What initial investigations should be ordered to evaluate a patient presenting with giddiness?

Initial Investigations for Giddiness

For a patient presenting with giddiness, begin with a careful history, physical examination including orthostatic blood pressure measurements, and a standard 12-lead ECG as the essential initial evaluation. 1

Step 1: Structured History Taking

The history is the most critical diagnostic tool and should systematically address:

• Timing and triggers: Determine if symptoms are acute (lasting days to weeks), episodic triggered (lasting seconds to minutes with position change), episodic spontaneous (lasting minutes to hours), or chronic (persistent for weeks to months) 1

• Position and activity: Document whether giddiness occurs while supine, sitting, standing, during position changes, during/after exercise, or with specific neck movements 1

• Associated symptoms: Ask specifically about:

  • Nausea, vomiting, sweating, visual changes, palpitations 1
  • Hearing loss, tinnitus, ear fullness (suggests Ménière's disease or other otologic causes) 1
  • Headache (suggests vestibular migraine) 1
  • Focal neurological symptoms (suggests central causes) 1

• Predisposing factors: Crowded/warm places, prolonged standing, post-prandial timing, recent medication changes 1

• Medical history: Previous cardiac disease, diabetes, Parkinson's disease, medications (especially antihypertensives, diuretics, antidepressants) 1

Step 2: Physical Examination

Orthostatic vital signs are mandatory and should be measured after 5 minutes supine, then at 1 and 3 minutes after standing. 1, 2, 3 Orthostatic hypotension is defined as a drop in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg within 3 minutes of standing. 2, 3, 4

Important caveat: Supine-to-standing measurements detect OH in 15% of patients versus only 2% with seated-to-standing measurements, and supine OH correlates better with falls and orthostatic symptoms. 5 Therefore, use supine-to-standing measurements when possible.

Additional physical examination components:

• Cardiovascular examination: Auscultate for murmurs (suggests structural heart disease), check for signs of heart failure 1
• Neurological examination: Assess cranial nerves, coordination, gait, and signs of Parkinsonism 1
• Otoscopic examination: If vertigo is prominent, examine for cerumen, tympanic membrane abnormalities 6

Step 3: Standard 12-Lead ECG

An ECG must be obtained in all patients with giddiness. 1 A completely normal ECG has >90% negative predictive value for excluding left ventricular systolic dysfunction and cardiac causes of syncope. 1

The ECG may reveal:

• Arrhythmias (bradycardia, tachycardia, heart block) 1
• Conduction abnormalities 1
• Signs of ischemia or prior infarction 1
• QT prolongation (suggests inherited arrhythmia syndromes) 1

Any ECG abnormality is an independent predictor of cardiac syncope and increased mortality, warranting further cardiac evaluation. 1

Step 4: Selective Additional Testing Based on Clinical Findings

Do not order routine laboratory panels or imaging without specific clinical indications. 1

When to order specific tests:

• Audiologic evaluation: Order if hearing loss, tinnitus, or unilateral symptoms are present 6

• Echocardiography: Indicated if syncope occurs during/after exertion, if there are cardiac symptoms (chest pain, dyspnea), abnormal cardiovascular examination, or abnormal ECG 1

• Carotid sinus massage: For older patients with syncope during neck turning or recurrent unexplained syncope 1

• Head-up tilt table testing:

  • If orthostatic vital signs are negative but clinical suspicion for orthostatic hypotension remains high 2, 3, 4
  • In young patients with recurrent syncope and no suspicion of heart disease 1

• Neuroimaging (MRI/CT): Only if focal neurological abnormalities, asymmetric hearing loss, or pulsatile tinnitus are present 6 Do not obtain imaging for routine giddiness evaluation without these red flags.

Common Pitfalls to Avoid

• Do not rely on seated-to-standing BP measurements alone—they miss the majority of orthostatic hypotension cases 5

• Do not order routine laboratory screening (CBC, metabolic panel, thyroid function) unless specific clinical features suggest these diagnoses 1

• Do not assume benign causes in elderly patients or those with cardiovascular risk factors—cardiac causes are more likely when syncope occurs in supine position, during exercise, or is preceded by palpitations 1

• Do not overlook medication review—antihypertensives, diuretics, antidepressants, and QT-prolonging agents are common culprits 1