Pseudobulbar and bulbar palsies

aka Neurological Mind-boggler 005

You have an emotionally labile patient in the department who sounds like ‘Donald duck’. Before rounding up some students to ‘pimp‘ you decide to test yourself on bulbar and pseudobulbar palsies so that you don’t get caught out…

Q1. What neurological lesions are involved in bulbar and pseudobulbar palsies?

A bulbar palsy is a lower motor neuron lesion of cranial nerves IX, X and XII.

A pseudobulbar palsy is an upper motor neuron lesion of cranial nerves IX, X and XII.

Q2. What are the clinical features of a bulbar palsy?

The clinical features include:

  • Gag reflex – absent
  • Tongue – wasted, fasciculations
    “wasted, wrinkled, thrown into folds and increasingly motionless”.
  • Palatal movement – absent.
  • Jaw jerk – absent or normal
  • Speech – nasal
    “indistinct (flaccid dysarthria), lacks modulation and has a nasal twang”
  • Emotions – normal
  • Other – signs of the underlying cause, e.g. limb fasciculations.

Q3. What are the clinical features of a pseudobulbar palsy?

The clinical features include:

  • Gag reflex – increased or normal
  • Tongue – spastic
    “it cannot be protruded, lies on the floor of the mouth and is small and tight”.
  • Palatal movement – absent.
  • Jaw jerk – increased
  • Speech – spastic: “a monotonous, slurred, high-pitched, ‘Donald Duck’ dysarthria”  that “sounds as if the patient is trying to squeeze out words from tight lips”.
  • Emotions – labile
  • Other – bilateral upper motor neuron (long tract) limb signs.

Q4. What are the causes of a bulbar palsy?

Causes include:

  • Motor neurone disease
  • Syringobulbia
  • Guillain-Barre syndrome
  • Poliomyelitis
  • Subacute menignitis (carcinoma, lymphoma)
  • Neurosyphilis
  • Brainstem CVA

Q5. What are the causes of a pseudobulbar palsy?

The commonest cause is bilateral CVAs affecting the internal capsule.

Other causes include:

  • Multiple sclerosis
  • Motor neurone disease
  • High brainstem tumours
  • Head injury

Check out the ‘Brainstem Rules of 4‘ for a (relatively) simple and useful way to understand the brainstem clinically.

References

  • Ryder RE, Mir MA, Freeman EA. An Aid to the MRCP Short Cases. Blackwell. 2nd edition, 1999.
  • Talley NJ, O’Connor S. Clinical Examination: A Systematic Guide to Physical Diagnosis. MacLennan and Petty. 3rd edition, 1998.
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Comments

  1. says

    What an awesome site! I am doing some research having been told to expect some pimping from our Paediatric Neurology consultant this coming Wednesday… Now I’m going to stalk through the rest of your resources. Thanks for sharing!

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