Saturday 13 January 2007

Wallenberg Syndrome

This is an anonymised case of Wallenberg (Lateral Medullary) Syndrome, passed to me from another institution, in an elderly male patient whom had otherwise been of good health.

He had complained of sudden onset vertigo and nausea with vomiting. He described being unable to stand properly and he fell towards the right side. He also described double vision. He did not describe any subjective sensory abnormality or any limb weakness.

He had no previous medical history and took no regular medications.

He is a non-smoker and drinks occasional alcohol.

On examination, he was afebrile and looked well, pulse was regular and good volume, respiratory rate was 14 per minute and oxygen sats were 96% on room air.

His PNS examination was remarkable.

Tone was normal but he had a Left Pronator drift (consistent with an upper motor neurone defect). Power was 5/5 in the upper and lower Right limbs, but 4+/5 in the left upper and lower limbs albeit that his left side is the Non-Dominant side.

He was generally areflexic throughout.

However, the modality that had been alluded to was SENSORY testing and this revealed decreased sensation to light touch and painful stimuli (nociception) on the Left side.

His Right Plantar response was normal and the Left was Unresponsive.

Examination of his CNS revealed a Right sided Ptosis. Decreased sensation to both light touch and nociception of the RIGHT side of his face. His swallow reflex was normal.

Cerebellar examination revealed
rotatory nystagmus on the Right side and some mild horizontal nystagmus to the left. The patient had past-pointing on the Right side and dysdiadochokinesis was negative.


In summary, the Clinical Findings showed:

1) Dissociated sensory deficit (loss of sensation on the right face and left body)

2) Positive Cerebellar signs suggestive of a Right Sided Cerebellar Insult

3) Horner's Syndrome on the Right


4) Areflexia


5) Mild left sided weakness (although, this may be a natural difference due to it being the non-dominant side)


6) Vestibular dysfunction (symptoms of vertigo/nystagmus)


These above symptoms and clinical signs were consistent with a diagnosis of Wallenberg Syndrome (this diagnosis had also been confirmed by a very astute neurologist) a somewhat rare diagnosis, and this case will forever be in my mind as a typical case.

His CT scan showed a small infarct in his lower medulla and the MRA was non-diagnostic, nor was the diffusion MRI.

It reinforces for me that history and physical are a superb way to find out the problem, and putting all the pieces of the jigsaw together one can form the diagnosis where a scan may be unhelpful or at least difficult to interpret. Physical examination can show the physician where the problem is likely to be, and even if the scan is negative, the physical signs cannot be ignored nor should they be, as they will tell the doctor that the problem is present. Repeated physical examination will also tell the doctor whether the patient is getting better or worse!!

This patient was commenced on anti-platelet therapy and underwent rehabilitation.

A really great case!!


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