Cases for finals #2 – Examination

Speech slurred – dysarthric

Higher mental function (HMF) – normal

“Cranial nerves”:

  • bilateral ptosis – left more than right
  • restricted upgaze in left eye; restricted abduction bilaterally
  • lower facial weakness
  • palatal movements poor

Limbs – normal

Gait – normal

So what have you got to help you?

Dysarthria, as we know can be either UMN (spastic), LMN (flaccid) or cerebellar. The lower facial weakness and poor palatal movements hint strongly at a “LMN” pathology. Why the inverted commas? Because by “LMN” we usually mean nerve nucleus, nerve root, NMJ or muscle – and not all of these are, strictly speaking, a lower motor neurone.
Confusing nomenclature aside, this has the feel of a peripheral presentation, rather than a central one.

The ptosis and odd eye movements are also helpful. Ptosis and restricted up gaze might make you think of a third nerve palsy but this would not explain the restricted abduction in the other other eye (a sixth nerve function). There is also ptosis on that side so, basically, this is not a “nerve” palsy at all – it is a COMPLEX OPHTHALMOPLEGIA.

There aren’t too many things that give you ptosis, ophthalmoplegia and bulbar (speech & swallowing) problems.

If you haven’t tumbled the diagnosis yet, it is myasthenia gravis.

TOP TIPS

Investigations:

  • ABC! This patient is at risk of aspiration and respiratory failure. Make this the first thing you say
  • FVC is the respiratory investigation of choice but oximetry, respiratory rate and effort, abdominal paradox and even a blood gas can be helpful
  • You can check Acetyl Choline receptor antibodies (but these takes weeks to come back)
  • You can do a Tensilon (edrophomium) test – but these are rare now (see the doggie video on the myasthenia page for a vivid representation of how helpful they can be, though)
  • NCS show a decrement during repetitive stimulation and EMG shows “jitter”. This is not core knowledge so if you were to say that NCS/EMG could be used to confirm a clinical diagnosis, then that would suffice

Treatment

  • SALT input
  • Pyridostigmine – to BOOST THE JUNCTION FUNCTION!!!
  • Immunosuppression – steroids, IVIG, plasma exchange, etc.
  • Specialist neurological input

For more information, follow this link

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