Neuropathic pain and Atypical Odontalgia Flashcards
What are the different pain assessments used when investigating facial pain?
Physical symptoms
-> PAIN scores (McGill)
Emotional symptoms
-> Psychological scores (HAD)
QOL scores (OHIP)
What pain assessments can be used to investigate severity of pain in children?
Face modified pain scales
Linear analogue scales- mark on line what level of pain you experience (10cm long)
Lego pain assessment tool
What occurs in nociceptive pain?
Acute pain
- Stimulus (inflammation) causes pain to pass into CNS and be perceived
What occurs in neuropathic pain?
Pain perception generated beyond nociceptor
- Pain stimulus is generated beyond nociceptor
- Damage has occurred to pathway sending pain signal to brain (dysfunction)
- Patient feels pain- but connect wrong tissue even although this has nothing wrong with it (mimics pain in other regions)
What causes stroke pain?
Damage has occurred to nerve pathways in brain resulting in pain signals passing through pain nerves from damaged section leading to it being perceived as somatic pain when it is in fact damage within CNS
What occurs in diabetic neuropathy?
Nerve damage due to change in vascular supply to peripheral nerve
- Patient feels pain from tissue supplied by damaged nerve even although tissue is healthy (neuropathic pain)
What occurs in Post Herpetic Neuralgia
Herpetic lesions damage nerves in which it is living
- Symptoms from vesiculation in peripheral tissues is experienced due to virus
- After lesions resolve the pain continues
- Aim to limit damage at time patient presents- consequences in subsequent months can be reduced
What are the features of neuropathic pain?
- Constant burning/aching- nerve damage present all the time
- Fixed intensity- damage to nerve remains the same
- Fixed location- nerve damage equates to particular tissue
What are the genetic abnormalities that can lead to neuropathic pain?
Predisposed susceptibility to nerve damage
Inheritance of different types of ion channel within nerve structure
What are the common types of neuropathic pain?
Diabetic peripheral neuropathy
PHN
Cancer-related pain
Spinal cord injury
Chronic regional pain syndrome
MS
Phantom limb pain
Stroke pain
HIV-associated pain
TN
What are the causes of neuropathic pain?
Follows history of injury:
Facial trauma
Extractions
‘routine’ treatment without complications
Herpes Zoster (Shingles) episode
-> POST HERPETIC NEURALGIA
Can follow destructive treatment for pain
What causes neuropathic pain to be present even when injury has healed?
- Nerve has been damaged and heals in a way that causes constant input of signal into CNS
- If relatively minor event that has caused initial damage- problem is likely to get worse as it would cause more damage to tissue and nerves
What is destructive treatment in neuropathic pain, what are the drawbacks?
Damage nerve supplying area of pain causing numbness (no sensory input so shouldn’t get pain)
If this nerve is not fully damaged it can regenerate and heal leading to original neuralgic pain returning and neuropathic pain from damage to nerve
What systemic medications are used to treat neuropathic pain?
Use gabapentin/pregabalin/TCAs- reduce pain transmission within CNS (reduce effect of signal being passed to central appreciation by slowing pain signalling in brain)
Valproate
Mirtazepine
Opioid analgesics
What is topical treatment of neuropathic pain based off?
Gate hypothesis- use of peripheral stimulation
-> medication causes sensory nerve activation over area of pain which helps gate off pain signals coming from neuropathic damage
What topical medicines are used in treatment of neuropathic pain?
Capsaicin (depolarisation of peripheral nerve)
EMLA
Topical lignocaine- irritates surface nerves and helps gate off pain perception
Ketamine
Benzdamine
What physical treatments can be helpful for neuropathic pain?
TENS (low frequency)- electrical stimulation of area causing the pain
-> Gates pain off by electrical modification by sensory nerves
Acupuncture- allows opioids to reduce transmission within CNS
-> Only helps for short duration
Why is psychological treatment helpful for neuropathic pain? What can be done?
As pain is designed to catch attention of individual (especially if it passes through basal ganglia)
-> Training patient to distract themselves can be helpful- less intrusive if they don’t pay attention to it (behaviour change)
-> correction of abnormal illness behaviour
-> improve outlook/self esteem
Psychologists are part of pain MDT
-> May be more beneficial than pharmacological treatment
What is Atypical Odontalgia?
Dental pain without dental pathology
- Patient will report information that sounds like dental pathology (acute pulpitis) but on examination you find health (can be hard if patient has heavily restored dentition)
- Follows no particular characteristics/trends
How does atypical odontalgia differ from pulpal pain?
Intense unbearable pain lasts 2-3 weeks then settles spontaneously (pain free period between episodes)
-> different from pulpal pain which continues until treated (*unless pulp necroses)
What can happen when a patient presents with dental pain which the dentist does not realise is being caused by Atypical Odontalgia?
Dental treatment (RCT)is carried out as the patient has described pain of an acute pulpitis then pain returns after short time
- Can lead to dentist thinking they have missed a canal or not fully removed the pulp and retreating the tooth to help settle the pain
- This may lead to extraction as patient feels pain to be unbearable
- The patient can then come back in a few weeks with pain in adjacent tooth leading to belief from patient that they took out wrong tooth (dentist may believe this)
- Same pattern occurs- many teeth may be extracted as a result of atypical odontalgia (contact oral medicine if you start to suspect it)
- As toothache settles it can feel like intervention was successful
What checks/tests can dentists do to help diagnose Atypical Odontalgia?
Check for hyperocclusion- fix if present
Check radiographs for signs pf pathology
Sensibility test to see if tooth vital
Attempt Endodontics and see if pain persists
Anaesthetic tests
What should a dentist do in primary care if they suspect AO?
Refer to oral medicine
How is AO managed in OM?
- Reduce number of episodes
- Reduce chronic pain severity- gabapentin
- Opioids analgesics are effective for pain- high doses when needed for short burst of neuropathic pain which lasts 2 weeks
- Patient may want tooth still to be extracted as they feel like they cannot bear to continue with tooth (done by OM team)
What is Persistent Idiopathic Facial Pain?
Pain which poorly fits into standard chronic pain syndromes:
Neuropathic
CRPS
TMD
Trigeminal Neuralgia
Migrainous Pain
Atypical odontalgia
Diagnosis if cause of pain is not known
Often high disability level – autonomic component
What is unusual about where pain is felt in PIFP?
Felt in areas of common Embryological origin of tissue- if neuropathic/autonomic problem all the tissues of the same origin may feel pain
How is PIFP managed?
Clinical psychology
-> Patients may become depressed due to pain (not depression causing pain- treating mental health will not help)
Surgery is not helpful
Monitor quality of life and disease impact
-> use of pain scores
Suggest that you are trying to improve life rather than pain (reducing pain even slightly can help them cope)
-> Be realistic with patient, let them know what would be considered a success
