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

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

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

Clinical Features

• Classical TN — purely paroxysmal: Brief, paroxysmal, electric shock-like pain in trigeminal distribution
• Duration: Seconds to <2 minutes per attack; occurs in clusters
• Refractory period: After each paroxysm there is a brief refractory period during which the trigger cannot evoke pain — a characteristic diagnostic feature
• Distribution: V2/V3 >> V1 (V1 alone is the least common distribution)
• Triggered by innocuous (non-noxious) stimuli: Light touch to face, wind, washing face, eating, talking, brushing teeth, shaving
• Between attacks (purely paroxysmal form): Pain-free intervals; no neurological deficits
• TN with concomitant continuous pain: Continuous background aching/burning pain with superimposed paroxysms
• Trigger zone: typically nasolabial fold or perioral region
• ICHD-3 / Cruccu 2016 classification: Classical TN (neurovascular compression with morphologic change of the trigeminal root), Secondary TN (MS, tumor, or other identifiable structural cause), and Idiopathic TN (no identifiable cause) — each further subdivided into purely paroxysmal vs with concomitant continuous pain. The older Burchiel “Type 1/Type 2” terminology is outdated.

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

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; diagnosed by CT. Two variants — classic (stylopharyngeal/CN9 irritation, often post-tonsillectomy) and stylocarotid (carotid artery impingement → TIA, syncope, neck pain)
• 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

Clinical Features

• Sharp, shooting, stabbing pain in distribution of greater occipital nerve (GON) or lesser occipital nerve (LON)
• GON = medial branch of the C2 dorsal ramus; 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 the trigeminocervical complex (convergence of C1–C3 afferents with 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

Tolosa-Hunt Syndrome

• Diagnosis of exclusion — must rule out tumor, lymphoma, sarcoidosis, IgG4-related disease, carotid-cavernous fistula, pituitary apoplexy, cavernous sinus thrombosis, dissection, GCA, and infection before labeling; do not let a dramatic steroid response become the diagnostic anchor
• 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
• Pain typically precedes ophthalmoplegia by ≤2 weeks (ICHD-3 criterion)
• MRI: enhancing lesion in cavernous sinus (contrast-enhanced with fat suppression)
• Dramatic response to corticosteroids supports the diagnosis (pain relief typically within 72 hours), though ICHD-3 no longer requires steroid response for diagnosis

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 preferred (dissolve in mouth and spit; systemic second-line), alpha-lipoic acid, CBT

Key Facial Pain Syndromes Comparison

Clinical Features

• Neuropathic pain persisting >90 days after rash onset of herpes zoster
• Ophthalmic (V1) zoster is the most common cranial site and carries the highest PHN risk; consider HZ ophthalmicus with Hutchinson sign (nasociliary involvement)
• Burning, lancinating, or aching pain with allodynia and hyperalgesia in prior dermatome
• Risk factors: older age, severe acute pain, severe rash, immunocompromise

Treatment

• First-line: Gabapentinoids (gabapentin, pregabalin) and TCAs (amitriptyline, nortriptyline)
• Topical: Lidocaine 5% patch; capsaicin 8% patch (single-application, in-office)
• Last-resort: Opioids/tramadol — reserved for refractory pain
• Prevention: Recombinant zoster vaccine (Shingrix) for age ≥50; reduces zoster and PHN incidence

Clinical Features (Sjaastad Criteria)

• Unilateral pain without side-shift, starting in the neck/occiput and radiating anteriorly
• Provoked by neck movement, sustained awkward posture, or external pressure over the upper cervical/occipital region
• Reduced cervical range of motion; ipsilateral neck/shoulder/arm discomfort
• Most commonly arises from the C2–C3 zygapophyseal (facet) joint via the third occipital nerve

Diagnosis & Treatment

• Diagnostic anesthetic blocks of cervical medial branches or the third occipital nerve confirm the diagnosis
• Physical therapy targeting upper cervical mobility and posture
• Occipital nerve block; cervical medial branch blocks
• Radiofrequency ablation of cervical medial branches for refractory cases

Clinical Features

• Two broad categories: myofascial pain (masticatory muscle pain) and internal derangement (disc displacement ± reduction)
• Pre-auricular pain, often referred to temple, ear, or jaw
• Joint clicking, popping, or locking; restricted/asymmetric mouth opening
• Strong association with bruxism, clenching, and psychosocial stress

Management

• Conservative first: Soft diet, jaw rest, moist heat, NSAIDs, occlusal splints/night guards
• Physical therapy; behavioral therapy for bruxism/clenching
• Refer to dental medicine or oral/maxillofacial surgery for persistent or structural disease

• True rhinosinusitis-related headache (ICHD-3) requires purulent rhinorrhea, fever, or imaging-confirmed acute rhinosinusitis — not merely facial pressure or congestion
• Most self-diagnosed or clinician-labeled “sinus headache” is actually migraine — ~88% in the Schreiber 2004 study (SAMS study)
• Migraine commonly features autonomic symptoms (nasal congestion, rhinorrhea, lacrimation) that mimic sinus disease
• Treat as migraine first when ICHD-3 rhinosinusitis criteria are not met

• ICHD-3 4.7 — pain confined to a well-circumscribed, coin-shaped area of the scalp (typically 1–6 cm)
• Small, fixed area; does not migrate; may be continuous or intermittent
• Benign; no underlying structural cause typically identified
• Treatment: gabapentin, topical agents (lidocaine, capsaicin), occasionally botulinum toxin or local nerve block

• Self-induced ulceration of the face after trigeminal nerve injury or ablation (e.g., post-rhizotomy, post-zoster, post-stroke involving trigeminal pathway)
• Patients describe paresthesia/itching and unconsciously pick/scratch the anesthetic skin
• Classic finding: crescent-shaped ulcer at the ala nasi (the nasal tip is spared because it is innervated by the external nasal branch)
• Management: behavioral interventions to prevent self-manipulation, wound care, occlusive dressings; treat underlying neuropathic pain

• Anterior neck tenderness over the carotid artery, often radiating to the jaw, ear, or face
• Historically described as an idiopathic syndrome; the term “idiopathic carotidynia” was removed from ICHD-2
• ICHD-3 4.11 now recognizes only TIPIC syndrome (Transient Perivascular Inflammation of the Carotid artery) — demonstrable perivascular inflammation on imaging (MRI/CT/US)
• Workup must exclude carotid dissection, giant cell arteritis, lymphadenitis, and other structural carotid pathology
• TIPIC is typically self-limited; NSAIDs and short corticosteroid courses are often used