Secondary causes of headaches

• Traumatic: post-concussion, SAH, SDH, postcraniotomy
• ↑ ICP: mass (tumor, abscess, vascular malformations, ICH), hydrocephalus, idiopathic intracranial hypertension (pseudotumor cerebri), altitude-associated cerebral edema
• ↓ ICP: post-LP headache, CSF leak/dural tear, overshunting
• Vascular: stroke (esp. posterior circ), dissection, vasculitis (incl. temporal arteritis), reversible cerebral vasoconstriction syndrome (RCVS), ICH, venous sinus thrombosis
• Meningeal irritation: meningitis, SAH
• Extracranial: sinusitis, TMJ syndrome, glaucoma
• Systemic: hypoxia (OSA), hypercapnia, dialysis, HTN, cardiac cephalalgia, hypoglycemia, ↓ TSH, pheo, medication overuse (analgesics), withdrawal (caffeine, opioids, estrogen)