J Korean Thyroid Assoc.  2014 Nov;7(2):185-189. 10.11106/cet.2014.7.2.185.

A Case of Severe Thyrotoxicosis Caused by Graves' Disease Presenting with Myasthenic Crisis

• Kim SH
• Park TS
• Baek HS
• Jin HY

• KMID: 2095132
• DOI: http://doi.org/10.11106/cet.2014.7.2.185

Abstract

Thyrotoxicosis due to autoimmune thyroid disease occurs in approximately 5% to 10% of patients with myasthenia gravis (MG), whereas the incidence of MG in patients with Graves' disease is much less at approximately 0.2%. Recently, we experienced a 40-year-old male patient diagnosed with thyroid storm with severe respiratory failure and lower extremity weakness. At first, he was diagnosed with Graves' disease and critical illness neuropathy. His thyroid function was improved by anti-thyroid drug, but his neurologic function aggravated at the same time. He accordingly diagnosed with myasthenia gravis. We studied that when we should examine the neurologic function from this case. Our case highlights the importance of investigating muscle weakness or other neurologic problems in the thyrotoxic patient during their management.

Keyword

Graves; Myasthenia gravis; Neuropathy

MeSH Terms

Adult
Critical Illness
Graves Disease*
Humans
Incidence
Lower Extremity
Male
Muscle Weakness
Myasthenia Gravis
Respiratory Insufficiency
Thyroid Crisis
Thyroid Diseases
Thyroid Gland
Thyrotoxicosis*

Figure

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  Fig. 1. The neostigmine test. After neostigmine injection, transient increasement of acetylcholine at neuromuscular junction, it caused transient improvement of eyeball movement such as ptosis.

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  Fig. 2. The repetitive nerve stimulation test. These findings demonstrate a significant decrement in the muscle action potential amplitude of about 30.2% at the abductor digiti minimi muscle and 15.6% at orbicularis oculi muscle (positive test result: more than 15% decrement) at low/high frequency stimulation.

Reference

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