Endocrine Abstracts

Introduction

Multiple autoimmune syndrome (MASI) is a rare entity, defined by the presence of at least three autoimmune diseases in the same person. We report two specific observations of myasthenia gravis in the context of an SAIM3.

Observation 1

A 58-year-old man initially presented bilateral ptosis, difficulty chewing and swallowing, dysphonia and fatigability. Myasthenia gravis was suspected due to the aggravation of this complaints with effort and confirmed by prostigmine test and EMG which showed a post-synaptic block in the neuromuscular junction. The diagnosis of hypothyroidism was suggested by mucocutaneous infiltration and constipation and confirmed by a TSH elevated to 100IU/ml with a low FT4 of 5 pmol/l. It was hypothyroidism secondary to Hashimoto’s thyroiditis with highly positive antithyroglobulin and Anti thyroperoxydase antibodies. The onset of melanoderma and hypotension suggested adrenal insufficiency, confirmed by low basal cortisolemia at 53 ng/ml and insufficient response to synactene 250g to 150 ng/ml after optimal thyroid hormone substitution. Anti-adrenal Antibodies were negative. The cervico-thoracic CT scan ruled out the presence of a thymoma. The diagnosis of SAIM type 3 was retained. The patient was trated by Mestinon, Cortef and Levothyroxine. The evolution was favorable.

Observation 2

A 14 year old patient, initially hospitalized for ptosis, asthenia and thermophobia. Clinical examination showed bilateral ptosis, ophthalmoplegia with limitation of lateral and vertical movements. The diagnosis of myasthenia gravis was made by a positive prostigmine test: correction of the deficiency within a few minutes after VILI injection of an ampoule of prostigmine. The electro-neuro-myogram was in favor of the diagnosis of myasthenia gravis. Anti-acetylcholine receptor antibodies were positive. Clinical examination of the patient also showed weight loss, fine tremors of the extremities, tachycardia and glare. The diagnosis of hyperthyroidism was confirmed by an elevated FT4 of 27.8 pmol/l (8.6–25 pmol/l) and a braked TSH of 0.001 mU/l. This hyperthyroidism was related to Hashimotoxicosis guiven the positivity of anti thyroglobulin and anti thyroperoxydase antibodies. Signs of hypocorticism such as asthenia, weight loss, melanoderma and hypotension were objectified. Addison’s disease was confirmed by low baseline cortisolemia at 37.4 ng/ml and positive adrenal antibodies. The patient was treated with prostigmine 240 mg/dr, cortef 15 mg/dr and radioactive iodine for her hyperthyroidism with good evolution.

Conclusion

The association of the different autoimmune diseases reflects the presence of a common genetic ground on which environmental factors determining clinical aspects are grafted.