Red flags warranting further Ix or referral:

• worsening headache with fever
• sudden‑onset headache reaching maximum intensity within 5 minutes
• new‑onset neurological deficit or cognitive dysfunction
• change in personality
• impaired level of consciousness
• recent head trauma (typically within the past 3/12) suggestive of Subdural Haematoma
• headache triggered by cough, valsalva, sneezing or exercise
• orthostatic headache
• symptoms suggestive of giant cell arteritis
• symptoms and signs of acute narrow angle glaucoma
• a substantial change in the characteristics of their headache.

• Current opinion favours a primarily neural cause involving feedback loops through innervation of cranial arteries in the trigeminovascular system
• Theories include: relative deficiency of 5-hydroxytriptamine (5-HT), Ca channel abnormalities and calcitonin gene related peptide
• usually infrequent compared with tension type headache which is a frequent occurrence in sufferers

Differentiating Migraine from TIA/Stroke in the ED is difficult:

• gradual onset of CNS symptoms in Migraine vs sudden for Stroke/TIA
• Stroke can develop in patient during migraine
• some rare genetic links to both, the most common of which is CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leuko-encephalopathy)
  • 90% patients suffer Migraine with aura
  • present with stroke at a young age, with median age at onset of 48y

The International Classification of headache disorders outlined the following criteria for the diagnosis of basilar migraine.

• (A) Symptoms not attributed to another disorder
• (B) At least 2 attacks that fulfill criteria C, D, or E
• (C) Aura with more than one of the following symptoms: dysarthria, vertigo, tinnitus, hearing impairment, diplopia, ataxia, decreased level of consciousness, bilateral paresthesia, with no motor or retinal symptoms and completely reversible symptoms
• (D) At least one of the following: At least 1 aura symptom occurring gradually over 5 minutes or more and/or 2 or more symptoms occurring in succession over 5 minutes or more, each aura symptom lasts more than 5 minutes, but less than 60 minutes, at least 1 aura symptom is unilateral
• (E) Migraine without aura begins during the aura or within 1 hour.

• Sexual activity is common cause of Primary Headache
• also one of numerous triggers of arterial dissection
• arterial dissection is a well recognised cause of secondary Orgasmic Headache
• arteries most frequently involved are internal carotid or vertebral arteries

• rare, life-threatening disorder of 2 types: 1. septic (usually) secondary to facial infection, sinusitis, orbital cellulitis, pharyngitis, or otitis or 2. aseptic - following traumatic injury or surgery, especially in the setting of a thrombophilic disorder.
• acute or sub-acute over several days - fever, headache (50-90%), periorbital swelling and pain, visual disturbance eg. photophobia, diplopia, loss of vision.
• Less common - rigors, stiff neck, facial numbness, confusion, seizures, stroke symptoms, or coma.
• Eye findings are nearly universal (90%).
  • periorbital edema (initially unilateral but typically bilateral), lid erythema, chemosis, ptosis, proptosis (due to impaired venous drainage of the orbit)
  • restricted or painful eye movement, papilledema, retinal hemorrhages, decreased visual acuity (7% to 22%), photophobia, diminished pupillary reflex, and pulsating conjunctiva.
  • Blindness can result in 8% to 15% of cases.
• CN-VI most common single neuropathy, causing partial ophthalmoplegia with reduced abduction. Most cases, progress rapidly to complete external ophthalmoplegia from CN-III, IV, VI involvement.

NCBI Cavernous Sinus Thrombosis

• rare and mostly congenital. Occasionally secondary to trauma/hydrocephalus
• often a protrusion of the cerebellum and sometimes part of brainstem through the foramen magnum
• highly variable neurological signs and symptoms dependent on degree of herniation
• most common - occipital headaches of variable nature - throbbing, pulsating, stabbing, sharp, exacerbated by cough, strain etc
• graded:
  • Chiari type 0
    • minimal or no herniation but associated syringomyelia
    • occipital headaches probably from altered CSF flow
  • Chiari type I
    • most common type
    • >5mm descent of the caudal tip of cerebellar tonsils past the foramen magnum
    • usually no other neurological abnormality but may get some symptoms
  • Chiari type II
    • brainstem, fourth ventricle, and >5 mm descent of the caudal tip of cerebellar tonsils past the foramen magnum with spina bifida.
    • obvious problem in childhood with brainstem and lower cranial nerve dysfunction
  • Chiari type III
    • extremely rare, debilitating condition with life threatening complications
    • herniation of the cerebellum with or without the brainstem through a posterior encephalocele.
  • Chiari type IV
    • Cerebellar hypoplasia or aplasia with normal posterior fossa and no hindbrain herniation.
    • usually fatal in infancy

Chiari Malformation - raredisease.org
Emed - Chiari

• Older people with new headache should have an ESR to assess the possibility of giant cell (temporal) arteritis
• Imaging is rarely needed acutely
  • CT scan if emergency presentation suggests intracranial haemorrhage - eg 'thunderclap' presentation or localising CNS signs
  • MRI is otherwise preferred imaging modality

• simple analgesia and anti-emetics - including aspirin, paracetamol & NSAIDs.
• Opiates should not be routinely used in part because of worsening of GI symptoms
• 5HT1-receptor agonists (Triptans) eg sumatriptan, especially in combination with NSAID or paracetamol. Caution with patients at risk of ACS
  • Dose: Oral: 50–100 mg and repeat after ≥2/24 hours if needed, S/C: 6mg and repeat after ≥1/24 if needed
• metoclopramide and prochlorperazine initially are useful for headache apart from their anti-emetic actions
• Ergots, eg. ergotamine - 5HT agonist, ∝agonist etc.
  • Side effects including N&V and other vascular effects mutually exclusive
  • less predictable than more effective Triptans
• high flow ≥12Lpm Oxygen for cluster headaches

Headache in over 12s NICE 2015
Migraine - Dx & Mx
Chronic Daily Headache - Dx & Mx
Headache - Dx & Mx
Brit Assoc Guidelines 2010
https://touchneurology.com/cluster-headache-diagnosis-and-treatment/
J Neurol Neurosurg Psych: orgasmic headache and MCA dissection case review
Migraine and stroke - A link?
Migraine and Stroke article 2017
https://rarediseases.org/rare-diseases/hemiplegic-migraine/
Basilar migraine review 2020
cuh_headache_pathway_july_2016.pdf