hypotension-mediated syncope:
- Volume depletion:
- Autonomic Dysreflexia
- Autonomic failure due to meds
- Other serious causes
- Stroke
- SAH
- TIA
- Vertebrobasilar Insufficiency
- Subclavian steal
- Heat syncope
- Hypoglycemia
Evaluation
- Diagnosis of exclusion
Management
- Supine position
- Remove patient from heat source
- Give PO or IV rehydration
Disposition
- Hospitalization usually not necessary
See Also
References
- ↑ Waters T. Heat Emergencies In: Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 7th ed. McGraw Hill Medical. 2011: 1339
