Age > 50, unilateral temporal headache, jaw claudication, polymyalgia rheumatica, ESR > 50, amaurosis fugax; give IMMEDIATE high-dose Prednisone BEFORE temporal artery biopsy!
Obese young women, vitamin A / isotretinoin / tetracyclines; headache, papilledema, CN VI palsy, normal MRI/MRV, LP opening pressure > 250 mm H2O; Rx: Weight loss + Acetazolamide.
Cluster: 15–180m periorbital pain + ipsilateral lacrimation/Horner; 100% O2 (1st-line acute), Verapamil (prophylaxis). Migraine: 4–72h throbbing + aura/photophobia; Triptans (acute), Topiramate/Propranolol.
BPPV: < 1 min positional vertigo, Dix-Hallpike rotary nystagmus → Epley maneuver. Meniere: triad of episodic vertigo + tinnitus + low-frequency SNHL (endolymphatic hydrops) → thiazide.
Eye is 'down and out' with ptosis. Surgical (PComm aneurysm / uncal herniation): outer parasympathetic fibers compressed → BLOWN PUPIL! Medical (diabetes ischemia): pupil SPARED.
INO (MLF lesion in MS): ipsilateral adduction failure + contralateral abducting nystagmus (convergence intact). Horner: Ptosis, Miosis, Anhidrosis (Pancoast tumor, carotid dissection, Wallenberg).
Supratentorial: Glioblastoma (butterfly corpus callosum, pseudopalisading necrosis, GFAP+); Meningioma (dural tail, psammoma bodies); Schwannoma (CPA CN VIII, NF2, Antoni A/B).
Infratentorial: Pilocytic Astrocytoma (cystic + mural nodule, Rosenthal fibers, BRAF); Medulloblastoma (vermis, Homer-Wright rosettes, drop mets); Ependymoma (4th ventricle, perivascular pseudorosettes).
Primary Headache Syndromes Differential
Primary headache syndromes—Tension-Type Headache, Migraine (with or without aura), and Cluster Headache (a trigeminal autonomic cephalalgia)—are differentiated clinically by pain laterality, quality, duration (30 minutes–7 days vs. 4–72 hours vs. 15–180 minutes), patient behavior during the attack (lying quietly in a dark room vs. pacing/rocking in agitation), and ipsilateral cranial autonomic signs. Simultaneously, every headache evaluation screens for secondary 'Red Flag' emergencies (SNOOP4: Thunderclap Subarachnoid Hemorrhage, Giant Cell Arteritis, Idiopathic Intracranial Hypertension, and Meningitis/Mass).
| Headache Type | Pain Location & Characteristics | Associated Manifestations | Acute Abortive & Prophylactic Therapy |
|---|---|---|---|
| Migraine Headache | Unilateral (60%), throbbing/pulsatile; aggravated by routine physical activity; lasts 4–72 hours | Nausea, vomiting, photophobia, phonophobia; visual or sensory aura (scintillating scotoma) in 25% | Abortive: Sumatriptan (contraindicated in CAD/Prinzmetal angina), NSAIDs; Prophylaxis: Propranolol, Topiramate, Amitriptyline, Erenumab (CGRP inhibitor) |
| Cluster Headache | Strictly unilateral, excruciating, piercing, stabbing periorbital / retro-orbital pain; lasts 15–180 min; occurs at same time daily (wakes from sleep) | Ipsilateral autonomic signs: Conjunctival injection, lacrimation, rhinorrhea, nasal congestion, partial Horner syndrome (ptosis/miosis) | Acute: 100% high-flow oxygen (12 L/min via non-rebreather) + Subcutaneous Sumatriptan; Prophylaxis: Verapamil (first-line) |
| Tension Headache | Bilateral, non-pulsatile, dull, aching, 'band-like' constricting pain around head; NOT aggravated by exertion | Pericranial muscle tenderness; NO nausea, vomiting, or focal neurologic signs | Acute: Acetaminophen, NSAIDs; Prophylaxis: Amitriptyline, stress reduction, physical therapy/OMT |
Primary Headaches: Cluster (100% O2 & Verapamil) vs. Migraine (Triptans/CGRP & Contraindications) vs. Tension
Compare the three primary headaches across five clinical dimensions: (1) Cluster Headache affects men aged 20–50 (often heavy smokers), presenting with excruciating, stabbing, strictly unilateral orbital/supraorbital pain lasting 15 to 180 minutes, occurring in repetitive nightly 'clusters' at the same clock hour for weeks; unlike migraine patients who lie completely still, cluster patients are restless and pace or rock in agony, and exhibit prominent ipsilateral trigeminal-autonomic signs: conjunctival injection, lacrimation, nasal congestion/rhinorrhea, forehead sweating, and partial Horner syndrome (ptosis + miosis). First-line abortive therapy for Cluster Headache is 100% High-Flow Oxygen (12–15 L/min via non-rebreather mask for 15 minutes) (or subcutaneous Sumatriptan); first-line prophylactic therapy is Verapamil (with a prednisone bridge). (2) Migraine Headache (mnemonic POUND: Pulsatile/throbbing, One-day duration [4 to 72 hours], Unilateral, Nausea/vomiting, Disabling intensity with photophobia and phonophobia; 25% preceded by a 15–60 minute reversible visual/sensory cortical spreading depression Aura) is treated abortively with NSAIDs/acetaminophen for mild attacks or Triptans (Sumatriptan — 5-HT1B/1D agonists causing cranial vasoconstriction and inhibiting trigeminal CGRP release) or Gepants (rimegepant/ubrogepant) for moderate-to-severe attacks. CRITICAL BOARD RULE: Triptans and Ergots are STRICTLY CONTRAINDICATED in Coronary Artery Disease, Prinzmetal Angina, Uncontrolled Hypertension, Prior Stroke/TIA, Hemiplegic/Basilar Migraine, and Pregnancy; additionally, Combined Estrogen-Progestin Oral Contraceptives (OCPs) are STRICTLY CONTRAINDICATED in women who have Migraine WITH Aura due to ischemic stroke risk! First-line migraine prophylaxis (≥4 headaches/month) includes Propranolol, Topiramate, Amitriptyline, Valproate, or CGRP monoclonal antibodies (erenumab/fremanezumab). (3) Tension-Type Headache (#1 headache overall) presents with bilateral, band-like squeezing pain without nausea, photophobia/phonophobia, or throbbing (abortive: NSAIDs; prophylaxis: Amitriptyline).
Secondary Red-Flag Headaches: Giant Cell Arteritis (Immediate Steroids Before Biopsy), IIH (Pseudotumor) & Thunderclap SAH
Never miss the three catastrophic secondary headaches on board exams: (1) Giant Cell (Temporal) Arteritis (GCA) is a granulomatous large-vessel vasculitis of extracranial carotid branches occurring exclusively in patients ≥50 years old (strongly associated with Polymyalgia Rheumatica: symmetric aching/stiffness of the shoulders and hip girdle), presenting with a new unilateral temporal headache, scalp tenderness when combing hair, jaw claudication (most specific symptom!), fever, and an ESR >50–100 mm/hr (or elevated CRP). Because occlusion of the ophthalmic and posterior ciliary arteries causes sudden, permanent anterior ischemic optic neuropathy (irreversible blindness; amaurosis fugax), administer High-Dose IV/Oral Corticosteroids (Methylprednisolone / Prednisone 60 mg/day) IMMEDIATELY upon clinical suspicion—NEVER delay steroids to wait for the Temporal Artery Biopsy (biopsy remains diagnostic for 1–2 weeks after starting steroids; skip lesions require a long 2–3 cm biopsy segment)! (2) Idiopathic Intracranial Hypertension (IIH / Pseudotumor Cerebri) occurs in obese women of childbearing age (or triggered by Vitamin A / Isotretinoin, Tetracyclines [minocycline/doxycycline], Growth Hormone, or Danazol), presenting with a daily positional headache worse on awakening/Valsalva, pulsatile tinnitus ('whooshing' sound), transient visual obscurations, horizontal diplopia (from stretching of CN VI [abducens nerve]), and bilateral Papilledema with enlarged blind spots. Head CT/MRI is normal (or shows empty sella; MR venography excludes dural venous sinus thrombosis), and lumbar puncture confirms an elevated opening pressure >250 mmH2O with normal CSF composition; treat with Weight Loss + Acetazolamide (carbonic anhydrase inhibitor reducing choroid plexus CSF production), with optic nerve sheath fenestration or VP shunt for threatened vision loss. (3) Thunderclap Headache (Subarachnoid Hemorrhage) reaches maximal '10/10 worst headache of life' intensity within seconds to 1 minute from ruptured saccular (berry) aneurysm; obtain an emergent Non-Contrast Head CT, and if negative after 6 hours, perform a Lumbar Puncture looking for Xanthochromia (bilirubin from lysed RBCs that does not clear from Tube 1 to Tube 4), and administer Oral Nimodipine (60 mg every 4h for 21 days) to prevent delayed cerebral ischemia from vasospasm!
Cranial Neuropathies: CN V vs. CN VII
Cranial nerve neuropathies affecting the trigeminal (CN V), facial (CN VII), and oculomotor/trochlear/abducens (CN III, IV, VI) nerves are localized anatomically by testing motor branch sparing (forehead sparing in upper motor neuron CN VII lesions), pupillary parasympathetics (compressive vs. microvascular CN III palsies), and demyelinating brainstem internuclear pathways (MLF syndrome).
| Neuropathy | Anatomical Mechanism | Clinical Presentation | First-Line Management |
|---|---|---|---|
| Trigeminal Neuralgia (Tic Douloureux) | Vascular compression of the CN V root entry zone (superior cerebellar artery) | Repetitive, lightning-like, stabbing electric shocks in V2/V3 dermatomes triggered by chewing, brushing teeth, light breeze | Carbamazepine (voltage-gated sodium channel blocker; monitor for agranulocytosis/hyponatremia); microvascular decompression |
| Bell's Palsy | Idiopathic inflammation/edema of CN VII in facial canal (frequently post-HSV reactivation) | Unilateral upper AND lower facial paralysis (inability to close eye, flatten nasolabial fold, cannot furrow forehead), loss of taste anterior 2/3 tongue, hyperacusis | Oral Prednisone within 72 hours of onset + artificial tears / eye taping at night to prevent corneal abrasion |
| Central (UMN) Facial Palsy | Cerebral cortex or internal capsule infarction (contralateral MCA stroke) | Paralysis of contralateral lower face ONLY; forehead wrinkling is preserved (bilateral cortical projection to upper facial nucleus) | Acute stroke code activation; non-contrast head CT -> IV thrombolysis / endovascular thrombectomy |
Facial Nerve (CN VII): UMN Forehead Sparing (Stroke) vs. LMN Bell Palsy, Ramsay Hunt & Bilateral CN VII (Lyme/Sarcoid/GBS)
When a patient presents with acute unilateral facial droop, the immediate clinical step is to ask the patient to wrinkle their forehead (raise their eyebrows) and tightly close both eyes: the superior portion of the facial motor nucleus (innervating the frontalis and upper orbicularis oculi muscles of the upper face/forehead) receives BILATERAL corticobulbar upper motor neuron (UMN) input from both motor cortices, whereas the inferior portion of the facial motor nucleus (innervating the lower face) receives purely CONTRALATERAL UMN input. Therefore: (1) A Central Upper Motor Neuron Lesion (Contralateral MCA Stroke) paralyzes only the contralateral LOWER face while SPARING the forehead (the patient can still wrinkle their forehead and close their eye, and often exhibits ipsilateral arm weakness or aphasia). (2) A Peripheral Lower Motor Neuron Lesion (Bell Palsy / CN VII nucleus or nerve lesion) paralyzes the ENTIRE ipsilateral upper AND lower hemiface—causing loss of forehead wrinkles, inability to close the eyelid (lagophthalmos with upward-rolling Bell phenomenon and risk of exposure keratitis), flattening of the nasolabial fold, drooping of the mouth corner, hyperacusis (loss of stapedius muscle dampening), and loss of taste on the anterior two-thirds of the tongue (chorda tympani). Idiopathic Bell Palsy (driven by HSV-1 reactivation within the geniculate ganglion in the facial canal) is treated within 72 hours with Oral Corticosteroids (Prednisone) (+ valacyclovir if severe) and artificial tears + nighttime eye taping/patching. Always check the external auditory canal and pinna for painful erythematous vesicles—which diagnose Ramsay Hunt Syndrome (Herpes Zoster Oticus, VZV reactivation in the geniculate ganglion) requiring Valacyclovir/Acyclovir + Prednisone—and remember the 3 classic causes of BILATERAL Facial Nerve Palsy: Lyme Disease (Borrelia burgdorferi), Sarcoidosis (Heerfordt syndrome), and Guillain-Barré Syndrome!
Trigeminal Neuralgia (Carbamazepine & MS Bilateral), CN III Pupil Rule (PCom Aneurysm vs. Diabetes) & Internuclear Ophthalmoplegia
Three high-yield cranial nerve lesions complete the neuro-ophthalmology and facial pain board blueprint: (1) Trigeminal Neuralgia (Tic Douloureux, CN V) presents with brief (seconds to <2 minutes), paroxysmal, electric-shock or stabbing unilateral facial pain in the maxillary (V2) and/or mandibular (V3) divisions (almost never ophthalmic V1 alone) triggered by light touch, chewing, brushing teeth, or cold wind, typically caused by neurovascular compression of the CN V root entry zone by the superior cerebellar artery. First-line therapy is Carbamazepine or Oxcarbazepine (blocks voltage-gated Na+ channels; check HLA-B*1502 in Asian patients for SJS risk and monitor CBC/Na+ for agranulocytosis and SIADH!). BOARD TRAP: If Trigeminal Neuralgia occurs in a young patient (<40 years) or is BILATERAL, suspect pontine demyelination from Multiple Sclerosis and obtain a Brain MRI! (2) The Oculomotor Nerve (CN III) 'Rule of the Pupil': CN III palsy causes the eye to rest 'down and out' (unopposed lateral rectus [CN VI] and superior oblique [CN IV]) with severe ptosis (levator palpebrae). Because parasympathetic pupilloconstrictor fibers travel on the superficial outer perimeter of CN III while somatic motor fibers travel in the deep central core, an extrinsic Compressive Lesion (ruptured/expanding Posterior Communicating [PCom] Artery Aneurysm or uncal herniation) crushes the outer fibers first—producing a 'Pupil-Involving' CN III Palsy (blown, dilated, fixed pupil) that requires an emergent CT Angiogram (CTA); conversely, Microvascular Ischemia (Diabetes Mellitus or Hypertension) infarcts the deep central vasa nervorum while sparing the outer perimeter—producing a 'Pupil-Sparing' CN III Palsy. (3) Internuclear Ophthalmoplegia (INO) results from demyelination (Multiple Sclerosis when bilateral in a young woman) or stroke of the Medial Longitudinal Fasciculus (MLF) connecting the contralateral CN VI nucleus to the ipsilateral CN III medial rectus subnucleus: on attempted conjugate lateral gaze away from the lesion, the ipsilateral eye FAILS TO ADDUCT while the contralateral abducting eye exhibits horizontal nystagmus, yet convergence remains completely intact!
Secondary Headache Red Flags (SNOOP4): Giant Cell Arteritis, IIH, Brain Abscess & Venous Sinus Thrombosis
| Secondary Headache Disorder | Classic Patient & Risk Factors | Signature Clinical Presentation | Diagnostic Gold Standard | Immediate / Definitive Management |
|---|---|---|---|---|
| Giant Cell (Temporal) Arteritis | Age > 50 yr (mean 70); 50% have Polymyalgia Rheumatica | Unilateral temporal headache, jaw claudication, scalp tenderness, amaurosis fugax (AION); ESR > 50 | Temporal artery biopsy (granulomatous inflammation, fragmented internal elastic lamina) | Immediate high-dose Prednisone / IV Methylprednisolone BEFORE biopsy! (+ Tocilizumab) |
| Idiopathic Intracranial Hypertension (IIH) | Obese young female; Vitamin A (isotretinoin), tetracyclines | Positional throbbing headache, papilledema, pulsatile tinnitus, CN VI palsy (diplopia) | Normal Brain MRI/MRV → LP opening pressure > 250 mm H2O with normal CSF | Weight loss + Acetazolamide (Optic nerve sheath fenestration or VP shunt if vision threatened) |
| Cerebral Venous Sinus Thrombosis (CVST) | Pregnancy/postpartum, OCPs, Factor V Leiden, mastoiditis/sinusitis | Severe headache, papilledema, seizures, stroke crossing arterial territories | MR Venography (MRV) or CTV ('empty delta sign') | Immediate Heparin/LMWH anticoagulation (even if hemorrhagic venous infarct is present!) |
| Brain Abscess | Otitis/mastoiditis (temporal/cerebellum), sinusitis/dental (frontal), endocarditis | Dull constant headache, fever, focal deficit, seizures | Contrast MRI/CT (ring-enhancing mass + restricted diffusion); NO LP! | Stereotactic drainage + IV Ceftriaxone + Metronidazole (± Vancomycin); Dexamethasone if mass effect |
| Subarachnoid Hemorrhage (SAH) | Ruptured saccular ('berry') aneurysm (AComm #1), ADPKD, Ehlers-Danlos, smoking/HTN | Sudden 'thunderclap' worst headache of life, nuchal rigidity, photophobia, coma | Non-contrast Head CT (1st test); if negative → LP for Xanthochromia (bilirubin from lysed RBCs) | Surgical clipping / endovascular coiling + oral Nimodipine (CCB to prevent delayed ischemic vasospasm!) |
Giant Cell (Temporal) Arteritis (GCA): Amaurosis Fugax & Immediate Steroids Before Biopsy
Idiopathic Intracranial Hypertension (Pseudotumor Cerebri): Vitamin A, CN VI Palsy & Acetazolamide
Cerebral Venous Sinus Thrombosis (CVST) vs. Brain Abscess
Vestibular & Vertigo Differential: BPPV vs. Vestibular Neuritis vs. Meniere vs. Schwannoma vs. Stroke
| Vertigo / Vestibular Disorder | Episode Duration & Triggers | Hearing Loss & Tinnitus | Pathognomonic Exam / Histology Clues | Definitive Management |
|---|---|---|---|---|
| Benign Paroxysmal Positional Vertigo (BPPV) | Seconds (< 1 min); triggered by head position changes | Absent (normal hearing, no tinnitus) | Posterior canal otolith; Dix-Hallpike maneuver evokes fatigable torsional nystagmus | Epley canalith repositioning maneuver (avoid chronic meclizine) |
| Vestibular Neuritis vs. Labyrinthitis | Continuous for days (2–7 d); follows viral URI | Neuritis: Absent; Labyrinthitis: Unilateral SNHL + tinnitus | Abnormal Head Impulse test (catch-up saccade), unidirectional horizontal nystagmus | Short-term meclizine/ondansetron, oral corticosteroids, vestibular physical therapy |
| Meniere Disease (Endolymphatic Hydrops) | 20 minutes to 12 hours; recurrent spontaneous bouts | Unilateral fluctuating low-frequency SNHL + roaring tinnitus + ear fullness | Distension of endolymphatic compartment in cochlea and semicircular canals | Low-salt diet + Thiazide diuretic (HCTZ); intratympanic dexamethasone/gentamicin |
| Vestibular Schwannoma (Acoustic Neuroma) | Chronic progressive imbalance (minimal acute spinning) | Progressive unilateral high-frequency SNHL + tinnitus | Cerebellopontine angle mass (± CN V/VII palsy); Bilateral in NF2 (chr 22 merlin); Antoni A/B, Verocay bodies, S-100+ | Microsurgical resection or stereotactic radiosurgery (Gamma Knife) |
| Brainstem / Cerebellar Stroke (PICA / AICA) | Sudden onset continuous vertigo + inability to walk | Absent in PICA (present in AICA / labyrinthine artery stroke) | Central HINTS ('INFARCT'): Normal Head Impulse, vertical/direction-changing nystagmus, skew deviation, Wallenberg signs | Emergent Brain MRI/MRA; IV Alteplase / thrombectomy; posterior fossa decompression if edema |
BPPV (Dix-Hallpike & Epley) vs. Vestibular Neuritis vs. Labyrinthitis vs. Meniere Disease
Vestibular Schwannoma (Acoustic Neuroma): Cerebellopontine Angle, NF2 & Antoni A/B
Central Vertigo & Brainstem/Cerebellar Stroke (HINTS Exam & Wallenberg Syndrome)
Neuro-Ophthalmology: CN III, IV, VI Palsies, Internuclear Ophthalmoplegia, RAPD & Horner Syndrome
| Neuro-Ophthalmic Lesion | Anatomical Structure Injured | Eye Position & Motility Deficit | Pupillary & Eyelid Findings | High-Yield Board Etiologies & Workup |
|---|---|---|---|---|
| Surgical CN III Palsy | Outer superficial dorsomedial parasympathetic + core motor fibers of CN III | 'Down and out' (exotropic & hypotropic); impaired adduction/elevation | Dilated, fixed 'BLOWN' pupil + severe complete ptosis | PComm berry aneurysm or uncal herniation; Emergent CTA/MRA head! |
| Medical CN III Palsy | Deep central microvascular core of CN III (sparing outer pial fibers) | 'Down and out' eye position | PUPIL SPARED (normal size and light reflex) + complete ptosis | Diabetes mellitus or hypertension vasa nervorum ischemia; HbA1c/BP control |
| Trochlear (CN IV) Palsy | CN IV (dorsal midbrain exit) → Superior Oblique | Hypertropia (elevated eye); worse looking down and medially (going downstairs) | Normal pupil and lid; compensatory head tilt AWAY from lesion | Closed head trauma (whiplash/concussion), microvascular ischemia |
| Abducens (CN VI) Palsy | CN VI (pons-medulla junction / Dorello canal) → Lateral Rectus | Medially deviated (esotropic); cannot abduct eye | Normal pupil and lid | Elevated ICP ('false localizing sign' in IIH), pontine stroke, Wernicke encephalopathy |
| Internuclear Ophthalmoplegia (INO) | Medial Longitudinal Fasciculus (MLF) in dorsomedial pons/midbrain | Ipsilateral eye fails to adduct on lateral gaze + contralateral abducting nystagmus | Convergence is PRESERVED! Normal pupils | Young adult: Multiple Sclerosis; Older adult: dorsal pontine lacunar stroke |
| Marcus Gunn Pupil (RAPD) | Afferent Optic Nerve (CN II) or severe retina lesion | Full extraocular movements (pain on eye movement in optic neuritis) | Swinging flashlight test: paradoxical bilateral pupillary dilation when light hits bad eye | Optic neuritis (MS), CRAO, ischemic optic neuropathy; Rx: IV Methylprednisolone (if MS) |
| Horner Syndrome | 3-neuron oculosympathetic pathway (Hypothalamus → C8–T2 → SCG → ICA) | Full extraocular movements | Ptosis (mild, Müller muscle), Miosis (worse in dark), Anhidrosis | 1st: Wallenberg (PICA); 2nd: Pancoast lung tumor; 3rd: Internal carotid dissection |
CN III (Surgical vs. Medical Rule of the Pupil), CN IV (Head Tilt) & CN VI Palsies
Internuclear Ophthalmoplegia (MLF Lesion) vs. One-and-a-Half Syndrome & Marcus Gunn Pupil
Horner Syndrome: 3-Neuron Oculosympathetic Pathway Localization (Pancoast vs. Carotid Dissection)
Primary & Metastatic Adult vs. Pediatric Brain Tumors Master Matrix
| Brain Tumor | Age Group & Typical Location | Imaging Appearance (MRI/CT) | Pathognomonic Histopathology & Markers | Genetic / Systemic Associations |
|---|---|---|---|---|
| Glioblastoma (Grade IV Astrocytoma) | Adult; Cerebral hemispheres crossing corpus callosum | 'Butterfly glioma' with central necrosis and irregular ring enhancement | Pseudopalisading necrosis, microvascular proliferation, GFAP+ | EGFR amplification, MGMT methylation (predicts temozolomide response), Turcot |
| Meningioma | Adult female; Extra-axial parasagittal dura / falx / convexity | Well-circumscribed dural-based mass with enhancing 'dural tail' | Arachnoid cap cells in whorled pattern + calcified psammoma bodies | Estrogen/progesterone receptor+, prior head radiation, NF2 (chr 22) |
| Oligodendroglioma | Adult (35–45 yr); Frontal lobe (presents with seizures) | Calcified frontal lobe mass in white/gray matter | 'Fried-egg' cells (perinuclear halo) + 'chicken-wire' capillary network | IDH1/2 mutation + 1p/19q chromosomal co-deletion (favorable prognosis) |
| Pilocytic Astrocytoma (Grade I) | Child; Posterior fossa (cerebellar hemisphere) or optic chiasm | Cystic cerebellar lesion with an enhancing mural nodule | Rosenthal fibers (eosinophilic corkscrew bundles), eosinophilic granular bodies, GFAP+ | Activating BRAF fusion; NF1 (bilateral optic nerve gliomas) |
| Medulloblastoma (Grade IV) | Child; Midline cerebellar vermis (compresses 4th ventricle) | Solid enhancing midline vermian mass + spinal 'drop metastases' | Small round blue cells + Homer-Wright rosettes (central neuropil); synaptophysin+ | Originates from external granular layer; Turcot syndrome (APC), Gorlin (PTCH1) |
| Ependymoma | Child: 4th ventricle floor; Adult: Spinal cord central canal | Intraventricular mass causing non-communicating hydrocephalus | Perivascular pseudorosettes + rod-shaped blepharoplasts | NF2 (chr 22) in adult spinal ependymomas |
| Hemangioblastoma | Young adult; Cerebellum, brainstem, spinal cord, retina | Cystic cerebellar mass with hypervascular mural nodule | Thin-walled packed capillaries + foamy lipid-laden stromal cells | von Hippel-Lindau (VHL chr 3p) + secondary polycythemia (↑ EPO) |
Adult Supratentorial Tumors: Glioblastoma, Meningioma & Oligodendroglioma
Pediatric Infratentorial Tumors: Pilocytic Astrocytoma, Medulloblastoma & Ependymoma
Hemangioblastoma (von Hippel-Lindau Syndrome) & Primary CNS Lymphoma
Cranial Foramina, Suboccipital / Sphenopalatine Ganglia, Chapman Points & OMT Contraindications
- Cranial Bone & Foramina Entrapment Mechanics: Mastery of cranial nerve exit foramina directs osteopathic cranial manipulative medicine (OCMM): CN I pierces the cribriform plate of the ethmoid; CN II traverses the optic canal of the sphenoid; CN III, IV, V1, and VI pass through the superior orbital fissure (between the lesser and greater wings of the sphenoid—making sphenoid strains a primary cause of orbital venous congestion and diplopia); CN V2 exits foramen rotundum and CN V3 exits foramen ovale (in the greater wing of the sphenoid); CN VII and CN VIII enter the internal acoustic meatus of the petrous temporal bone (where temporal bone internal/external rotation dysfunctions aggravate tinnitus, vertigo, and Bell palsy as CN VII exits the stylomastoid foramen); and CN IX, X, and XI exit the jugular foramen (located at the occipitomastoid [OM] suture between the occiput and temporal bone).
- Headache & Head/Neck Autonomics: Sympathetic vasomotor innervation to the entire head, intracranial vasculature, eye, and inner ear originates from T1–T4 and ascends to synapse in the superior cervical ganglion (C1–C3). Parasympathetic innervation to the lacrimal and nasal glands travels via CN VII (greater petrosal nerve) to the sphenopalatine (pterygopalatine) ganglion (targeted via intraoral sphenopalatine ganglion release for cluster headaches and trigeminal neuralgia), while the greater occipital nerve (C2 dorsal ramus) pierces the semispinalis capitis and suboccipital triangle (treated via suboccipital release / inhibition for tension and migraine headaches).
- Anterior & Posterior Chapman Reflex Points: The eye and retina anterior Chapman point resides on the surgical neck of the humerus (posterior: occiput/C1–C2 suboccipital region). The middle ear anterior Chapman point lies on the superior aspect of the clavicle just lateral to the insertion of the clavicular head of the sternocleidomastoid (posterior: superior border of the spine of the scapula and C1 tip). The sinus anterior Chapman point is in the 1st intercostal space (and along the inferior border of the clavicle).
- Absolute Cranial & Cervical OMT Contraindications: Cranial manipulation (especially CV4) and cervical HVLA are ABSOLUTELY CONTRAINDICATED in acute intracranial hemorrhage (subarachnoid/subdural/epidural bleed), acute ischemic stroke, brain abscess, space-occupying tumors with elevated ICP, or suspected vertebral/internal carotid artery dissection!
- Temporal Arteritis Biopsy Delay Trap: In a patient over age 50 with a new temporal headache, jaw claudication, or visual disturbances, NEVER delay high-dose corticosteroid therapy to wait for a temporal artery biopsy; untreated ophthalmic artery vasculitis causes permanent bilateral blindness within hours.
- Surgical ('Blown Pupil') vs. Medical ('Pupil-Sparing') CN III Palsy: A CN III palsy ('down and out' eye) with a dilated, unreactive pupil indicates extrinsic compression of the superficial parasympathetic fibers by a Posterior Communicating (PComm) Artery aneurysm or uncal herniation—order an emergent CTA/MRA immediately!
- Carotid Artery Dissection Presenting with Horner Syndrome: Unilateral head/neck pain accompanied by a partial Horner syndrome (ptosis and miosis WITHOUT anhidrosis, because sweat fibers travel on the external carotid artery) after neck trauma or hyperextension is an Internal Carotid Artery Dissection until proven otherwise; obtain immediate CTA/MRA of the neck to prevent a catastrophic MCA stroke.
- HINTS Exam Normal Head Impulse Trap: In a patient with acute continuous vertigo and nystagmus, a NORMAL Head Impulse test (intact vestibulo-ocular reflex) is a dangerous red flag for a Central Cerebellar/Brainstem Stroke (PICA/AICA), NOT benign peripheral vestibular neuritis!
- Triptan Contraindications in Migraine: Sumatriptan and other 5-HT1B/1D agonists cause potent vasoconstriction and are strictly contraindicated in patients with coronary artery disease, Prinzmetal vasospastic angina, prior stroke/TIA, uncontrolled hypertension, or basilar/hemiplegic migraine.
- Lumbar Puncture Contraindication in Brain Abscess / Mass: Never perform a lumbar puncture before obtaining neuroimaging (CT/MRI) in a patient with headache plus papilledema, focal neurologic deficits, altered mental status, or immunosuppression; removing CSF below a space-occupying mass precipitates fatal transtentorial or tonsillar herniation.