Case #3 Answer!

Horner’s syndrome (also miosis/anhydrosis)

Myasthenia Gravis (diplopia/fatigue)

Muscle Disease (other muscles affected)

Lambert Eaton

ALS

Cranial Nerve 3 palsy – ANEURISM! (impaired EOMI, dilated pupil)

Aneurism

SAH

Meningitis

Cavernous sinus thrombosis

CVA

Congenital levator muscle defect (amblyopia, strabismus)

Aponeurotic ptosis

Mechanical ptosis (neurofibromatosis with tumor in nerve)

Complication of botulism injection (possible in botulism infection, but rare)

Mitochondrial myopathy

Oculopharyngeal Muscular Dystrophy (rare, auto dom, presents middle age, typical dysarthria/dysphagia/EOM weakness)

Myotonic Dystrophy (auto dom, weakness, frontal balding, variable intellect impairment)

Fake outs: lid retraction of other eye, old people redundant eyelid skin, faking

Myesthenia Gravis! Clinically relevant questions would include increased fatigability with repetitive movements or worse symptoms as the day progressed

Pathophys: autoantibody against cholinergic receptors

Repetitive action lead to INCREASED FATIGUE which is different from Lambert-Eaton in which repetitive action leads to decreased fatigue.

>50% present with solely ocular weakness

10-15 % have underlying thymoma

In ED

1. Ice Pack Test –put ice pack on eye for 2 minutes. If MG, symptoms will resolve

2. Tensilon (edrophonium) test – give a fast on/fast off acetylcholinesterase inhibitor. Dose is 2mg every 1 minute up to 10mgs. If MG, symptoms should improve.

– Edrophonium is contraindicated if asthmatic, elderly, or CAD/CV disease as the muscarinic side effects – bronchorrhea/bradycardia/bronchospasm  –  can be bad/life-threatening, and the SLUDGE part seems, at the very least, moderately unpleasant.

– Also if give large doses of edrophonium all at once, you can get the above cholinergic side effects

– High dose edrophonium can result in paradoxical weakness

– Can have atropine at bedside just in case.

– false positives in motor neuron disease, brainstem tumors, compressive cranial neuropathies). Also, false negatives.

3.  Lab testing

– AChR- Ab/muscle specific tyrosine kinase (MuSK-Ab)

– Can send from ED, but obviously do not come back during ED visit.

Out of ED

4. Non-ED random testing

– Nerve stimulation testing, single fiber electromyography.

Respiratory muscle weakness

Evaluate by calling the respiratory therapist to test: Negative Inspiratory Force (NIF) which is also called the Maximal Inspiratory Pressure (MIP), and vital capacity (VC).

If NIF/MIP/VC normal and no respiratory symptoms, can discharge with neurology follow-up

If these are low, patient may require elective intubation – see table here.

Intubate If…

– Declines in serial measures of VC below 15 to 20 mL/kg ideal body weight

– Declines in serial measurements of MIP less negative than -25 to -30 cmH₂O (ie, 0 to -30 cmH₂O)

– Clinically necessary (respiratory distress, cannot tolerate secretions, worsening respiratory acidosis)

1. Intubate if indicated

2. Admit if respiratory complications or severe symptoms.

3. If severe: Plasmapharesis or IVIG

4. Immunosuppresion (steroids/rituximab/azathioprine/cyclosporine)

5.  Eventually, thymectomy if thymoma