Fatigue in multiple sclerosis

Clinical vignette
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By Tiffany Braley MD MS

Patient A was a 36-year-old female with a 5-year history of relapsing-remitting multiple sclerosis, who had enjoyed clinical and radiographic stability since starting immunomodulatory therapy 2 years ago. During a routine visit, she described an overwhelming lack of energy, as if her “life force was being drained.” She indicated that she had a finite amount of energy to “spend” each day and had to use it wisely because when she exceeded it, the aforementioned symptoms occurred. She denied a change in her mood, feelings of guilt, or anhedonia. She denied an urge to fall asleep in quiet or sedentary situations or the need to nap. Her bed partner denied a history of snoring or apneic episodes. She denied nocturia or difficulty falling asleep or maintaining sleep. She otherwise reported good general health and a review of systems was negative. Medications included interferon beta-1a and a multivitamin. General examination including the head and neck, heart, lungs, and extremities was unremarkable. Mood and affect were appropriate. Neurologic exam was within normal limits with the exception of a right afferent pupillary defect and moderate vibratory loss at the toes. Her Fatigue Severity Scale (FSS) score was 54 (score > 36 is suggestive of fatigue). Amantadine was prescribed, and at a 2-month follow up visit, the patient reported a moderate improvement in her level of energy and had a repeat FSS score of 34.

Patient B was a 42-year-old male with a 10-year history of relapsing-remitting multiple sclerosis, punctuated by 2 episodes of myelitis. During a routine visit, he described profound fatigue that interfered with his 8-hour workday. He denied any change in his mood. He admitted to taking frequent naps in his car during his lunch hour to get through the afternoon. He reported a bedtime of 10 p.m. but said he was unable to fall asleep until 1 to 2 a.m. due to a combination of “aching” legs (relieved by movement) and anxiety over his insomnia. He was able to sleep through the night but was required to rise at 6:30 a.m. for work. He had a history of urinary urgency that was well-controlled with an anticholinergic. He otherwise reported good general health. Neurologic exam was notable for a subtle left intranuclear ophthalmoplegia and bilateral lower extremity hyperreflexia. His Epworth Sleepiness Scale (ESS) score was 12 (score > 10 indicates excessive daytime sleepiness). He was diagnosed with restless legs syndrome and prescribed a dopamine agonist before bedtime. He was also instructed to avoid watching television in the bedroom or going to bed before feeling sleepy. During a follow-up appointment 2 months later, he reported a “50%” improvement in his energy level, which he attributed to improved sleep hygiene and improvement of his restless legs symptoms, which allowed him to fall asleep at 11 p.m. and avoid napping. A repeat ESS score improved to 8. Despite his improved hypersomnolence, he was still somewhat dissatisfied with his energy level and scored 40 on the FSS. He was prescribed amantadine with little improvement in his symptoms. He was then prescribed modafinil, which substantially improved his energy level.

In This Article

Historical note and nomenclature
Clinical manifestations
Clinical vignette
Differential diagnosis
Diagnostic workup
Prognosis and complications
References cited
Web resources