Bell’s Palsy Flashcards
What is Bell’s palsy?
Complete paralysis of one half of the face is a LMN lesion, Bell’s palsy. It’s a clinical diagnosis that doesn’t require investigation if there are no other neurological symptoms. The cause is unknown - viral aetiology suspected.
What advice should be given to a patient with Bell’s palsy?
- Steroids given early in the disorder has shown to help (ibuprofen within 72hr onset, prednisolone 1mg/kg for 10 days)
- Tape the eye closed at night to prevent corneal damage
- Facial weakness can worsen in first few days
- Most make complete recovery in 4-6 months
- Time taken to recover depends on severity of initial weakness
- Recurrence is uncommon
What is facial synkinesis?
Activation of one muscle in the face triggers another muscle to activate, causing involuntary movements.
What is crocodile tear syndrome?
The nerve that is supposed to supply the salivary gland gets damaged and regrows into a tear duct, causing tears to flow and sweating. Treatment usually not needed but can give botulin toxin therapy and facial physiotherapy.
How do you differentiate between stroke and Bell’s palsy?
- Typically stroke causes an UMN facial weakness, nearly always with involvement (UMN weakness) of the ipsilateral arm and often leg
- Stroke will come on suddenly and Bell’s palsy over a period of hours to days
- Stroke comes on without warning, Bell’s palsy can have warning sign like hearing change (hyperacusis), taste
- There are no other clinical signs in Bell’s palsy e.g. double vision, no weakness elsewhere
- In a stroke there is forehead sparing, can move eyebrows + close eyes
What is Ramsay Hunt Syndrome?
A complication of shingles and describes the symptoms of a shingles (Varicella Zoster Virus) infection affecting the facial nerve - it gets inflamed and irritated. Typically associated with painful vesicles affecting the external ear and occasionally the palate.
What causes reactivation of the VZV?
- Immunocompromised
- Stress
What are the symptoms of VZV?
- A rash or blisters in or around the ear, scalp or hair line. Blisters may also appear in the mouth.
- Rash/blisters often painful (burning sensation) - hearing loss on affected side, dizziness, vertigo, tinnitus
- Complete weakness on affected side of face
- Altered taste on affected half of tongue (chorda tympani nerve affected)
- Difficulty eating, drinking and speaking due to weakness in lip and cheek on affected side
- Ear, face or head pain
What happens if you don’t have the rash in VZV?
Some people don’t get the rash. Alert doctor if you’ve got chronic facial pain and have been diagnosed with Bell’s palsy.
What investigations do you do for VZV?
- History and exam of facial nerve/ear
- Bloods - antibodies against VZV
- Hearing tests
- MRI to identify areas of inflammation along the track of facial nerve
What is the treatment for VZV?
- Antivirals within 72 hours of symptom onset e.g. acyclovir (the faster the better the recovery)
- Short course high dose steroids
- Painkillers
What do you want to know in a history with the presenting complaint of foot drop?
- Enquire about back pain, especially any radiation to the leg. Do they have any numbness/tingling? Any bladder symptoms?
- Could this be a consequence of problems in the lumbar spine? Is there any history of trauma?
- Have they been involved in any unusual activity prior to onset of symptoms?
What are the differentials for foot drop?
- Femoral nerve palsy: weakness of knee extension and loss of knee jerk, sensation typically affected along medial side of leg
- L3-4 radiculopathy: knee extension weakness and reduced knee jerk on affected side
- L5/S1 radiculopathy: worsening back pain, CN and upper limbs normal, weakness of dorsiflexion, reflexes present at knees but absent at ankles.
- Common peroneal nerve palsy (CPN) is typically painless, the ankle reflex is preserved and often occurs after a period of unaccustomed activity involving prolonged kneeling.
Describe the function of the common peroneal nerve
- Winds around fibular head and is susceptible to compression at this site, especially in the setting of activities involving prolonged/repeated knee flexion
- The CPN innervates tibialis anterior (responsible for ankle dorsiflexion) and the peroneal muscles (evert the foot) but not tibialis posterior (tibial nerve).
- It does not subserve the ankle reflex so this is spared
What is the most commonest cause of a foot drop?
Prolapsed intervertebral disc, causing compression of the L5 root. The L5 root contributes a significant number of fibres to the tibialis anterior, peroneal muscles and tibialis posterior so there is weakness of both inversion and eversion of the foot.
Often there is also compression of S1 so there will be loss of the ankle reflex.
