Paroxysmal symptoms

Reviewed by: HU Medical Review Board | Last reviewed: May 2015. | Last updated: January 2022

Paroxysmal symptoms, involving unusual sensations or muscular contractions, are relatively unique to MS and are sometimes confused for seizures that occur with epilepsy. However, MS-related paroxysmal symptoms, unlike epileptic seizures, do not result from a short-circuiting of brain waves and do not have the features typical of seizures in brain wave studies.

What are paroxysmal symptoms?

Paroxysmal symptoms typically have a sudden onset and usually only last for a short time. For example, they may manifest as spasms or twitching that comes on suddenly and resolves within seconds. They can be triggered by a number of conditions or symptoms, including fatigue, change in temperature, emotional changes, certain sensory stimuli (touch), or a sudden shift in body position. Paroxysmal symptoms that occur without warning and last for an extended period (several days) may be a sign that an exacerbation or relapse is about to begin. This is especially true if they accompany symptoms that often signal an exacerbation in the individual patient, such as bladder or bowel dysfunction, fatigue, or vision problems.

Types of paroxysmal symptoms

The most common spasms seen with MS affect the leg or arm and involve a loss of muscle tone or abnormal posturing that appears similar to an epileptic seizure. These tend to recur every few seconds or minutes, lasting for seconds with each recurrence.

Hot flashes, speech and swallowing problems, and intense shooting pain

Other types of paroxysmal symptoms include sudden shifts in body temperature (sometimes called ‘hot flashes’), a flutter or tic affecting the lip or eyelid, a problem with swallowing, failure to recall a word in the middle of a conversation or speech, sudden emotional changes (sometimes call mood swings), dental pain or facial pain that occurs after eating or drinking hot or cold food or liquids, and sudden intense shooting pain in limbs or extremities.

Trigeminal neuralgia, Lhermitte’s sign, and Uhthoff’s symptoms

Spasms can also affect speech muscles resulting in slurring of speech or interfere with swallowing. Additional examples of paroxysmal symptoms include paroxysmal pain, such as trigeminal neuralgia, Lhermitte’s sign (an electrical sensation traveling down the spine that occurs when the neck is bent forward), or Uhthoff’s symptoms (a blurring of vision brought on with physical exertion or high temperatures).


Paroxysmal symptoms can be alarming and are easily misdiagnosed. However, they are self-limiting and will usually disappear on their own.

Treatment options include older anti-epileptic medications, Dilantin (phenytoin), Depakote (valproate), and Tegretol (charbamazepine), and newer anti-seizure medications, including Neurontin (gabapentin), Lyrica (pregabalin), Gabatril (tiagabine), Keppra (levetiracetam), and Trileptal (oxcarbazepine).

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