What are the differential diagnoses for a 63‑year‑old male presenting with hypertensive emergency (blood pressure 190/110 mm Hg), diplegia, and elevated random blood sugar?

Differential Diagnosis: Hypertensive Emergency with Diplegia and Elevated Blood Sugar

This 63-year-old male with diplegia (bilateral paralysis), hypertensive emergency (BP 190/110), and elevated blood sugar most likely has an acute ischemic or hemorrhagic stroke as the primary diagnosis, with hypertensive encephalopathy and posterior reversible encephalopathy syndrome (PRES) as important alternative considerations.

Primary Differential Diagnoses

1. Acute Stroke (Ischemic or Hemorrhagic) - Most Likely

• Diplegia strongly suggests bilateral cerebral involvement, which can occur with:
  • Bilateral hemispheric infarctions
  • Brainstem stroke affecting bilateral motor pathways
  • Large territory infarction
• The combination of severe hypertension and focal neurological deficits (diplegia) makes stroke the leading diagnosis 1
• Hemorrhagic stroke is particularly associated with hypertensive emergencies, though ischemic stroke is more common overall 2, 3
• Critical distinction: Focal neurological lesions are RARE in hypertensive encephalopathy and should raise immediate suspicion for stroke 1

2. Hypertensive Encephalopathy with PRES

• Presents with neurological symptoms including seizures, lethargy, cortical blindness, and altered consciousness 1
• Key differentiating feature: Hypertensive encephalopathy typically causes diffuse symptoms (somnolence, seizures, confusion) rather than focal deficits like diplegia 1
• PRES shows characteristic posterior white matter lesions on MRI (T2-weighted or FLAIR imaging) that are fully reversible with treatment 1
• However, focal neurological lesions like diplegia are atypical for pure hypertensive encephalopathy 1

3. Malignant Hypertension with Thrombotic Microangiopathy (TMA)

• Can present with acute renal failure, advanced retinopathy, and neurological complications 1
• The elevated blood sugar may reflect stress hyperglycemia or unmasked diabetes
• Look for evidence of microangiopathic hemolytic anemia (schistocytes, elevated LDH, low haptoglobin) 1

Critical Diagnostic Workup Required

Immediate imaging is essential to differentiate these conditions:

• CT brain (or MRI): Mandatory to distinguish ischemic stroke, hemorrhagic stroke, and hypertensive encephalopathy 1
• MRI with FLAIR imaging: Superior for detecting PRES and subtle ischemic changes 1
• Laboratory assessment 1:
  • Complete blood count (hemoglobin, platelets for TMA)
  • Creatinine, electrolytes, LDH, haptoglobin
  • Blood glucose (confirm hyperglycemia)
  • Urinalysis for proteinuria and cellular casts
  • Peripheral blood smear if TMA suspected
• Fundoscopy: Essential to assess for advanced hypertensive retinopathy (though often underutilized in practice 4)
• ECG and cardiac markers: To exclude concurrent acute coronary syndrome

Key Clinical Pitfalls

1. Do not assume hypertensive encephalopathy when focal deficits are present - diplegia demands immediate stroke evaluation 1

2. The absolute BP value (190/110) is less important than the presence of acute organ damage - the rate of BP rise matters more than the absolute number 1

3. Hyperglycemia may be:

   • Stress response to acute stroke
   • Pre-existing uncontrolled diabetes
   • Part of metabolic derangement in severe hypertensive crisis

4. Advanced retinopathy may be absent in up to one-third of patients with hypertensive encephalopathy, so its absence does not exclude the diagnosis 1

Additional Considerations

• Acute aortic dissection: Less likely given diplegia presentation, but check for BP differential between arms and consider if chest/back pain present 1
• Acute coronary syndrome: Can coexist with stroke in hypertensive emergency (39.6% of hypertensive emergencies) 4
• Posterior circulation stroke: Particularly relevant given bilateral motor involvement
• Metabolic encephalopathy: Hyperglycemic hyperosmolar state could contribute to altered mental status but would not explain focal diplegia

The presence of diplegia (focal neurological deficit) in this hypertensive emergency mandates immediate neuroimaging to exclude stroke before attributing symptoms to hypertensive encephalopathy alone 1.