The word ataxia derives from ataktos, a Greek word meaning ‘lack of order’; it has been defined variously as a failure of coordination of the muscles; irregularity of muscle action; difficulty with walking/gait; the problem with movement orientation because of abnormal agonist-antagonist muscle coordination; or motor incoordination most notable when walking or sitting.

2. The word ataxia derives from ataktos, a Greek word meaning ‘lack of
order’; it has been defined variously as a failure of coordination of the
muscles; irregularity of muscle action; difficulty with walking/gait; the
problem with movement orientation because of abnormal agonist-
antagonist muscle coordination; or motor incoordination most notable
when walking or sitting.
There is a spectrum of unsteadiness in walking, from ‘clumsy’ to
profound ataxias.

3. •Acute.
•Recurrent (also called episodic or intermittent).
•Chronic/progressive.

4. Acute ataxia (meaning evolution of symptoms within 3
days) has a few common causes which account for 80%
of children with this:
1. intoxications;
2. infectious causes (varicella)
3. post-infectious causes (Guillain-Barré syndrome).

5. Recurrent ataxia can be due to mitochondrial
disorders or other metabolic disorders (aminoacidurias
[e.g., Hartnup disease], organic acidaemias [e.g.,
Maple Syrup Urine Disease (MSUD)], or lysosomal
storage diseases [e.g., Niemann-Pick type C]).

6. Progressive ataxia has a wide differential including
hereditary ataxias, metabolic disorders, brain tumors,
and neurodegenerative conditions such as
leucodystrophies (adrenoleukodystrophy,
metachromatic, Pelizaeus–Merzbacher disease).
Although acute ataxia usually has a benign cause,
recurrent and progressive ataxia generally indicates
more serious pathology.

7. F=FRDA (Friedreich ataxia)
L=Labyrinthitis (vertigo causing ataxia)/Lysosomal storage
diseases
A=
 AT (ataxia-telangiectasia),
 Abetalipoproteinaemia,
 Argininosuccinic aciduria
M=
 Medulloblastoma,
 Metabolic: MSUD (maple syrup urine disease),
 MLD (metachromatic leucodystrophy, also called
arylsulfatase A [ARSA] deficiency),
 Metal disease: Wilson Disease,
 Migraine: basilar artery,
 Mitochondrial disorders (Kearns-Sayre, MERRF
(myoclonic epilepsy with ragged red fibers), NARP
(neuropathy, ataxia, and retinitis pigmentosa),
 Multiple sclerosis,
 Myxedema (hypothyroidism)

8. I=
 Infection (e.g., cerebellitis, meningitis, mastoiditis),
 IEMs (Inborn errors of metabolism, e.g., OTC [ornithine transcarbamylase
deficiency]
N=Neuroblastoma (occult)
G=GBS (Guillain-Barré syndrome)/Genetic (hereditary) ataxias (many)
S=
 SCAs (spinocerebellar ataxias, autosomal dominant),
 SCARs (spinocerebellar ataxias, autosomal recessive),
 SPAX (spinocerebellar ataxias with prominent spasticity),
 Supratentorial tumours
P=
 Post-infectious cerebellitis,
 Posterior fossa tumors,
 Paroxysmal vertigo,
 Pellagra (niacin deficiency; can cause the four Ds: dermatitis
(photosensitive), diarrhea, dementia, and death),
 Pellagra-like dermatosis (Hartnup disorder [HND]),
 Pyruvate Carboxylase deficiency,
 Psychogenic (not real ataxia, but impersonating this)

9. I=Intoxication/Ingestion (drugs)/Inner ear pathology (e.g.
labyrinthitis)
N=Nutritional deficiencies: deficiencies of vitamin B1
(thiamine), B3 (niacin/nicotinic acid), B6 (pyridoxine), B12
(cobalamin), E
N=Neurodegenerative disorders
E=Ependymoma/EA (episodic ataxias)
R=Refsum disease, Rett syndrome

10. •Start by introducing yourself to the parent and the child.
•Note the child’s level of consciousness,
• alertness (medications [toxins] or encephalopathies—e.g., acute disseminated
encephalomyelitis [ADEM] can alter these),
• quality of movement (e.g., choreoathetosis with AT)
• any obvious asymmetry, such as head tilt (ataxia plus head tilt equals posterior fossa
tumor until proved otherwise),
• scoliosis (can occur in ataxic cerebral palsy or FRDA),
• asymmetrical ataxia (which can mean brain tumor, stroke, or demyelinating disease).
•If the child is sitting or lying down when first seen, look around for any nearby
peripheral aides such as a wheelchair.
•If the child’s feet are uncovered, note any pes cavus (FRDA).

11. Stand back and look for
o any rash, such as telangiectasia over the eyes and ears and bridge
of the nose in AT,
o resolving varicella (acute cerebellitis, post-infectious cerebellar
ataxia);
o pellagra-like rash, with hyperpigmented, crusted, and fissured well-
defined plaques on sun-exposed areas of the face,
o dorsum of hands and legs (Hartnup disease; ‘pellagrous glove and
boot’);
o urticaria (Kawasaki) or
o purpura (Henoch–Schönlein);
o ichthyosis with Refsum disease.

12.  Ask the child a few age-appropriate questions (e.g., their age, school,
grade, teacher’s name, favorite subjects, and in older children,
specifically ask their full name, current location, and day of the week),
to get an impression of their orientation in time, place and person (for
intoxications or encephalopathies) and the quality of their speech (e.g.,
slurring with AT).
 If the child is sitting or lying down initially, ask the child, parent, or
examiners whether the child can walk. If the child can walk, then
perform a gait examination. Focus on heel-toe (tandem) walking in
particular to check cerebellar vermis function.

13.  Also, note any scoliosis during the gait examination, which can
occur with any more progressive neurodegenerative disorders, or
with FRDA, Rett disorder, or ataxic cerebral palsy.
 When the child is walking on their heel and toes, any pes cavus
should be easily seen (FRDA).
 In the lower limbs, focus on cerebellar and proprioceptive
function and muscle strength;
 examine the upper limbs. Take note of the muscle bulk in the
hands (for peripheral neuropathy), and take the pulse for any
arrhythmia (embolic cause of cerebellar stroke, mitochondrial
disease with pre-excitation, cardiomyopathy with mitochondrial
disease or FRDA).

14. During the cranial nerve examination,
o thoroughly check the third, fourth and sixth nerve
function,
o look for nystagmus (many hereditary ataxias) or
opsoclonus (neuroblastoma),
o checking the hearing (acute middle and inner ear
pathology, FRDA, Refsum).
o Check the eyes carefully for visual acuity, visual
fields, and then ask to examine the fundi (for evidence
of papilloedema, retinitis, or optic atrophy).

15. The other findings sought on the head and neck examination including
o checking the head circumference (for hydrocephalus, such as from
aqueduct stenosis or tumors),
o looking for scars of shunts or other neurosurgery, feeling the head
for shunts, reservoirs.
o Feel the hair (abnormal in argininosuccinic acid and AT),
o look at the eyes (bulbar conjunctivae), nose and ears, for
telangiectasia (AT).
o Next, check the ears, nose, throat, and mastoids for infection
(labyrinthitis) and,
o if relevant, perform the Dix-Hallpike maneuver (only suggest this if
you think the patient could have benign paroxysmal vertigo).
o Then check for any other site of infection (for infectious or post-
infectious ataxia causes), including checking for signs of meningitis
if the child is febrile.

16.  A full cardiorespiratory examination is appropriate.
o The BP is checked for hypertension (neuroblastoma, or
hypertension as cause of stroke).
o The heart is examined for murmurs or arrhythmias
(embolic stroke).
 The chest is examined for two reasons: first to check for
involvement in any neurological process that can affect
respiratory reserve, as with GBS (get the child to count out
loud; how far can they count?), and second to check for signs
of chest infection, such as Mycoplasma which may present
with crackles and wheezes.

17.  The abdomen should be examined for
hepatosplenomegaly (EBV) or any masses
(neuroblastoma).
 After your examination, present a relevant
differential diagnosis and suggest the investigations
most appropriate to confirm your diagnosis. This is a
vast area. Suggesting brain (+/– spinal cord) imaging
and gene tests are often appropriate.

18. Ataxia-telangiectasia (AT) (ATAXIA CASE):
 ATM (ataxia-telangiectasia mutated) gene codes for serine-protein kinase
ATM; only known cause/Age: ataxia/cerebellar dysfunction (onset 1–4
years) antedates telangiectasia/IgA (Immunoglobulin A) decreased
 Telangiectasia of exposed areas (bulbar conjunctivae, nose [bridge],
ears, neck, antecubital fossa): age 3 to 10 years/Ten years of age often
require wheelchair/Truncal ataxia/Tone decreased/Three out of ten
develop malignancy (usually [85%] leukemia or lymphoma)
 Apraxia of eye movement (cannot follow object across field; vertical and
horizontal saccadic movements affected) and nystagmus
 X-ray of the chest (CXR) for sinopulmonary infection (increased
susceptibility)
 Immune deficiency (cell-mediated immunity decreased)/Ionising
radiation sensitivity
 Absent reflexes
 Choreoathetosis
 Cancer risk 40–100 times normal; especially ALL, AML, lymphoma, brain
tumors, adenocarcinoma of the stomach, basal cell carcinoma, ovarian
dysgerminoma
 Alpha-fetoprotein (AFP) increased/Ageing appears premature (grey hair)
 Speech slurred (dysarthria)/Susceptibility to sinobronchopulmonary
infections and serious neoplasia (as above)
 Elevated carcinoembryonic antigen/Endocrine: insulin-resistant
diabetes/Elasticity of skin is lost/Eleven = chromosome locus (11q22.3)

19. FRIEDREICH ATAXIA (FRDA) (FRIEDREICHS):
 FXN gene (at 9q13) codes for frataxin, a mitochondrial protein; only known
cause/Five–fifteen age group/Feet: pes cavus
 Reduced sense of vibration, position/Romberg test positive/Recessive
 Impaired sense of vision
 Eyes: optic atrophy/nystagmus
 Dysarthria
 Deafness
 Reflexes in lower limb absent, but …
 Extensor plantar/Equinovarus feet (plantar flexors, inverters affected)
 Insulin requirement (T1DM)
 Iron misdistribution in mitochondria allows oxidative damage, decreased
ATP production
 Cardiac disease; hypertrophic non-obstructive cardiomyopathy
 Hyperglycaemia (diabetes in up to 30%)
 Spastic lower limbs (pyramidal weakness)/Scoliosis

20. Mitochondrial disorders (MITOCHONDRIAL):
 Myopathy (proximal)
 Myoclonus
 Migraine
 Inheritance recessive
 Tubular (renal) defects
 Optic atrophy
 Cataract/Chorea
 Heart: cardiomyopathy/pre-excitation syndromes
 Ophthalmoplegia
 Neuropathy
 Neurogenic weakness
 Neurologic: encephalopathy
 Deafness (sensorineural)/Diabetes/Dementia
 Retinopathy (pigmentary)
 Increased lactate: blood (fasting > 3.0 mmol/L); CSF > 1.5 mmol/L
 Ataxia
 Lid: ptosis
 Seizure
 Stroke-like episodes
 Spasticity