Week 12- Dysaesthesia & Atypical Facial Pain Flashcards
What is dysaesthesia?
Descriptive term
Abnormal unpleasant sensation (when touched) due to damage to peripheral nerves.
What are the differences between dysesthesia and atypical facial pain?
Dysesthesia: descriptive term, myriad of aetiologies, tx depends on cause, outcome depends on aetiology.
Atypical facial pain: a clinical entity, aetiology is hypothetical, tx is difficult and outcome is speculative
What is a syndrome?
Group of several things that occur together that don’t appear to be related
Where is fluid located in oedema?
Fluid is interstitial
What are the most frequent causes of iatrogenic neuropathies in dental practice?
- 3rd molar surgery: IAN, lingual, long buccal nerve
- Md nerve blocks: IAN, lingual nerve
- Implant insertion
How can you avoid iatrogenic neuropathies in dental practive?
- Pre-op assessment (IOPA, OPG, CBCT, CT)
- Operative technique
- Darkening of root of 8’s and narrowing of IAN canal in OPG indicates superimposition of root and IAN canal.
Does CBCT reduce risk of iatrogenic neuropathy in 3rd molar exo’s compared to using just OPG?
No. It allows us to risk stratify but it does not change what happens to the patient.
What are LA-associated neurosensory disorders associated with?
IAN blocks (>90%)
4% solution LA
What are the disturbances of dysesthesia following IAN block?
- Funcitonal difficulties
- eating
- drinking
- speaking
- Sensory issues
- paraesthesia/anaesthesia
- allodynia (extreme sensitivity)
- pain (spontaneous or provoked)
- tingling
- burning
- formication (ants crawling)
What are the methods for evaluating patients with dysesthesia?
- Area affected (dermatomes)
- Subjective function
- Light touch
- Sharp-blunt discrimination
- 2 point discrimination
What is dysaesthesia caused by?
Occurs due to abnormality in neuronal function (either peripherally or centrally). Pathophysiology varies according to cause.
What is the definition for neurology, neurogenic and neuropathy?
- Neurogenic: arising from nerves
- Neuropathic: disease affecting nerves
- Neurological: associated with nerves
What are non-iatrogenic causes of dysaesthesia?
More common in general population
- Diabetes
- Excess alcohol
- Nutritional
- Drugs
- MS
What can happen when nerves are injured?
Depends on type and degree of injury
- Wallerian degeneration: nerve cut completely and distal part degenerates
- Inside-out progression: when nerve is stretched there is physiological disturbance (Na and K channels) and then structural disturbance (axons and sheath degenerate)
What does the degree of injury indicate?
Can be indicative of extent to which return to normal can be expected and can also guide management
What happens when the tiny blood vessels running along nerves are damaged?
Doesn’t take much stretch to cause damage and needles can pierce the vessels leading to intra-neuronal hematoma and increase in internal pressure and thrombosis. Normal conduction doesn’t happen and that area of nerve can become ischaemic. Pt will go numb. No way of imaging this.
What is neuropraxia?
Injury to peripheral nerves causes burning, stinging and pain. Typically heal on their own
What is axonotmesis?
More severe type of peripheral nerve injury and usually is caused by crush, stretch, or percussion.
What is neurotmesis?
Complete transection of a peripheral nerve
What are the types of facial pain?
- Headaches
- tension headaches
- myofascial pain/headaches
- Neuralgias
- trigeminal neuralgia
- post-herpetic neuralgia
- atypical facial pain
What is the new term for atypical facial pain?
Persistent idiopathic facial pain?
When does atypical facial pain often arise?
After minor operation or injury to face
What is the definition of atypical facial pain?
Persistent facial and/or oral pain with varying presentations but recurring daily for >2 hours/day or >3 months in the absence of clinical neurological deficit.
What are the most frequent features of a pt diagnosed with AFP?
- Female
- 40’s
- Not hormonally related
- Sleep not disturbed (no pain when they wake up unlike myofacial pain)
- Pain free interval after waking
- Very rare
