Differential Diagnosis for Headaches and Near Blackout Episodes

The patient's symptoms of bad headaches, near blackout episodes when sitting up or standing, and severe pain in the right eye warrant a thorough differential diagnosis. Here's an organized approach:

• Single Most Likely Diagnosis

  • Migraine with orthostatic intolerance: This condition is characterized by severe headaches, often accompanied by sensitivity to light and sound, and can include visual auras. Orthostatic intolerance, which involves symptoms like dizziness or fainting when standing up, can sometimes be associated with migraines, especially if there's a significant drop in blood pressure upon standing.

• Other Likely Diagnoses

  • Tension headache: While typically less severe than migraines, tension headaches can cause significant discomfort and, in some cases, may be exacerbated by positional changes.
  • Sinusitis: Inflammation of the sinuses can cause headaches, facial pain, and, if the sinuses are severely congested, could potentially lead to positional dizziness due to increased pressure and possible middle ear effusion affecting balance.
  • Cluster headaches: These are extremely painful headaches that occur in cycles or clusters, often on one side of the head, and can be accompanied by eye pain and other symptoms.

• Do Not Miss Diagnoses

  • Subarachnoid hemorrhage: A life-threatening condition caused by bleeding into the space surrounding the brain, which can present with a sudden, severe headache (often described as "the worst headache" ever experienced) and could potentially cause near blackout episodes due to increased intracranial pressure.
  • Stroke or transient ischemic attack (TIA): Although less common, a stroke or TIA could present with sudden onset of headache and dizziness, especially if there's a significant vascular event affecting the brainstem or cerebellum.
  • Glaucoma: Acute angle-closure glaucoma is an emergency that can cause severe eye pain, headache, and blurred vision, and can lead to nausea and vomiting, potentially causing dizziness when standing.

• Rare Diagnoses

  • Temporal arteritis: An inflammation of the blood vessels in the head, which can cause headaches, visual disturbances, and jaw pain, and is more common in older adults.
  • Idiopathic intracranial hypertension (IIH): Characterized by increased pressure within the skull without any apparent cause, leading to headaches, vision changes, and potentially tinnitus.
  • Postural orthostatic tachycardia syndrome (POTS): A condition characterized by a rapid increase in heart rate and other symptoms that occur upon standing, which could potentially cause near blackout episodes due to inadequate blood flow to the brain.

Each of these diagnoses requires careful consideration of the patient's symptoms, medical history, and potentially, further diagnostic testing to determine the underlying cause of their condition.