a)    List four causes and four clinical features of pseudo-bulbar palsy. (60% marks)
 

b)    With regard to injury of the cervical spine, what are the key clinical findings that would differentiate a complete C3/4 injury from a complete C6/7 injury?    (40% marks)
 

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College answer

a)

Causes: (any four)                                                                                (2 Marks)

    • Bilateral strokes (Internal Capsule Infarcts)
    • Multiple sclerosis
 
    • Progressive Supranuclear Palsy
    • Parkinsons Disease
    • Multisystem Atrophy
    • Amyotrophic Lateral Sclerosis (motor neuron disease)
    • High brainstem tumours
    • Head Trauma

Clinical Features: (any four)                                                                    (4 Marks)

    • Facial expressions: absent (expressionless face)
    • Speech: spastic dysarthria (husky, nasal voice)
    • Difficulty in chewing
    • Dysphagia, drooling, and nasal regurgitation
    • Tongue : Spastic, pointed; Difficulty in tongue protrusion due to spasticity (No wasting/ fasciculations)
    • Palatal movement: absent
    • Gag reflex: brisk (exaggerated)
    • Jaw jerk: exaggerated; clonic
    • Emotional lability (pseudobulbar affect)

b)

What are the key clinical findings that would differentiate a complete C3/4 injury from a complete C6/7 injury? (4 marks)

C3/4

C6/7

Motor function

  • 4 limb tetraplegia
  • Intact        shoulder       shrug (deltoids)
  • No power in UL or LL
  • Variable weakness of wrist flexion, elbow extension and hand function depending on the level
  • Preserved elbow flexion and shoulder girdle
  • Absent lower limb power

Reflexes

o Absence of all reflexes in upper and lower limbs

  • Biceps intact
  • Brachioradialis may be present
  • Triceps and LL absent

Sensation

  • Sensory level at C4 (Runs just below clavicles but can extend to nipple line)
  • Absent sensation in UL and LL
  • Sensory level at C7 with preservation of sensation over forearm and radial aspect of hand (thumb side)
  • Loss or reduced sensation affecting middle finger, lateral aspect of hand

and medial aspect of forearm

Respiratory

o Phrenic nerve affected with weak diaphragm and reduced vital capacity

o Phrenic nerve preserved, maybe mild or no reduction in VC depending on effect on other respiratory mechanics

Examiners Comments:

Answers generally lacked enough detail and were poorly structured.

Discussion

It was something of a surprise to the author, when he discovered that the words "spastic", "spasticity" and "jaw" were hyperlinked to amboss.com in the college answer. This easter egg is of course unintentional, because the content of the answer was a lazy cut-and-paste from this article, and Word preserves hyperlinks.  

  a)  The best article to cover this briefly turned out to be the pseudobulbar palsy chapter from StatPearls (NIH)

Causes:

  • Vascular problems:
    • Stroke (bilateral thalamic infarct)
  • Infection:
    • Classically, neurosyphilis
    • Cerebral malaria
  • Neoplasm 
    • Large petroclival meningioma
  • Drug-induced:
    • Methorexate-induced neurotoxicity
  • Primary neurological problems
    • Myotrophic lateral sclerosis
    • Multiple sclerosis
    • Parkinson disease
    • Progressive supranuclear palsy
    • Progressive multifocal leukoencephalopathy
  • Congenital causes:
    • Congenital malformations of the opercular or insular cortex
  • Autoimmune cauises:
    • Autoimmune encephalitis
    • Hashimoto encephalopathy
  • Trauma
    • Traumatic brain injury
  • Electrolyte abnormalities:
    • Central pontine myelinolysis

Clinical features:

  • Dysarthria
  • Dysphagia
  • Dysphonia
  • Hypernasal voice, slurred speech
  • Paralysis of the tongue
  • Weakness of the mastication muscles
  • Paralysis of facial muscles
  • Emotional lability (pseudobulbar affect); classically,  pathological laughter
  • Trismus
  • Exaggerated facial cranial nerve reflexes (suggesting an upper motor neuron cause)
    • Brisk jaw jerk
    • Retained or increased palatal reflexes.
    • No atrophy or fasciculations of the affected muscles 

b) 

C3/C4:

  • Motor:
    • Motor power is lost except for shoulder shrug (spinal accessory nerve)
    • Phrenic nucleus is affected: motor power is lost to diaphragm, i.e. spontaneous breathing is impossible
  • Sensory:
    • Sensation below the clavicles is absent

C67/C7: 

  • Motor:
    • Elbow flexion and wrist extension is preserved
    • Motor supply to the diaphragm is preserved
  • Sensory:
    • Sensation is present at the C6/7 level, which could include most of the lateral arms, thumb, index and middle finger

References

Saleem, Fatima, and Sunil Munakomi. "Pseudobulbar Palsy." (2020).