Question

Case 2

Clinical History and Physical E*am: This 34 year old woman first noted intermittent horizontal diplopia and droopiness of her eyelids in her early twenties. It was worse when she was tired and it slowly progressed to the point that the diplopia became constant by age 30. The following year, she developed weakness in her legs with frequent falls and difficulty climbing stairs. She noted muscle pain if she walked for a prolonged time. She denied having fatigability in her limb muscles. Cranial nerve testing revealed an almost complete external opthalmoplegia with only a few degrees of movement in all directions. There was also bilateral eyelid ptosis and fatigability. Motor e*amination showed normal tone and bulk. There was mild proximal weakness in the upper and lower extremities with fatigability after repetitive movement. Reflexes were diminished. The rest of the neurological e*am was normal.

Laboratory Findings: A tensilon test showed a positive response with improvement of at least 50% of her eyelid ptosis. Electrodiagnostic studies done to rule out a neuromuscular junction disorder (repetitive nerve conductions and single fiber EMG) were normal. Acetylcholine receptor antibodies were not detected. The serum CK was normal.

Microscopic Analysis: Sections of muscle tissue revealed mild variation in fiber size. Some of the fibers had the features of ragged red fibers with disruption of the intermyofibrillar network and abnormal subsarcolemmal accumulations of granular refractile material which may represent mitochondria. Several fibers had internally placed nuclei. Inflammatory infiltrates were absent.

Diagnosis and medication/treatments?

Answer 1

The important findings in the case are as follows :

intermittent horizontal diplopia and droopiness of her eyelids that exaggerates with fatigue and improves on rest.
weakness in her legs with frequent falls and difficulty climbing stairs.

Bilateral ptosis

proximal weakness in the upper and lower extremities with fatigability, diminished reflexes.
positive tensilon test

no antibodies for ACh

The above findings are common with myasthenia gravis. Myasthenia gravis a neurodegenerative disease that results in formation of antibodies against acetylcholine receptor at neuromuscular junction. This results in marked muscular weakness. Weakness increases with fatigue and improves with rest. Ocular manifestations such as diplopia, nystagmus and ptosis are seen.
Treatment : There is no cure

Treatnent is symptomatic and aimed to slow the progression of disease.
AChE inhibitors like pridostigmine are used.

corticosteroids are given for immunosuppression

Plasmapharesis and ivIG are used

Phtsical therapy to maintain muscular strength and flexibi