Polyneuropathy - CIDP

 

Thank you for asking me to examine Mr. X, who presented difficulty walking.

 

The most salient findings on examination were a high stepping gait (distal weakness) and/or proximal weakness (waddling gait) [it can affect distal and/or proximal]  with a symmetrical motor deficit in a non-length dependent distribution affecting both proximal and distal muscles with associated large fibre sensory loss (proprioception and vibration), which would be most consistent with demyelinating neuropathy such as chronic inflammatory demyelinating polyneuropathy. Note this is the classical presentation, and is variable. 

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In reality, you will keep it broad to begin with. 

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The most salient findings on examination were a symmetrical motor weakness affecting both proximal and distal muscles with lower motor neuron signs, with an associated large fibre sensory loss, which is suggestive of a peripheral neuropathy, however there are other differentials and I would like to present my findings in full...

 

In further detail...

 

On inspection the patient was comfortable and did / did not have any gait aids. There were/were not any shoe or ankle supports.

 

The gait was high stepping / waddling  (distal and proximal) with/without ataxia and broad based with stamping (if sensory involvement). The patient could/could not walk heel to toe, suggesting the presence/absence of a cerebellar pathology. The patient could/could not walk on their toes (S1), and the heels (foot drop, L4 or L5). Romberg’s sign was/was not positive (eyes closed - posterior columns, eyes open - cerebellar).

 

There were/were no scars on the back.

 

On inspection of the legs, there were/were not scars. There was/was not evidence of muscle wasting, and fasciculations (may or may not be atrophy).

 

There was not muscle tenderness. Tone was reduced/normal in the knee and ankle, and there was not clonus (tone may be reduced or normal). There was/was not an enlarged common peroneal nerve (CMT).

 

Power was reduced symmetrical with both proximal and distal muscles affected, with __/5 power on the left leg, and __/5 power on the right.

 

There was hyporeflexia/areflexia in the knee and ankle. Plantar response was /downgoing/inadequately assessed due to withdrawal.

 

Coordination was normal on heel-shin, toe-finger and foot tapping assessment.

 

Sensation was reduced symmetrically (tends to be worse distally, unlike motor findings), with reduced sensation to vibrations sensation to ___, and proprioception to the ___. Pain sensation was intact/impaired (pain and temperature loss possible but less common).

 

In summary this patient has a non-length dependent sensorimotor/predominately motor neuropathy, which may be consistent with a demyelinating neuropathy such as CIDP.

 

Other differentials include:

• Sub-acute combined degeneration

• Anterior horn cell

• NMJ

• Myopathy

 

Differential for a predominately motor neuropathy include:

• GBS/CIDP

• Hereditary motor and sensory neuropathy - CMT

• Diabetes

• Other - porphyria, lead, diphtheria, drugs (dapsone)

 

Differential for a sensorimotor neuropathy include:

• Metabolic causes - primarily diabetes, CKD/uraemia, thyroid

• Drug and alcohol related - vincristine, cisplatinum

• B12

• Immune mediate such as GB and CIDP - however, typically these have less sensory involvement, and no pes cavus, and are non-length dependent with proximal and distal muscles affected similarly

• Paraneoplastic - tumour, or paraproteinemia

• Connective tissue disease and vasculitis

• Idiopathic

 

I would proceed from here by:

• Confirming my diagnosis with nerve conduction studies (low conduction velocity, low amplitude if axonal)

• Assessing for other aetiology by:

  • History

  • Screen for diabetes, CKD, thyroid function

  • B12 level, holotranscobalamin, methylmalonic acid (elevated if deficient)