MS is a lifelong neurological disease affecting the brain and spinal cord. Based on the place where the inflammatory changes are happening, MS can cause various signs and symptoms. To make sure the terms are used appropriately, “symptoms” describe patients’ own perceptions of something, while “signs” are the actual changes physicians find during neurological exams. We consider a sign or symptom to be caused by MS if it is present for at least 24 hours. The following are the most common symptoms and signs caused by MS:
Optic neuritis is an inflammation of the optic nerve and one of the most frequent initial neurological events in MS. It usually affects one eye at a time, and common symptoms include blurry vision, pain during eye movement and decreased color perception, most frequently for red. Other signs include decreased visual acuity and color vision, as well as decreased contrast vision. Vision impairment is reversible for the majority of patients, with vision returning back to normal within a few weeks to a few months.
MS can cause different sensory changes, ranging from absolute loss of sensation to increased sensation and pain. Different symptoms usually include tingling, electric sensation, numbness and pain. Any part of the body can be affected, with spread to adjacent areas over time. Signs found on exam usually include decreased or increased sensation to touch, temperature or sharp touch. While a majority of sensory changes are not functionally limiting, they can cause walking difficulty by changing the perception of different surfaces.
Various degrees of muscle weakness can be experienced during an acute attack of MS and also during the remission period. The weakness can be minimal and cause clumsiness or heaviness in hands and feet or dragging of the legs after long walks. More pronounced muscle weakness causes visible impairments that are usually easy identifiable by patients and by physicians.
Often accompanying muscle weakness, muscle tightness or spasticity is frequently experienced during the attack as well as during periods of remission. A feeling of tight and painful muscles after more strenuous activity is common. Muscle cramps can be painful and occur at random. Nightly cramps can significantly alter sleep patterns.
Frequently described by patients as “the room is spinning,” vertigo can cause periods of incapacitation when walking is difficult and often accompanied by nausea or vomiting. Less severe balance problems are frequently described as “dizziness” and usually results in a state of almost constant imbalance in space, but not an actual sensation of spinning. During the exam it manifests as problems with walking in a straight line with heels and toes touching (similar to a sobriety test). Hearing problems and ringing in the ears are also possible, although not frequent.
Bladder and Bowel Problems
Bladder habits can change significantly during MS, and patients might experience increased frequency and urgency. This can also be mixed with problems starting urination, urinary hesitancy and incomplete emptying. Impairment of the bladder function increases the risk of infections and disease relapses and worsens quality of life. Both diarrhea and constipation can be present and sometimes also mixed together.
MS can affect sexuality in many different ways — directly by inflammatory lesions in the brain and spinal cord, but also by MS-associated symptoms like fatigue, bladder and bowel problems, weakness and tightness in the muscles, pain and problems with mobility. Among women, difficulty with physical arousal and achieving orgasm are the most common symptoms. For men, erectile dysfunction and problems with reaching orgasm are the most common symptoms. Changes in mood, energy levels and other aspects of life-long diseases can also lead to decreased sexual appetite and desire in both genders.
Depression and anxiety are the most commonly reported mood changes in MS by the patients or their families. Both can either worsen or start at the time of MS diagnosis, and both can significantly impact patients’ quality of life and coping ability. Less frequently reported are another two mood changes: euphoria and pseudobulbar affect. Euphoria presents as overly optimistic attitude despite very severe physical disability. Patients with pseudobulbar affect notice bursts of laughing or crying at inappropriate social situations that cannot be controlled and doesn’t reflect the person’s true feelings.
Fatigue and Sleep Disorders
Fatigue is one of the most frequent MS symptoms reported by patients and is considered to be the most disabling. We do not know exactly what causes fatigue in MS, but the current theory is that it is most likely a multifactorial problem only partially caused by the disease itself, with other contributing factors like sleep problems and depression. Two kinds of MS fatigue have been recognized by specialists: mental and physical.
Sleep problems, just like a few other MS symptoms, can be either caused by the disease alone or by associated symptoms, such as muscle tightness, bladder and bowel problems, pain and depression. Patients most commonly experience problems with falling asleep and staying asleep, but also have problems with breathing during sleep, obstructive sleep apnea and REM sleep disorder.
Cognitive dysfunction in MS is an umbrella term describing problems with short-term memory, concentration, multitasking and speed of processing new information. Cognitive problems can occur relatively early in the disease and can impact social and professional life, employability and relationships.
Many (but not all) MS patients can experience sensitivity to heat and transient worsening of their already-present neurological symptoms. This phenomenon, called Uhthoff’s phenomenon, can be most likely explained by a worsening ability to carry signals through the areas of damaged myelin that happens when body core temperature increases. The most important fact of this phenomenon is its temporal nature and improvement of symptoms back to baseline after cooling off. Activities and situations causing increased body core temperature, such as hot weather, hot baths, exercise and fevers, can produce this effect.
As a consequence of this phenomenon, many MS patients avoid hot baths and saunas and use different cooling strategies before and during exercise. Since exercise is proven to be beneficial, we do not discourage patients from it, but rather recommend hydration with cold drinks, air-conditioned gyms and cold showers before planned activity.