Orofacial pain Flashcards
What is pain?
An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage
What cranial nerve, artery and associated muscles are derived form the 1st pharyngeal arch?
TRIGEMINAL NERVE
Maxillary artery
MOM, anterior belly of digastric, mylohyoid, and general sensation of the face.
What cranial nerves, artery and muscles are derived from the 2nd pharyngeal arch?
FACIAL NERVE
Hyoid artery
Muscles of facial expression
Stylohyoid
Posterior belly of digastric
What cranial nerves, artery and muscles are derived from the 3rd pharyngeal arch?
GLOSSOPHARYNGEAL
Internal carotid artery
Stylopharyngeus
What cranial nerves, artery and muscles are derived from the 4th pharyngeal arch?
VAGUS
Right subclavian artery and aorta
Pharyngeal and laryngeal musculature
Why might a patient get referred pain?
Multiple primary sensory neurons converging on a single ascending tract
What is the difference between somatic and autonomic?
Difference is what target tissues are EFFECTORS
Somatic - skeletal muscle - essentially the outside bits. Involved in conscious activities
Autonomic - nerves that connect CNS to organs such as heart and GI tract. Mediates unconscious activities and reflexes
What are afferent neurons?
Carry information from sensory receptors of the skin and other organs to the CNS (brain and spinal cord)
What are efferent neurons?
Carry motor information away from the CNS to the muscles and glands of the body.
What is nociceptive pain?
Caused by activity in neural pathways in response to potentially tissue damaging stimuli
What is neuropathic pain?
When the nerves that carry pain become damaged and so the patient feels pain with no pain stimulus.
Caused by primary lesion or dysfunction in the nervous system.
Pain is always in the same area where the nerve is damages
What is post herpetic neuralgia?
Nerve has been damages via viral infection and not healed properly and even when infection removed nerve isn’t healed
What does neuropathic pain feel like?
Constant burning/ aching pain.
What are the 2 most common types of neuropathic pain?
Diabetic neuropathy
Post-herpetic neuralgia
What SYSTEMIC medication can be used for neuropathic pain management?
Gabapentin
Tricyclics
What TOPICAL management can be used for neuropathic management?
Capsaicin
EMLA
Benzydamine
Ketamine
What is atypical odontalgia?
Dental pain without dental pathology
What are the 2 most frequent causes of trigeminal neuralgia?
Focal demyelination of the peripheral nerve
Vascular compression of the trigeminal nerve - most commonly from the superior cerebellar artery
What 2 neurological disorders may cause trigeminal neuralgia?
Multiple sclerosis
Brain tumour
How does trigeminal neuralgia present?
Usually unilateral
Stabbing paroxysmal pain
Worst ever pain
Electric shock lasting a few seconds
Triggers - cutaneous, wind, cold, touch, chewing
What would “typical patient” for trigeminal neuralgia be?
Usually older patient
“Mask-like” face
Appearance of excruciating pain
NO obvious precipitating pathology
What is first-line drug therapy for trigeminal neuralgia?
Carbamazepine - short-term and long-term modified release
Oxcarbazepine
Lamotrigine
What is second-line drug therapy for trigeminal neuralgia?
Gabapentin
Pregabalin
Phenytoin
Baclofen
What are side effects of carbamazepine?
Liver dysfunction
Blood dyscrasias
Nausea
Allergy
Dry mouth
Ataxia - loss of co-ordination
Electrolyte imbalance
At what point would you consider surgery for trigeminal neuralgia?
When pt. gets severe side effects from medication
If patient requests it
Symptoms persist with medical management
When approaching maximum tolerable medical management even if pain controlled
“Younger” patients with significant drug use - will be medicated for many years
What would be red flags for trigeminal neuralgia (abnormal presentation)?
Younger patients - >40 years
Sensory deficit in facial region - hearing loss
Other cranial nerve lesions
ALWAYS TEST CRANIAL NERVES
Why do you need to be careful when combining carbamazepine with diuretics?
Carbamazepine can cause electrolyte imbalance, which would be completely thrown off if combined with diuretics.
What are causes of painful trigeminal neuropathy?
Herpes zoster virus - related to active VZV infection, post-herpetic neuralgia
Trauma
Idiopathic
What are trigeminal autonomic cephalalgias (TAC’s)?
Unilateral EXTREME head pain - predominantly ophthalmic branch
Primary headaches with a common clinical side effects consisting of trigeminal pain with autonomic signs, which may include lacrimation, runny nose and miosis.
Characteristics of painful trigeminal neuropathy (dysfunction of sensory/ motor funcitons along nerve)?
Pain is localised to distribution of trigeminal nerve
Burning, squeezing or pins and needle sensation
Primary pain usually continuous
What are some KEY FEATURES of cluster headaches?
Pain located to orbital and temporal region
STRICTLY UNILATERAL
Rapid onset - within 9 mins for majority
Patients are RESTLESS AND AGITATED during attack
What class of drug is carbamazepine?
Anti-convulsant
What investigations can you do to discover the cause of trigeminal neuralgia?
MRI
Blood test - FBC, haematinics, blood glucose
If the cause of your patient’s TN was MS, what symptoms might they experience?
Intention tremor
Loss of proprioception
If the cause of your patient’s TN was a brain tumour, what symptoms might they experience?
Diplopia (double vision)
Memory loss
Name some surgical managements of trigeminal neuralgia?
Balloon compression
Stereotactic radiosurgery - Gamma knife
Cryosurgery
