Neuralgias T R I G E M I N A L N E U R A L G I A (MEANS PAIN IN A NERVE)
Definition of pain
Facial pain Cranial neuralgias are commonly distinct in two groups: typical neuralgias and atypical facial pain. Unlike headache syndromes, which are mediated centrally, neuralgias are more characteristic of peripheral nerve localisation.
The main difference between the two forms, typical and atypical, is based on the pain quality. The former is a stabbing, lancinating, brief shocklike sensation, strictly unilateral and limited to the distribution of the cranial nerve affected. The pain is precipitated by trivial stimuli (trigger factors) and there is no pain between attacks. The latter is a continuous, drawing, burning, pressing or throbbing facial pain that typically does not follow anatomical boundaries, often with bilateral localisation.
Facial pain The International Headache Society (IHS) classification considers all these painful syndromes such as Trigeminal, glossopharyngeal, nervus intermedius, superior laryngeal and occipital neuralgia are well characterized entities. A typical facial pain is usually referred to unclassifiable pain syndromes in the facialregion and includes an ill understood group of conditions.
Pain of oral & paraoral region: Pain of the dental origin Pain of non dental origin
Pain of dental origin: 1. Pulpal pain 2. Periodontal pain 3. Gingival pain 4. Bone pain 5. Others!!!
Pain of non dental origin 1. Neurologic (Neuralgias, MS, Bell s palsy) 2. Vascular origin ( migraines, referred pain) 3. Maxillary antrum (sinusitis, CA) 4. SG (infections, stones, malignancies) 5. ORAL MUCOSA (infections, non infective stomatitis& malignancies. 6. JAW, MASTICTORY MUSCLES 7. EAR 8. EYES 9. Pschyogenic (atypical facial pain).
introduction Trigeminal neuralgia means disorder of trigeminal nerve that causes episodes of unilateral intense, stabbing, electric shock like pain in the areas of the face(areas of branches of the nerve distribution). Typical trigeminal neuralagia is caused by dyfunction in the peripheral nervous system. Though not fatal but considered one of the most painful afflictions known.
Predisposing factors Etiology and pathogenesis are unclear, however the following predisposing factors were suggested: 1. Cerebrovascular disease can lead to severe orofacial pain (TN) but with physical signs such as sensory or motor impairment. 2. Multiple sclerosis. 3. Infection (HIV) 4. Space occuping lesion (neoplasm & aneurysm). 5. Lesion that may irritate or even traumatize TN root along the pons. 6. Idiopathic but may be increased during emotional & physical stress.
Clinical features It is uncommon idiopathic disorder (yet the most common cause of facial pain). Age of onset 50-70 years (except for secondary neuralgia tend to occur in younger age). females are more commonly affected. Pain distribution is unilateral and follows the sensory distribution of the CN (V) typically radiating to the maxillary V2 or mandibular V3 area. Paroxymal attack of facial pain that last few seconds (less than 2 minutes) rarely at night.
clinical features Sudden intense, sharp, superficial, stabbing or burning quality. Distribution along one or more division of the trigeminal nerve. Precipitation from trigger area by certain daily activity(talking, touching, brushing, shaving etc) Patient is usually entirely asymptomatic between paroxysms but some patients experience dullache at other times.
1. history. Diagnosis 2. Examination: neurological especially of cranial nerve. 3. Investigation: i. imaging radiography, MRI, CT. ii. Blood test : ESR to exclude vascultides, serology, antibodies for MCTDs.
Management Patient information (TN is intermittent with apparent remission for months or years.) Medical treatment: 1. Anticonvulsant such as Carbamezapin. Sometimes combined with muscle relaxants(baclofen). 2. Acupuncture. 3. Self hypnosis. 4. Surgical treatment
Carbamezapine Effective in 60% of the patients. Must given continuously and prophylacticlly. Given as 100 mg bd for 2 weeks. (then increase to 300 mg then 100 mg every three days till 1000mg bd/day). Monitoring of the patient for side effects is mandatory. S/Es include: Tetratogenic, ataxia, drowsiness, visual disturbance, headache, HTN, rashes, pancytopenia, GIT effects, folate deficiency.
Anticonvulsants Some use Baclofen with Carbamezapine. Other alternatives include: Phenytoin, antidepressants, clonazepam, oxacarbazepine, sumatriptan, valoproate.
Surgical treatment Used if medication are ineffective, or if it produce undesirable side effects. Four main surgical options: 1.Peripheral surgery interrupting nerve conduction in a division or a branch (using local cryosurgery, injection of streptomycin or glycerol) around mandibular or infraorbital foramen). Peripheral neuroectomy of a whole division of trigeminal nerve using alcohol or phenol. Radiofrequency thermocoagulation.
Surgical treatment Open surgical procedure: include microvascular decompression of trigeminal root. Percutaneous approach to trigeminal ganglionlysis. Stereostatic gamma knife radiosurgery: effective but risk of radiation as it need 6 weeks (at least) to be considered successful.
A typical trigeminal neuralgia: presented as less intense constant dull boring or aching pain, sometimes with occassional electric shock like stabs, usually unilateral but some patients experience pain on both sides (e.g. MCTD).
Glossopharyngeal neuralgia Less common than trigeminal neuralgia. Similar to TN in nature but typically affect throat and ear. Trigger zone is located in the oropharynx and triggered by swallowing or coughing. Middle aged & elderly are mainly affected. May be associated with multiple sclerosis and multiple myeloma.
Clinical features Pain is identical to TN but affecting glossopharyngeal rather than the trigeminal nerve. Two distributions of pain are recognized: 1.Otic related to ear 2.Pharyngeal (pain related to the angle of the jaw, throat and neck). features may include nausea, bradycardia (communicating branch to vagus nerve). Treatment as for trigeminal neuralagia but respond less and majority of the patients require microvascular decompression (MVD)!!!
Postherpetic neuralgia Usually occur as complication of herpes zoster. The ophthalmic division of the trigeminal nerve is most commonly affected.
Clinical features: Characterized by persistent, unilateral, very severe, dull, boring pain(persistent for 4 months following onset of rash). A previous history of skin lesion and any scarring may aid diagnosis. Overlying skin may be red due to scratching in attempt to relieve pain. pain may be severe and persistent and may lead to suicidal depression
management Patient support No treatment is fully effective, however tri-cyclic antidepressants, anticonvulsants and local anesthesia(cream) may be used.
Vascular origin
headache Headache is a symptom and non specific one at that. Classic format for taking pain history should be followed e.g. main site, radiation, character, severity, onset, duration, course, pattern, aggrevating & relieving factor and associated sympptoms
Migraine (migraine headache, migraine syndrome) Usually affect females more than males(4:1). Increased prevalence during second decade and decrease with age. It has got autosomal dominant inheritance pattern. In 50% of cases there is family history. Caused by initial constriction of branches of the external carotid artery causing aura followed by dilatation(compensatory mechanism) which lead to headache.
types Migraine with aura In this an aura or pre-headache period occurs! Characterized by visual disturbances, partial or complete loss of light perception (scotoma), sometimes loss of ability to express thoughts(aphasia) Rarely numbness over one side of face and arm. Migraine without aura!!!
Trigerring or intiating factors Pschycological stress, anxiety and depression Some food or drink e.g. cheese, chocolate, beer and red wine. Starvation Premenstruation, contraceptives Drugs(histamin, nitroglycerine Physical exertion Any cause that may initiate headache in a healthy person. weekend migraine.
Clinical features: Prodromal stage (15-30 minutes) which causes lethargy, aura, tingling of the face and occassionally the mouth. The pain started as mild headache. This stage followed by severe throbbing, temporal, frontal and orbital pain. Rarely in other areas(occipital, postauricular etc). Unilateral pain which persist for 12 hours & occur during the day. The patient is ill, pale, sweating, nauseaous & may have photophobia. Attacks may vary from week to months.
Treatment Diagnosis mainly clinical Medicament: Simple analgesics are of no great help! Antiemetic Others which include ergotamine &sumatriptan. Non pharmacological include diet control, stress management, sleep regulation
Periodic migraineous neuralagia Other nomenclatures 1.Cluster headache( often once every 24 hours and followed by remission for weeks. 2. Sphenopalatine neuralgia 3.Alarm clock headache: recur at similr times at the night. 4.Episodic migraineous neuralagia 5.Horton syndrome 6.Histaminic cephalgia
Most severe headache and has been referred to it as suicide headache(uncommon) Caused by arterial spasm followed by dilatation. Or may be due to disorder of maxillary branch of external carotid artery or even internal carotid artery. Trigerring alcohol, cocaine and nitroglycerine. Common age 20-40 years. Male more than females. Usually history of migraine as a child or family history.
The deep intense pain may last for 15 to 3hours Unilateral involve the periorbital area and often radiating to ipisilateral maxilla and temple.(distribution of ophthalmic division. Pain is paroxymal, lacinating, burning without trigger zone. Associated features include: lacrimation from the eye, nasal congestion, rhinorrhea, forhead and facial sweating, eyelid edema, paraestic sensation of the lower half of the face.
Diagnosis(clinical) Management: medication include ergotamine(2mg sublingual), prednisolone, sumatotriptan.
Tension headache Commonest type of headache Due to muscle tension in occipito frontalis and may be felt as band like Usually worse as the day progresses. Responds to reassurance, anxiolytic and analgesic.
Raised intracranial pressure A cause of headache demanding urgent further investigation. Charcterized by pain that is worse on awaking accompanied by decreased level of conciousness,vomiting, irritation, abscent pupillary reflexes. Rising blood pressure and slowing pulse are late premorbid sign of ICP.
Causes of headache Primary: Migrainne Tennsion type headache Cluster headache Idiopathic stabbing headache Exertional and postcoital headache Medication misuse (analgesic) headache
s Secondary causes