Lambert-Eaton myasthenic syndrome (LEMS) – What are the signs and why you need to know?

Lambert-Eaton myasthenic syndrome

Lambert-Eaton myasthenic syndrome

Lambert-Eaton myasthenic syndrome (LEMS) is a very rare condition that affects the signals sent from the nerves to the muscles.

It means the muscles are unable to tighten (contract) properly, resulting in muscle weakness and a range of other symptoms.

About half of LEMS cases occur in middle-aged or older people with lung cancer. The remaining cases aren’t associated with cancer and can start at any age.

LEMS is also known as myasthenic syndrome or Eaton-Lambert syndrome.

 

Symptoms of LEMS

The symptoms of LEMS develop gradually over weeks or months.

The main symptoms are weakness in the legs, arms, neck and face, as well as problems with automatic body functions, such as controlling blood pressure.

Common symptoms include:

aching muscles

difficulty walking and climbing stairs

difficulty lifting objects or raising the arms

drooping eyelids, dry eyes and blurred vision

swallowing problems

dizziness upon standing

dry mouth

constipation

erectile dysfunction in men

strength that temporarily improves when exercising, only to reduce as exercise continues

See your GP if you have a combination of these symptoms.

Causes of LEMS

LEMS is caused by the body’s natural defences (the immune system) mistakenly attacking and damaging the nerves.

Normally, nerve signals travel down the nerves and stimulate the nerve endings to release a chemical called acetylcholine. This chemical then helps activate the muscles.

If the nerve endings are damaged, the amount of acetylcholine they produce decreases, which means nerve signals don’t reach the muscles properly.

It’s not known what triggers the immune system to attack the nerves. It’s often associated with lung cancer, but can occur in people without cancer.

LEMS is not inherited.

Tests for LEMS

Your GP will first check your medical history, ask about your symptoms, carry out a physical examination, and test your reflexes.

If they think you have a problem with your nerves, they may refer you to a specialist called a neurologist for further tests to determine the cause.

Tests you may have include:

blood tests – a blood test can detect substances in the blood (antibodies) resulting from the immune system attacking the nerves

nerve studies – a needle may be inserted into your skin to check how well signals are reaching the muscles from the nerves

scans – you may have a computerised tomography (CT) scan or positron emission tomography (PET) scan to check for lung cancer

If initial scans don’t find cancer, you may be advised to have regular scans every few months for a few years to check that it doesn’t develop later on.

Treatments for LEMS

There’s currently no cure for LEMS, but a number of treatments can help reduce the symptoms.

These include:

treatment for lung cancer – if you have lung cancer, treating it can significantly improve the symptoms of LEMS

medication to help nerve signals reach the muscles – commonly used medicines include 3,4-diaminopyridine and pyridostigmine

to reduce the activity of the immune system (immunosuppressants) – commonly used medicines include steroid tablets (prednisolone), azathioprine and methotrexate

immunoglobulin therapy – injections of antibodies from donated blood that temporarily stop your immune system attacking your nerves

plasmapheresis – a procedure to redirect your blood through a machine that filters out the antibodies attacking your nerves

Medication is the main treatment, although immunoglobulin therapy and plasmapheresis may be recommended in the short term, or if muscle weakness is severe and other treatments haven’t helped.

Outlook for LEMS

Some people respond well to treatment and are eventually able to stop taking medication, although this may not be for several years.

Others respond less well and find the condition affects their everyday activities and quality of life.

LEMS doesn’t affect life expectancy if it’s not associated with cancer. But people with lung cancer and LEMS tend to have a shorter life expectancy because it’s often not diagnosed until the cancer has spread, and by this point it’s very difficult to treat.

Dystonia – what is Dystonia and who can be affected?

Dystonia

Dystonia

Introduction

Dystonia is a medical term for a range of movement disorders that cause muscle spasms and contractions.

The spasms and contractions may either be sustained or may come and go.

Movements are often repetitive and cause unusual, awkward and sometimes painful postures. Tremor (shaking) can also be a characteristic of some types of dystonia.

Dystonia is thought to be a neurological condition (caused by underlying problems with the brain and nervous system). However, in most cases, brain functions such as intelligence, memory and language remain unaffected.

Types of dystonia

Dystonia can affect only one muscle or a group of muscles. There are five main types of dystonia:

Focal dystonia – where a single region, such as the hand or eyes, is affected. Cervical dystonia, blepharospasm (abnormal twitch of the eyelid), laryngeal dystonia and writer’s cramp are all examples of focal dystonia. If it only affects someone during specific activities, such as writing, it’s described as task-specific dystonia.

Segmental dystonia – where two or more connected regions of the body are affected. Cranial dystonia (blepharospasm affecting the lower face and jaw or tongue) is an example.

Multifocal dystonia – where two or more regions of the body that aren’t connected to each other, such as the left arm and left leg, are affected.

Generalised dystonia – where the trunk and at least two other parts of the body are affected. The legs may or may not be affected.

Hemidystonia – where one entire side of the body is affected.

About 90% of all cases are either cervical dystonia (which affects the neck muscles) or blepharospasm (which affects the eyelids). These are both focal dystonias that tend to develop later in life. They don’t usually get any worse and no other muscles are affected.

Read more about the symptoms of dystonia.

Causes of dystonia

Exactly how dystonia develops remains uncertain, but it’s thought to be caused by a problem with the part of the brain that controls muscle movement (the basal ganglia).

If there’s no identifiable cause of dystonia, or if the cause is genetic, it’s described as primary dystonia.

Secondary dystonia is where dystonia occurs as a symptom of an underlying condition or injury. Common causes include stroke, brain injury, encephalitis and Parkinson’s disease.

Read more about the causes of dystonia.

Diagnosing dystonia

Dystonia is diagnosed by a specialist examining and recognising the typical symptoms. The type of dystonia is then classified by which area of the body is affected.

When diagnosing dystonia, it’s important to confirm whether you have primary or secondary dystonia, because this may determine the type of treatment you need.

If you have typical signs of late-onset focal dystonia, specific investigations may not be required. However, tests may be needed to confirm whether you have primary or secondary dystonia. These may include brain scans, urine or blood tests, and genetic testing.

Read more about how dystonia is diagnosed.

Treating dystonia

There’s no cure for dystonia, but the condition can usually be effectively managed.

Treatment will vary, depending on the type of dystonia you have and the precise nature of your symptoms. However, the four main types of treatment are:

botulinum toxin – widely used to treat neurological conditions that involve abnormal muscle contractions, such as dystonia; it’s injected into the affected muscles to temporarily weaken them and reduce spasms

medication – such as anticholinergics, Baclofen and muscle relaxants

physiotherapy – where exercises are used to improve range of motion and posture, and prevent muscle weakness

surgery – if other treatments are unsuccessful, the nerves controlling the muscles causing spasms can be cut (selective peripheral denervation), or electrodes can be implanted within the brain, which are connected to a small device that’s similar to a pacemaker (deep brain stimulation)

Read more about how dystonia is treated.

Outlook

Dystonia is an unpredictable condition. It tends to progress slowly and the severity of a person’s symptoms can vary from one day to another.

Focal dystonia usually progresses gradually over a period of about five years and then doesn’t get any worse.

Sometimes, a person’s symptoms improve or disappear completely. This is known as total remission and it’s thought to occur in around 5-10% of people.