Nerves (Neuropathy)

Different types of neuropathy

There are three main types of neuropathy: sensory, motor and autonomic.

Sensory neuropathy

Sensory neuropathy affects the nerves that carry messages from the skin, bones and muscles to the brain. As the name suggests, it tends to influence the senses, in particular touch, and affects how we feel temperature, pain and other sensations. It is the most common form of neuropathy, mainly occurring in nerves in the feet and legs, but can sometimes occur in the arms and hands. It can lead to a loss of feeling and a failure to sense pain. For example, if you trod on something sharp, stepped in to a hot bath or wore ill-fitting shoes, you may not be aware of damage to your feet. This lack of sensation can lead to damage becoming worse, and the potential for infection. Neuropathic ulcers may also occur.

The symptoms of sensory neuropathy can include pain and numbness, tingling in the hands, legs or feet and extreme sensitivity to touch. Some treatments are available to help with the pain and tablets that are usually used for depression but can also have a calming effect on the nerves.

A test should be carried out at least every year, to check for signs of this type of neuropathy.

Motor neuropathy

Motor neuropathy affects the nerves that transmit signals to the muscles enabling them to carry out movements like walking and moving the hands. Sometimes painful, it causes muscle weakness and, in areas like the thigh, muscle wasting can occur. However it is possible for some people to recover from this condition after a period of time.

If the nerves that supply the muscles in your feet are affected, motor neuropathy can lead to the development of foot deformities. One such condition is Charcot’s foot, where a loss of sensation and weakened muscles cause bones in the foot to fracture or break when stressed. As you may not feel the damage, subsequently you may not heal properly and this can result in the shape of the foot becoming distorted. Your podiatrist will know more about treatments for this. 

Autonomic neuropathy

Autonomic neuropathy affects the nerves that control involuntary activities of the body ie, those which occur automatically. This means the action of the stomach, intestine, bladder, penis or sometimes the heart, can be affected. If autonomic neuropathy occurs in the stomach or intestine, symptoms may include altered bowel movements, such as intermittent diarrhoea or constipation. Additionally, a condition known as gastroparesis can develop. This occurs when the stomach takes too long to empty because the vagus nerve (which controls the movement of food through the gut) has been affected. Other symptoms sometimes include feeling sick, vomiting, stomach bloating, discomfort and weight loss. There are some treatments available to help alleviate the symptoms.

If autonomic neuropathy occurs in the bladder, symptoms may include an inability to pass urine properly and in particular, feeling like the bladder hasn’t emptied completely. In later stages this may lead to incontinence and more rarely, a total inability to pass urine.

Autonomic neuropathy of the penis may gradually lead to erectile dysfunction. However there are a number of treatments that can be prescribed, which help with erectile dysfunction.

Occasionally, the cardiovascular system (the heart and blood vessels) can be affected by nerve damage. This may result in pain from heart disease being masked.

For example, you might experience a heart attack but be unaware that it has happened (this is known as a ‘silent MI’ or myocardial infarction). Additionally, you may not feel pain when an attack of angina occurs, which is often a warning sign of heart disease.

Postural hypotension (low blood pressure that occurs when you stand up) can also be attributed to neuropathy. Symptoms include dizziness, weakness, visual impairment or possibly a loss of consciousness — most frequently occurring when getting out of bed in the morning. Treatment might involve excluding drugs that can reduce blood pressure further, such as water tablets.

Sweating disturbances can also be a sign of autonomic neuropathy. Nerve damage can interfere with the activity of the sweat glands, making it difficult for the body to regulate temperature. This type of neuropathy commonly occurs in the feet, causing a lack of sweating (in severe cases this extends to the whole leg and lower trunk). This lack of sweating leads to the skin of the feet becoming dry and cracked. Gustatory sweating (when eating) may start quite soon after chewing and can be brought on by certain foods. It often starts on the forehead, and spreads to the face, scalp and neck, sometimes affecting the upper part of the body.