Guillain-Barre syndrome; Horners Syndrome; Facial Nerve Palsy Flashcards
Describe what is meant by Guillain-Barre syndrome [1]
What is it usually caused by? [3]
Guillain-Barré syndrome is an acute paralytic polyneuropathy that affects the peripheral nervous system. It causes acute, symmetrical, ascending weakness and can also cause sensory symptoms. It is usually triggered by an infection and is particularly associated with to Campylobacter jejuni, cytomegalovirus (CMV) and Epstein-Barr virus (EBV).
Describe the pathophysiology of GBS [2]
Guillain-Barré is thought to occur due to a process called molecular mimicry:
- The B cells of the immune system create antibodies against the antigens on the triggering pathogen.
- These antibodies also match proteins on the peripheral neurones.
- They may target proteins on the myelin sheath or the nerve axon itself.
- correlation between anti-ganglioside antibody (e.g. anti-GM1) and clinical features has been demonstrated; anti-GM1 antibodies in 25% of patients
Describe the clinical feature of GBS [+]
progressive weakness of all four limbs.
- The weakness is classically ascending i.e. the lower extremities are affected first, however it tends to affect proximal muscles earlier than the distal ones
Reduced reflexes
Neuropathic pain
Sensory symptoms tend to be mild (e.g. distal paraesthesia) with very few sensory signs. Some patients experience back pain in the initial stages of the illness
There may be peripheral loss of sensation or neuropathic pain. It may progress to the cranial nerves and cause facial weakness.
Autonomic dysfunction can lead to urinary retention, ileus or heart arrhythmias.
Lecture:
- Often involves cranial nerves (eyes - III/IV/VI and face – bilateral VIIth)
- Ascending weakness (Legs>arms) over days.
- Often starts with paraesthesiae in hands and feet + back pain
Describe the disease course of GBS [1]
Symptoms usually start within four weeks of the triggering infection. They begin in the feet and progress upward.
- Symptoms peak within 2-4 weeks. Then, there is a recovery period that can last months to years.
Describe the two types of GBS [2]
Describe the investigations for GBS [2]
The diagnosis of Guillain-Barré syndrome is made clinically (using the Brighton criteria), supported by investigations:
* Nerve conduction studies (showing reduced signal through the nerves)
* Lumbar puncture for cerebrospinal fluid (showing raised protein with a normal cell count and glucose)
Mx for GBS? [4]
Management:
* plasma exchange
* VTE prophylaxis (pulmonary embolism is a leading cause of death)
* IV immunoglobulins (IVIG): as effective as plasma exchange. No benefit in combining both treatments. IVIG may be easier to administer and tends to have fewer side-effects
* Plasmapheresis is an alternative to IVIG
* steroids and immunosuppressants have NOT been shown to be beneficial
* FVC regularly to monitor respiratory function
NB: Severe cases with respiratory failure may require intubation, ventilation and admission to the intensive care unit.
What do you need to rule out initially in a person with ?GBS? [1]
Rule out acute spinal cord compression presentation (MRI whole spine). Clinically early on mimics GBS.
What are the underlying causes of Horner’s syndrome? [2]
What’s the difference in cause between First, Second & Third order Horner’s? [2]
The underlying causes of Horner’s syndrome can vary, including tumours, injuries, or neurological disorders affecting the sympathetic nerves.
First-order (central) Horner’s
- lesion from hypothalamus to T1 spinal cord segment; causes include multiple sclerosis, brain tumours, and strokes (e.g., Wallenberg’s syndrome).
Second-order Horner’s
- lesion from spinal cord to superior cervical ganglion; causes include Pancoast tumours, thyroid malignancies, iatrogenic, and traumatic causes.
Third-order (postganglionic) Horner’s:
- lesion from superior cervical ganglion to the eye; causes include carotid artery dissection, cavernous sinus thrombosis, and cluster headaches.
Describe the clinical features of Horner’s syndrome [5+]
Anisocoria
* Miosis (constricted pupil) on the affected side
* Relative pupillary dilation lag in darkness (2-8 seconds)
Ptosis
* Partial ptosis due to weakness of Muller’s muscle
* Involvement of levator palpebrae superioris may lead to more pronounced ptosis
Facial Anhidrosis and Vasodilation
* Ipsilateral loss of sweating (anhidrosis) over forehead, face, and neck regions
* Facial vasodilation due to loss of sympathetic tone
Heterochromia Iridum (in congenital cases)
* Lighter iris colour in the affected eye compared to contralateral eye
* Due to a lack of melanin deposition during development
Enophthalmos (rare)
* Slight posterior displacement of the eyeball within the orbit
* Attributed to the loss of sympathetic innervation to orbital smooth muscles
Which structures are specifically innervated (and therefore affected) in Horner’s syndrome? [3]
Structures innervated: Dilator pupillae (pupil dilation), superior tarsal muscle (upper eyelid elevation), sweat glands.
How do you confirm Horner’s? [1]
The presence of systemic features with Horner’s can help guide the identification of lesion location and inform further investigations. For example, patients with cough and weight loss should undergo a chest X-ray to screen for a Pancoast tumour.
Apraclonidine is now the commonly used alternative to confirm Horner’s, which reverses the pupillary constriction in Horner’s due to its agonistic effect on alpha-2-receptors.
Hydroxyamphetamine drops can subsequently be used to identify the location of the lesion to guide imaging. Hydroxyamphetamine will dilate a constricted Horner’s pupil if there is an underlying preganglionic lesion (first or second-order).
If the pupil fails to dilate, this suggests that the lesion is in the third order or postganglionic neuron.2
Describe the features of central lesions of Horner’s [1]
What are the specific causes? [5]
Anhidrosis of the face, arm and trunk
Stroke
Syringomyelia
Multiple sclerosis
Tumour
Encephalitis
Describe the features of pre-ganglionic lesions of Horner’s [1]
What are the specific causes? [4]
Anhidrosis of the face
Pancoast’s tumour
Thyroidectomy
Trauma
Cervical rib
Describe the features of post-ganglionic lesions of Horner’s [1]
What are the specific causes? [4]
No anhidrosis
Carotid artery dissection
Carotid aneurysm
Cavernous sinus thrombosis
Cluster headache
Describe the path of the facial nerve from brainstem [3]
The facial nerve exits the brainstem at the cerebellopontine angle.
On its journey to the face, it passes through the temporal bone and parotid gland.
It then divides into five branches:
* Temporal
* Zygomatic
* Buccal
* Marginal mandibular
* Cervical
What does the facial nerve supply? [4]
- What is the motor [3]; sensory [1] and parasympathetic [2] functions?
Supply - ‘face, ear, taste, tear’
face: muscles of facial expression
ear: nerve to stapedius
taste: supplies anterior two-thirds of tongue
tear: parasympathetic fibres to lacrimal glands, also salivary glands
Motor function for:
* Facial expression
* Stapedius in the inner ear
* Posterior digastric, stylohyoid and platysma muscles
Sensory function for taste from the anterior 2/3 of the tongue.
Parasympathetic supply to the:
* Submandibular and sublingual salivary glands
* Lacrimal gland (stimulating tear production)
How do you distinguish between upper and lower motor neurone lesions with ?Horners
Each side of the forehead has upper motor neurone innervation by both sides of the brain.
However, each side of the forehead only has lower motor neurone innervation from one side of the brain.
The forehead will be spared in an upper motor neurone lesion so the patient can move their forehead on the affected side
In a lower motor neurone lesion, the forehead is not spared, and the patient cannot move their forehead on the affected side.
Patients with new-onset upper motor neurone facial nerve palsy need immediate management as a possible stroke. In contrast, patients with lower motor neurone facial nerve palsy can be managed less urgently.
Unilateral upper motor neurone lesions occur in: [2]
Bilateral upper motor neurone lesions are rare. They may occur in [2]
Unilateral upper motor neurone lesions occur in:
* Cerebrovascular accidents (strokes)
* Tumours
Bilateral upper motor neurone lesions are rare. They may occur in:
* Pseudobulbar palsies
* Motor neurone disease
Mneumoinic for bilateral facial nerve palsy? [4]
Bilateral facial nerve palsy- Both Sides Go Low
B - Bell’s palsy
S - Sarcoidosis
G - Guillain Barre syndrome
L - Lyme disease
BUT - Be aware that although Bell’s palsy is able to cause bilateral facial nerve palsy it is much more common as a unilateral pathology.
Pathophysiology of Bells palsy?
Inflammation and oedema of the facial nerve → compression and damage to the nerve in the facial canal (passage of the nerve through the temporal bone) → symptoms of facial paralysis on the affected side.
Describe the presentation of Bell’s palsy
Acute onset (within 72 hours)
Involves the forehead and lower parts of the face on the affected side
* Upper facial signs include the inability to wrinkle forehead and close eye fully on the affected side
* Lower facial signs include the loss of the nasolabial labial fold, and drooping of the mouth, which is more pronounced when the patient tries to smile
* The severity of the paralysis can be quantified by the House-Brackmann facial paralysis scale, which is graded from 1 (normal) to 6 (complete paralysis).
Pain in the ear and surrounding area
Loss of taste in the anterior tongue in 35% of patients
Hyperacusis (increased sensitivity to noise) is a rarer symptom
Describe the investigations for Bell’s palsy? [+]
Bell’s palsy is usually a diagnosis of exclusion
Therefore a comprehensive clinical review is required -
Examination
* Forehead sparing suggests an upper motor neurone cause and therefore not Bell’s palsy, which is a lower motor neurone pathology.
* Any masses, particularly parotid swelling may suggest a tumour.
* Any other cranial nerve abnormalities or neurology of the upper or lower limbs may suggest a central or systemic pathology.
Imaging should be used if clinical features are not in keeping with Bell’s palsy or the patient is not recovering as expected.
* MRI Head is the modality of choice to view the facial nerve.
How would a stroke present similarly / differently to Bell’s palsy? [2]
Similarities - present with unilateral facial droop
.
Differences - there will be sparing of the forehead (patient will still be able to frown) as this is an upper motor neurone lesion and may also be accompanied by weakness of the arm/leg on the affected side, slurred speech and visual disturbances.
Describe the management plan for Bell’s palsy
Prednisolone for patients who present within 72 hours of symptom onset.
- Antivirals can be considered for use in conjunction with prednisolone (should not be used as monotherapy).
Good eye care is very important on the affected side as the inability to completely close the eyelid can cause dry eyes and other complications:
* Artificial tears or ocular lubricants to prevent dry eyes.
* Using tape (e.g.micropore) to close the eye overnight.
* Wearing sunglasses and avoiding irritants to the eye such as dust.
* If a patient has eye pain or irritation, they should be referred to ophthalmology (secondary care) for review as these patients are at risk of problems such as corneal ulceration which can lead to visual loss if not treated correctly
Describe disease course of Bell’s palsy and what this means clinically [2]
The majority of patients will recover with the acute management measures.
However, if no signs of recovery are seen after 3 weeks of initial symptoms (i.e. no improvement in House-Brackmann score), NICE recommends referral to secondary care (either to ENT or neurology) for further investigation and management.
Therefore it is very important that all patients diagnosed with Bell’s Palsy have a follow-up appointment arranged to monitor recovery.
What are the indications for referral to secondary care? [4]
- No recovery after 3 weeks of initial symptoms
- Worsening neurology or new neurology developing despite treatment initiation.
- Any signs of an upper motor neurone lesion.
- Signs of abnormal reinnervation of the facial nerve as the patient recovers.
While the majority of Bell’s palsy cases resolve spontaneously, a number of complications can occur. The most common complications are: [2]
Synkinesis:
- This is characterised by involuntary muscular movements accompanying voluntary movements. It occurs due to aberrant regeneration of the facial nerve and may present as crocodile tears syndrome (lacrimation during eating), gustatory sweating or hemifacial spasm.
Persistent facial weakness:
- Despite treatment, some patients may experience persistent facial weakness which can lead to functional impairment and cosmetic concerns. Severity varies from mild to severe disfigurement.
Bell’s palsy can also lead to several ocular complications including [3]
Corneal keratitis: Due to impaired eyelid closure, corneal exposure may result in desiccation, ulceration or even perforation if not managed promptly.
Lagophthalmos: Inability to close the eye completely could lead to exposure keratopathy.
Abrasive keratopathy: This results from irregular blinking leading to trauma on the corneal surface.
