Primary lateral sclerosis (PLS): a patient guide

Motor neurone disease is a group of conditions that affect nerves in the brain and spinal cord called motor neurones, which tell your muscles what to do. The NHS lists four main types: amyotrophic lateral sclerosis (ALS), progressive bulbar palsy, progressive muscular atrophy and primary lateral sclerosis. ALS is the most common.

Leeds Teaching Hospitals NHS Trust explains that upper motor neurones begin in the brain and travel down into the spinal cord, where they pass messages to lower motor neurones, which run out to the muscles. In PLS only the upper motor neurones degenerate. Damage to them causes disabling stiffness (spasticity) and weakness, without the wasting seen when lower motor neurones are involved.

The MND Centre describes PLS as generally affecting people above the age of fifty. It lists weakness in the lower limbs, loss of balance, stiffness in the limbs, clumsiness with the hands, slurred speech, emotionally inappropriate laughing or crying, difficulty speaking or swallowing, and occasionally bladder problems. The NHS says early symptoms are usually weak legs, sometimes with speech problems.

In practice, people may fall more often because balance is affected, and some have neck, back and leg pain. Washing, dressing, writing and cooking can become hard as mobility falls. Speech may become less clear if the throat and tongue muscles are involved, and swallowing problems can follow. Some people have less control over emotions. Symptoms vary from person to person, and the pace differs.

The NHS says MND can be difficult to diagnose in the early stages, and that tests include blood tests, tests of how well the nerves are working and an MRI scan to rule out other conditions of the brain and nerves. A GP who suspects it may refer you to a neurologist. NICE guideline NG42 advises referral without delay when MND is suspected.

For PLS in particular, the MND Centre explains that many tests exist to exclude other causes of the symptoms, including multiple sclerosis, viruses, brain or spine tumours and spinal damage. ALS has to be ruled out as well. The tests include MRI scans, nerve conduction tests, electromyography (EMG) and blood tests. Because ALS can only be excluded over time, the diagnosis is often confirmed after a period of follow-up rather than at the first visit.

Leeds Teaching Hospitals says that in true PLS life span may not be reduced, whereas ALS is usually life-shortening, according to the NHS. The MND Centre makes a similar point: life span with PLS could generally be normal, though this depends on whether the disease remains PLS or progresses to ALS.

This is why doctors speak cautiously early on. The Leeds page says some people first appear to have PLS but over time the lower motor neurones become involved and the diagnosis changes to ALS. It adds that after 5 years it is rare, but may still occur. Regular specialist review lets the team recognise any change in the pattern, for example new muscle wasting or twitching.

There is currently no cure for MND. The NHS says treatments can ease symptoms and that a team of professionals, which may include a specialist nurse, neurologist, physiotherapist and occupational therapist, provides support. The MND Centre says managing PLS is mostly done by managing individual symptoms as they appear.

For muscle stiffness, NICE guideline NG42 says to consider baclofen, tizanidine, dantrolene or gabapentin, and to consider referral to a specialist service for severe spasticity if these are not effective or tolerated. Physical therapy and gentle, low-impact exercise such as walking or water-based activity may help keep flexibility and range of movement. Stretching can ease cramps. Riluzole is listed by the NHS for ALS, not for PLS.

NICE guideline NG42 says speech and communication needs should be assessed by a speech and language therapist without delay, and that communication equipment should be provided promptly to maximise participation. Aids can help people keep talking and writing as speech changes.

Swallowing difficulty can affect eating and drinking. The MND Centre says that if feeding becomes difficult and tiring, it may be time to consider PEG feeding, and the NHS adds dietary advice to maintain weight. Mobility aids, home adaptations and help with personal care are part of the support, and the NHS lists talking therapy to help with emotions such as anxiety and depression. Equipment needs should be reviewed regularly as symptoms change.

The NHS says people with MND should have an appointment with their care team every two or three months to discuss symptoms and needs. NICE guideline NG42 recommends sensitive discussion of future care and advance care planning at trigger points such as diagnosis or a change in breathing, in line with the person's wishes.

Charities provide information and peer support. The NHS names the Motor Neurone Disease Association and the Brain and Spine Foundation, and about 1 in 10 people with MND have a family history, according to the NHS, which also says that having a relative with MND does not necessarily mean you will get it. If you want to talk about inheritance, ask your neurology team about genetic counselling.

The route usually runs from a GP to a neurologist, then to a specialist MND care centre or clinic where a coordinated team works together. Leeds Teaching Hospitals NHS Trust, for example, describes a dedicated MND centre. Private neurology can speed up appointments and scans, but ongoing multidisciplinary care is usually arranged through NHS MND services.

See a GP if you notice difficulty gripping, leg weakness or cramps that keep recurring, as the NHS advises. Many of these symptoms have less serious causes, and checking is the sensible first step.