Dizziness / Syncope

Differentials

• Common Causes: Anxiety (hyperventilation), intoxication (alcohol/drugs), orthostatic hypotension, vasovagal

• Neurological: Vertebrobasilar insufficiency, TIA/stroke, hypoglycaemia, cataplexy, pseudoseizures, substance-induced

• Cardiac: Arrhythmias (heart block, SVT, VT), outflow obstruction (aortic stenosis, HOCM, pulmonary embolism)

• Vasovagal: Triggered by heat, stress, cough, strain

• Orthostatic: Dehydration, vomiting, bleeding, medications (diuretics, CCBs, nitrates)

• Key Assessment: Prodromal symptoms, differentiate syncope vs presyncope, orthostatic BP measurements

History

• Alcohol intake (risk of hypoglycaemia)

• Illicit drug use

• Neurological signs (weakness, sensory or speech changes suggest central cause)

• Hyperventilation episodes

• Palpitations, chest pain, SOB (possible cardiac cause)

• Sudden onset, rapid recovery (suggests arrhythmic/cardiac cause)

• Prolonged standing, stress event (vasovagal)

• Poor oral intake, recent bleeding

• Recent medication changes (risk of hypotension)

• Frequency, duration, triggers, witnessed LOC or incontinence

Investigations

• Bloods: FBC, BSL, UEC to exclude metabolic derangements

• ECG ± Holter monitor to detect arrhythmias

• CT brain if central neurological cause suspected

• Orthostatic BP: Check supine, immediately standing, then at 3 minutes

• Echocardiogram if cardiac abnormality suspected or ECG changes

• Medication review (deliriogenic or hypotensive agents)

Management

• Ensure adequate hydration, correct electrolyte imbalances

• Cardiology referral + echocardiogram if cardiac cause is likely

• Treat underlying cause based on investigations

• Vasovagal syncope: Educate on avoiding triggers, use counter-pressure maneuvers

• Medication review: Adjust diuretics, CCBs, nitrates if contributing to hypotension

• Lifestyle modifications: Slow positional changes, small frequent meals, increased salt intake if indicated