Ataxia

Topic: Ataxia

Ideal for: BPT and BOT students

Level: Beginner

1. ATAXIA

2. DEFINITION Ataxia (Greek word=“lack of order”) is a neurological disorder consisting of lack of voluntary coordination of muscle movements Ataxia is a non specific clinical manifestation implying dysfunction of parts of nervous system that coordinate movement such as CEREBELLUM.

3. TYPES OF ATAXIA There are over 50 to 100 types of ataxia but can be classified under 3 broad headings: HEREDITARY ATAXIA– one that runs in the family and is inherited genetically IDIOPATHIC LATE ONSET CEREBELLAR ATAXIA (ILOA)– cerebellum is progressively damage due to unexplained cause ACQUIRED ATAXIA– ataxia due to stroke or other brain disease.

4. HEREDITARY ATAXIA FRIEDREICH’S ATAXIA- This is the commonest type of ataxia having half of all its cases. Symptoms usually begins to appear in childhood between 8 to 15 years It is transmitted by autosomal recessive inheritance and is due to an expanded GAA trinucleotide repeat in a non coding region of an gene of chromosome 9

5. CLINICAL FINDINGS Initial symptom is progressive gait ataxia followed by ataxia of all limb within 2 yrs. During the same early period, knee and ankle tendon reflexes are lost and cerebeller dysarthria. Joint position sense (proprioception) and vibration are impaired in the legs, typically adding sensory component to gait ataxia Weakness of legs and less often in arms-is a later development and may be of UMN and LMN variety or both

6. Contd. Extensors planter responses appear during first 5 years Pes cavus is widely recognized Severe progressive kyphoscolosis contributes to functional disabilities and may lead to chronic restrictive lung disease. Cardiomyopathy is sometimes detectable Other abnormalities includes visual impairments including optic atropy , nystagmus , paresthesia , tremor, hearing loss, vertigo, spasticity, leg pains and DM

7. ATAXIA DUE TO VITAMIN-E DEFICIENCY Rare form of ataxia also begin in childhood. Lack of vitamin E leads to nerve damage. Symptom are similar to Friedreich’s ataxia but symptoms may be relieved by providing vitamin E as supplements

8. ATAXIA -TELANGIECTASIA This is rare type of ataxia seen in 1 in 100,000 babies. Symptoms usually begin in early childhood and progressively worsen with age

9. ATAXIA -TELANGIECTASIA The name is derived from small, spider like clusters of red blood vessels in the corner of their eyes and on their cheeks called telangiectases . This usually co-exists with a weak immune system making the children more vulnerable to infections.

10. SENSORY ATAXIA Results from disorders that affects the propioceptive pathways in peripheral sensory nerves, sensory roots, posterior column of SC, or medial lemniscus . Sensory ataxia from polyneuropathy or posterior column lesion typically affects the gait and legs in symmetric fashion: the arms are involved to a lesser extent. Examination reveals impaired sensations of joint position and movement in the affected limbs, and vibratory sense is also commonly distributed. Vertigo, nystagmus , and dysarthria are characteristically absent.

11. CEREBELLAR ATAXIA It is a generalized comprehensive terminology denoting the cerebellar dysfunction comprising problems of posture, movement patterns and gait. Cerebellar ataxias are a group of neurodegenerative disorders characterized by progressive degeneration of the cerebellum and often accompanied by a variety of neurological and other systemic symptoms.

12. CLASSIFICATION OF CEREBELLAR ATAXIA 1.HEREDITARY CEREBELLAR ATAXIA A.AUTOSOMAL DOMINANT CEREBELLAR ATAXIA(ADCA) -EPISODIC ATAXIAS (types 1-6) -SPINOCEREBELLAR ATAXIA(SCA)subtypes 1-28 -DENTATATORUBRAL-PALLIDOLUYSIAN ATROPHY(DRPLA)

13. CAUSES Hemorrhagic or ischaemic leisons Tumours ( Cerebellopontine angle tumors) Progressive sclerosis of cerebellum Trauma involving cerebellum (ex-head injury) Cerebrovascular disease Pontoneocerebellar hypoplasia Granule cell layer hypoplasia Hypoplasia of cerebellar vermis

14. Contd. B.AUTOSOMAL RECESSIVE CEREBELLAR ATAXIAS -With identified gene defect -with identified gene locus -As part of metabolic disorder -Other metabolic degenerative disease with congenital or childhood onset

15. Contd. X-linked cerebellar ataxia - Adrenoleukodystophy -fragile x-tremor ataxia syndrome(FXTAS) -Hereditary sideroblastic anemia and ataxia -other x-linked congenital and childhood ataxias D.MITOCHONDRIAL CEREBELLAR ATAXIA

16. 2.SPORADIC CEREBELLAR ATAXIA A.SYMPTOMATIC CEREBELLAR ATAXIA -STRUCTURAL LEISONS,MALFORMATION -TOXIC .ALCOHOL .DRUGS Antiepileptic drugs Benzodiazepines Lithium Antineoplastics Others Heavy metals ( mercury,lead ) chemicals ( solvents,pesticides )

17. Contd. -ENDOCRINE Hypothyriodism -MALABSORPTION celiac disease (gluten ataxia) vitamin deficiency -MISCELLANEOUS Paraneoplastic syndromes Demyelinating disorders -INFLAMMATORY whipple disease

18. Contd. IDIOPATHIC -Multiple system atrophy (MSA) -Idiopathic late onset cerebellar ataxia (ILOSCA)

19. CLINICAL FEATURES Aesthenia Heavinessin limbs Hypotonicity Diminished DTR Movement decomposition Dysmetria Rebound phenomenon Dysdiadochokinesia Intentional tremors Scanning speech Dysphagia Nystagmus CARDINAL FEATURES-NYSTAGMUS, SCANNING SPEECH AND INTENTIONAL TREMORS

20. CLINICAL FEATURES - Gait wide BOS, Step and stride length are unequal, absent or reduced arm swinging, can’t turn around, can’t walk in straight line, can’t step over the obstacle, stair climbing difficult, can’t walk slippery surfaces or unequal terrain.

21. SPINOCEREBELLAR ATAXIA Any of a group of inherited neurodegenerative disorders that are characterized by cerebellar dysfunction manifested especially by progressive ataxia. In addition, they are often associated with poor coordination of hand movements, eye movements, and speech. The onset of symptoms usually occurs after the age of 18.

22. SPINOCEREBELLAR ATAXIA INHERITANCE OF DOMINANT SCA It is autosomal dominant. Affects males and females equally.

23. SPINOCEREBELLAR ATAXIA Anticipation and penetrance Many types of SCA are characterized by a phenomenon called anticipation . Anticipation refers to an earlier age of symptoms and increasing severity of disease from generation to generation in a family. In other words, an affected child can have more severe disease symptoms than his or her affected parent.

24. SPINOCEREBELLAR ATAXIA Anticipation and penetrance The term penetrance refers to the proportion of individuals with the gene for SCA who will actually develop symptoms. In all types of SCA, penetrance is very high, meaning that almost everyone will develop symptoms of SCA at some point in their lifetime. In some cases, however, a may die of other causes before showing symptoms of SCA.

25. General description of the types of SCA (The number 9 is not used.)

26. General description of the types of SCA (The number 9 is not used.)

27. MRI scans of two brains. The brain on the left shows atrophy of the cerebellum in a person with SCA. The brain on the right shows a normal cerebellum.

28. EPISODIC ATAXIAS These are also known as PAROXYSMAL ATAXIAS They are characterized by episodes of ataxia including dysarthria, tremor and nystagmus lasting minutes to hours. The episodic ataxias are subdivided into two disorders on clinical and genetic grounds In both disorders episodes are suppressed by acetazolamide . Patients need to be warned about the risk of nephrolithiasis on long term acetazolamide therapy, the incidence of this complication is estimated at 20%. Some patients may experience a progressive ataxia underlying the short lived episodes

29. INVESTIGATIVE STUDIES BLOOD STUDIES Blood studies may disclose the hematologic abnormalities associated with vitamin B12 deficiency, the decreased levels of thyroid hormones in hypothyrodism , the elevated hepatic enzymes and low ceruloplasmin and copper concentrations in Wilson's disease, immunoglobulin deficiency and elevated alpha-fetoprotein in ataxia-telangiectasia, antibodies to Purkinje cell, antigens in paraneoplastic cerebellar degenerations, or genetic abnormalities associated with hereditary spinocerebellar degenerations.

30. CEREBROSPINAL FLUID STUDIES The CSF show elevated protein with cerebellopontine angle tumors (Ex-acoustic neuroma), brainstem or spinal cord tumors, hypothyroidism, and some polyneuropathies. Increased protein with pleocytosis is commonly found with infectious or parainfectious encephalitis, paraneoplastic cerebellar degeneration, and neurosyphilis .

31. IMAGING The CT Scan is useful for demonstrating posterior fossa tumors or malformations, cerebellar infarction or hemorrhage, and cerebellar atrophy associated with degenerative disorders. MRI-Provides better visualization of posterior fossa lesions, including cerebellopontine angle tumors, and is superior to CT scanning for detecting the lesions of multiple sclerosis.

32. EVOKED POTENTIAL TESTING Evoked potential testing, especially of optic pathways(visual evoked potentials),may be helpful in evaluating patients with suspected multiple sclerosis. Brainstem auditory evoked potentials may be abnormal in patients with cerebellopontine angle tumors even though CT Scans show no abnormality.

33. CHEST X-RAY & ECHOCARDIOGRAPHY The chest x-ray or echocardiogram may provide evidence of cardiomyopathy associated with Friedreich’s ataxia. The chest x-ray may also show a lung tumor in paraneoplastic cerebellar degeneration.

34. SPECIAL STUDIES In vestibular disorders, three additional special investigations may be of help. A. Audiometery - is useful when vestibular disorders are associated with auditory impairment, such testing can distinguish conductive, labyrinthine, acoustic nerve and brainstem disease. Tests of pure tone hearing are abnormal when sounds are transmitted through air with conductive hearing loss and when transmitted through air with conductive hearing loss and when transmitted through either air or bone with labyrinthine or acoustic nerve disorders. Speech discrimination is markedly impaired with acoustic nerve lesions, less so with disorders of the labyrinth. speech discrimination is normal in conductive or brainstem involvement.

35. B.ELECTRONYSTAGMOGRAPHY (ENG) This test can be used to detect and characterize nystagmus , including and elicited by caloric stimulation.

36. c.AUDITORY EVOKED RESPONSE This is test can localize vestibular disease to the peripheral vestibular pathways

37. MANAGEMENT Intoxications have to be cleared Vitamin deficiencies have to be recovered Endocrine disorders have to be dealt with Levo hydroxy tryptophan and iron chelation Genetic counseling PT and OT In autosomal dominant acetazolamide is very effective