Last Minute Review
Headache — Last Minute Review
Rapid Review
A last-minute review of high-yield headache facts for the RITE and board exams. Tables, key associations, and must-know one-liners — designed for a quick pass the night before.
Migraine Diagnostic Criteria (ICHD-3)
Migraine Without Aura
| Criterion | Requirement |
|---|---|
| A | ≥5 attacks fulfilling B–D |
| B — Duration | 4–72 hours (untreated or unsuccessfully treated) |
| C — ≥2 of 4 pain features | Unilateral • Pulsating • Moderate-to-severe intensity • Aggravated by routine physical activity |
| D — ≥1 associated feature | Nausea and/or vomiting • Photophobia AND phonophobia |
| E | Not better accounted for by another ICHD-3 diagnosis |
Migraine With Aura
| Criterion | Requirement |
|---|---|
| A | ≥2 attacks fulfilling B–C |
| B — ≥1 fully reversible aura | Visual • Sensory • Speech/language • Motor • Brainstem • Retinal |
| C — ≥3 of 6 features | ≥1 aura symptom spreads gradually over ≥5 min • ≥2 symptoms occur in succession • Each non-motor symptom lasts 5–60 min (motor aura in hemiplegic migraine may last up to 72 h) • ≥1 symptom is unilateral • ≥1 symptom is positive (scintillations, pins/needles) • Aura accompanied or followed within 60 min by headache |
Chronic Migraine
| Feature | Criterion |
|---|---|
| Frequency | Headache ≥15 days/month for >3 months |
| Migraine features | ≥8 days/month with migraine features or treated/relieved by triptan or ergot |
| Key distinction | Must rule out medication overuse headache as contributing factor |
💎 Board Pearl
- 5-4-3-2-1 rule for migraine without aura: 5 attacks, 4–72 h, ≥3 months for chronic, 2 pain features, 1 associated feature
- Migraine with aura only needs 2 attacks (not 5)
- Typical aura is visual → sensory → speech; motor aura = hemiplegic migraine (separate category)
- Aura WITHOUT headache is common in older patients — must rule out TIA
Headache Pattern Recognition by Duration (Board Quick Reference)
| Diagnosis | Typical Attack Duration | Key Distinguisher |
|---|---|---|
| Trigeminal neuralgia | Seconds (paroxysmal lightning jabs) | V2/V3 distribution; cutaneous triggers; NO autonomic features |
| SUNCT / SUNA | Seconds (1–600 sec; typically <1 min) | V1 distribution; prominent ipsilateral autonomic features (conjunctival injection / tearing); cutaneous triggers; NOT indomethacin-responsive |
| Primary stabbing headache ("ice-pick") | Seconds (often <3 sec) | Random extratrigeminal locations; jab-and-jolt; partial indomethacin response |
| Paroxysmal hemicrania | 2–30 minutes | Strict unilateral; autonomic features; absolute response to indomethacin |
| Cluster headache | 15–180 minutes | Severe unilateral V1; agitation/pacing; autonomic features; circadian/seasonal pattern |
| Hypnic headache | 15 min – 4 hours | "Alarm clock" headache — nocturnal only; >50 yo; NO autonomic features; bedtime caffeine first-line |
| Migraine | 4–72 hours (treated or untreated) | Photophobia, phonophobia, nausea; aggravated by activity; pulsating |
| Tension-type headache | 30 min – 7 days | Bilateral, pressing, mild-moderate; NOT worsened by routine activity |
| Hemicrania continua | Continuous (with exacerbations) | Strict unilateral, daily; absolute response to indomethacin; autonomic features during exacerbations |
| NDPH (new daily persistent headache) | Continuous from a known exact start date | Patient knows the exact date of onset; treatment difficult |
Indomethacin-Responsive Headaches
| Response Category | Headache |
|---|---|
| Absolute response (diagnostic criterion) | Paroxysmal hemicrania (episodic and chronic); Hemicrania continua |
| Often responsive | Primary cough headache; primary exercise headache; primary stabbing headache; primary headache associated with sexual activity (pre-orgasmic and orgasmic) |
| NOT responsive | Cluster headache; migraine; SUNCT/SUNA; trigeminal neuralgia; tension-type headache |
💎 Board Pearl
Indomethacin response is a diagnostic criterion for paroxysmal hemicrania and hemicrania continua — a properly conducted indomethacin trial (e.g., escalating to 150–225 mg/day for at least 3 days, with GI/renal monitoring) that fails to resolve the headache excludes these diagnoses. Always prescribe with a PPI given chronic NSAID use.
Headache Imaging Findings (Board Quick Reference)
| Disease | Classic Imaging Finding(s) |
|---|---|
| IIH (idiopathic intracranial hypertension) | Empty sella, optic nerve sheath distension/tortuosity, posterior globe flattening, transverse sinus stenosis on MRV |
| SIH (spontaneous intracranial hypotension) | Diffuse pachymeningeal enhancement (NOT leptomeningeal), brain sagging / tonsillar descent, pituitary engorgement, subdural collections; CT/MR myelography to localize leak |
| RCVS (reversible cerebral vasoconstriction syndrome) | "String of beads" / sausage-on-a-string multifocal segmental cerebral artery narrowing on CTA/MRA/DSA; reversible by ~12 weeks |
| CVT (cerebral venous thrombosis) | MRV/CTV filling defect; "empty delta sign" on post-contrast CT; cord sign; venous infarction (often hemorrhagic, atypical territory) |
| GCA (giant cell arteritis) | "Halo sign" on temporal artery ultrasound (hypoechoic wall thickening); MRA may show vessel wall enhancement; PET-CT for large-vessel GCA |
| Pituitary apoplexy | Hemorrhagic sellar/suprasellar mass; pituitary enlargement with mixed-signal hemorrhage; mass effect on optic chiasm/cavernous sinus |
| Aneurysmal SAH | Basal cistern hyperdense blood on non-contrast CT; CTA shows aneurysm; LP xanthochromia if CT negative >6–12 h |
| Chiari I (relevant to cough headache) | Cerebellar tonsils ≥5 mm below foramen magnum; ± syrinx |
Trigeminal Autonomic Cephalalgias (TACs) Comparison
Master TAC Comparison Table
| Feature | Cluster Headache | Paroxysmal Hemicrania | Hemicrania Continua | SUNCT/SUNA |
|---|---|---|---|---|
| Duration | 15–180 min | 2–30 min | Continuous (with exacerbations) | 1–600 sec |
| Frequency | 1 q.o.d. to 8/day | >5/day (for more than half the time) — ICHD-3 criterion C | Continuous background | 3–200/day |
| Gender predominance | Male (3–4:1) | Female (2–3:1) | Female (2:1) | Male (1.5:1) |
| Pain location | Orbital/supraorbital/temporal | Orbital/temporal | Orbital/temporal | Orbital/periorbital/temporal |
| Pain quality | Stabbing/boring, excruciating | Throbbing/stabbing, severe | Dull ache with sharp exacerbations | Stabbing/burning, severe |
| Autonomic features | Prominent (lacrimation, rhinorrhea, ptosis, miosis) | Prominent (same as cluster) | Mild (may be subtle) | Prominent (conjunctival injection + lacrimation = defining) |
| Restlessness/agitation | Yes (pacing, rocking) | Yes (can occur) | No | Yes (can occur) |
| Circadian/circannual pattern | Yes (hallmark) | No | No | No |
| Indomethacin response | No | Absolute (diagnostic criterion) | Absolute (diagnostic criterion) | No |
| First-line acute Tx | High-flow O2 (12–15 L/min) + sumatriptan 6 mg SC | Indomethacin | Indomethacin | No effective abortive (attacks too brief); IV lidocaine as bridge for severe exacerbations |
| First-line preventive Tx | Verapamil (requires ECG) | Indomethacin | Indomethacin | Lamotrigine |
| Alternate preventive Tx | Lithium, galcanezumab, suboccipital steroid injection | Verapamil, topiramate | Topiramate, gabapentin, CGRP mAbs | Topiramate, gabapentin, carbamazepine |
| Key board association | Posterior hypothalamus activation; Horner can persist | "Indomethacin-responsive TAC" (female) | "Continuous side-locked headache + indomethacin" | Must exclude pituitary adenoma |
💎 Board Pearl
- Indomethacin-responsive TACs = paroxysmal hemicrania + hemicrania continua (NOT cluster, NOT SUNCT/SUNA)
- SUNCT = Short-lasting Unilateral Neuralgiform headache with Conjunctival injection and Tearing; SUNA = only one or neither autonomic sign
- Cluster headache is the only primary headache where O2 is a first-line acute treatment
- Verapamil for cluster → ECG at baseline and ~10 days after each dose escalation (risk of heart block / PR prolongation)
Tension-Type Headache
Diagnostic Criteria (Episodic TTH)
| Criterion | Requirement |
|---|---|
| A | ≥10 episodes occurring <15 days/month (<180 days/year) for >3 months |
| B | Duration: 30 min to 7 days |
| C — ≥2 of 4 | Bilateral • Pressing/tightening (non-pulsating) • Mild-to-moderate • NOT aggravated by routine physical activity |
| D — Both of | No nausea or vomiting • No more than one of photophobia or phonophobia |
Episodic vs Chronic TTH
| Feature | Episodic | Chronic |
|---|---|---|
| Frequency | <15 days/month | ≥15 days/month for >3 months |
| Acute Tx | Simple analgesics (NSAIDs, acetaminophen) | Same, but watch for MOH |
| Preventive Tx | Usually not needed | Amitriptyline (first-line preventive) |
💎 Board Pearl
- TTH is the most common primary headache but rarely presents to neurology
- TTH is essentially the opposite of migraine on criteria: bilateral, non-pulsating, mild-moderate, not worsened by activity, no nausea/vomiting
- If both photo AND phonophobia are present → think migraine, not TTH
Red Flags (SNOOP)
SNOOP Mnemonic
| Letter | Red Flag | Think Of… |
|---|---|---|
| S | Systemic symptoms (fever, weight loss) or systemic disease (HIV, cancer) | Meningitis, metastases, infection |
| N | Neurological signs (confusion, papilledema, focal deficits, seizures) | Mass lesion, IIH, encephalitis, CVT |
| O | Onset — sudden/thunderclap (peak <1 min) | SAH, RCVS, CVT, dissection, pituitary apoplexy |
| O | Older age of onset (>50 years) | Giant cell arteritis, mass lesion, CVA |
| P | Pattern change / Progressive / Precipitated by Valsalva / Positional | Mass (Valsalva) • SIH (orthostatic) • IIH (worse supine) • Chiari |
Red Flag → Differential Diagnosis
| Red Flag Finding | Differential | First-Line Workup |
|---|---|---|
| Thunderclap onset (<1 min to peak) | SAH, RCVS, CVT, dissection, pituitary apoplexy | CT head → LP (xanthochromia) → CTA/MRA |
| Papilledema | IIH, mass lesion, CVT, meningitis | MRI brain + MRV → LP with opening pressure |
| Fever + headache + meningismus | Meningitis, encephalitis, abscess | LP (CSF analysis), blood cultures |
| Worse with Valsalva/cough | Posterior fossa mass, Chiari I | MRI brain with posterior fossa views |
| Positional (worse upright) | SIH / CSF leak | MRI brain with gadolinium (pachymeningeal enhancement) |
| New headache >50 years + ESR ↑ | Giant cell arteritis | ESR + CRP → temporal artery biopsy |
| Progressive over weeks + focal signs | Mass lesion, CVT, abscess | MRI brain with contrast |
| Post-partum + headache | CVT, pre-eclampsia/eclampsia, RCVS | MRV, labs (platelets, LFTs, uric acid) |
Board Trap: A normal non-contrast CT head does NOT rule out SAH — modern multidetector CT approaches ~100% sensitivity within 6 hours (Perry 2011), but sensitivity falls to ~85% at 48 hours. If CT is negative beyond the 6-hour window (or if pretest probability is high), LP is mandatory (look for xanthochromia). CTA can identify aneurysm but does not exclude SAH.
Secondary Headache Causes
High-Yield Secondary Headaches
| Cause | Key Clinical Features | Workup / Diagnosis |
|---|---|---|
| SAH | Thunderclap "worst headache of my life," meningismus, ± LOC | CT head → LP (xanthochromia) → CTA for aneurysm |
| Cerebral Venous Thrombosis (CVT) | Progressive headache, papilledema, focal deficits, seizures; risk: OCP, pregnancy, thrombophilia | MRI + MR venography; D-dimer may be elevated; Tx: anticoagulation (even if hemorrhagic) |
| IIH (Pseudotumor Cerebri) | Obese young woman, transient visual obscurations, pulsatile tinnitus, papilledema, CN VI palsy | MRI (empty sella, optic sheath distension, transverse sinus stenosis) → LP: OP >250 mm H2O (>25 cm H2O); >280 mm H2O in children, normal CSF |
| SIH (Low Pressure) | Orthostatic headache (worse upright, better supine), subdural collections, CN palsies | MRI brain + Gd: diffuse pachymeningeal enhancement; CT myelogram or MR myelogram for leak localization |
| Giant Cell Arteritis | Age >50, temporal tenderness, jaw claudication, visual loss (AION), PMR symptoms | ESR ↑ (>50) + CRP ↑ → temporal artery biopsy (skip lesions possible); start steroids BEFORE biopsy |
| Pituitary Apoplexy | Sudden headache + visual field defect (bitemporal hemianopia) + ophthalmoplegia (CN III) + hormonal crisis | MRI pituitary; stat cortisol; emergent endocrine + neurosurgery consult |
| Arterial Dissection (Carotid/Vertebral) | Unilateral head/neck pain, partial Horner (carotid), stroke in young, history of trauma/chiropractic | CTA or MRA neck with fat-sat (intramural hematoma); Tx: anticoagulation or antiplatelet |
| RCVS | Recurrent thunderclap headaches over days–weeks, ± stroke/hemorrhage; triggers: vasoactive drugs, post-partum | CTA/MRA: segmental vasoconstriction ("string of beads"); CSF is normal (unlike PACNS); resolves in ≤3 months |
| Meningitis | Headache + fever + meningismus + photophobia; ± rash (meningococcal), altered mental status | LP: ↑ WBC, ↑ protein, ↓ glucose (bacterial); blood cultures; empiric antibiotics ASAP |
💎 Board Pearl
- RCVS vs PACNS: RCVS = thunderclap onset, normal CSF, resolves in 3 months; PACNS = insidious onset, abnormal CSF (lymphocytic pleocytosis), progressive course, requires biopsy
- SIH MRI mnemonic — "SEEPS": Subdurals, Enhancement (pachymeningeal), Engorgement (venous), Pituitary enlargement, Sagging brain
- CVT treatment is anticoagulation even in the presence of hemorrhagic infarction
Acute Treatment
Acute Migraine Pharmacotherapy
| Drug | Class | Mechanism | Key Contraindication / Note |
|---|---|---|---|
| Sumatriptan, rizatriptan, eletriptan, zolmitriptan, naratriptan, frovatriptan, almotriptan | Triptans | 5-HT1B/1D agonist → vasoconstriction + inhibition of CGRP release | Contraindicated in CAD, uncontrolled HTN, prior stroke, hemiplegic/brainstem migraine; avoid within 24 h of ergots; naratriptan/frovatriptan = longer half-life (menstrual migraine) |
| Rimegepant (Nurtec) | Gepant (oral) | CGRP receptor antagonist | No vasoconstrictive risk; dual-use (acute + preventive); hepatotoxicity screening |
| Ubrogepant (Ubrelvy) | Gepant (oral) | CGRP receptor antagonist | Acute only; CYP3A4 interactions; no cardiovascular contraindication |
| Lasmiditan (Reyvow) | Ditan | 5-HT1F agonist (no vasoconstriction) | Schedule V (driving impairment risk, 8 h restriction); can use with cardiovascular disease; sedation, dizziness |
| Ibuprofen, naproxen, diclofenac, ketorolac | NSAIDs | COX-1/2 inhibition | GI bleeding, renal impairment; ketorolac IM/IV for ED; naproxen = longest half-life NSAID |
| Ergotamine, DHE (dihydroergotamine) | Ergot alkaloids | 5-HT1B/1D agonist + dopamine/adrenergic receptor activity | Contraindicated in CAD/PVD/pregnancy; avoid within 24 h of triptans; DHE IV/nasal for status migrainosus |
| Metoclopramide, prochlorperazine | Antiemetics (dopamine antagonists) | D2 receptor antagonism; independent analgesic effect | Akathisia, EPS; metoclopramide + diphenhydramine is an effective ED regimen |
| Dexamethasone | Corticosteroid | Anti-inflammatory; reduces headache recurrence | Adjunct for status migrainosus (>72 h); single dose 10–20 mg IV; does NOT abort acute attack alone |
💎 Board Pearl
- Gepants and ditans are safe in patients with cardiovascular disease (unlike triptans and ergots)
- Rimegepant is the only drug FDA-approved for both acute and preventive migraine treatment
- Treat early — triptans are most effective when taken during mild pain phase before central sensitization develops
Preventive Treatment
When to Start Preventive Therapy
| Indication | Detail |
|---|---|
| ≥4 migraine days/month | Most commonly cited threshold |
| ≥6 headache days/month | Even if not all meet migraine criteria |
| Significant disability despite acute Tx | Missed work/school, impaired function |
| Acute medication overuse or contraindication | Overusing triptans/analgesics or cardiovascular contraindication to triptans |
| Special subtypes | Hemiplegic migraine, brainstem aura, prolonged aura, migrainous infarction |
Preventive Drug Comparison
| Drug | Class | Evidence Level | Key Side Effect / Note |
|---|---|---|---|
| Topiramate | Antiseizure | Level A | Weight loss, cognitive slowing ("dopamax"), paresthesias, metabolic acidosis, kidney stones, teratogen |
| Divalproex / valproate | Antiseizure | Level A | Weight gain, tremor, hair loss, hepatotoxicity, PCOS; Category X for migraine prevention; black-box warning for neural tube defects (NTDs) — avoid in women of childbearing potential |
| Propranolol | Beta-blocker (non-selective) | Level A | Fatigue, depression, bradycardia, bronchospasm; avoid in asthma; good for comorbid anxiety/tremor |
| Timolol | Beta-blocker (non-selective) | Level A | Only other beta-blocker with Level A evidence; similar SE to propranolol |
| Metoprolol | Beta-blocker (β1-selective) | Level B | Better tolerated than propranolol; preferred if mild asthma/COPD |
| Amitriptyline | TCA | Level B | Weight gain, sedation, dry mouth, QT prolongation; good for comorbid insomnia/TTH |
| Venlafaxine | SNRI | Level B | Nausea, hypertension; good for comorbid depression/anxiety |
| Candesartan | ARB | Level B | Well tolerated; good for comorbid hypertension |
| Erenumab (Aimovig) | CGRP mAb (receptor) | Level A | SC monthly; constipation, hypertension; only CGRP mAb targeting the receptor (others target ligand) |
| Fremanezumab (Ajovy) | CGRP mAb (ligand) | Level A | SC monthly or quarterly; injection site reactions |
| Galcanezumab (Emgality) | CGRP mAb (ligand) | Level A | SC monthly; only CGRP mAb FDA-approved for episodic cluster headache |
| Eptinezumab (Vyepti) | CGRP mAb (ligand) | Level A | IV quarterly (only IV CGRP mAb); fastest onset of action |
| OnabotulinumtoxinA (Botox) | Neurotoxin | Level A | FDA-approved for chronic migraine only (not episodic); 31 injection sites, 155 units q12 weeks (up to 195 units / 39 sites with follow-the-pain paradigm); "PREEMPT" protocol |
| Atogepant (Qulipta) | Oral gepant | Level A | Daily oral; approved for episodic AND chronic migraine prevention; hepatotoxicity monitoring |
| Rimegepant (Nurtec ODT) | Oral gepant | Level A | Every other day dosing for prevention; dual acute + preventive approval |
💎 Board Pearl
- Botox is ONLY for chronic migraine (≥15 days/month) — no benefit for episodic migraine
- Erenumab = receptor blocker; fremanezumab / galcanezumab / eptinezumab = ligand blockers
- Galcanezumab is the only CGRP mAb with evidence for both migraine and cluster headache
- Give any preventive a 2–3 month trial at adequate dose before declaring failure
- Level A oral agents: topiramate, valproate, propranolol, timolol
Headache in Pregnancy
Acute & Preventive Therapy Considerations
| Drug / Class | Use in Pregnancy | Notes |
|---|---|---|
| Acetaminophen | First-line acute | Safest acute option across all trimesters |
| Metoclopramide / prochlorperazine | Acceptable | Useful adjuncts for nausea + headache; commonly used in pregnancy |
| Sumatriptan | If needed | Most safety data among triptans (pregnancy registry); reserve for refractory attacks |
| NSAIDs | AVOID after 20 weeks | Risk of oligohydramnios / fetal renal injury; premature ductal closure in 3rd trimester |
| Valproate | AVOID — Category X for migraine | Neural tube defects (NTDs); contraindicated for migraine prevention in women of childbearing potential |
| Topiramate | AVOID | Cleft lip / palate risk; oral contraceptive interaction |
| Ergots / DHE | AVOID | Uterotonic; contraindicated in pregnancy |
💎 Board Pearl
- Acetaminophen is the first-line acute treatment for migraine in pregnancy
- Valproate is Category X for migraine prevention (NTDs) — never start in a woman who could become pregnant without a confirmed plan
- Topiramate → cleft lip/palate risk; NSAIDs → avoid after 20 weeks
- Sumatriptan has the most pregnancy safety data among triptans; metoclopramide / prochlorperazine are acceptable adjuncts
- New or thunderclap headache in pregnancy / post-partum → rule out CVT, RCVS, PRES, pre-eclampsia/eclampsia, pituitary apoplexy
Medication Overuse Headache (MOH)
Overuse Thresholds
| Drug Class | Overuse Threshold | Notes |
|---|---|---|
| Triptans | ≥10 days/month for >3 months | Can worsen migraine frequency; lower threshold than simple analgesics |
| Simple analgesics (NSAIDs, acetaminophen) | ≥15 days/month for >3 months | Higher threshold; ASA/APAP/NSAIDs |
| Opioids | ≥10 days/month for >3 months | Most refractory MOH; avoid opioids for migraine entirely if possible |
| Combination analgesics (e.g., butalbital-containing) | ≥10 days/month for >3 months | Butalbital is the most common cause of difficult-to-treat MOH in the US |
| Ergots | ≥10 days/month for >3 months | Same threshold as triptans |
| Any combination of above | ≥10 days/month for >3 months | Mixed overuse of multiple classes |
Management
| Step | Action |
|---|---|
| 1. Education | Explain the overuse cycle; patient buy-in is essential |
| 2. Withdrawal | Abrupt discontinuation (preferred for triptans/analgesics) or taper (opioids/butalbital); expect 2–10 day rebound worsening |
| 3. Bridge therapy | Short course of naproxen, prednisone taper, or DHE protocol during withdrawal |
| 4. Initiate/optimize preventive | Start or up-titrate preventive therapy; topiramate, CGRP mAbs, and onabotulinumtoxinA all have evidence in MOH |
| 5. Limit acute Tx | Restrict acute medications to ≤2 days/week |
Board Trap: A patient presenting with "chronic daily headache" who takes OTC analgesics most days → MOH should be at the top of your differential. The headache will not improve until the overused medication is withdrawn.
Facial Pain Differentials
Facial Pain Comparison Table
| Condition | Key Features | Treatment |
|---|---|---|
| Trigeminal neuralgia — Classical | Brief electric shock-like pain in V2/V3 distribution; triggered by touch, chewing, wind; refractory period between attacks; caused by NVC (usually SCA) | First-line: carbamazepine or oxcarbazepine; second-line: baclofen, lamotrigine (± add-on gabapentin/pregabalin); surgery: MVD (microvascular decompression) — most durable; alternatives: gamma knife radiosurgery, percutaneous rhizotomy (radiofrequency, balloon compression, glycerol) |
| Trigeminal neuralgia — Secondary | Same pain pattern but with sensory deficit, bilateral involvement, or V1 predominance; caused by MS (young patient), tumor (CPA mass) | Treat underlying cause + carbamazepine; MRI brain mandatory |
| Glossopharyngeal neuralgia | Sharp stabbing pain in throat, ear, tonsillar area; triggered by swallowing, coughing, talking; can cause bradycardia/syncope (vagal reflex) | Carbamazepine; surgery if refractory; board pearl: syncope with throat pain = GPN |
| Occipital neuralgia | Sharp/stabbing pain in greater/lesser occipital nerve distribution (posterior scalp to vertex); tender occipital nerve; can follow trauma | Occipital nerve block (diagnostic + therapeutic); gabapentin/pregabalin; botulinum toxin |
| TMJ dysfunction | Jaw pain, clicking/crepitus, limited jaw opening; worse with chewing; temporal/preauricular pain | Bite guard, NSAIDs, physical therapy, muscle relaxants |
| Dental pathology | Well-localized pain, worse with hot/cold, percussion tenderness; dental exam reveals caries/abscess | Dental referral |
| Persistent idiopathic facial pain | Continuous, poorly localized facial pain; no sensory loss; does NOT follow nerve distribution; diagnosis of exclusion | Amitriptyline, duloxetine; CBT; avoid repeated procedures |
💎 Board Pearl
- Young patient + bilateral trigeminal neuralgia → think MS (demyelinating plaque at root entry zone of CN V)
- Classical TN: V2/V3 >> V1; if V1 dominant → suspect secondary cause
- Glossopharyngeal neuralgia + syncope = boards love this association (vagal reflex → bradycardia/asystole)
IIH (Pseudotumor Cerebri)
Friedman 2013 Criteria (updated diagnostic criteria for IIH; supersedes the older Modified Dandy)
| Criterion | Requirement |
|---|---|
| 1. Signs/symptoms of ↑ ICP | Papilledema, headache, transient visual obscurations, pulsatile tinnitus, CN VI palsy |
| 2. No localizing signs | Except CN VI palsy (false localizing sign of ↑ ICP) |
| 3. Normal neuroimaging | No mass, hydrocephalus, or structural cause; MRI brain with venography (or CT/CTV when MRI unavailable) is required to exclude CVT and structural causes before LP-based IIH diagnosis |
| 4. Elevated opening pressure | >250 mm H2O (>25 cm H2O) in adults; >280 mm H2O (>28 cm H2O) in non-obese, non-sedated children, otherwise >250 mm H2O |
| 5. Normal CSF composition | Normal protein, glucose, cell count |
MRI Findings Suggestive of IIH
| Finding | Detail |
|---|---|
| Empty sella | CSF pressure flattens pituitary |
| Optic nerve sheath distension | Peri-optic CSF expansion >2 mm |
| Posterior globe flattening | Scleral indentation from ↑ CSF pressure |
| Transverse sinus stenosis | Bilateral > unilateral; may be cause or consequence |
| Optic disc protrusion | Correlates with clinical papilledema grade |
Treatment Ladder
| Step | Intervention | Notes |
|---|---|---|
| 1 | Weight loss | 5–10% body weight can normalize ICP; only disease-modifying treatment |
| 2 | Acetazolamide | First-line medical therapy; carbonic anhydrase inhibitor → ↓ CSF production; up to 4 g/day; SE: paresthesias, dysgeusia, metabolic acidosis, kidney stones |
| 3 | Topiramate | Alternative to acetazolamide; also promotes weight loss; weak carbonic anhydrase inhibition |
| 4 | Serial lumbar punctures | Temporizing; not a long-term solution |
| 5 | ONSF (optic nerve sheath fenestration) | For progressive visual loss; protects optic nerve; may not help headache |
| 6 | CSF shunting (VP or LP shunt) | For threatened/declining vision or fulminant IIH; do NOT use shunting as routine treatment for headache alone — manage headache phenotype separately; high revision rate |
| 7 | Venous sinus stenting | Emerging option for transverse sinus stenosis with pressure gradient >8 mmHg |
Papilledema Grading (Frísén Scale)
| Grade | Appearance |
|---|---|
| 0 | Normal optic disc |
| 1 | C-shaped halo of disc edema (nasal border blurring) |
| 2 | Circumferential halo; nasal border obscured |
| 3 | Obscuration of ≥1 major vessel at disc margin |
| 4 | Total obscuration of a major vessel on the disc |
| 5 | Complete obscuration of all vessels + dome-shaped protrusion |
💎 Board Pearl
- CN VI palsy in IIH is a false localizing sign — due to long intracranial course of abducens nerve, vulnerable to diffuse ↑ ICP
- IIH without papilledema (IIHWOP) exists — diagnosed by elevated OP + symptoms + normal imaging; watch for it on boards
- Medications that can cause or worsen IIH: vitamin A / retinoids, tetracyclines (minocycline, doxycycline), growth hormone, lithium
- Must get MRI brain with venography (or CT/CTV when MRI unavailable) to exclude CVT and structural causes before LP-based IIH diagnosis — CVT mimics IIH perfectly
Classic Board Traps
Board Trap 1 — Cluster vs Migraine: Cluster = pacing/restless (will NOT lie still); migraine = lies still in a dark room. Unilateral headache with autonomic features can be either — the behavior during the attack is the distinguishing feature on boards.
Board Trap 2 — "Sinus Headache": Most self-diagnosed "sinus headaches" are actually migraine. Cranial autonomic features (rhinorrhea, lacrimation, nasal congestion) are common in migraine and TACs. True sinus headache requires purulent discharge + imaging evidence of sinusitis.
Board Trap 3 — Thunderclap Headache Workup: Thunderclap = SAH until proven otherwise. CT head then LP (if CT negative). CTA for aneurysm. Also consider RCVS, CVT, dissection, pituitary apoplexy. Never diagnose "primary thunderclap headache" until all secondary causes excluded.
Board Trap 4 — Triptan Contraindications: NEVER give triptans or ergots to patients with hemiplegic migraine, brainstem aura migraine, CAD, PVD, uncontrolled hypertension, or prior stroke. Use gepants or ditans instead.
Board Trap 5 — GCA: New headache in patient >50 + elevated ESR/CRP → start high-dose steroids immediately (do NOT wait for biopsy). Temporal artery biopsy should be obtained within 2 weeks but treatment must not be delayed. Biopsy can be positive up to 2–4 weeks after starting steroids.
Board Trap 6 — MOH Masquerading as Chronic Migraine: If a patient has chronic daily headache and is taking acute medications ≥10–15 days/month → must address MOH first. Preventives will fail if overuse is not stopped.
Board Trap 7 — IIH vs CVT: Both present with headache + papilledema + ↑ ICP. CVT can have normal CT. Always get MRV before diagnosing IIH. CVT treatment = anticoagulation (even if hemorrhagic); IIH treatment = acetazolamide + weight loss.
Board Trap 8 — RCVS Triggers: Vasoactive substances (triptans, SSRIs, nasal decongestants, cannabis, cocaine), post-partum, blood patch. Recurrent thunderclap headaches over 1–4 weeks with "beaded" arteries on CTA. Normal CSF distinguishes from PACNS.
Board Trap 9 — Botox Indication: OnabotulinumtoxinA is FDA-approved ONLY for chronic migraine (≥15 headache days/month, ≥8 migraine days). It has no proven benefit and is NOT indicated for episodic migraine.
Board Trap 10 — SUNCT/SUNA and Pituitary: Always get MRI of the pituitary in SUNCT/SUNA — pituitary adenoma is an important secondary cause that is treatable.
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