II. Epidemiology: Prevalence

  1. Episodic Headaches: 50% of U.S. adults suffer from Headaches at any period of time
    1. Progress to chronic Headaches in 3-4% of episodic Headache patients (Central Sensitization)
  2. Chronic Headaches: 2-4% of U.S. Adults
    1. Chronic daily symptoms in up to 30% of those with chronic Headaches
  3. Headaches are a common trigger for medical care visits
    1. Acute Headache is the fourth most common reason for Emergency Department evaluation
    2. Half of Migraine Headache visits are to primary care

III. Pathophysiology: Headache Central Sensitization

  1. Frequent episodic Headaches may progress to chronic Headaches without management
  2. Results in Central Sensitization and Neuronal dysfunction
  3. Central Sensitization Inappropriate response to low level stimuli
    1. Lower thresholds trigger pain response
    2. Exaggerated stimulus response
    3. Pain persists after trigger is removed
  4. Risk Factors for progression from episodic Headache to chronic Headache are specific to Headache type
    1. See Migraine Headache
    2. See Tension Headache

IV. Causes: Primary Headaches

  1. See Acute Recurrent Headache
  2. See Chronic Nonprogressive Headache
  3. Common Primary Headaches
    1. Tension Headache (50% of acute Headaches)
    2. Common Migraine Headache (10% of acute Headaches)
  4. Other Primary Headaches
    1. Migraine with Aura (Classic Migraine)
    2. Cluster Headache and other trigeminal autonomic Cephalgias (<1%)
    3. Sexual Headache

V. Causes: Secondary Headaches

  1. See Headache Red Flag
  2. Acute Localized Headache
    1. Sinus Headache (e.g. Acute Sinusitis)
    2. Myofacial pain
      1. Cervical Spine disorder (Cervical Spondylosis)
      2. Temporomandibular Joint Dysfunction
    3. Ophthalmologic Headache
      1. Acute Angle-Closure Glaucoma (severe Eye Pain)
      2. Migraine Headache (scintillating scotoma)
      3. Idiopathic Intracranial Hypertension (tunnel Vision and retro-orbital Headache)
      4. Temporal Arteritis (temporal Headache, Amaurosis Fugax)
  3. Generalized Headache
    1. See Acute Generalized Headache
    2. See Chronic Progressive Headache (Organic Headache)
    3. See Headache Red Flags
  4. Urgent or Life-treatening secondary causes with possible positive Head CT
    1. Subarachnoid Hemorrhage
    2. Acute or chronic Subdural Hematoma
    3. Cerebellar infarction
    4. Intracranial Mass
    5. Vertebral Artery Dissection
    6. Carotid Artery Dissection
    7. Cerebral Venous Thrombosis
  5. Urgent or Life-treatening secondary causes with negative Head CT
    1. Acute angle closure Glaucoma
    2. Bacterial Meningitis or Encephalitis
    3. Carbon Monoxide Poisoning
    4. Temporal Arteritis (Giant Cell Arteritis)
    5. Cerebral or dural venous sinus thrombosis
    6. Cavernous Sinus Thrombosis
    7. Cervical Artery Dissection (carotid dissection, Vertebrobasilar Dissection)
    8. Preeclampsia or Eclampsia (Pregnancy Induced Hypertension)
    9. Pituitary Apoplexy
    10. Hypertensive Emergency
    11. Reversible Cerebral Vasoconstriction Syndrome (RCVS)
  6. Miscellaneous secondary causes
    1. Hormonal Headache
      1. Menstrual Migraine
      2. Estrogen in Oral Contraceptive
    2. Idiopathic Intracranial Hypertension (Pseudotumor Cerebri, esp. in women with Obesity)
    3. Post-Traumatic Headache (Postconcussion Syndrome)
    4. Post-Dural Puncture Headache (Spinal Headache)
    5. Obstructive Sleep Apnea
    6. Temporomandibular Joint Disorder
    7. Frontal Sinusitis

VI. History

VII. Exam

VIII. Differential Diagnosis

  1. See Headache Causes
  2. See Headache Red Flag
  3. See Organic Headache

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