Ataxia

Ataxia is not a diagnosis but a sign: movements stop being accurate and coordinated, even though strength in the arms and legs may be perfectly normal. A person sways while walking, misses when reaching for an object, speaks unclearly. Dozens of causes sit behind it, from poisoning by a medicine or the lack of a single vitamin to a stroke in the cerebellum or an inherited disease. That is why the question with ataxia is always the same: what is causing it, and how quickly did it appear.

What breaks down in the control of movement

For a step to be steady, the brain needs three things: a plan for the movement, a constant report from the body about where it is in space, and a cerebellum that compares the two and corrects the movement as it happens. Ataxia appears when any one of those links is broken.

• Cerebellar. The cerebellum or its connections are affected. The gait is broad and unsteady, speech slows down and breaks into syllables, the hands overshoot. Closing the eyes changes almost nothing.
• Sensory. The nerves or the back columns of the spinal cord are damaged, so the brain gets no report on where the legs are. The person watches the ground while walking, puts the foot down with a slap, and in the dark loses balance abruptly.
• Vestibular. The problem is in the inner ear or its nerves. Dizziness and nausea dominate, walking veers to one side, and hand movements stay accurate.

In everyday life it looks like this: your walking drifts to one side, your hand misses the button and shakes more towards the end of the movement, handwriting sprawls, speech slows and its volume becomes uneven, the eyes move in jerks, swallowing gets harder. From the outside all of this is often taken for drunkenness, and because of that reading someone with a cerebellar stroke or a poisoning is occasionally left to sleep it off.

How fast it came on points to the cause

How quickly the problem developed is the single most useful thing you can tell a doctor.

Minutes and hours. A stroke or bleed in the cerebellum, a head injury, poisoning by alcohol, sleeping tablets, anti-seizure medicines or lithium, an acute lack of vitamin B1, less often an infection of the brain. In children, unsteadiness can follow chickenpox and other viral infections, or turn out to be caused by tablets they have swallowed.

Weeks and months. A tumour in the back of the skull, multiple sclerosis, vitamin B12 deficiency, an underactive thyroid, coeliac disease, autoimmune inflammation of the cerebellum, and the nervous system's reaction to a tumour elsewhere in the body, which is sometimes noticed before the tumour itself.

Years. Inherited ataxias, long-standing heavy drinking, degenerative diseases of the nervous system. The change is so slow that people notice it indirectly: they stopped cycling, they started running a hand along the wall.

When waiting is not an option

Call your local emergency number, 112 across much of Europe, if coordination has broken down suddenly, over minutes or hours, especially together with a severe headache, vomiting, double vision, weakness or numbness down one side of the body, or slurred speech. A cerebellar stroke looks milder than it turns out to be: within a day or two, swelling in that tight space at the back of the skull can press on the brainstem, and the window for restoring blood flow is short.

Memorise one combination separately, because it is missed more often than any other: unsteadiness, confusion and disturbed eye movements together. That is how an acute lack of vitamin B1 shows itself, typically after long-term drinking, after days of vomiting, after weight-loss surgery on the stomach, and in states of severe undernutrition or starvation. It is reversible if the vitamin is given straight away, and it leaves permanent memory damage if treatment is delayed. A glucose drip without vitamin B1 makes matters worse here, so say the suspicion out loud to the medical staff.

Do not put off getting help when unsteadiness appears in a child either, or when it grows alongside morning headaches and vomiting: that is how a tumour at the back of the skull behaves.

Causes that can be put right

Investigation is worth doing even when the picture looks hopeless, because some of the causes are reversible.

• lack of vitamins B1, B12 and E: it can be replaced, and the earlier that happens, the fuller the recovery;
• an underactive thyroid, where correcting the hormone also clears the unsteadiness;
• coeliac disease, where coordination can improve on a strict gluten-free diet;
• too much medication, whether anti-seizure drugs, lithium, benzodiazepines or certain chemotherapy agents, when adjusting the dose is sometimes enough;
• stopping alcohol halts the damage to the cerebellum, and part of what was lost comes back;
• Wilson's disease in younger people, a disorder of copper handling that is treatable and that ends badly without treatment;
• inflammation of the cerebellum, either autoimmune or linked to a tumour;
• episodic ataxia, where the attacks become less frequent on a medicine chosen by the doctor.

When ataxia runs in the family

Inherited forms build up over years; similar cases in the family happen, but far from always. Friedreich's ataxia starts in childhood or adolescence and affects more than coordination: a curved spine, damage to the heart muscle, loss of sensation in the legs and, in some people, diabetes are added to it. Here a cardiologist matters as much as a neurologist.

The spinocerebellar ataxias are a large group, usually starting in adulthood and passed down from one parent. Ataxia-telangiectasia shows itself in early childhood: alongside the unsteadiness come widened blood vessels on the whites of the eyes and on the skin, weak immunity and a raised risk of blood cancers. Episodic ataxia comes in attacks, with the person well in between.

A precise diagnosis matters for more than the label: the exact form determines which organs need watching and what to discuss with a genetic counsellor when planning children.

How the cause is tracked down

It starts with the conversation: how fast the problem came on, what the person takes, how much they drink, what their relatives have had. The neurologist then examines walking, the accuracy of movements, speech, eye movements, sensation and reflexes; the difference between the types of ataxia is already visible on examination and sets the direction of the search.

An MRI scan shows the cerebellum, the brainstem and any signs that they have shrunk; a CT scan sees that area less well and is mainly used to rule out bleeding urgently. Blood tests cover vitamins B12 and E, thyroid function, antibodies to gluten, copper metabolism and the levels of any medicines being taken. Depending on the case, doctors add spinal fluid analysis, a search for antibodies, nerve conduction studies and genetic testing; genetic tests are arranged together with genetic counselling, because the result concerns the whole family.

What helps you live with it

If the cause can be removed, that is what gets treated. For inherited and degenerative forms there is still no medicine that stops the disease. But everyday difficulty depends a great deal on what is actually done.

• work with a physiotherapist on balance and walking, one of the few things shown to improve steadiness, though the benefit lasts only while the sessions continue;
• speech and language therapy, both for speech and for swallowing;
• a walking aid set to the right height, handrails, thresholds and loose rugs removed, a light in the hall at night: falls are the main source of fractures here;
• medicines aimed at symptoms: muscle stiffness, tremor, bladder problems;
• giving up alcohol and being careful with sleeping tablets and sedatives, which make unsteadiness worse;
• cardiology follow-up in the forms that involve the heart.

Swallowing problems must not be left alone: constant choking on food and drink, repeated chest infections and weight loss are a reason to see a specialist, not to "eat more carefully". Low mood and anxiety are common with this diagnosis and respond to help.

Online consultation

In an online consultation the doctor will go through how quickly the unsteadiness appeared and how it has changed, review the medicines you take and any results you already have, and help you work out which type of problem it is and which tests come first. If what you describe fits an emergency picture, they will say so straight away.

This material is for information only and does not replace medical advice.