Differential Diagnosis for Hypertensive Emergency

The patient's presentation with severely elevated blood pressure (systolics over 200 and diastolics over 100) without signs of volume overload on chest X-ray requires a thorough evaluation to determine the underlying cause. The differential diagnosis can be categorized as follows:

• Single Most Likely Diagnosis
  • Pain or Anxiety: This is often a common cause of acute hypertension in the emergency setting. The patient's hypertension could be exacerbated by pain, anxiety, or stress related to an underlying condition or the hospital environment itself.
• Other Likely Diagnoses
  • Medication Non-adherence: The patient might have missed doses of their antihypertensive medications, leading to a rebound effect and severely elevated blood pressure.
  • White Coat Hypertension: Although less likely given the severity of the elevation, this phenomenon, where blood pressure is elevated in a clinical setting but normal at home, could contribute to the presentation.
  • Sleep Apnea: This condition is common in older adults and can lead to resistant hypertension due to intermittent hypoxia and increased sympathetic tone.
  • Chronic Kidney Disease (CKD): CKD can lead to hypertension due to fluid overload, renin-angiotensin-aldosterone system activation, and other mechanisms. However, the absence of volume overload on the chest X-ray does not rule out CKD.
• Do Not Miss Diagnoses
  • Pheochromocytoma: A rare tumor of the adrenal gland that secretes catecholamines, leading to episodic or sustained hypertension. Although rare, missing this diagnosis could be catastrophic.
  • Aortic Dissection: A life-threatening condition where there is a tear in the aorta's inner layer. It often presents with severe, tearing chest pain and hypertension. The absence of chest pain does not rule out this condition entirely.
  • Hypertensive Encephalopathy: A condition characterized by severely elevated blood pressure leading to cerebral edema and potentially life-threatening complications. Symptoms can include headache, confusion, and seizures.
• Rare Diagnoses
  • Hyperthyroidism: Can cause hypertension due to increased sympathetic activity and increased cardiac output.
  • Hyperparathyroidism: Rarely, primary hyperparathyroidism can lead to hypertension, possibly through increased calcium levels affecting vascular smooth muscle.
  • Cushing's Syndrome: A rare endocrine disorder caused by excess cortisol, which can lead to hypertension among other symptoms.
  • Renal Artery Stenosis: Narrowing of the arteries that supply blood to the kidneys, which can lead to renovascular hypertension.

Recommended Work-up

• History and Physical: Detailed history to assess for medication adherence, symptoms of secondary hypertension (e.g., palpitations, sweating, weight loss), and physical examination to look for signs of end-organ damage.
• Laboratory Tests: Complete blood count (CBC), basic metabolic panel (BMP), liver function tests (LFTs), urinalysis, and urine protein-to-creatinine ratio to evaluate for kidney disease.
• Imaging: Echocardiogram to assess cardiac function and look for signs of hypertensive heart disease. Consider CT angiography of the chest if aortic dissection is suspected.
• Specialized Tests: 24-hour urine metanephrines or plasma free metanephrines if pheochromocytoma is suspected. Thyroid function tests (TFTs) if hyperthyroidism is considered.

This approach ensures a comprehensive evaluation to identify the underlying cause of the patient's hypertensive emergency and guide appropriate management.