2HISTORYA 62-year old woman complained to her dentist about suddenbouts of excruciating pain on the left side of her face.The bouts had started ~ 2 months previously and had beenincreasing in severity. The stabbing pains lasted seconds,occurred several times a day and were so severe that she hadonce contemplated suicide.After examination the dentist told her there was no dental causefor the pain and he referred her to a physician.
3PHYSICAL EXAMINATIONThe woman told the physician that the onset of the pain wassometimes triggered by chewing or a cold wind blowing on herupper lip.When asked to point out the area where the pain occurred shepointed to her left upper lip and cheek. She indicated that thepain also radiated to her lower eyelid, lateral side of the nose andthe inside of the mouth.The physician applied firm pressure over the patient’s left cheekand over her infraorbital area, but detected no tendernessindicative of maxillary sinusitis.The physician did detect acute sensitivity to touch on the leftupper lip and to pin-pricking over the entire left maxillary region.No abnormality of sensation was found in the forehead ormandibular regions.
41. What is the diagnosis? What is the diagnosis? Trigeminal neuralgia (tic douloureux). The term “tic” (twitch) derives from the fact that the patient winces because of the intense pain.
5TRIGEMINAL NEURALGIA (“TIC DOULOUREUX”) This patient is typical as far as age, sex and involved distribution of the trigeminal nerve is concerned. Thus, the disease is more common in the elderly female.
62. Which branch of what major nerve supplies the area of skin and mucous membrane where theparoxysms (sudden recurringattacks) of stabbing pain werefelt?Which branch of what major nerve supplies the area of skin and mucous membrane where the paroxysms (sudden recurring attacks) of stabbing pain were felt?Maxillary branch of the trigeminal nerve (V2). Trigeminal neuralgia usually involves V2 (V3 less frequently, V1 least frequently).
8Infraorbital n.Zygomaticofacial n.Zygomaticotemporal n.
9Through what foramen and what bone does this nerve leave the skull? Through the foramen rotundum in the greater wing of the sphenoid bone.
10Greater wing of sphenoid Foramen rotundum(for V2)
11Why was no abnormality of sensation found in the forehead region? In the mandibular region?Why was no abnormality of sensation found in the forehead region? In the mandibular region?Because sensation in the forehead and mandibular regions is mediated via the ophthalmic (V1) and mandibular (V3) branches of the trigeminal nerve, respectively.
12Ophthalmic n. (V1)Maxillary n. (V2)Mandibular n. (V3)
13Where are the cell bodies of the affected nerve located? In the trigeminal ganglion, which lies in a depression on the apex of the petrous part of the temporal bone in the middle cranial fossa.
15Depression for V ganglion (in petrous temporal bone)
166. Why were no motor deficits observed in this patient? Because V2 is purely sensory (as is V1). Only V3 contains motor fibers (to the muscles of mastication, etc.).
17Mesencephalic nucleus of V (proprioceptive) Sensory rootMesencephalic nucleus of V(proprioceptive)V1Pontine sensory nucleus of V(fine touch)V2V3Motor nucleus of V(mm of mastication,etc.)Motor rootSpinal nucleus of V(pain, temperature)Motor fibersSensory fibers
18SENSORY AND MOTOR ROOTS OF V MidbrainANTERIORV1V2V ganglionMotor root of VV nerve cut & reflectedSensory root of V
19What may be the cause(s) of this condition? Usually the cause of the neuralgia is unknown. However, the following causes have been suggested by various investigators:1) Inflammation of the petrous part of the temporal bone (osteitis). (Note: This is understandable in view of the location of the trigeminal ganglion—see #5 above.)2) Presence of an aberrant artery that lies close to the sensory root of V and compresses it.3) A pathological process affecting neurons in the trigeminal ganglion or nucleus of the spinal tract of V.
20Usually the cause of trigeminal neuralgia is unknown.
22COMPRESSION OF SENSORY ROOT OF V BY AN ABERRANT ARTERY Usually a branch of the superior cerebellar a. forms an aberrant loop that can compress the sensory root of V. (Netter’s Neurology, p. 106)
23Pathological processinvolving cells of theV ganglionor spinal nucleusof V
24How might this condition be treated? Several treatments are possible, including partial cutting of the sensory root of V (rhizotomy) between the trigeminal ganglion and the brainstem. In this procedure, fibers of V2 or V3 are cut, thus eliminating the sensations of pain, temperature and touch in their respective areas of distribution. (V1 fibers are spared because destruction of the sensory fibers from the cornea leads to abolishment of the protective corneal reflex. The absence of this reflex makes the cornea susceptible to inflammation and ulceration due to dessication and trauma, with possible loss of eyesight.)
25Medications can be used to treat this condition. These drugs increase the threshold to neuralstimulation.
27PERCUTANEOUS RADIOFREQUENCY RHIZOTOMY OF SENSORY ROOT OF V Partial rhizotomy of sensory root of VInformation from Netter’s Neurology (p. 106).1. These two procedures result in partial and irreversible destruction of the sensory root and trigeminal ganglion.Trigeminal ganglionPERCUTANEOUS BALLOON COMPRESSIONOF TRIGEMINAL GANGLION
28ADDITIONAL NOTEIt is noteworthy that the patient first consulted her dentist about her problem and thather physician examined her for possible maxillary sinusitis. Under the mistaken beliefthat the pain of trigeminal neuralgia is due to dental disease or sinusitis, patients havehad upper teeth extracted and their maxillary sinuses drained, but with no relief.
29MAXILLARY NERVE (V2) V1 V ganglion Sensory root of V Infraorbital n. Anterior superior alveolar n.V3V2Mucosa of maxillary sinusDental and gingival branchesMiddle superior alveolar n.Posterior superior alveolar n.