Question

A 60 year-old male patient is admitted to the emergency room complaining of problems talking and swallowing, double vision and shortness of breath during any physical activity.  They also complain of general muscle weakness.

1. List locations along the motor nerve pathway where some defect could be causing muscle weakness.

2. During the initial emergency room workup, the following observations were made:

-Repetitive voluntary activity lead to muscle fatigue and decrease in muscle force

-Ability to chew a soda cracker and swallow was diminished

-Blood oxygen saturation levels were running about 80-85% Assuming that a single site of pathology is present, where along the motor pathway is this patient’s problem?  Explain your reasoning and your answer must incorporate all of the above symptoms.  

3.What might be done to help such patients?

Answer 1

1.List locations along the motor nerve pathway where some defect could be causing muscle weakness?

The above symptoms leading to the diagnosis of myasthenia gravis.In whcih the affected location of a motor nerve pathway is the synapse region between the neuron and the receptor muscle for the contraction.

a.Here the acetylcholine antibodies bind with the postsynaptic muscle recptors and hindering the passing of nerve stumilus across the muscle receptor.

b.some antibodies which destory the muscle specific kinase(MUSK) and Low density lipoprotien receptor (LRP4) which ultimately led to the damage of post synaptic receptors in the muscle receptor.

Here the muscle receptors of extraoccular muscles affected which led to double vision.Muscle receptors of facial muscle affected which led to swallowing difficulty and talking disturbancesMuscle receptors of respiratory muscles affected which in turn made the dysponea .

2.Assuming that a single site of pathology is present, where along the motor pathway is this patient’s problem?  Explain your reasoning and your answer must incorporate all of the above symptoms. ?

Assuming the above mentioned symptoms of muscle twitching ,blurred vision,difficulty in chewing and swallowing,muscle weakness and respiratory muscle weakness, which made the decrease in saturation, the diagnosis of this patient will be myasthenia gravis.

post synaptic receptors of facial muscle affected whic lead to facial weaknes-here speech disturbance and swallowing difficulty reflect it.

post synaptic receptors of extraoccular muscle affected which lead to double vision.

post synaptic receptors of respiratory muscles affected which lead to the difficulty in breathing and desaturation to 80-85%.

3.What might be done to help such patients?

-Reassure the patient.

-provide complete rest to avoid further fatigue of muscles.

-Administer oxygen to keep a saturation above 94%,as the patients respiratory muscle paralysis present consider Non invasive ventilation or invasive ventilation.

-consult speech therapist for assesing swallowing and change the diet accordingly.if severe swallowing issues found change the feeding to a tube feeding.

-Diagnosis should be confirmed with the help of further physical examination ,and blood test like acetylcholine receptor antiobodies,Musk antibodies and LRP4 antibodies.Also consider Endophronium test.

-MRI or CT scans to rule out thymus gland tumor.

-consider medicaiton management such as immunoglobulin therapy,plasmapheresis etc.