Fatigue and falls in relapsing-remitting MS: prescribing exercise safely
Ms S is a 38-year-old secondary school teacher with relapsing-remitting multiple sclerosis diagnosed 6 years ago, EDSS 4.0. She walks outdoors with a single stick and reports three falls in the last 2 months, all while turning or carrying books. Her Fatigue Severity Scale score is 5.8/7 and she naps for 90 minutes after work. Six-minute walk test is 285 m; she stopped twice for fatigue, heart rate rose from 82 to 118 bpm, SpO2 stayed at 97%. She reports that symptoms are worse for 30-45 minutes after a hot shower and after a busy teaching day. Her last relapse (left optic neuritis and leg heaviness) was treated with oral steroids and resolved 6 weeks ago; she has been neurologically stable since. She wants to start exercise because she has read that it slows MS, and asks whether she can join a high-intensity gym class. Medications: natalizumab, baclofen 10 mg three times daily, vitamin D.
1. Differentiate the contributors to her fatigue and falls, and explain the heat phenomenon and its practical implications.
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Three overlapping contributors. (1) Primary MS fatigue: FSS 5.8 with a 90-minute daily nap and disproportionate fatigue after a normal teaching day. (2) Deconditioning and gait inefficiency: a 6-minute walk of 285 m is low for EDSS 4.0 and she needed two fatigue stops, suggesting her walking is near her aerobic ceiling. (3) Heat sensitivity - the worsening 30-45 minutes after a hot shower is the Uhthoff phenomenon, a reversible conduction block from raised core temperature, not new demyelination.
Why it matters practically: a hot, crowded gym class will reproduce her symptoms, shorten her tolerance, and may be misread by her (or by staff) as a relapse. Precooling and a cool environment are therefore part of the prescription, not an optional extra.
Falls: all three occurred during turning or while carrying - pointing to reduced reactive balance, divided attention and axial control rather than pure weakness. Dual-task turning should be the primary balance target.
Timing: 6 weeks of neurological stability after steroid-treated relapse means she is out of the relapse window and safe to exercise, but a baseline must be recorded now so that later deterioration can be compared against it. Her request for a high-intensity class is not inherently unsafe in stable MS; the problem is the format - heat, standing balance demands, complex choreography and no supervision - given her falls risk.
2. Prescribe an exercise programme with mode, intensity, frequency, monitoring and cooling, and justify your decision about the high-intensity class.
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Aerobic: cycle, treadmill or pool at 26-28 degrees Celsius; 60-70% of age-predicted maximum or RPE 11-13 (Borg 6-20) for the first 4 weeks, progressing to 70-80% if tolerated; 2 supervised sessions plus 2-3 home sessions weekly; 20-40 minutes, adding 5 minutes per week.
Resistance: 2-3 times weekly, 2-3 sets of 8-12 at RPE 5-7, focusing on hip extensors, knee extensors, plantar flexors and trunk; progress load by 5-10% when she completes sets easily with good control.
Balance and dual task: 3 times weekly, progressing from static to dynamic turning, carrying a weighted bag, and counting backwards while walking - directly targeting her fall mechanism.
Cooling: cool shower or 20 minutes of precooling before sessions, room at 18-22 degrees Celsius, fan, cold drink, avoid midday heat, and a rest in a cool room if symptoms escalate.
Monitoring: heart rate, RPE, symptom and falls diary; stop and cool if vision blurs or symptoms escalate, and treat symptoms that resolve within 30 minutes of cooling as heat-related rather than a relapse.
The high-intensity class: defer it for 6-8 weeks. Moderate-to-high intensity is not contraindicated in stable MS, but unsupervised, hot and balance-demanding is the wrong starting format; offer a supervised progression once she has tolerance and no falls.
3. Which outcome measures will you use to track progress, and which findings should trigger medical review rather than more physiotherapy?
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Outcome measures: six-minute walk test repeated under identical conditions (time of day, temperature, same corridor) at baseline, 4 and 8 weeks, with a 30 m change taken as meaningful; Berg Balance Scale or Mini-BESTest for falls risk; Fatigue Severity Scale and Modified Fatigue Impact Scale; Timed 25-Foot Walk; a simple falls diary and a dual-task gait measure. Record EDSS-relevant walking distance so the neurologist receives comparable data.
Red flags for medical review, not more physiotherapy: any new or worsening neurological deficit lasting more than 24 hours or not resolving with cooling (suggests relapse); new optic neuritis; new bowel, bladder or sexual dysfunction; a new sensory level; a fall with head injury or loss of consciousness; unexplained fever or infection (particularly relevant on natalizumab); and any change in spasticity control or baclofen tolerance. Also escalate if her walking deteriorates sharply over days rather than weeks, or if fatigue becomes overwhelming and unresponsive to pacing.
Why this matters: the physiotherapy plan depends on the assumption that she is in a stable phase. If that assumption fails, the correct action changes from progression to neurological review - and continuing to load her would be both ineffective and potentially harmful. Document the baseline and the review thresholds in the notes.