Ch 28 Pain Flashcards
(25 cards)
What are the different types of pain?
Nociceptive (somatic vs visceral)
Deafferentation
CRPS
What is the definition of neuropathic pain?
International association of pain study definition = pain caused by a lesion of the peripheral or central nervous system with sensory symptoms or signs
What classes of medications are used to treat neuropathic pain?
- Antiepileptics
- Gabapentin / pregabalin - unknown but thought to act upon pre- and post-synaptic voltage gated calcium channels.
- TCAs e.g. amitriptyline.
- Topical therapies - lignocaine patch
- Opiates
What are the different cephalic neuralgias?
Trigeminal neuralgia Glossopharyngeal neuralgia Geniculate neuralgia Tic convulsive (geniculate neuralgia + hemifacial spasm) Occipital neuralgia Supraorbital neuralgia Sphenopalatine neuralgia Superior laryngeal neuralgia Ramsay-Hunt syndrome SUNCT
What is SUNCT?
Short lasting unilateral neuralgiform headache with conjunctival injection and tearing
What are the features of SUNCT?
Usually affects males between 25-50 years, stabbing pain near the eyes with autonomic findings including ptosis, conjunctival injection, lacrimation, hyperaemia.
What are the treatment options for SUNCT?
AEDs MVD if vascular conflict May be associated with CPA AVMs
What is Tolosa-Hunt syndrome?
Inflammation of the superior orbital fissure / cavernous sinus resulting in a painful opthlamoplegia.
What is Raeder’s paratrigeminal neuralgia?
Unilateral Horner’s syndrome and trigeminal neuralgia
What cranial nerves provide innervation to the ear?
CN5 (Top of ear - Auriculotemporal nerve V3)
CN7 (EAM)
CN9 (EAM)
CN10 (Arnold’s nerve)
Occipital nerves (Lesser occipital - C2)
Greater auricular nerves (C2/3)
What are the features of primary otalgia?
Unilateral ear pain associated with hearing loss, tinnitus and vertigo. Exacerbated by cold air / water
What are the treatments for primary otalgia?
Medications (carbamazepine, phenytoin etc)
Pharyngeal nerve block
MVD of nervus intermedius
Rupa et al recommend sectioning of nervus intermedius if MVD fails (or selective sectioning of CN9 if glossopharyngeal neuralgia)
What are the branches of V1?
Frontal n. - supra-orbital and supra-trochlear nerves
Nasocilliary n.
Lacrimal n.
Where are the supraorbital and supratrochlear nerves?
Supraorbital nerve exits through the supraorbital foramen within the medial third of the orbital roof.
Supratrochlear nerve exits without a foramen more medially.
How can supraorbital neuralgia be differentiated from V1 TN?
Tenderness in the supra-orbital notch and temporal relief with nerve block
What is hemicrania continua?
A unilateral pain that is continuous and responsive to indomethicin
What is nummular?
A coin like headache area described as a continuous pressure headache. Patients have hypoesthesia and paraesthesias
What are the management principles for neuralgias?
Oral medications for neuropathic pain e.g. Gabapentin / TCAs / AED such as carbamazepine
Topical treatments e.g. capsaicin and lignocaine
Nerve block / decompression e.g. MVD
Neurolysis / rhizotomy / neurectomy
What % of post-herpectic neuralgias affect the trigeminal nerve?
20% with predilication for V1 = opthalmic zoster
What is post-herpetic neuralgia?
If the pain after herpes zoster persists for >1 month after the vesicular eruption has healed. Inflammatory changes within the nerve are thought to be replaced with fibrosis resulting in chronic pain.
What is the treatment for herpes zoster infection?
Nerve block for pain
Antivirals (Aciclovir / Valacyclovir) shorten the duration of the pain and reduce the incidence of post-herpetic neuralgia
What is valacyclovir?
Prodrug of acyclovir. Acts by inactivating viral DNA polymerase and therefore prevents viral DNA synthesis
What is the difference between CRPS 1 and 2?
1 = Reflex sympathetic dystrophy - implies no nerve damage
2 = Causalgia - implies nerve damage
What are the features of CRPS?
Pain syndrome affecting a limb with burning sensation associated with vascular and trophic changes (skin, hair, sweating and joint changes)
