Headache Flashcards
International Headache Society Classification
- Primary - without identifiable structural cause
(migrain, cluster, tension (episodic & chronic), miscellaneous) - Secondary - Headaches with underlying structural/metabolic cause
(brain tumor, meningitis/encephalitis, idiopathic intracranial HTN (pseudotumor cerebri), subarachnoid hemorrhage, giant cell (temporal) arteritis, cerebral vein thrombosis, post-traumatic headache)
Temporal Mode of onset/progression of signs/symptoms
- headaches of acute onset (abrupt-onset, rapid worsening)
- headaches of subacute onset (gradual onset, progressive buildup)
Pathophysiology Common Among Headaches
-inflammation or physical traction of pain sensitive nerve fibers underlies all types of headaches
Pain sensitive structures:
-dura & meninges at base of brain
-large arteries at base of brain, meningeal arteries
-scalp muscles
-upper cervical muscles
-periosteum of the skull
-facial & head structures/organs (skin, eyes, teeth, nasal sinuses, muscles)
-brain parenchyma has no sensory receptors & is thus INSENSITIVE to pain
How is headache pain transmitted?
- centrally via CNs V, VII, IX, X, and the upper cervical nerve roots C2-3
- ophthalmic branch of CN V innervates pain sensitive structures of the anterior/middle fossa and scalp; CN IX & X and cervical nerve roots C2 and C3 innervate the posterior fossa, the cervical muscles & posterior scalp
- pain sensitive nerve fibers synapse in trigeminal nucleus caudalis & dorsal horn of the upper cervical spine
- central pain fibers synapse in VPL & VML nucleus of thalamus and then onto sensory cortex
Headache Pain Red Flags
- red flag due to “secondary” etiology
- abrupt onset, recent head trauma, fever, Hx of immunosuppression, altered consciouses, focal neurologic signs/symptoms, new onset >50, neck pain or stiffness, anticoag use, headache progression over days, recently altered cognition, “worst headache of my life”
Primary Headaches: Migraine
-chronic neurological disorder causing recurrent headaches w/some or all of the following:
frequently unilateral (may switch sides)
pulsating
moderate to severe intensity
duration of 4-72hr
nausea with or without vomiting
photophobia and/or phonophobia
may be preceded by prodromal phase
may be preceded by an aura in ~20% migraineurs
“triggers” or precipitating factors are frequent
family history
Stages of Migraine
- Preheadache (prodrome & aura)
- headache
- post headache
- begin or stop at any stage
Migraine Prodrome
in ~40% of migraineurs
-vague constellation of symptoms: mood swings (depression, anxiety, irritability), odd food cravings, malaise or vague feeling of un-wellness, fatigue, muscle aches & stiffness
Migraine Aura
-visual disturbance with precedes headache (no more than 60min)
-begin near center of visual field as small gray area with indefinite boundaries
-in minutes, gray expands into horseshoe with bright zigzag lines
-lines grow as a blind (scotoma) area expands and moves outward toward periphery of visual field
(20%)
Migraine Epidemiology
- lifetime prevalence ~15-20% of pop.
- women 10-15%, men 5-10%
- begins before age 20
- dec. occurrence after age 25
Migraine Genetics
- family history
- polygenic - one loci at 10q23
- familial hemiplegi migraine (dominant gene)
Anatomical Substrate for Migraine
- Trigeminovascular System involving CN V1 innervation of pain receptors located in the dura, meninges, and medium/large cerebral arteries & veins that lie on the surface of the brain & above the tentorium
- C2 (back of head)
- CN VII & parasympathetic innervation of Superior salivatory nucleus (vasodilation & other parasympathetic symptoms associated w/migraine reflect central connections b/w pain pathways from CN V & superior salivatory nucleus
Brain Stem Nuclei important for Migraine
- magnus raphe, locus ceruleus, dorsal raphe nuclei
- connection b/w trigeminal nucleus caudalis and superior salivatory nucleus
Migraine Pathogenesis
-Central Sensitization (brain stem, thalamus)
to central pain (thalamus, cortex, limbic, parasym.)
-Internal, External Triggers (emotional, physical, chemical) to Central Generator (brain stem) or to Aura (cortical)
-Both go to Neurogenic Inflammation (triminovascular system) to central pain
Migraine Pathogenesis: Cortical Spreading Depression
- wave of brief neuronal excitation
- prolonged depolarization
- moves across cortex at 2-5mm/min
- brief hyperemia with excitation
Migraine Pathogenesis: Migraine Aura
- brief scintillations at leading edge
- move across the visual field that correspond to movement across cortex at 2-5mm/min
- scintillations replaced by scotoma
- CBF measurements in humans during aura show oligemia in affected territory
Chemicals Irritate Trigeminal Nerve
2 important neurotransmitters
1) Calcitonin gene related peptide (CGRP)
2) Substance P (SP)
- trigeminal ganglion may function as afferent system and efferent system (sending action potentials from neuron body orthodromically to the sensory nerve terminals where a variety of neurotransmitters chemicals may be released (CGRP and SP into dural & meningeal blood vessels, both vasodilators)
Role of CGRP
- mediate neurogenic inflammation & pain in migraine (37 AA peptide)
- CGRP receptors present on dural & cerebral vascular smooth muscle
- potent vasodilator
- causes mast cell degranulation
- serum plasma levels elevated during migraine
- triptans block CGRP release
- CGRP give iv causes migraine like headache
Migraine Treatment: Triptans
- sumatriptan first approved for migraine
- agonists at serotonin or 5HT1 receptors, inhibits release of GCRT
Migraine Treatment: Gepants
-CGRP antagonists
Primary Headaches: Cluster
- Chronic Neurological disorder causing recurrent headaches with some or all of:
- pain always unilateral, frontal, retro-orbital
- unilateral conjunctival infection & rhinorrhea
- unilateral Horner’s syndrome & lacrimation
- Constant, severe, non-pulsing pain
- duration of minutes (3 hrs)
- daily attacks for weeks/months, remission for yrs
- men to women: 4:1
- ~25yrs at onset
- “triggers” are alcohol & tobacco
- rare family history
Cluster Headache: Treatment
-acute Rx: nasal oxygen at 8-10l l/min
subcutaneous Sumatriptan
-Prophylaxis: calcium channel blockers (Verapamil)
lithium
valproic acid
prednsonePrimary Headaches: Episodic/Chronic Tension
- chronic neurological disorder causing recurrent headaches with some or all or:
- pain bilateral & bandlike
- not associated with auras, nausea/vomiting, photo or phonophobia
- duration - 3 hrs
- daily attacks < 15 days/month = episodic
- daily attacks > 15 days/month = chronic
Episodic/Chronic Tension Headaches: Pathophysiology
-complex & multifactorial
