What is the differential diagnosis for a 40-year-old patient with headache, dizziness, loss of consciousness, hypertension (high blood pressure), and diminished peripheral pulses?

Differential Diagnosis: Takayasu Arteritis

The most likely diagnosis in this 40-year-old patient with headache, dizziness, syncope, hypertension, and diminished peripheral pulses is Takayasu arteritis, a large-vessel vasculitis that characteristically presents with this exact constellation of findings. 1

Primary Differential Diagnosis

Takayasu Arteritis (Most Likely)

• This vasculitis affects the aorta and its major branches, causing stenosis that produces the classic triad of hypertension (from renal artery stenosis), diminished peripheral pulses, and neurological symptoms 1
• The 4-month duration fits the progressive nature of large-vessel vasculitis 1
• Neurological symptoms (headache, dizziness, syncope) result from cerebrovascular involvement and impaired cerebral perfusion 1
• Key diagnostic features include asymmetrical blood pressure measurements between arms (>20 mmHg systolic or >10 mmHg diastolic difference), absent or diminished pulses, and vascular bruits on auscultation 1
• Diagnosis requires aortography or MR angiography to visualize arterial stenosis and wall thickening 1

Aortic Coarctation

• Presents with upper extremity hypertension and diminished/delayed femoral pulses 1
• Critical finding: left-right arm blood pressure difference and reduced femoral BP compared to simultaneous arm BP 1
• More common in younger patients but can present in adults 1
• Auscultation reveals precordial or chest murmurs 1

Fibromuscular Dysplasia (FMD)

• Nonatherosclerotic segmental angiopathy affecting renal and carotid arteries 1
• Causes hypertension from renal artery stenosis 1
• Neurological symptoms from carotid involvement or embolic events 1
• Diagnosis confirmed by characteristic "string of beads" appearance on angiography 1

Secondary Considerations

Hypertensive Emergency with End-Organ Damage

• The presence of neurological symptoms (headache, dizziness, syncope) with severe hypertension indicates potential hypertensive encephalopathy requiring immediate evaluation 2, 3
• However, diminished peripheral pulses are NOT typical of primary hypertensive emergency and strongly suggest underlying vascular pathology 1
• Emergency symptoms requiring immediate attention include confusion, focal neurological deficits, visual disturbances, and seizures 2

Cerebral Venous Thrombosis

• Can present with headache and altered consciousness 1
• Does NOT explain diminished peripheral pulses 1
• Less likely given the chronic 4-month course 1

Vertebrobasilar Insufficiency

• Causes episodic vertigo and dizziness, typically lasting <30 minutes 1
• Can precede stroke by weeks to months 1
• Does NOT explain diminished peripheral pulses or sustained hypertension 1

Critical Diagnostic Workup

Immediate Physical Examination Priorities

• Measure blood pressure in BOTH arms and compare—differences >20/10 mmHg indicate vascular abnormality 1
• Palpate all peripheral pulses (carotid, radial, femoral) and document asymmetry 1
• Auscultate for bruits over carotid, subclavian, renal, and abdominal arteries 1
• Fundoscopic examination for hypertensive retinopathy or papilledema 1
• Complete neurological examination for focal deficits 1

Essential Laboratory Studies

• Erythrocyte sedimentation rate (ESR) and C-reactive protein—markedly elevated in active Takayasu arteritis 1
• Complete blood count, creatinine, electrolytes, urinalysis 3
• Consider coagulation studies if thrombotic etiology suspected 1

Imaging Studies

• MR angiography or CT angiography of the aorta and major branches is the diagnostic test of choice for large-vessel vasculitis 1
• Brain MRI with contrast if hypertensive encephalopathy or stroke suspected 1, 2
• Echocardiography to assess for cardiac complications of hypertension 3

Critical Pitfalls to Avoid

• Do not attribute all symptoms to "essential hypertension" when diminished pulses are present—this combination mandates vascular imaging 1
• Do not rapidly lower blood pressure before establishing the diagnosis—patients with chronic hypertension from vascular stenosis may not tolerate acute BP reduction 3, 4
• Do not miss bilateral arm BP measurements—this single examination finding can immediately suggest the diagnosis 1
• Do not ignore subtle neurological symptoms as "just dizziness"—syncope with hypertension can indicate impending stroke or hypertensive encephalopathy 2, 3