The ice pack test — a simple procedure in which a bag filled with ice is placed over the eyelids for a few minutes — eased ptosis (upper eyelid drooping) in a man with Lambert-Eaton myasthenic syndrome (LEMS), according to a recent case report.
These findings suggest this test cannot distinguish between ptosis associated with LEMS and that caused by myasthenia gravis (MG), an autoimmune disease characterized by generalized muscle weakness and that also can affect the eyes.
The study, “Positive ice pack test in a patient with Lambert‐Eaton Myasthenic Syndrome,” was published in the journal Muscle & Nerve.
The ice pack test is a fast and cost-effective procedure that can be used easily to help identify MG. Because cold tends to alleviate MG symptoms, including ptosis, those with eyelid drooping associated with MG tend to experience improvements shortly after the test.
Although this test is used routinely to screen for the presence of MG, its usefulness in other disorders associated with muscle weakness and fatigue, such as LEMS, is still unclear.
Here, physicians at St. John’s Medical College Hospital in India described the case of a man with LEMS whose symptoms of ptosis were relieved shortly after having the ice pack test.
For the past year, the 72 year-old man had been having increasing difficulties climbing stairs and standing from a seated position.
He also had been experiencing constipation, erectile dysfunction, and dry mouth for the past 10 months, as well as drooping in his right upper eyelid for the past six months. Yet, he did not complain of muscle weakness in his arms, and had no difficulties articulating words, swallowing, or breathing.
After having a bag of ice placed over his right upper eyelid for two minutes, his ptosis immediately eased, consistent with a MG diagnosis.
Nerve conduction tests — used to measure nerves’ ability to send electrical signals — performed afterward revealed several impairments in nerve-muscle communication in the arms and legs, consistent with a neuromuscular junction disorder.
The neuromuscular junction is the region where nerves and muscle fibers communicate. Disorders affecting this structure, which include both MG and LEMS, usually cause delays in nerve-muscle communication, along with muscle weakness and fatigue.
Yet, subsequent tests found no anti-acetylcholine receptor and anti-muscle-specific kinase antibodies — the two types of self-reactive antibodies more commonly found in MG patients — in the patient’s bloodstream.
However, those tests also revealed he had antibodies targeting P/Q-type voltage-gated calcium channels, which are found in patients with LEMS, confirming his final diagnosis.
Unlike MG, ptosis usually is considered a late manifestation of LEMS that is estimated to occur in up to 50% of patients one year after disease onset.
“Here, an ice pack test resulted in improvement in ptosis in a patient with confirmed LEMS. This suggests that the ice pack test cannot be used to differentiate [LEMS] from [MG],” the scientists wrote.
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