Multiple Cranial Nerve Palsies

Question 1

Describe how you know where a lesion is based on the symptoms/signs at the eye in multiple cranial nerve palsies?

Answer 1

• More nerves affected must be closer to eye
• CS, SOF – where everything gathers before it comes in eye
• Problem closer to eye – likely to get proptosis
  o If unilateral proptosis – then in CS or orbital cavity
  o If bilateral proptosis – then thyroid eye disease
• Tumours happening close to the eye will give proptosis
• SOF syndrome – can be inflammatory
• Tolosa Hunt Syndrome – granulomatous syndrome – but benign
  If in Cavernous Sinus (CS) then vision will be unaffected but eye cannot move

Question 2

What are the causes of multiple cranial nerve palsies (MCNP)?

Answer 2

• Combined or multiple cranial nerve paresis (MCNP) can occur due to a variety of different causes such as some syndromes or systemic diseases, extracranial or intracranial pathologies (brain stem, meninx, & base of skull (BoS)
  o 1-6CN paresis including CN III, IV, V, VI & VII are eye-associated MCNP
• Common causes of eye-associated MCNP often include cavernous sinus syndrome (CSS), superior orbital fissure syndrome (SOFS), Tolosa-Hunt syndrome (THS) & orbital apex syndrome (OAS)
• Other common causes (in frequency order):
  o Infarctions
  o Tumour near eye must be treated
  o Infection
  o Guillain-Barre Syndrome – systemically v unwell – v bad virus
  o COVID can affect any nerve so could be viral
  o Miller Fisher syndrome
  o Idiopathic cavernous sinusitis
  o Surgery
  o Multiple sclerosis
  o Demyelinating encephalomyelitis
  o Diabetes mellitus
  o Could be trauma – blow-out fracture

Question 3

Describe Cavernous Sinus Syndrome (CSS)/Carotid Cavernous Sinus (CCS) - including signs and aetiology?

Answer 3

• CS is a venous plexus located between periosteal & dural layers of the meninx & at central BoS, on both sides of pituitary gland
• Signs:
  o Ophthalmoplegia (w/ a red eye) – immediately think CS is affected
   Eye will not move, it may have lost sensation but it can still see well
  o Ptosis & facial sensory loss (because of trigeminal supply)
  o Proptosis
  o Orbital (ocular & conj) congestion
  o Sympathetic disturbance
  o Horner’s syndrome due to MCNP of CN III, IV & VI responsible for ocular movements & pupillary function & at least one branch of CNV
  o CSS does not involve optic nerve
• Tumours that grow here are often aggressive & carcinogenic
• Aetiology:
  o Most common cause – neoplastic (metaplastic including ead & neck tumours & primary tumours such as lymphoma)
  o Traumatic vascular – aneurysms, fistulas, thrombosis
  o Congenital
  o Infectious – fungal infection
  o Inflammatory or granulomatous pathologies involving CS
  o Tolosa Hunt syndrome (THS)
  o Idiopathic granulomatous inflammation involving CS

Question 4

What is an alarm bell with multiple cranial nerve palsies?

Answer 4

Unilateral proptosis

Question 5

Describe superior orbital fissure syndrome (SOFS) - including aetiology & clinical features?

Answer 5

• Superior orbital fissure (SOF) lies at back of orbit between lesser & greater wing of sphenoid bone
• SOF contains SOV & IOV, superior & inferior branches of CN III, IV, VI, V1 and its branches including lacrimal, frontal, supraorbital, supratrochlear & nasociliary nerves
• SOFS is a symptom complex caused by compression of structures which exist in SOF just anterior to orbital apex
• Main difference of SOFS from OAS is no optic nerve involvement in SOFS
• Aetiology:
  o Known that most common cause of SOFS is trauma (craniomaxillofacial injury) including Road Traffic Accident’s (RTAs), zygomatic & orbital fractures
  o Tumours including lymphoma & rhabdomyosarcoma
  o Infectious diseases including syphilis (syphilitic periostitis)
  o Meningitis
  o Sinusitis
  o Herpes Zoster
  o Ischaemic
  o Vasculitis and Inflammatory diseases – THS, sarcoidosis, systemic lupus or temporal arteritis
  o Vascular events including carotid-cavernous fistulas (CCF), retro-orbital haematoma& carotid aneurysm
  o Idiopathic
• CN VI is most commonly damaged due to its location in central SOF & close to greater wing
• CN IV is least commonly involved CN because of its protection by common tendinous ring
• Clinical Features:
  o Ophthalmoplegia due to damage to CN III, IV, & VI
  o Ptosis due to CN III injury & loss of sympathetic input
  o Proptosis due to decreased tension in EOMs with loss of innervation
  o Fixed dilated pupil due to loss of parasympathetic innervation of pupil by CNIII
  o Lacrimal hyposecretion (dry-eye type symptoms) & eyelid or forehead anaesthesia & decreased corneal sensation due to damage to CN V1
  o Chemosis & bruits (hear a whooshing sound – too much blood supply) caused by vascular congestion & occasionally visual loss due to mechanical compression of CN II
  o The proptosis, eyelid swelling & chemosis indicate significant orbital masses

Question 6

Describe Tolosa Hunt Syndrome?

Answer 6

• Painful ophthalmoplegia in 5th decade w/ unknown aetiology located in SOF & anterior CSS
• Cause of pain is granulomatous inflammation due to infiltration of walls of SOF or CS by lymphocytes & macrophages
• If pain reduces with steroid treatment within 72 hours it is diagnostic
• Not malignant – inflammatory, treated with steroids
• Inflammatory syndrome
• Respond well to steroid

Question 7

What do you do assume in a patient that does not present with trauma but has multiple cranial nerve palsies?

Answer 7

If px does not present with trauma, then have to assume it is a tumour

Question 8

What happens when tumour/trauma affects orbital apex?
If vision is affected, where is the lesion? If vision not affected, where is the lesion?
Which bone is likely to be affected in a traumatic fracture?
Which conditions are suggested by pain on eye movements?
What is the cause if there is pain involved?
Whatdoes fistula mean?

Answer 8

Once tumour/trauma affects orbital apex then vision is gone
If vision is affected then lesion/tumour in orbit, if vision is not affected then lesion in CS or SOF
Sphenoid bone is likely to be affected in a traumatic fracture
What is the cause of the proptosis? – Compression of optic nerve? Mechanical vs neurogenic?
If pain on eye movements then ocular myositis or Tolsa-Hunt Syndrome
If pain is involved then means it is inflammatory
Fistula – too much blood supply going to it

Question 9

Describe orbital apex syndrome (OAS) and the causes?

Answer 9

• Orbital apex (OA) is most posterior part of pyramidal shaped orbit at craniofacial junction
• OA includes tendinous ring (where rectus EOMs originate) & entry of neuro-vascular structures transmitted from intracranial compartment into orbit through bony apertures (optic canal, SOF & inferior orbital fissure)
• OAS characterised by involvement of CNs II, III, IV & VI
• Vision loss (if CN II involvement is present), optic neuropathy & ophthalmoplegia
• Causes:
  o Nasopharyngeal carcinoma
  o Haematological tumours
  o Neural tumours
  o Lymphoma
  o Metastasis or middle cranial fossa (near the apex of the orbit)
  o Inflammatory causes such as idiopathic orbital inflammation, collagen vascular disease, sarcoidosis, systemic lupus, giant cell arteritis, thyroid disease
  o Iatrogenic causes (following sinonasal surgery)
  o Orbital apex fracture
  o Vascular events like carotid aneurysm or trauma