Headache Mimics & Facial Pain
Headache Mimics & Facial Pain
What Do You Need to Know?
- GCA: Age >50, new headache, jaw claudication (most specific symptom), ESR/CRP elevated, temporal artery biopsy gold standard (skip lesions → get ≥1 cm); start steroids BEFORE biopsy
- RCVS: Recurrent thunderclap headaches, “string of beads” on angiography, normal CSF, resolves <3 months; distinguish from PACNS (insidious onset, abnormal CSF, progressive course)
- Trigeminal neuralgia: V2/V3 > V1, brief electric shock-like pain triggered by light touch, carbamazepine first-line, MRI for neurovascular compression (SCA most common vessel)
- Glossopharyngeal neuralgia: Ear/throat lancinating pain triggered by swallowing; can cause syncope via vagal reflex; rule out Eagle syndrome
- Tolosa-Hunt syndrome: Painful ophthalmoplegia from granulomatous cavernous sinus inflammation; dramatic steroid response
- Key distinction: Thunderclap + normal CSF + reversible = RCVS; insidious + abnormal CSF + progressive = PACNS
Giant Cell Arteritis (GCA)
Epidemiology
- Age >50 (mean onset ~70 years); almost never occurs before age 50
- Female:male ratio 2–3:1
- Highest incidence in Northern European descent (Scandinavian populations)
- Polymyalgia rheumatica (PMR) overlap: 40–60% of GCA patients have PMR; ~15% of PMR patients develop GCA
Clinical Features
- New-onset headache: Temporal region, often unilateral, persistent; most common presenting symptom (~75%)
- Jaw claudication: Pain with chewing that resolves with rest — most specific clinical feature (LR+ ~34); caused by ischemia of masseter/temporalis muscles
- Scalp tenderness: Pain when brushing hair or resting head on pillow
- Vision loss: Most feared complication; anterior ischemic optic neuropathy (AION) — pale disc edema; permanent if untreated
- Diplopia: CN3, CN4, or CN6 palsy from vasa nervorum ischemia
- Constitutional symptoms: Fever, weight loss, malaise, fatigue
- Tongue claudication: Less common but highly specific
Laboratory & Diagnostic Studies
| Test | Findings | Key Points |
|---|---|---|
| ESR | Typically >50 mm/hr (often >100) | Sensitivity ~85%; can be normal in 5–10% (“occult GCA”) |
| CRP | Elevated | More sensitive than ESR alone; combined ESR + CRP sensitivity >95% |
| CBC | Thrombocytosis, normocytic anemia | Thrombocytosis correlates with disease activity |
| Temporal artery biopsy | Gold standard; granulomatous inflammation with giant cells, intimal hyperplasia, fragmented internal elastic lamina | Get ≥1 cm (ideally 2 cm); skip lesions reduce sensitivity (~85%); bilateral biopsy if unilateral negative + high suspicion |
| Temporal artery ultrasound | Halo sign — hypoechoic wall thickening | Sensitivity ~77%, specificity ~96%; operator-dependent; increasingly used as first-line imaging |
| 18F-FDG PET/CT | Vascular wall uptake | Best for large-vessel GCA (aorta, subclavian, axillary); complements temporal biopsy |
ACR/EULAR 2022 Classification Criteria
- Requires age ≥50 + score ≥6 from: temporal artery abnormality, ESR ≥50 or CRP ≥10, morning stiffness, sudden visual loss, jaw/tongue claudication, temporal artery biopsy/halo sign
- Designed for classification (research), not diagnosis — but clinically useful framework
Treatment
- High-dose prednisone 40–60 mg/day: Start IMMEDIATELY upon clinical suspicion — do NOT wait for biopsy
- IV methylprednisolone 1 g/day × 3 days: If vision threatened (acute visual loss, impending second eye involvement)
- Tocilizumab (IL-6 receptor inhibitor): GiACTA trial demonstrated superior relapse-free remission vs. prednisone alone at 52 weeks; used as steroid-sparing agent
- Slow prednisone taper over 12–24 months; monitor ESR/CRP for relapse
- Low-dose aspirin: consider for prevention of ischemic complications
- Biopsy remains positive for up to 2 weeks after steroid initiation
💎 Board Pearl
- Jaw claudication is the most specific clinical feature of GCA (LR+ ~34)
- Start steroids BEFORE biopsy — temporal artery biopsy remains positive for up to 2 weeks after steroid initiation; delaying treatment risks permanent vision loss
RCVS vs. PACNS
Reversible Cerebral Vasoconstriction Syndrome (RCVS)
- Recurrent thunderclap headaches (peak intensity <1 min) over 1–3 weeks
- Young to middle-aged women; common triggers: vasoactive drugs (triptans, SSRIs, sympathomimetics, cannabis), postpartum, exertion, Valsalva, sexual activity
- Angiography: “string of beads” pattern — multifocal segmental vasoconstriction of medium/large cerebral arteries
- CSF: normal (critical distinguishing feature from PACNS)
- Complications: convexity SAH (most common hemorrhage type), ICH, ischemic stroke (usually later in course)
- Course: self-limited; resolves within 12 weeks; angiographic normalization by 3 months
Primary Angiitis of the CNS (PACNS)
- Insidious progressive headache over weeks to months
- Focal neurological deficits, cognitive decline, personality changes
- CSF: abnormal in ~90% — elevated protein, lymphocytic pleocytosis
- MRI: white matter lesions, multifocal infarcts in multiple vascular territories
- Angiography: may show beading but can be normal (small vessel vasculitis undetectable)
- Brain biopsy is gold standard — granulomatous or lymphocytic vasculitis of small/medium leptomeningeal and cortical vessels
- Treatment: cyclophosphamide + high-dose corticosteroids; progressive without treatment
RCVS vs. PACNS: Key Differentiating Features
| Feature | RCVS | PACNS |
|---|---|---|
| Headache onset | Thunderclap (<1 min peak) | Insidious (weeks–months) |
| Age/sex | Young–middle-aged women | Any age; slight male predominance |
| Triggers | Vasoactive drugs, postpartum, exertion | None |
| CSF | Normal | Abnormal (↑ protein, pleocytosis) |
| Angiography | “String of beads” — reversible | Beading or normal (small vessel) |
| Course | Self-limited; resolves <12 weeks | Progressive without treatment |
| Complications | Convexity SAH, ICH, ischemic stroke | Multifocal infarcts, cognitive decline |
| Diagnosis | Clinical + reversible vasoconstriction | Brain biopsy (gold standard) |
| Treatment | CCB (verapamil/nimodipine); remove triggers | Cyclophosphamide + corticosteroids |
💎 Board Pearl
- RCVS = thunderclap + normal CSF + reversible; PACNS = insidious + abnormal CSF + progressive
- Triptans and ergots are CONTRAINDICATED in RCVS — they are vasoconstrictors and may worsen vasospasm, precipitating stroke
Trigeminal Neuralgia (TN)
Clinical Features
- Classic TN (type 1): Brief, paroxysmal, electric shock-like pain in trigeminal distribution
- Duration: Seconds to <2 minutes per attack; occurs in clusters with refractory periods between attacks
- Distribution: V2/V3 >> V1 (V1 alone is the least common distribution)
- Triggered by non-noxious stimuli (allodynia): Light touch to face, wind, washing face, eating, talking, brushing teeth, shaving
- Between attacks (type 1): Pain-free intervals; no neurological deficits
- TN type 2 (atypical): Continuous background aching/burning pain with superimposed paroxysms
- Trigger zone: typically nasolabial fold or perioral region
Etiology & Neurovascular Compression
- SCA (superior cerebellar artery): Most common vessel causing neurovascular compression of CN5 at the root entry zone
- Compression → focal demyelination of trigeminal root → ephaptic transmission (cross-talk between pain and touch fibers)
- MRI protocol: High-resolution sequences (CISS/FIESTA) to visualize neurovascular contact
- MRI also to exclude secondary causes: MS plaques, CPA tumors, skull base lesions
Secondary Causes
- Multiple sclerosis: Bilateral TN in a young patient → strongly consider MS; demyelinating plaque at pontine root entry zone
- CPA tumors: Vestibular schwannoma (acoustic neuroma), meningioma, epidermoid cyst
- Skull base lesions: Chordoma, metastasis, Meckel cave lesion
- Red flags for secondary TN: age <40, bilateral symptoms, sensory loss, abnormal trigeminal reflex
Treatment
| Treatment | Details | Key Points |
|---|---|---|
| Carbamazepine | First-line; NNT 1.7–1.8 | Best evidence of any medication for TN; check HLA-B*1502 in Asian descent (SJS/TEN risk) |
| Oxcarbazepine | First-line alternative | Better tolerability than CBZ; fewer drug interactions; risk of hyponatremia |
| Baclofen | Add-on therapy | Useful in combination with CBZ/OXC; can be used as monotherapy if CBZ not tolerated |
| Lamotrigine | Second-line | Slow titration required; useful for TN type 2 with continuous pain component |
| MVD (microvascular decompression) | Surgical first-line | Highest long-term success: ~80% pain-free at 10 years; Teflon pad placed between vessel and nerve |
| Percutaneous rhizotomy | Radiofrequency, balloon, glycerol | For patients who are poor surgical candidates; higher recurrence than MVD; causes some facial numbness |
| Gamma Knife radiosurgery | Focused radiation to trigeminal root | Least invasive; delayed onset of relief (weeks–months); lower success rate than MVD |
💎 Board Pearl
- Bilateral TN in a young patient = think MS — demyelinating plaque at the pontine root entry zone of CN5
- SCA is the most common vessel causing trigeminal neurovascular compression
Glossopharyngeal Neuralgia (GPN)
Clinical Features
- Lancinating, electric shock-like pain in CN9 distribution: ear, tonsillar fossa, base of tongue, angle of jaw, deep pharynx
- Triggers: Swallowing, talking, coughing, yawning, chewing
- Brief paroxysms (seconds to <2 min); similar temporal pattern to TN
- Much rarer than TN (incidence ~0.7/100,000 vs. TN ~12/100,000)
Vagoglossopharyngeal Neuralgia
- GPN + syncope/bradycardia/asystole: CN9 afferents → nucleus tractus solitarius (NTS) → dorsal motor nucleus of vagus → cardioinhibitory reflex
- Can cause life-threatening cardiac arrest during pain paroxysms
- May require cardiac pacing in addition to GPN treatment
Secondary Causes to Exclude
- Eagle syndrome: Elongated styloid process (>3 cm) or calcified stylohyoid ligament compressing CN9; diagnosed by CT
- CPA tumors, oropharyngeal/skull base malignancy, vascular compression (PICA most common)
Treatment
- Carbamazepine/oxcarbazepine: First-line (same as TN)
- MVD of CN9: Surgical option for refractory cases; separates compressing vessel from CN9/CN10 root entry zone
- Intracranial sectioning of CN9 + upper rootlets of CN10 if MVD fails
💎 Board Pearl
- Glossopharyngeal neuralgia + syncope = CN9 afferents → NTS → vagal cardioinhibitory reflex (“vagoglossopharyngeal neuralgia”)
Occipital Neuralgia
Clinical Features
- Sharp, shooting, stabbing pain in distribution of greater occipital nerve (GON) or lesser occipital nerve (LON)
- GON = C2 dorsal ramus (medial branch of C2); innervates posterior scalp to vertex
- Paroxysmal pain with or without continuous aching between attacks
- Tenderness over occipital notch (GON exit point, ~1/3 of the way lateral from external occipital protuberance)
- May radiate anteriorly to the forehead via trigeminocervical convergence (C2 → trigeminal nucleus caudalis)
Etiology
- Post-traumatic (whiplash, direct trauma), C1–C2 arthropathy, muscular entrapment (semispinalis, trapezius)
- Cervicogenic causes: degenerative disc disease, Arnold-Chiari malformation
- Often idiopathic
Diagnosis & Treatment
- GON block with local anesthetic ± steroid: Diagnostic AND therapeutic — positive response confirms diagnosis
- Preventive: gabapentin, pregabalin, tricyclic antidepressants
- Botulinum toxin injection: emerging evidence for refractory cases
- Rarely: surgical decompression, occipital nerve stimulation (ONS), or pulsed radiofrequency
Clinical Pearl
- Do not confuse occipital neuralgia with cervicogenic headache or migraine with occipital predominance — GON block response helps differentiate, but can also partially improve cervicogenic headache and migraine via trigeminocervical convergence
Other Facial Pain Syndromes
Tolosa-Hunt Syndrome
- Painful ophthalmoplegia from granulomatous inflammation of the cavernous sinus or superior orbital fissure
- Unilateral periorbital/retro-orbital pain + ipsilateral CN3, CN4, CN6, or V1 involvement
- MRI: enhancing lesion in cavernous sinus (contrast-enhanced with fat suppression)
- Dramatic response to corticosteroids (pain relief within 72 hours) — part of diagnostic criteria
- Diagnosis of exclusion: must rule out tumor, lymphoma, sarcoidosis, IgG4-related disease, carotid-cavernous fistula, infection
Persistent Idiopathic Facial Pain
- Formerly “atypical facial pain”
- Daily, deep, poorly localized facial pain; does not follow nerve distribution
- No neurological deficits on exam; no structural or organic cause found
- Diagnosis of exclusion after thorough workup (MRI, dental evaluation)
- Treatment: TCAs (amitriptyline), SNRIs (duloxetine), CBT; avoid opioids
Burning Mouth Syndrome
- Burning sensation of tongue, palate, lips; often bilateral
- Most common in postmenopausal women (F:M 7:1)
- Normal oral exam; may worsen through the day, improve with eating
- Etiology likely small fiber neuropathy of intraoral mucosa
- Treatment: clonazepam (topical or systemic), alpha-lipoic acid, CBT
Key Facial Pain Syndromes Comparison
| Syndrome | Location | Quality | Trigger | Treatment |
|---|---|---|---|---|
| Trigeminal neuralgia | V2/V3 (unilateral) | Electric shock, seconds | Light touch, wind, eating | Carbamazepine; MVD |
| Glossopharyngeal neuralgia | Ear, throat, tongue base | Lancinating, seconds | Swallowing, talking | Carbamazepine; MVD CN9 |
| Occipital neuralgia | Posterior scalp (C2) | Sharp, shooting | Neck movement, pressure | GON block; gabapentin |
| Tolosa-Hunt | Periorbital/retro-orbital | Deep, boring, constant | None | Corticosteroids |
| Persistent idiopathic facial pain | Variable, poorly localized | Deep, aching, constant | None | TCAs, SNRIs, CBT |
| Burning mouth syndrome | Tongue, palate, lips | Burning, continuous | None; worsens through day | Clonazepam; alpha-lipoic acid |
💎 Board Pearl
- Tolosa-Hunt = painful ophthalmoplegia + cavernous sinus inflammation + dramatic steroid response — always a diagnosis of exclusion; MRI with contrast mandatory to rule out tumor, lymphoma, IgG4 disease
References
- Hunder GG, Bloch DA, Michel BA, et al. The American College of Rheumatology 1990 criteria for the classification of giant cell arteritis. Arthritis Rheum 1990;33(8):1122–1128.
- Ponte C, Grayson PC, Engelbrecht M, et al. 2022 ACR/EULAR classification criteria for giant cell arteritis. Ann Rheum Dis 2022;81(12):1647–1653.
- Stone JH, Tuckwell K, Dimonaco S, et al. Trial of tocilizumab in giant-cell arteritis (GiACTA). N Engl J Med 2017;377(4):317–328.
- Ducros A. Reversible cerebral vasoconstriction syndrome. Lancet Neurol 2012;11(10):906–917.
- Salvarani C, Brown RD Jr, Hunder GG. Adult primary central nervous system vasculitis. Lancet 2012;380(9843):767–777.
- Cruccu G, Finnerup NB, Jensen TS, et al. Trigeminal neuralgia: new classification and diagnostic grading for practice and research. Neurology 2016;87(2):220–228.