Ataxia refers to poor coordination of movement and balance. It is a symptom of neurological dysfunction rather than a specific disease. The summary discusses the causes, presentation, and classification of ataxia: 1. Ataxia can be caused by disorders of the cerebellum, sensory pathways, vestibular system, or cortical regions. It affects coordination of gait, limbs, speech, and eye movements. 2. Common signs include titubation, nystagmus, hypotonia, intentional tremors, dysarthria, and dysmetria. Causes include genetic, vascular, infectious, autoimmune, metabolic, and neoplastic etiologies. 3. Ataxias are

1. ATAXIA
Moderator : Dr VPS Punia
Presenter : Dr Akash Bharti
PG 2nd year
Department of Medicine

2. Introduction
• Ataxia is derived from greek word
• ‘a’ - not
• ‘taxis’ – orderly
• ( not orderly/ not in order)
• The term ataxia is used by clinicians to denote a syndrome of imbalance
and incoordination involving gait and limbs, as well as speech; it usually
connotes a disorder involving the cerebellum or its connections

3. • Ataxia is a symptom, not a specific disease or diagnosis.
• Ataxia means poor coordination of movement.
• The term ataxia is most often used to describe walking that is uncoordinated
and unsteady.
• Ataxia can affect coordination of fingers, hands, arms, speech (dysarthria) and
eye movements (nystagmus).
• Ataxia can also result from disturbances of sensory input to the cerebellum,
especially proprioceptive input and also involvement of vestibular system.

4. Schematic representation of the major anatomical
subdivisions of the cerebellum.

9. When to suspect ?
• Titubation : Nodding of head in AP or side to side direction

10. • Nystagmus : horizontal and jerky movements present and direction of
nystagmus towards the side of lesion
• Hypotonia: decrease in resistance to passive movement of muscles related
to depression of gamma motor neuron activity (usually seen transiently in
acute phase of cerebellar lesions), pendullar knee jerk.
• Intentional tremors : when tremors appear at the goal point of action

11. • Dysarthria: often scanning type with irregularities in tone, with words
broken into syllables; often slow with occasional rapid portions
("explosive speech")
• Dysdiadochokinesis: irregularities of force, speed, and rhythm

12. • Dyssynergia: results in jerky decomposed movements
• Dysmetria: inaccuracy in reaching target due to premature arrest of
movement (hypometria) or overshoot the target (hypermetria)
• Rebound phenomenon : inability to stop the movement of a body part
when released suddenly after applying active resistance.
• Pendular knee jerk : the first movement is followed by series of
diminishing oscillation before the leg finally comes to rest

17. Cortical Ataxias
FRONTAL LOBE ATAXIA refers to disturbed coordination due to
dysfunction of the contralateral frontal lobe;
-Results from disease involving the frontopontocerebellar fibers en route
to synapse in the pontine nuclei.
▪ Hyperreflexia,
▪ Increased tone.

19. Muscle weakness/pseudo ataxia
▪ The severe ataxia and intention tremor are presumably a result of a highly
selective peripheral disorder of spinocerebellar nerve fibers.
▪ Simple “tests of muscle power” can help detect muscle weakness in various
muscle groups

20. Labrynthine Disorders
▪ Ataxia associated with vestibular nerve or labyrinthine disease.
▪ It results in a disorder of gait associated with a significant degree
of dizziness, light-headedness, or the perception of movement

22. Thalamic Ataxias
- transient ataxia affecting contralateral limbs after lesion of anterior
thalamus
- may see associated motor (pyramidal tract) signs from involvement of
internal capsule
- also can result in asterixis in contralateral limbs (hemiasterixis)

24. THE “FOUR” QUESTIONS????
History
▪ Mode of ONSET ?
▪ PROGRESSION ?
Examination
▪ Focal /Symmetric involvement ?
▪ Localisation of the cerebellar lesion ?

26. ACUTE ONSET ATAXIA
▪ INTOXICATION: alcohol(Vermian Atrophy), lithium , phenytoin( should
be avoided in seizure with ataxia) , barbiturates
▪ POST INFECTIOUS: Acute Viral Cerebellitis(CSF supportive of acute
Viral infection), Varicella zoster virus.
▪ VASCULAR: Infarction (AICA, PICA syndromes), Haemorrhage,
Subdural hematoma ( Focal and ipsilateral cerebellar signs)

27. SUB ACUTE ATAXIA
▪ INTOXICATION: Mercury(parasthesiass, restricted visual defects), Solvents,
Glue
▪ NUTRITIONAL: B1 and B12 deficiency
▪ INFECTION: HIV
▪ DEMYELINATING: Multiple Sclerosis
▪ NEOPLASTIC: Glioma, Metastases

28. CHRONIC ATAXIA
▪ AUTOIMMUNE CAUSES : Paraneoplastic syndromes, Gluten
hypersensitivity, Anti GAD(Glutamic acid decarboxylase) antibodies.
▪ HYPOTHYROIDISM
▪ INFECTIONS: Syphilis (Tabes Dorasalis)
▪ CONGENITAL LESIONS: Arnold-Chiari and Dandy Walker Syndromes
▪ INHERITED ATAXIAS: AD,AR,XR,XD,Mitochondrial

29. PROGRESSION
▪ Progressive
▪ Static
▪ Intermittent symptoms
▪ Reversible Ataxias

30. PROGRESSIVE ATAXIA
CLASSIFICATIONS OF GREENFIELD AND OF HARDING into three
main groups:
▪ (1) SPINOCEREBELLAR ATAXIAS, with unmistakable involvement of
the spinal cord (Romberg sign, sensory loss, diminished tendon reflexes,
Babinski signs);
▪ (2) PURE CEREBELLAR ATAXIAS, with no other associated
neurologic disorders; and

31. ▪ (3)COMPLICATED CEREBELLAR ATAXIAS, with a variety of
pyramidal, extrapyramidal, retinal, optic nerve, oculomotor, auditory,
peripheral nerve, and cerebrocortical accompaniments including what is
now referred to as multiple system atrophy

32. STATIC ATAXIAS
▪ Vascular causes
REVERSIBLE ATAXIAS
• Infectious causes – post viral
• Thyroid( hypothyroidism)
• Drugs
• Toxins
INTERMITTENT SYMPTOMS
• Episodic Ataxias (Inherited etiology)

33. FOCAL / SYMMETRIC ATAXIAS
▪ Cerebellar symptoms on same side of lesion, or
▪ Bilateral symptoms
FOCAL ATAXIAS
Vascular causes, Multiple Sclerosis, Cerebellar abscess, cerebellar glioma,
PML (HIV), Congenital causes.
SYMMETRIC ATAXIAS Intoxication, Nutritional, Post in hectious,
Hypothyroid, Autoimmune causes

38. ACQUIRED ATAXIAS
▪ First rule out the Structural causes (MRI Brain/ CT head)
-CVJ (Cranio vertibro Junctional) anomalies
-Posterior fossa tumors
-Demyelinating diseases
-Hypoxic encephalopathies
-Vascular causes- infarct, haemorrhage

39. INHERITED ATAXIAS
▪ AD
▪ AR
▪ MITOCHONDRIAL DISTURBANCES
▪ X LINKED RECESSIVE
▪ X LINKED DOMINANT

40. AUTOSOMAL DOMINANT
▪ SPINO CEREBELLAR ATAXIAS (Types1-40)- previously
olivopontocerebellar atrophies
▪ DentatoRubroPallidoLuysian Atrophy
▪ EPISODIC ATAXIAS (Types 1-7)

41. SCA(spino cerebellar ataxia)
SALIENT FEATURES
▪ 3-5th decade of life ONSET, loss of ambulation over 10-15 yrs. from
onset
▪ Differs from each SCA responsible for various ages of presentation
and variable phenotypic expression
▪ CAG polyglutamate repeat expansion in most of them.

42. Salient features
• UMN SIGNS- SCA 1, SCA7, SCA 8
• OLDER AGE- SCA 6
• MENTAL RETARDATION- SCA 13
• VISUAL LOSS- SCA 7
• CHOREA, MYOCLONUS- DRPLA

43. • SEIZURES- SCA 10
• AREFLEXIA- SCA 2
• INTEREPISODIC NYSTAGMUS- EA 2
• INTEREPISODIC MYOKYMIA- EA1
• NO FAMILY h/o- SCA 6

44. Machado-Joseph Disease/Sca3
• In most populations, it is the most common autosomal dominant ataxia.
Symptoms and Signs
• MJD has been classified into three clinical types.
In type I MJD (amyotrophic lateral sclerosis–parkinsonism–dystonia type),
• Neurologic-deficits appear in the first two decades and
• Involve weakness and spasticity of extremities, especially the legs, often with dystonia of
the face, neck, trunk, and extremities.
• Patellar and ankle clonus are common, as are extensor plantar responses. The gait is slow
and stiff, with a slightly broadened base and lurching from side to side; this gait results
from spasticity, not true ataxia.

45. - There is no truncal titubation.
- Pharyngeal weakness and spasticity cause difficulty with speech and
swallowing.
- Horizontal and vertical nystagmus, loss of fast saccadic eye movements,
hypermetric and hypometric saccades, and impairment of upward vertical
gaze.
- Facial fasciculations, facial myokymia, lingual fasciculations without
atrophy, ophthalmoparesis, and ocular prominence are common early
manifestations.

46. • In type II MJD (ataxic type)
- True cerebellar deficits of dysarthria and gait and extremity ataxia begin in
the second to fourth decades along with corticospinal and extrapyramidal
deficits of spasticity, rigidity, and dystonia.
- Type II is the most common form of MJD. Ophthalmoparesis, upward
vertical gaze deficits, and facial and lingual fasciculations are also present.
- Type II MJD can be distinguished from the clinically similar disorders
SCA1 and SCA2.

47. • Type III MJD (ataxic-amyotrophic type)
- Presents in the fifth to the seventh decades with a pancerebellar disorder
that includes dysarthria and gait and extremity ataxia.
- Distal sensory loss involving pain, touch, vibration, and position senses and
distal atrophy are prominent, indicating the presence of peripheral
neuropathy.
- The deep tendon reflexes are depressed to absent, and there are no
corticospinal or extrapyramidal findings.

48. • The mean age of onset of symptoms in MJD is 25 years.
• Neurologic deficits invariably progress and lead to death from debilitation
within 15 years of onset, especially in patients with types I and II disease.
• Usually, patients retain full intellectual function.
• The major pathologic findings are variable loss of neurons and glial
replacement in the corpus striatum and severe loss of neurons in the pars
compacta of the substantia nigra.

49. • A moderate loss of neurons occurs in the dentate nucleus of the cerebellum and
in the red nucleus.
• Purkinje cell loss and granule cell loss occur in the cerebellar cortex.
• Cell loss also occurs in the dentate nucleus and in the cranial nerve motor
nuclei.
• Sparing of the inferior olives distinguishes MJD from other dominantly
inherited ataxias.

50. AUTOSOMAL RECESSIVE ATAXIAS
▪ FRIEDREICH’S ATAXIA
▪ ATAXIA TELANGIECTASIA
▪ ATAXIA WITH ISOLATED VIT.E DEFICIENCY
▪ ABETALIPOPROTEINEMIA
▪ ENZYME DEFICIENCIES (Maple Syrup urine disease, Urea cycle
defects, Sialidosis, Adrenoleucodystrophy, Organic aciduria,
Pyruvate dehydogenase def.)

51. FRIEDREICH’S ATAXIA
▪ Friedreich's ataxia is an autosomal recessive inherited disease that causes
progressive damage to the nervous system.
▪ Unstable expansion of GAA repeats
FRATAXIN protein
iron accumulation in mitochondria
neuronal injury.
▪ May present as classical or associated with vit E deficiency.

52. ▪ Progressive staggering gait, frequent falling and titubation.
▪ May be associated with progressive scoliosis, foot deformity,
cardiomegaly, conduction defects.
▪ NATURAL HISTORY:
-onset <25 yrs. At ADOLESCENCE
-loss of ambulation 15 yrs. Since onset
-Death usualy due to cardiac complications.
Median age of death 35 years.

54. ATAXIA TELANGIECTASIA
▪ Present in 1st decade.
▪ OCULOMOTOR APRAXIA , TELANGIECATSIAS IN EYES, SKIN,
deficits in cerebellar function and nystagmus

55. SPORADIC or IDIOPATHIC ATAXIAS
▪ Unknown genetic defects after ruling out acquired causes
▪ Old age of onset
▪ Presents with Dysautonomia –Orthostatic hypotension, erectile dysfunction,
Urinary incontinence

56. Investigations
• MRI Brain and Upper cervical cord
• CT Head
• Vit. E, B12 levels
• Total cholesterol levels, Thyroid hormones
• NCV and EMG studies (to rule out other systems’ involvement)
• Toxicology screen (includes phenytoin levels)

57. • Serology screen (for autoantibodies)
• CSF analysis
• Genetic Analyses (GAA, CGG, CAG repeat analyses)

58. TREATMENT
▪ Reversible causes to be identified and treated
▪ Structural lesions to be considered for surgery
▪ Dietary modifications
▪ IDEBENONE- in Friedreich’s Ataxia
▪ RILUZOLE- in Friedereich’s Ataxia
▪ ACETAZOLAMIDE- in Episodc Ataxia
▪ GENETIC COUNSELLING

59. • Treatable causes of ataxia
• Hypothyroidism
• Vitamin B12 deficiency
• Refsum’s disease
• Wilson’s Disease

60. • Ataxia with anti-gliadin antibodies and gluten senstive enteropathy
• Ataxia due to malabsorption syndromes
• Lyme’s disease
• Mitochondrial encephalomyopathies, aminoacidopathies,
Leukodystrophies and urea cycle abnormalities

61. SUMMARY
▪ RULE OUT “ATAXIA MIMICKERS”
▪ CONFIRM PREDOMINANT CEREBELLAR INVOLVEMENT
WITH RESPECTIVE TESTS
▪ ANSWER THE “FOUR” QUESTIONS (Onset, progression,
Symmetry, Localisation of lesion)
▪ RULE OUT ACQUIRED CAUSES
▪ GENETIC ANALYSES

62. Thank you