Isaacs–Mertens syndrome

Isaacs–Mertens syndrome, also known as cramp-fasciculation syndrome, is a rare neuromuscular disorder characterized by muscle cramps, fasciculations, and stiffness. The condition is named after the neurologists who first described it, Hyam Isaacs and W. King Engel. Isaacs–Mertens syndrome is considered a peripheral nerve hyperexcitability disorder, which is a group of neurological conditions that involve the spontaneous activation of peripheral nerves, leading to muscle twitching, cramps, and other sensory disturbances.

Symptoms and Diagnosis

The primary symptoms of Isaacs–Mertens syndrome include persistent muscle fasciculations (twitching), muscle cramps, stiffness, and fatigue. These symptoms can vary in intensity and may be exacerbated by physical activity, stress, or fatigue. Unlike similar neuromuscular disorders, such as amyotrophic lateral sclerosis (ALS), Isaacs–Mertens syndrome does not lead to muscle wasting or significant weakness.

Diagnosis of Isaacs–Mertens syndrome is primarily clinical, based on the patient's symptoms and medical history. Electromyography (EMG) tests, which measure the electrical activity of muscles, are crucial in diagnosing this condition. EMG findings in patients with Isaacs–Mertens syndrome typically show continuous muscle fiber activity even at rest. Additional tests, such as blood tests and nerve conduction studies, may be conducted to rule out other conditions.

Treatment

There is no cure for Isaacs–Mertens syndrome, but treatment focuses on managing symptoms and improving the quality of life for affected individuals. Medications such as anticonvulsants (e.g., carbamazepine, phenytoin), immunoglobulins, and corticosteroids have been used to reduce muscle cramps and fasciculations. Physical therapy and regular exercise may also help alleviate some symptoms by improving muscle strength and flexibility.

Prognosis

The prognosis for individuals with Isaacs–Mertens syndrome is generally favorable, as the condition does not typically progress to more severe neuromuscular disorders. However, the symptoms can be persistent and may significantly impact the individual's quality of life. Ongoing management and treatment are often necessary to control symptoms.

See Also

• Peripheral nerve hyperexcitability
• Neuromuscular disease
• Electromyography