Differential Diagnosis for Migraine vs SAH

When differentiating between a migraine and a Subarachnoid Hemorrhage (SAH), it's crucial to consider various diagnoses due to the significant difference in treatment and prognosis. Here's a structured approach:

• Single Most Likely Diagnosis:

  • Migraine: This is often the most common diagnosis in patients presenting with headache, given its high prevalence. A migraine can present with severe headache, nausea, vomiting, and sometimes neurological symptoms like aura, which can mimic more serious conditions.

• Other Likely Diagnoses:

  • Tension headache: Although typically less severe, tension headaches are very common and can sometimes be confused with migraines or other headache types.
  • Cluster headache: Known for its severe, unilateral pain, cluster headaches can be mistaken for migraines or SAH due to their intensity.
  • Sinus headache: Inflammation of the sinuses can cause headache that might be confused with migraine, though it usually includes other symptoms like facial pain and nasal congestion.

• Do Not Miss Diagnoses:

  • Subarachnoid Hemorrhage (SAH): This is a medical emergency. SAH presents with a sudden, severe headache (often described as "the worst headache of my life"), and it can be accompanied by loss of consciousness, seizures, or other neurological deficits. Missing this diagnosis can be fatal.
  • Meningitis: Infection of the meninges can cause severe headache, fever, and neck stiffness. It's a medical emergency that requires prompt treatment.
  • Temporal arteritis: This condition, involving inflammation of the blood vessels, can cause severe headache and visual disturbances. If untreated, it can lead to blindness.

• Rare Diagnoses:

  • Cervicogenic headache: Originating from the cervical spine, these headaches can mimic migraines but are less common.
  • Trigeminal neuralgia: Characterized by intense pain in the face, it's much rarer than migraines and usually involves specific triggers.
  • Pituitary apoplexy: A rare condition involving hemorrhage or infarction of the pituitary gland, presenting with sudden, severe headache, and potentially life-threatening if not promptly treated.

Each of these diagnoses has distinct features, but the key to differentiating them lies in a thorough history, physical examination, and, when necessary, diagnostic imaging and laboratory tests. The sudden onset and severity of the headache, presence of neurological deficits, and accompanying symptoms are critical factors in distinguishing between these conditions.