Investigations

Adults

Details of appropriate investigations for adults are found in Table 3. Primary care investigations to be done by the GP comprise those that are relatively inexpensive, common and widely available. Their purpose is to exclude medical and neurological conditions that may contribute to ataxia. Secondary care investigations are generally done by a neurologist, with referral and input from other specialists as appropriate.

It is important to consider genetic tests for common inherited ataxias, particularly if there is a family history. In certain cases the potential diagnosis may be apparent following the first clinical consultation and therefore a ‘third line’ genetic test, for example, may be undertaken immediately. See also section Genetics for genetic tests.

Table 3: Diagnostic investigations in adults

*With blood
† In patients with rapid progression

All the diagnostic tests in Table 3 should be readily available in primary or secondary care.
Tests marked a-c are only available in certain laboratories:

1. If testing for gluten ataxia is not readily available clinicians can contact Professor Marios Hadjivassiliou who runs a specialised gluten ataxia clinic. Contact details: Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield S10 2JF. Tel: 0114 271 2502.
   Also see section Treatable ataxias on gluten ataxia.
2. Testing for 14-3-3 protein in the CSF can be carried out at the National Creutzfeldt-Jakob Disease Research & Surveillance Unit, Western General Hospital, Edinburgh. Contact details: Main office telephone: 0131 537 1980/2128/3103; website: www.cjd.ed.ac.uk.
3. Coenzyme Q10 (CoQ10) levels to test for ataxia with CoQ10 deficiency. Testing of CoQ10 deficiency can be performed on skeletal muscle samples or on blood mononuclear cells²³. Testing is available at the Neurometabolic Unit, National Hospital for Neurology and Neurosurgery, London. Contact Dr Iain Hargreaves or Prof Simon Heales: iain.hargreaves@uclh.nhs.uk or simon.heales@uclh.nhs.uk  Tel: 0203 44 83844.

Children

If a child presents with ataxic symptoms, an urgent referral to local paediatric services is necessary. Targeted investigations will then depend on the clinical assessment. This includes obtaining details such as family history, whether the ataxia is acute, intermittent or chronic, any precipitants and associated conditions. It is important to consider examination findings, especially those distinguishing central from sensory ataxia. See Table 4 for differential diagnoses of ataxia that guide the choice of appropriate diagnostic tests.

The investigation of acquired ataxia in children is generally more urgent because of the necessity of excluding posterior fossa and brainstem tumours. It is also important to consider that there is a need for investigation in children as there is a risk that the cause will be genetic, and their parents may wish to have further children.

Table 4: Differential diagnoses of ataxia to guide diagnostic investigations in children

Table 5 is not exhaustive but covers diagnostic investigations in children for most conditions. These investigations are generally carried out in tertiary care. Local paediatric services should only investigate in the light of clinical judgment and in consultation with the local tertiary paediatric neurology service. Urgent referral to tertiary paediatric neurology services is almost always necessary to complete investigations and for advice about management.

In first line investigation neuroimaging is mandatory, to exclude a tumour and to look for a white matter disorder or structural condition. MR imaging of the brain (+/- spine) is the best way to view the posterior fossa²⁴, but if urgent MR imaging is not available, a CT scan will help to exclude a tumour. If possible MR spectroscopy should be obtained as well. In acute ataxia MR angiography might be indicated.

For further information on the availability of diagnostic tests see Adults section above and section Genetics.

Table 5: Diagnostic investigations in children within tertiary care