The Uhthoff phenomenon

According to research, around 80% of MS patients are affected by Uhthoff's phenomenon. Symptomatically, Uhthoff's phenomenon manifests itself in temporary, short-term neurological symptoms such as visual disturbances, impaired motor function or loss of strength. In Uhthoff's phenomenon, these symptoms are associated with an increase in body temperature (e.g. due to hot outside temperatures, hot bath/shower, sauna, physical exertion).

Multiple sclerosis leads to nerve damage caused by the body's own cells (demyelination). This results in scarred areas on the nerves. In the Uhthoff phenomenon, the nerve conduction velocity is presumably reduced in precisely these areas by heat or increased temperature, which leads to a reversible neurological worsening of symptoms. In this case, it is also referred to as a pseudo-flare-up, as the symptoms are triggered by physical influences and not by inflammatory activities in the body.

According to studies on peripheral nerves, an increase in body temperature of just 0.5 °C can slow down or block the transmission of stimuli in demyelinated nerve fibres. As demyelination progresses, the sensitivity of the nerve fibres to temperature changes increases.

The Uhthoff phenomenon also occurs in other diseases in which demyelination of the nerves occurs. Diseases include Guillain-Barré syndrome, acute disseminated encephalomyelitis (ADEM) or chronic inflammatory demyelinating polyneuropathy.

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The fatigue syndrome

Fatigue syndrome describes a persistent state of exhaustion that does not subside even after periods of rest and sleep. Typical symptoms include persistent tiredness, reduced physical performance, difficulty concentrating and an unsatisfied need for sleep.

According to studies, up to 90% of MS patients suffer from fatigue. Due to non-specific symptoms and a lack of biomarkers, diagnosis is difficult and requires the exclusion of other diseases such as diabetes, hypothyroidism and anemia. It is still unclear why fatigue syndrome occurs. It is referred to as a “multifactorial (i.e. influenced by many factors) event”. It is possible that fatigue is influenced by damage to the nerve cells, but also by other factors such as the psyche, diet and possibly the intake of medication.

Fatigue syndrome does not only occur in MS patients. Fatigue can also occur in patients suffering from other chronic illnesses. For example, up to 90% of cancer patients undergoing chemotherapy or radiotherapy are affected. Fatigue can also occur in rheumatological diseases, cancer, Long Covid, diabetes.

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Uhthoff's phenomenon vs. fatigue syndrome

Uhthoff's phenomenon manifests itself in temporary, short-term neurological symptoms such as visual disturbances, impaired motor skills or loss of strength, which are triggered by an increase in body temperature.

In general, it is important to avoid hot showers and saunas, intense heat and direct sunlight, as these have a direct effect on body temperature. Airy summer clothing or cooling clothing such as cooling vests are very useful. As high fluid loss can exacerbate the symptoms, it is important to drink plenty of fluids. Ice cubes, ice and chilled drinks can help to cool the body from the inside.Arms and feet can also be held in a bowl of cool water to cool down quickly. In midsummer, cold washcloths can be placed on the body, especially at night, to cool the body slightly.

Anyone who suffers from Uhthoff's phenomenon should therefore be well prepared, especially in summer. Preparation is half the battle; if it is foreseeable that the next few days will be very hot, then prepare accordingly. Keep ice cubes cold, have plenty of cold drinks in the fridge or get your garden shower out of the garage.

Fatigue syndrome is less specific and the symptoms are more varied. Common symptoms include a general feeling of exhaustion and weakness, difficulty concentrating, disturbed sleep, loss of motivation and loss of physical resilience. According to current scientific knowledge, fatigue is not directly related to external influences, but is influenced by behavior such as physical activity, sleep, stress and much more. To cope with fatigue, Pacing is a recommended strategy.