A patient presents with recurrent episodes of sharp pain over his right cheek that is precipitated on chewing. Between attacks patients is otherwise normal. The most probable diagnosis is -
Ans. is 'b' i.e., Trigeminal Neuralgia Epidemiologyo TN is a rare condition that affects women more than men.o The incidence increases gradually with age: most idiopathic cases begin after age 50.Etiology and pathogenesiso Most cases of TNare caused by compression of the trigeminal nerve root, usually within a few millimeters of entry into the pons (the root entry zone).o Compression by an aberrant loop of an artery or vein is thought to account for 80 to 90 percent of cases.o Idiopathic TN or TN caused by a vascular compression is considered classic TN.o Other causes of TN via nerve compression include vestibular schwannoma (acoustic neuroma), meningioma, epidermoid or other cyst, or, rarely, a saccular aneurysm or arteriovenous malformation.Classificationo In the International Classification of Headache Disorders, 3rd edition (ICHD-3), TN is divided into classic (or classical) trigeminal neuralgia caused by neurovascular compression and painful trigeminal neuropathy caused by a number of other conditions.Trigeminal neuralgia||ClassicPainful trigeminalo Classic TN encompasses both idiopathic TN c cases and those related to vascular compression.o Painful trigeminal neurooathv is caused by lesions other than vascular compression:# The rationale is as follows.# Painfid trigeminal neuropathy attributed to acute herpes zoster.# The ICHD-3 acknowledges that TN found to be related to compression of the trigeminal nerve by a vascular loop, as demonstrated by surgery\ should strictly be regarded as secondary.# Postherpetic trigeminal neuropathy# Painful posttraumatic trigeminal neuropathy# Painful trigeminal neuropathy attributed to multiple sclerosis plaque# However, most patients do not have surgery, and it is often uncertain as to whether they have primary or secondary neuralgia.# Painful trigeminal neuropathy attributed to space-occupying lesion# For this reason, the ICHD-3 uses the term"classical'' instead of "primary" for patients with a typical history of TN who have a presumed or demonstrated vascular source of compression as the cause.# Painfid trigeminal neuropathy'attributed to other disorderClinical featureso TN is defined clinically by paroxysmal, stereotyped attacks of usually intense, sharp, superficial, or stabbing pain in the distribution of one or more branches of the fifth cranial (trigeminal) nerve.o The pain of TN tends to occur in paroxysms and is maximal at or near onset.o Facial muscle spasms can be seen with severe pain.#This finding gave rise to the older term for this disorder, "tic douloureux"o The pain is often described as electric, shock-like or stabbing.o It usually lasts from one to several seconds, but may occur repetitively.o A refractory' period of several minutes during which a paroxysm cannot be provoked is common.o Some patients with longstanding TN may have continuous dull pain that is present between paroxysms of pain.o Unlike some other facial pain syndromes, TN typically does not awaken patients at night,o TN is typically unilateral.#Occasionally the pain is bilateral though rarely on both sides simultaneously.o The distribution of pain most often involves the V2 and/or V3 subdivisions of the trigeminal nerve.o Trigger zones in the distribution of the affected nerve may be present and are often located near the midline. Lightly touching these zones often triggers an attach leading patients to protect these areas.# Other triggers of TN paroxysms include chewing, talking, brushing teeth, cold air smiling, and/or grimacing.o Autonomic symptoms, usually mild or moderate, can occur in association with attacks ofTNin the VI trigeminal distribution, including lacrimation, conjunctival injection, and rhinorrhea.Diagnosiso The diagnosis of TN is based upon the characteristic clinical features described above, primarily paroxysms of pain in the distribution of the trigeminal nerve.o Once the diagnosis of TN is suspected on clinical grounds, a search for secondary causes should be undertaken.Diagnostic criteria for trigerm in at neuralgiao The International Classification ofHeadache Disorders, 3rd edition (ICHD-3) diagnostic criteria for classic TN are as follows:A)At least three attacks of unilateral facial pain fulfilling criteria B and CA) Occurring in one or more divisions of the trigeminal ner\>e, with no radiation beyond the trigeminal distributionA) Pain has at least three of the following four characteristics:# Recurring in paroxysmal attacks lasting from a fraction of a second to two minutes.# Severe intensity.# Electric shock-like, shooting, stabbing, or sharp in quality.# At least three attacks precipitated by innocuous stimuli to the affected side of the face (some attacks may be, or appear to be, spontaneous).D) No clinically evident neurologic deficit.E) Not better accounted for by another ICHD-3 diagnosis.
Preherpetic neuralgia
Trigeminal neuralgia
Mumps
Thalamic syndrome
C.N.S.