What is the ice pack test in myasthenia gravis?

The ice pack test may be helpful in establishing that ptosis is due to ocular myasthenia gravis, since cold improves neuromuscular transmission. However, the role of the test in determining whether diplopia is of myasthenic origin has yet to be established.

What is the ice pack test?

The ice pack test (ie, placing ice over the lid) has gained interest among ophthalmologists for assessing improvement in ptosis and diplopia in ocular MG. The rationale behind this test is that cooling might improve neuromuscular transmission.

How do you test for ocular myasthenia gravis?

The most accurate test to diagnose myasthenia gravis is called a single fiber electromyogram (SFEMG). An SFEMG test involves very small needles that can measure responses from two nearby muscle fibers. Both the EMG and SFEMG tests can reveal a pattern of responses that suggests myasthenia gravis.

How do you perform an ice pack test?

It is quick and easy: An ice pack is applied to the ptotic lid for 2 minutes, and ptosis is measured with a ruler before and after cooling. A rise of 2 mm is a positive result.

How do you test for ice in myasthenia gravis?

The ice test is useful for ptosis. An ice pack is applied to the affected upper eyelid for 2-5 minutes. A positive test is the improvement of ptosis by > 2mm or more. This transient improvement in ptosis is due to the cold decreasing the acetylcholinesterase break-down of acetylcholine at the neuromuscular junction.

How rare is ocular myasthenia gravis?

Although most people have eye problems at the onset of MG, they may have other muscle weakness or develop other muscle weakness in the first two years after MG symptoms begin. About 15% of people with MG will have only ocular problems (ocular MG).

Is ocular myasthenia gravis a disability?

Objective: Ocular myasthenia gravis is a subtype of myasthenia gravis that causes relatively mild disability, but may convert into severe generalised muscle weakness. A universal management plan for ocular myasthenia gravis has not been established.

How does myasthenia gravis cause ptosis?

Variable ptosis is one of the most common manifestations of MG. Ptosis occurs primarily due to the involvement of the levator palpebrae superioris (LPS) complex. It may be unilateral or bilateral– in bilateral cases, it is often asymmetrical.

Does cold weather affect myasthenia gravis?

Scientific literature clearly establishes that weather, particularly temperature, can influence the severity of myasthenia gravis symptoms. Cold weather is infamous for being worse for pain and hot weather results in reduced muscle strength.

How quickly does myasthenia gravis progress?

Background Generalized myasthenia gravis will develop in more than 50% of patients who present with ocular myasthenia gravis, typically within 2 years.

How is the ice test used to diagnose myasthenia gravis?

Background: Diagnosis of myasthenia gravis is difficult, especially when the disease is restricted to ocular muscles. It is a well-known observation that myasthenic ptosis improves with cold and based on this, the ice pack test has been used as a tool in its differential diagnosis.

Is there an ice test for myasthenic ptosis?

Conclusions: The ice test is a simple, short, specific, and relatively sensitive test for the diagnosis of myasthenic ptosis. The sensitivity of the ice test in patients with complete ptosis decreases considerably.

Is there a sleep test for ocular myasthenia gravis?

The sleep test is performed by having the patient sleep for 30 minutes. One study revealed 100% specificity and sensitivity of this test in patients with edrophonium-confirmed OM with ptosis and with extraocular muscle (EOM) dysfunction (Clin Neurophysiol. 2000;111 (7):1203–1207).

How is the diagnosis of ocular myasthenia made?

The clinical history and examination provide the most important data for making the diagnosis of myasthenia. Patients with ocular myasthenia often have negative serum tests for acetylcholine receptor antibodies, and recently published studies confirm that several office-based tests can aid in…