[Validation of the ice pack test in ophthalmoparesis due to myasthenia gravis]

Myasthenia gravis is an autoimmune disease of the neuromuscular junction that presents clinically as fluctuating weakness of skeletal muscles, as of the ocular region (myasthenia ocular).

To demonstrate that the sensitivity and specificity of the ice pack test are high, in the differential diagnosis of palpebral ptosis and ophthalmoparesis for myasthenia gravis and myasthenia ocular.

Observational, analytical, and non-randomized study of 43 subjects, 21 with myasthenia gravis and 22 controls. All patients received a glove with ice on your upper eyelids affected for 2 minutes, after which we assessed the degree of improvement in palpebral ptosis and ophthalmoparesis. All patients had repetitive nerve stimulation study.

We analyzed 36 patients, 18 patients with myasthenia gravis or myasthenia ocular and 18 controls. All patients had palpebral ptosis but ophthalmoparesis only 20 of them. Ice pack test for ophthalmoparesis showed a sensitivity of 83%, specificity 100%, positive predictive value (PPV) of 100% and negative predictive value (NPV) of 80% in the diagnosis of myasthenia gravis. Ice pack test for palpebral ptosis was determined a sensitivity of 89%, specificity 100%, PPV of 100% and NPV of 90%. For repetitive nerve stimulation was calculated a sensitivity of 61%, specificity of 83%, PPV of 79% and NPV of 68%.

Ice pack test, both palpebral ptosis and ophthalmoparesis is a simple test, safe, cheap, fast and reliable to be used routinely in patients suspected of palpebral ptosis and/or ophthalmoparesis due to myasthenia gravis, and which has a high validity, safety, and reproducibility as a diagnostic test.