TARGET TISSUES OF ORAL FACIAL PAIN
MENINGES, CORNEA, TOOTH PULP, ORAL AND NASAL MUCOSA, TMJ
TRIGEMINAL MECHANISMS OF PAIN
THE SENSORY PATHWAYS THAT CONVEY CRANIOFACIAL NOCICEPTIVE INPUT OT HIGHER LEVELS OF BRAIN ORIGINATE IN THE TRIGEMINAL GANGLION NOCICEPTORS AND THEIR ASSOCIATED NUCLEI WITHIN TRIGEMINAL BRAIN STEM SENSORY COMPLEX AND UPPER CERVICAL SPINAL CORD
3 BRANCHES OF THE TRIGEMINAL NERVE
1.) OPTHALMIC (V1)
2.) MAXILLARY (V2)
3.) MANDIBULAR (V3)
CRANIAL NERVES C2 AND C3 INNERVATE THE OTHER PORTIONS OF THE HEAD
SPINAL TRIGEMINAL SENSORY NUCLEUS
SP5O - ORALIS (TOP)
SP5I - INTERPOLIS
SP5C - CAUDALIS (BOTTOM)
A-DELTA AND C FIBERS TERMINATE IN A DORSAL TO VENTRAL FASHION
MANDIBULAR AFFERENTS (BOTTOM) = DORSALLY (TOP)
MAXILLARY FIBERS (MIDDLE) = CENTRALLY (MIDDLE)
OPTHALMIC FIBERS (TOP) = VENTRALLY (BOTTOM)
TRIGEMINAL VS. SPINAL AFFERENT SYSTEM
TRIGEMINAL HAS MORE SUBSTANCE P THAN SPINAL
TRIGEMINAL IS MORE RESISTANT TO HSV REACTIVATION AND SPREADS CONTRALATERALLY (SPINAL SPREADS 10% CONTRALATERALLY)
TRIGEMINAL CONSISTS OF LESS SPONTANEOUS DISCHARGE IN (DE)MYELINATED FIBERS
ESTRADIOL AND PROLACTIN SENSITIZERS NEURONAL RESPONSES IN THE TRIGEMINAL SYSTEM
ODONTOGENIC PAIN
TWO PAIN STATES WITHIN…
1.) DENTINAL TUBULE PAIN - SHARP BRIGHT STABBING (MYELINATED)
CONSIDERED A-DELTA PAIN B/C EXPOSED TUBULE NEURONS ARE A-DELTA FIBERS
2.) PULPITIS PAIN - DULL ACHING, THROBING (UNMYELINATED)
C FIBER PAIN B/C PULP IS C FIBERS
INFLAMMATION OF PULP CAUSES THE RELEASE OF INFLAMMATORY MEDIATORS
PULPITIS
PERIPHERAL CHANGES -
ABORIZATION OF TRIGEMINAL AFFERENTS INNERVATING REGIONS NEAR THE INJURED TISSUE CAUSES…
BLOOD FLOW AND PLASMA EXTRAVAGINATION
ALTERED EXPRESSION OF NAV AND CAV CHANNELS => HYPER-RESPONSIVENESS
CENTRAL CHANGES -
CENTRAL SENSITIZATION - TRIGEMINAL NUCLEUS IN THE BRAIN => ALLODYNIA
MEDULLARY TRIGEMINAL NUCLEI NEURONAL CHANGES OCCUR
ACUTE PAIN
POST-SURGICAL PAIN TRIGGERS AN INCREASE IN PAIN, SWELLING AND HYPERTHERMIA
GOLD STANDARD MODEL FOR TESTING PAIN
ORAL CANCER PAIN
HEAD AND NECK CANCER - PREDOMINANTLY SQUAMOUS CELL CARCINOMA
FUNCTIONAL (CHEWING, TALKING, SWALLOWING) RATHER THAN SPONTANEOUS PAIN
THERAPY-ASSOCIATED PAIN FROM CHEMOTHERAPY AND RADIATION THERPY
ORAL MUCOSITIS - INFLAMMATION AND ULCERATION OF MUCOUS MEMBRANES (FASTEST GROWING - CHEMO DRUGS TARGET FAST GROWING CELLS)
ORAL CANDIDIASIS - YEAST INFECTION
NEUROTOXICITY - OXALIPLATIN (PRODUCES PERIPHERAL NEUROPATHY)
OSTEONECROSIS OF THE JAW - CAUSED BY BISPHOSPHONATES AND DENOSUMAB (USED TO TREAT OSTEOPOROSIS - CANCER RELEASES FACTORS THAT CAUSE BONE LOSS)
CHRONIC OROFACIAL PAIN
TMJ PAIN - (PREVALENCE - 3-10% IN M, 6-15% IN F, DECEASES WITH INCREASING AGE)
BURNING MOUTH SYNDROME - BURNING PAIN IN THE TONGUE, LIPS AND OTHER SOFT TISSUE (PREVALENCE - 1-8% IN POST-MENOPAUSAL F)
IDIOPATHIC/TRAUMATIC TRIGEMINAL NEUROPATHIC PAIN - CHRONIC AND CONTINUOUS
CONSISTS OF…
ATYPICAL ODONTALGIA - CONTINUOUS PAIN LOCALIZED TO A TOOTH OR A REGION NEXT TO A MISSING TOOTH
TRIGEMINAL NEURALGIA
SUDDEN, SEVERE, BRIEF PAIN IN ONE OR MORE BRANCHES OF THE 5TH CRANIAL NERVE
TRIGGER ZONES
MISDIAGNOSED AS DENTAL, SINUSITIS OR TMD PAIN
GENERALLY UNILATERAL
ARTERIAL COMPRESSION OF TRIGEMINAL NERVE IN TRIGEMINAL NEURALGIA
OCCURS IN THE POSTERIOR FOSSA
NERVE COMPRESSED IN THE ROOT ENTRY BONE BY A BLOOD VESSEL
COMPRESSION RESULTS IN DEMYELINATION AND EXTRASYNAPTIC TRANSMISSION OF IMPULSES FROM TOUCH FIBERS TO PAIN FIBERS => PAROXYSMS OF PAIN
DISEASE IS RARE, UNCLEAR ETIOLOGY, SPONTANEOUS REMISSION, VARYING SEVERITY
TREATMENT - CARBAZAPINE - BENEFICIAL IN 70% OF PATIENTS (GOLD STANDARD DRUG), GABAPENTIN (CAV CHANNELS), BACLOFEN (GABA AGONISTS)
GLOSSOPHARYNGEAL NEURALGIA
SUDDEN, SEVERE, STABBIND PAIN IN THE DISTRIBUTION OF GLOSSOPHARYNGEAL NERVES
PAIN IN POSTERIOR TONGUE, TONSILLAR FOSSA, PHARYNX, AREA BENEATH ANGLE OF THE MANDIBLE
TREATMENT - CARBAZAPINE - BENEFICIAL IN 70% OF PATIENTS (GOLD STANDARD DRUG), GABAPENTIN (CAV CHANNELS), BACLOFEN (GABA AGONISTS)
HEADACHE TYPES
SINUS - PAIN BEHIND THE FOREHEAD/CHEEKBONES
CLUSTER - PAIN AROUND 1 EYE
TENSION - PAIN LIKE HAND SQUEEZING THE HEAD
MIGRAINE - PAIN, NAUSEA, AND VISUAL CHANGES TYPICAL OF CLASSIC FORMS
SUBSTANTIAL INHERITED COMPONENT
MIGRANES
EPISODIE, UNILATERAL, THROBBING WITH SENSORY MODULATION OR NAUSEA AND VOMITING
CHANNEL DYSFUNCTIONS IN BRAIN NE AND 5-HT BRAIN STEM REGIONS
CLUSTER
SHORT, UNILATERAL, ORBITAL, SUPRAORBITAL, OR TEMPORAL PAIN WITH EYE OR NOSE SECONDARY SYMPTOMS, CIRCANNUAL AND CIRCADIAN RHYTHMICITY
TREATMENT - SUMATRIPTAN OR 5-HT1B/D AGONISTS
PROPHYLAXIS - VERAPAMIL (CA2+ BLOCKER - PREVENTS CA2+ -MEDIATED EXOCYTOSIS), LITHIUM (USED IN BPD WHICH IS ALSO CYCLICAL) AND METHYSERGIDE (CONTROLS ACTIVITY OF BLOOD VESSELS)
PAROXYSMAL HEMICRANIAS
HIGH FREQUENCY, SHORT DURATION, AND RESPONSIVE TO INDOMETHACIN (POTENT NSAID)
HEADACHE SENSORS
FREE NERVE ENDINGS SURROUNDING BLOOD VESSELS FIRE WHEN THERE IS A SUDDEN INCREASE/DECREASE IN BLOOD FLOW
SENSED BY THE 5-HT1B/D - ACTED ON BY SUMATRIPTAN (CAUSES FIRING OF THE 5-HT1B/D NEURONS THEN DESENSITIZATION)
TENSION HEADACHES
DIAGNOSED DUE TO THE ABSENCE OF NAUSEA, VOMITING, AND PHONO- OR PHOTOPHOBIA
BILATERAL, PRESSING AND NON-PULSATING
TENDERNESS UPON MANUAL PALPATION
MECHANISMS = PERIPHERAL MYOFASCIAL AND CENTRAL DYSREGULATION IN PAIN PROCESSING MATRIX
TREATMENT - IBUPROFEN (NSAID - VERY EFFICACIOUS)
