Differential Diagnosis in Neurology

Topic 5. Cranial Nerves

5.5. Cranial Nerve V

Anatomy

  • Innervates: head, mouth, nasal cavity, motor and proprioceptive innervation of the muscles of mastication
  • Sensation: spares the angel of the jaw (C2); innervates scalp to the bregma; tragus of the ear; anterior wall of external auditory meatus; anterior part of the tympanic membrane; dura of the anterior and middle fossa; may decrease taste on ipsilateral tongue or palate (may need somatic as well as special sensation for full taste)
  • Mental nerve; buccal nerve; auricular temporal nerve; great auricular nerve
  • Main sensory nucleus; (light touch); the spinal tract and nucleus; (pain and temperature)
  • Mesencephalic nucleus takes origin from the rostral tip of the main sensory nucleus to the superior colliculus; subserves proprioception of muscles of mastication and the mechanoreceptors of the peridental membrane
  • Motor root: innervates muscles of mastication the tensor tympani and tensor veli palatini

Trauma

  • Dental treatment
  • Pressure on the mental nerve from dentures (bone resorption)
  • Surgical trauma
  • Head and facial trauma
  • Skull base fracture; trigeminal abducent nerve synkinesis may occur with lesions at the petrous apex

Migraine Variants

  • Facial paresthesias and numbness are common with both common and classic migraine
  • Lower face migraine affecting V2 and V3
  • Paroxysmal hemifacial pain; multiple attacks of severe pain primarily in V2 division daily; responsive to indomethacin
  • Classic cluster migraine with severe orbital and retroorbital V1 pain
  • Raeder's paratrigeminal neuralgia pain in V1 distribution with associated photophobia, phonophobia and nausea. Type I with ptosis and miosis; type II with no cranial nerve abnormality.
  • SUNCT: sudden unilateral neuropathic pain in V1 with conjunctival injection and tearing

Tumors

  • Trigeminal neurinoma:
    • 0.2% of intracranial tumors; 14–67 years of age; most often occur in middle age; incidence equal in both sexes
    • Arise in the distal portion of the nerve; probable Schwann cell origin; at the region of the ganglion; rarely may extend through the foramen rotundum or ovale.
    • 2.5 cm by time of diagnosis; may undergo malignant transformation
    • Numbness or paraesthesias in the distribution of the nerve; trigeminal neuralgia or painful paresthesias less common
    • Erode the medial part of the floor of the middle fossa; erosion of apex of the petrous bone
  • Meningoma:
    • More often arise in Meckel's cave than trigeminal neurinoma
    • Spread en plaque along the floor of the middle fossa; along the trigeminal nerve root into the middle fossa
    • Meningioma affects V3 more often than trigeminal neuroma
  • Gangliocytoma (rare primary malignant tumor of the ganglion)
  • Epidermoids primary or secondary
  • Chondroma
  • Chondromyxoma
  • Sarcoma
  • Lymphoma
  • Fibrous xanthoma (fibrous histiocytoma)
  • Hemangioblastoma
  • Malignant Schwannoma (from the trigeminal ganglion or its divisions):
    • Numbness or paresthesia in distribution of the nerve or its branches in 2/3 of patients
    • Painful burning and paresthesias 1/3 of patients
    • May erode into the cavernous sinus; V1, IVth, IIIrd nerve involvement with consequent proptosis and visual loss
  • Nasopharyngeal cancer (fossa of Rosenmüller is its origin)
  • Maxillary sinus cancer
  • Neural spread of squamous cell cancer of the face
  • Prostate cancer spread to Meckel's cave (spread via Batson's plexus; paravertebral veins)
  • Cholesterol granulomatosis; benign; striking MRI findings (positive T2 weighted images; apex of the petrous bone)
  • Salivary gland adenoma
  • Submaxillary gland cylindroma

Congential Trigeminal Anesthesia

  • May be isolated and is usually bilateral; may present with corneal ulceration
  • May be associated with ectodermal or mesenchymal structural defects:
    • Goldenhar syndrome: oculoauricular vertebral dysplasia
      • Abnormalities of the first and second branchial arches, vertebrae and eyes. These include: preauricular tags, malformed pinnae, epibulbar dermoids
    • Associated with Möebius syndrome: congenital facial diplegia and horizontal gaze

Vascular Lesions

  • Wallenberg's syndrome (medial branch of PICA or vertebral artery occlusion)
  • Pontine ischemia (short circumferential arteries)
  • Aberrant branch of AICA that abuts the Vth nerve
  • AVM of the ganglion
  • Ischemia of the inferolateral trunk of the external carotid artery; usually involved with VII or with nerves of the superior orbital fissure
  • Internal carotid artery aneurysm (compresses the trigeminal ganglion and concomitantly the IIIrd nerve)
  • Cavernous sinus aneurysm:
    • Affects primarily middle aged women
    • VIth nerve involved first followed by severe pain in V1 and V2
    • Often bilateral
    • Pain is predominant symptom

Systemic Disease

  • Hypothyroidism (may present with severe facial pain: V1, V2 divisions)
  • Sarcoid (rare)
  • Wegener's granulomatosis (often V2)
  • Scleroderma (Vth nerve involvement may be presenting symptom)
  • SLE
  • Sjögren's disease
  • Periarteritis nodosa
  • Mixed collagen vascular disease

Idiopathic Trigeminal Neuropathy

  • After exclusion of all known entities that affect the Vth nerve
  • Motor function rarely affected
  • 10% of trigeminal lesions
  • Numbness most often V2, V3, spreads to adjacent divisions in days to weeks; recovery over weeks to months
  • Sensation of numbness, swelling, coldness and tingling
  • Inflammatory process of the ganglion (pathologically)
  • Reported with arteritis: rheumatoid arteritis, Sjögren's, MCTD, most commonly associated with scleroderma
  • Taste affected over the anterior 2/3 of the tongue (affected in some patients)
  • Trigeminal trophic syndrome (very rare)

Trigeminal Neuralgia

  • General Features:
    • Young patients:
      • Multiple sclerosis
      • Vascular loop compressing the entry zone
      • Spinocerebellar degeneration
    • Older patients:
      • Idiopathic
      • Vascular loop originates
        • Superior cerebellar artery > AICA > basilar artery
  • Clinical Presentation:
    • Lancinating severe pain
    • Less than 15 seconds in duration
    • Most often unilateral; V3 division > V2 division <10% in V1
    • No associated motor or sensory symptoms
    • Refractory period between attacks
    • Triggering events include:
      • Light touch of the affected division
      • Chewing, swallowing, talking
      • Positional (if arterial compression)
      • Cold
    • Tic convulsive (associated with hemifacial spasm; need to r/o extracranial lesion of the VIIth nerve

Trigeminal Neuralgia and Associated Syndromes

Associated with hemifacial spasm of the ipsilateral side; paroxysms of pain occur independently of the hemifacial spasm. Termed "tic convulsive." Either symptom may precede the other usually by a few months. Unusual pathology is a loop of the vertebral or basilar artery touching the nerve in the cerebellopontine angle. Differential diagnosis includes meningioma, neurofibroma, cholesteatoma, arteriovenous malformation or cirsoid aneurysms of the vertebral artery. Concurrence of trigeminal and glossopharyngeal neuralgia

Immune Mediated Trigeminal Neuralgia

  • MS and Vth nerve involvement:
    • 2% of trigeminal neuralgia patients have MS; bilateral tic is frequently MS
    • Triggers for attacks less common in MS
    • Plaque most often in the root entry zone
    • CIDP (V3 involved during relapses)
    • Idiopathic trigeminal sensory neuropathy

Infection

  • Syphilis (root entry zone); mid-face numbness; gumma of the pons
  • Herpes simplex; V2, V3 pain following oral sores
  • Herpes zoster; V1 infection often associated with CSF involvement; occasionally associated encephalitis; delayed MCA stroke of ipsilateral side (7–14 days)
  • Gradenigo's syndrome:
    • Purulent middle ear infection
    • Pneumatized petrous bone
    • Petrous apicitis; V and VIth nerve involved (Dorello's canal where the VIth nerve is involved at the petrous clinoid ligament)
    • Occasionally associated with lateral venous sinus thrombosis
  • Actinomycosis
  • Leprosy

Toxins and Physical Agents

  • Trichloroethylene (defrigerent)
  • Stilbamidine (treatment for blastomycosis)
  • Post radiation therapy

Structural Lesions

  • Meckel's cave arachnoid cyst
  • Brainstem syringobulbia
  • Brainstem glioma
  • Fibrous dysplasia (foraminal stenosis)

Unusual Entities

  • Kennedy's syndrome (motor V)
  • ALS
  • Spinocerebellar atrophy type 4
  • Component of the superior orbital fissure syndrome
  • Numb chin and cheek syndrome:
    • Lesions of the mental nerve or the mandibular division of V3; sickle cell disease; breast cancer
    • Elderly patients:
      • Impingement of the mental nerve at the mental foramen
    • Inferior alveolar nerve involvement:
      • Metastasis (lung, breast and nasopharyngeal cancer)
      • Lower lip anesthesia
    • Numb cheek:
      • Malar anesthesias
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