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Approach to sensory ataxia
Susanth MJ
1
Ataxia
• Greek ‘taxis’ = order
• Incoordination without significant weakness
• Impaired balance and/or directional limb mo...
Visual impulses from
retinae
Proprioception from ocular
muscles
judge the distance of objects from
the body
Labyrinths
Cha...
Proprioceptors
• Position of our body or parts of our body
• Force, direction, and range of movement of
the joints (kinest...
Somatotopic laminations in the posterior column
5
Posterior column sensations
• Touch-pressure
• Vibration
• Direction of movement and position of
joints
• Stereoesthesia -...
Other mediators of proprioception in the spinal cord
• Cells in the more loosely
structured "reticular" part of the
dorsal...
Clinical Testing of Sensory Ataxia
Proprioception
• Awareness of the position and movements of our limbs, fingers, and
toe...
Clinical Testing of Sensory Ataxia
Pseudoathetosis
• "piano-playing" movements
• When the patient has his arms
outstretche...
Clinical Testing of Sensory Ataxia
Romberg sign
• Compares balance as the patient stands with eyes
open and eyes closed
• ...
Clinical Testing of Sensory Ataxia
Romberg sign
• Most certain indication of abnormality is the need to
step to the side o...
Clinical Testing of Sensory Ataxia
Testing of Vibratory Sense
• Composite sensation comprising touch and rapid alterations...
Clinical Testing of Sensory Ataxia
Testing of Vibratory Sense
• Vibration and position sense are usually lost together
• O...
Sensory ataxia
Worth considering in any patient with ataxia who
has
• No nystagmus or cerebellar dysarthria.
• Romberg’s s...
Sensory ataxia Vs Cerebellar Ataxia
• Sensory ataxia is often mistaken for cerebellar ataxia,
leading to diagnostic errors...
Clinical differences between sensory and cerebellar
ataxia
Sensory ataxia Cerebellar ataxia
Nystagmus Absent Except sensor...
Clinical differences between sensory and cerebellar
ataxia
Sensory ataxia Cerebellar ataxia
Heel–shin ataxia Present (sign...
Clinical differences between sensory and cerebellar
ataxia
Sensory ataxia Cerebellar ataxia
Romberg’s sign Positive Classi...
Proposed criteria for diagnosing clinically probable
sensory ataxia
1. Ataxia confirmed by clinical examination:
– Finger–...
DDs Of Sensory Ataxia
• Pathology is most likely in the
proprioceptive system
• Anywhere in the pathway from the
periphera...
DDs Of Sensory Ataxia
21
Secondary To Peripheral
Neuropathies
Paresthesia, tingling, Pseudocramp
Symmetrical distal sens...
DDs Of Sensory Ataxia
22
Acute
Miller Fisher syndrome
Sensory variant of GBS
Semisynthetic penicillins
Subacute
Lyme d...
Miller Fisher syndrome
• Characterised by ophthalmoplegia, ataxia and
areflexia
• May be either antecedent infection (main...
Sensory variant of Guillain–Barré syndrome
• Rare
• Solely involves the large sensory fibres
• Sensory ataxia, impaired jo...
MFS and Sensory GBS
NCS
• Both may show demyelinating polyradiculoneuropathy
• MFS may often have either normal or show sm...
CIDP
• Typically presents with monophasic, relapsing or
progressive symmetrical sensory and motor neuropathy
• Evolving ov...
Sensory Ataxic form of CIDP
• Uncommon
• Manifests as prominent numbness in the extremities,
ataxia, areflexia and impaire...
Sensory Ataxic form of CIDP
• NCS show motor abnormalities typical of CIDP
• Nerve biopsy shows demyelination and remyelin...
It is worthwhile measuring antiganglioside antibodies in
all patients with otherwise idiopathic sensory ataxic
neuropathie...
Paraproteinaemic neuropathy
• Late onset slowly progressive, demyelinating neuropathy
• Distal and symmetrical, mainly sen...
Paraproteinaemic neuropathy
• NCS usually show symmetrical and predominantly distal
demyelination with disproportionately ...
Waldenström’s macroglobulinaemia
• Lymphoplasmacytoid malignancy producing IgM paraprotein
• Can present with sensory atax...
Diabetic neuropathy
• Commonly presents with distal symmetrical polyneuropathy
• Small fibres are usually affected first, ...
Coeliac ataxia
• Chronic inflammatory enteropathy
• Associated with sensitivity to ingested gluten.
• Neurological complic...
Coeliac ataxia
Clinicians should request serum antigliadin antibodies
in patients presenting with sporadic idiopathic atax...
Mitochondrial neuropathy
SANDO
Sensory Ataxic Neuropathy, Dysarthria and
Ophthalmoparesis
• Rare Triad due to mutations in...
DDs Of Sensory Ataxia
37
Subacute
HIV, HTLV-1, HCV
Small cell lung cancer
Pyridoxine intoxication
Chemotherapeutic age...
Dorsal Root Ganglionopathy
• Frequently associated with paraneoplastic disorders,
dysimmune conditions like Sjögren’s synd...
Dorsal Root Ganglionopathy
• Asymmetric, patchy neuropathic symptoms of pain, burning,
paraesthesia and sensory loss, with...
Paraneoplastic dorsal root ganglionopathy
• Subacute and rapidly progressive sensory ataxia, pain and
paraesthesia
• Most ...
Paraneoplastic dorsal root ganglionopathy
• Associated with anti onconeural antibodies
• May develop before the cancer bec...
Paraneoplastic dorsal root ganglionopathy
Antionconeural Antibodies
• anti-Hu (antineuronal nuclear autoantibodies type 1)...
Immune mediated dorsal root ganglionopathy
Sjogren’s syndrome
• Lymphocytic infiltration in the dorsal root ganglion
• Pre...
Sjogren’s syndrome
• Sensory symptoms of numbness, tingling, burning pain
and dysaesthesia
• Often asymmetric at onset
• P...
Medication-induced dorsal root ganglionopathy
Pyridoxine overuse
• Pure sensory neuropathy with features of large fibre
in...
Medication-induced dorsal root ganglionopathy
Anticancer drugs, particularly platinum compounds
like cisplatin
• Severity ...
Infection-associated dorsal root ganglionopathy
HIV
• Most common infection associated with sensory
ataxia
• Typically pre...
Infection-associated dorsal root ganglionopathy
Other infections causing sensory ataxia
• Hepatitis C
• Measles
• Epstein–...
Chronic idiopathic ataxic neuropathy
• No identifiable cause
• Indolent, slowly progressive, dorsal root
ganglionopathy
• ...
DDs Of Sensory Ataxia
50
Chronic
Chronic immune sensory
polyradiculopathy
Due to sensory nerve
root involvement
Severe sen...
Chronic immune sensory polyradiculopathy
• Preferential involvement of the large myelinated
sensory nerve roots proximal t...
Chronic immune sensory polyradiculopathy
• NCS normal, but somatosensory-evoked potentials are
abnormal, suggesting sensor...
DDs Of Sensory Ataxia
53
Due to posterior spinal
column involvement
Paresthesias in the form of tingling and
pins-and-nee...
DDs Of Sensory Ataxia
54
Chronic
Vitamin B12 deficiency
Copper deficiency
Tabes dorsalis
HIV, HCV
Cervical myelopathy...
Vitamin B12 deficiency
• Classical malabsorption disease uncommon
nowadays
• More likely occurs with
– Nitrous oxide expos...
Vitamin B12 deficiency
• Present with limb paraesthesia, subacute gait disorder
with sensory ataxia and/or spasticity
• Ex...
Vitamin B12 deficiency
• MR scan of spine may show increased T2 signal,
most commonly in the dorsal cervical and thoracic
...
Copper deficiency
• Under-recognised cause of neurological and
haematological abnormalities
Risk factors for copper defici...
Copper deficiency
• Clinical picture is often clinically and radiologically
indistinguishable from vitamin B12 deficiency
...
HIV infection
• Can cause vacuolar myelopathy
• Causes symptoms in about 10% of patients with
AIDS, although half show pat...
HIV infection
• Slowly progressive painless spastic paraparesis,
sensory ataxia and sphincter dysfunction
• MR scan of the...
Tabes dorsalis
• In late-stage or tertiary neurosyphilis
• Degeneration of the dorsal columns of the spinal cord and
senso...
Hepatitis C infection
• May cause transverse myelopathy
• Sensory ataxia may be its only manifestation
63
Compressive and demyelinating disorders
Cervical myelopathy
• Painful stiff neck, upper limb paraesthesia and gait and
bal...
Compressive and demyelinating disorders
Multiple sclerosis
• Can cause sensory ataxia if demyelination involves
the centra...
DDs Of Sensory Ataxia
66
Due to Thalamus lesions
• Involvement of the VPL and
VPM nuclei of the thalamus
• Usually because...
DDs Of Sensory Ataxia
67
Due to Parietal lesions
•Loss of proprioceptive sensation,
or to lack of spatial orientation
•Due...
Inherited causes of sensory ataxia
Complete absence of SNAPs in someone with no positive
sensory symptoms strongly suggest...
Role Of Neurophysiology
• Slowing and reduced amplitude of SNAP
– Lesions of nerve or sensory ganglion
• Severe sensory lo...
Role Of Neurophysiology
Dorsal root ganglionopathy
• SNAPs may be more affected in the upper than the lower
limbs
• Non-le...
To Detect And Diagnose Sensory Ataxias
• Initial differentiation relies heavily on a careful and
targeted clinical examina...
Other investigations
Aetiology Ancillary investigations
Miller Fisher syndrome Anti-GQ1b antibodies, CSF, NCS
Sensory vari...
Other investigations
Aetiology Ancillary investigations
HIV, HTLV-1, HCV Serology
Paraneoplastic Anti-Hu, CRMP-5, Relevant...
Other investigations
Aetiology Ancillary investigations
CISP NCS, SSEP, CSF, MRI
Vitamin B12 deficiency Serum B12, Schilli...
75
Thank you
76
Clinical Approach To Ataxia
• First step is to distinguish cerebellar, sensory and
vestibular ataxia
77
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Sensory ataxia

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Sensory ataxia

  1. 1. Approach to sensory ataxia Susanth MJ 1
  2. 2. Ataxia • Greek ‘taxis’ = order • Incoordination without significant weakness • Impaired balance and/or directional limb movements and/or dysarthria • Result from cerebellar, vestibular or sensory disorders 2
  3. 3. Visual impulses from retinae Proprioception from ocular muscles judge the distance of objects from the body Labyrinths Changes in the velocity of motion and position of the body Proprioceptors of the joints and muscles esp neck Reflex, postural, and volitional movements Cerebellar & Brainstem Structures Maintenance of Equilibrium
  4. 4. Proprioceptors • Position of our body or parts of our body • Force, direction, and range of movement of the joints (kinesthetic sense) • Sense of pressure, both painful and painless 4 Proprioceptive fibers predominantly in motor nerves Dorsal root ganglia Cell bodies of all the sensory neurons Posterior (Dorsal) Roots Posterior Columns
  5. 5. Somatotopic laminations in the posterior column 5
  6. 6. Posterior column sensations • Touch-pressure • Vibration • Direction of movement and position of joints • Stereoesthesia - recognition of surface texture, shape, numbers, and figures written on the skin • Two-point discrimination 6 Depend on patterns of touch-pressure
  7. 7. Other mediators of proprioception in the spinal cord • Cells in the more loosely structured "reticular" part of the dorsal column nuclei that receive secondary ascending fibers from the dorsal horns of the spinal cord • Project to brainstem nuclei, cerebellum, and thalamic nuclei
  8. 8. Clinical Testing of Sensory Ataxia Proprioception • Awareness of the position and movements of our limbs, fingers, and toes Two modalities comprising proprioception • Sense of position • Sense of movement – Normally, a very slight degree of movement is appreciated in the digits (as little as 1 degree of an arc) – Rapid movements are more easily detected than are slow ones 8 Usually lost together Clinical situations occurs where position is lost but movement (kinesthesia) is retained Opposite occurs but is infrequent
  9. 9. Clinical Testing of Sensory Ataxia Pseudoathetosis • "piano-playing" movements • When the patient has his arms outstretched and eyes closed, the affected arm will wander from its original position 9
  10. 10. Clinical Testing of Sensory Ataxia Romberg sign • Compares balance as the patient stands with eyes open and eyes closed • Only a marked discrepancy in balance with eyes open and with eyes closed qualifies as a Romberg sign • Mild degrees of unsteadiness in a nervous or suggestible patient may be overcome by diverting his attention 10
  11. 11. Clinical Testing of Sensory Ataxia Romberg sign • Most certain indication of abnormality is the need to step to the side or backward to avoid falling • Positive due to sensory ataxia, vestibulopathy, or motor disorder • May be difficult to perform or interpret in a grossly ataxic patient with a cerebellar disorder 11
  12. 12. Clinical Testing of Sensory Ataxia Testing of Vibratory Sense • Composite sensation comprising touch and rapid alterations of deep-pressure sense • Only cutaneous structure capable of registering such stimuli of this frequency is the rapidly adapting pacinian corpuscle • Conduction of vibratory sense depends on both cutaneous and deep afferent fibers – Rarely affected by lesions of single nerves but will be disturbed in patients with disease of multiple peripheral nerves, dorsal columns, medial lemniscus, and thalamus 12
  13. 13. Clinical Testing of Sensory Ataxia Testing of Vibratory Sense • Vibration and position sense are usually lost together • One of them (most often vibration sense) may be affected disproportionately • With advancing age, vibration is the sensation most commonly diminished, especially at the toes and ankles 13
  14. 14. Sensory ataxia Worth considering in any patient with ataxia who has • No nystagmus or cerebellar dysarthria. • Romberg’s sign • Pseudoathetosis, • Impaired joint position or vibration sense 14
  15. 15. Sensory ataxia Vs Cerebellar Ataxia • Sensory ataxia is often mistaken for cerebellar ataxia, leading to diagnostic errors and delays • Cerebellar ataxia is more common and easier to identify with certainty • ‘Sensory ataxia-plus’ syndromes may have a component of cerebellar ataxia 15
  16. 16. Clinical differences between sensory and cerebellar ataxia Sensory ataxia Cerebellar ataxia Nystagmus Absent Except sensory ataxia-plus syndromes Present Dysarthria Absent Scanning/staccato speech Eye movements Sometimes abnormal (eg, CANOMAD) Normal/slow Finger–nose ataxia Present (significantly worse with eye closure) Present 16
  17. 17. Clinical differences between sensory and cerebellar ataxia Sensory ataxia Cerebellar ataxia Heel–shin ataxia Present (significantly worse with eye closure) Present Deep tendon reflexes Absent/present Normal/pendular Joint position sense Impaired Normal Pseudoathetosis Usually present Absent Exteroceptive sensation Reduced Normal 17
  18. 18. Clinical differences between sensory and cerebellar ataxia Sensory ataxia Cerebellar ataxia Romberg’s sign Positive Classically negative Gait High stepping (stamping)/unsteady Broad-based, staggering 18
  19. 19. Proposed criteria for diagnosing clinically probable sensory ataxia 1. Ataxia confirmed by clinical examination: – Finger–nose incoordination and/ or heel–toe ataxia and/or broad-based ataxic gait 2. Two or more of: a) Romberg’s sign or ataxia significantly worse with eyes closed, or history of ‘wash basin sign’3 b) Pseudoathetosis and/or impaired joint position and/or vibration sense/s. c) Absence of nystagmus and/or cerebellar dysarthria. 19
  20. 20. DDs Of Sensory Ataxia • Pathology is most likely in the proprioceptive system • Anywhere in the pathway from the peripheral sensory nerves, dorsal root ganglia, sensory nerve roots, dorsal column of spinal cord, medial lemnisci of the brainstem and parietal cortices • Dorsal root ganglia is often the major site of pathology 20
  21. 21. DDs Of Sensory Ataxia 21 Secondary To Peripheral Neuropathies Paresthesia, tingling, Pseudocramp Symmetrical distal sensory loss Areflexia or hyporeflexia Weakness, if present, symmetrical When the neuropathy is primarily demyelinating rather than axonal, paresthesia is an early feature
  22. 22. DDs Of Sensory Ataxia 22 Acute Miller Fisher syndrome Sensory variant of GBS Semisynthetic penicillins Subacute Lyme disease Neurosarcoidosis Chronic CIDP Paraproteinaemia Diabetes mellitus Coeliac disease Vitamin E deficiency Secondary To Peripheral Neuropathies
  23. 23. Miller Fisher syndrome • Characterised by ophthalmoplegia, ataxia and areflexia • May be either antecedent infection (mainly Campylobacter jejuni and Haemophilus influenzae) and/or underlying autoimmune or neoplastic disorder • Serum anti-GQ1b IgG antibody titre is elevated in over 80% of cases 23
  24. 24. Sensory variant of Guillain–Barré syndrome • Rare • Solely involves the large sensory fibres • Sensory ataxia, impaired joint position and vibration sense and areflexia, but usually normal strength • Serum antibodies to GD1b and GQ1b gangliosides may be positive 24
  25. 25. MFS and Sensory GBS NCS • Both may show demyelinating polyradiculoneuropathy • MFS may often have either normal or show small SNAPs CSF • Normal cell count but raised protein 25
  26. 26. CIDP • Typically presents with monophasic, relapsing or progressive symmetrical sensory and motor neuropathy • Evolving over 8 weeks • Paraesthesia, proximal weakness without wasting, areflexia and loss of vibration and/or joint position sense • NCS may show either conduction slowed to the demyelinating range or partial conduction block 26
  27. 27. Sensory Ataxic form of CIDP • Uncommon • Manifests as prominent numbness in the extremities, ataxia, areflexia and impaired vibration and/or joint position sense • Weakness may be mild or absent 27
  28. 28. Sensory Ataxic form of CIDP • NCS show motor abnormalities typical of CIDP • Nerve biopsy shows demyelination and remyelination • Management is along lines similar to typical CIDP • Often responds to corticosteroids and/or intravenous immunoglobulins 28
  29. 29. It is worthwhile measuring antiganglioside antibodies in all patients with otherwise idiopathic sensory ataxic neuropathies, as intravenous immunoglobulin treatment is often effective 29
  30. 30. Paraproteinaemic neuropathy • Late onset slowly progressive, demyelinating neuropathy • Distal and symmetrical, mainly sensory neuropathy. • Monoclonal IgM antibodies against myelin-associated glycoprotein • Predominant impairment of joint position and vibration sense • May have tremor but little weakness. 30
  31. 31. Paraproteinaemic neuropathy • NCS usually show symmetrical and predominantly distal demyelination with disproportionately prolonged distal motor latencies • History of diabetes mellitus and alcohol excess (both common causes of neuropathy) do not preclude the possibility of coexisting pathology • Serum immunoelectrophoresis and immunofixation are, therefore, important investigations in the diagnostic workup of ataxic neuropathy 31
  32. 32. Waldenström’s macroglobulinaemia • Lymphoplasmacytoid malignancy producing IgM paraprotein • Can present with sensory ataxia if the IgM paraprotein shows antimyelin-associated glycoprotein activity CANOMAD • Chronic Ataxic Neuropathy, Ophthalmoplegia, Monoclonal IgM protein, Cold Agglutinins and AntiDisialosyl antibodies • Associated with anti-GQ1b and antidisialosyl antibodies 32 Paraproteinaemic neuropathy
  33. 33. Diabetic neuropathy • Commonly presents with distal symmetrical polyneuropathy • Small fibres are usually affected first, giving pain, burning, impaired spinothalamic sensations and autonomic dysfunction. • Large fibre sensation is affected later- develop paraesthesia and gait imbalance. • Often impaired vibration, joint position and pressure sensations and loss of ankle reflex • In advanced stage, there may be sensory ataxia 33
  34. 34. Coeliac ataxia • Chronic inflammatory enteropathy • Associated with sensitivity to ingested gluten. • Neurological complications occur in 6–10% – Ataxia and peripheral neuropathy are the common presentations – Ataxia may be cerebellar or sensory 34
  35. 35. Coeliac ataxia Clinicians should request serum antigliadin antibodies in patients presenting with sporadic idiopathic ataxia 35
  36. 36. Mitochondrial neuropathy SANDO Sensory Ataxic Neuropathy, Dysarthria and Ophthalmoparesis • Rare Triad due to mutations in polymerase gamma (POLG) or TWINKLE genes • As the clinical features include dysarthria, this leads to confusion with cerebellar pathology 36
  37. 37. DDs Of Sensory Ataxia 37 Subacute HIV, HTLV-1, HCV Small cell lung cancer Pyridoxine intoxication Chemotherapeutic agents Thalidomide Organophosphate exposure Colonic carcinoma Neuroendocrine tumour Breast and ovarian cancer Chronic Sjögren’s syndrome Chronic active hepatitis Due to Dorsal Root Ganglionopathies
  38. 38. Dorsal Root Ganglionopathy • Frequently associated with paraneoplastic disorders, dysimmune conditions like Sjögren’s syndrome or toxic exposure to drugs, such as chemotherapeutic agents and pyridoxine • Leads to degeneration of peripheral axons and central sensory projections in the dorsal columns • Unique pattern of non-length dependent sensory nerve degeneration 38
  39. 39. Dorsal Root Ganglionopathy • Asymmetric, patchy neuropathic symptoms of pain, burning, paraesthesia and sensory loss, with predilection for upper limbs • Early sensory ataxia, areflexia, markedly impaired proprioception, pseudoathetosis, but relatively preserved muscle strength NCS • Often marked involvement of the sensory fibres, with reduced or absent SNAPs in a non-length-dependent fashion 39
  40. 40. Paraneoplastic dorsal root ganglionopathy • Subacute and rapidly progressive sensory ataxia, pain and paraesthesia • Most commonly associated with small cell lung cancer • Other malignancies – Colonic carcinoma – Hodgkin’s lymphoma – Neuroendocrine tumours – Breast and ovarian carcinoma 40
  41. 41. Paraneoplastic dorsal root ganglionopathy • Associated with anti onconeural antibodies • May develop before the cancer becomes clinically overt • Can antedate the cancer diagnosis by 0.5–62 months 41
  42. 42. Paraneoplastic dorsal root ganglionopathy Antionconeural Antibodies • anti-Hu (antineuronal nuclear autoantibodies type 1) – Most commonly associated antibody – Sensitivity of 82% and specificity of 99% Other antibodies • antiamphyphysin • anticollapsin response mediator protein-5 (CRMP-5) 42
  43. 43. Immune mediated dorsal root ganglionopathy Sjogren’s syndrome • Lymphocytic infiltration in the dorsal root ganglion • Present with dry eyes and dry mouth • Lip biopsy can show destruction of small salivary glands and inflammatory infiltrates • Ganglionopathy almost always predates the diagnosis of Sjögren’s syndrome 43
  44. 44. Sjogren’s syndrome • Sensory symptoms of numbness, tingling, burning pain and dysaesthesia • Often asymmetric at onset • Predominantly involve the upper limbs • With progression, the symptoms and signs become symmetrical and generalised • Negative ANA/ENA (antinuclear antibody/extractable nuclear antigen) (Anti-SSA (Ro))/SSB (La) antibodies) does not exclude the diagnosis. 44
  45. 45. Medication-induced dorsal root ganglionopathy Pyridoxine overuse • Pure sensory neuropathy with features of large fibre involvement • Rarely cause sensory dorsal root ganglionopathy • Doses as little as 200 mgs per day may be the cause 45
  46. 46. Medication-induced dorsal root ganglionopathy Anticancer drugs, particularly platinum compounds like cisplatin • Severity of neuropathy usually correlates with the cumulative drug dose • Coasting – Sensory deficits may progress for several months after stopping treatment 46
  47. 47. Infection-associated dorsal root ganglionopathy HIV • Most common infection associated with sensory ataxia • Typically presents acutely or subacutely. • Peripheral neuropathy commonly associated 47
  48. 48. Infection-associated dorsal root ganglionopathy Other infections causing sensory ataxia • Hepatitis C • Measles • Epstein–Barr • Varicella zoster • Human T-cell lymphotropic virus type I 48
  49. 49. Chronic idiopathic ataxic neuropathy • No identifiable cause • Indolent, slowly progressive, dorsal root ganglionopathy • Normal strength with areflexia • CSF, EMG and motor NCS are often normal, but sensory potentials are absent • Often refractory to treatment 49
  50. 50. DDs Of Sensory Ataxia 50 Chronic Chronic immune sensory polyradiculopathy Due to sensory nerve root involvement Severe sensory loss with preserved sensory nerve action potentials
  51. 51. Chronic immune sensory polyradiculopathy • Preferential involvement of the large myelinated sensory nerve roots proximal to the dorsal root ganglion. • Presents with ataxia and limb paraesthesia. • On examination sensory ataxia, areflexia, impaired joint position and vibration sense but normal strength 51
  52. 52. Chronic immune sensory polyradiculopathy • NCS normal, but somatosensory-evoked potentials are abnormal, suggesting sensory root involvement • MRI Lumbar spine may show enlarged and enhancing nerve roots • CSF may show raised protein • Sensory rootlet biopsies may show demyelination similar to CIDP • May respond to immunomodulation 52
  53. 53. DDs Of Sensory Ataxia 53 Due to posterior spinal column involvement Paresthesias in the form of tingling and pins-and-needles sensations or girdle- and band-like sensations Loss of vibratory and position sense occurs below the level of the lesion May simulate a parietal "cortical" lesion, but differs in that vibratory sense is also lost in spinal cord syndromes
  54. 54. DDs Of Sensory Ataxia 54 Chronic Vitamin B12 deficiency Copper deficiency Tabes dorsalis HIV, HCV Cervical myelopathy Due to posterior spinal column involvement
  55. 55. Vitamin B12 deficiency • Classical malabsorption disease uncommon nowadays • More likely occurs with – Nitrous oxide exposure—anaesthesia and dental staff or recreational abusers – Gastric or ileal resections with bacterial overgrowth in blind loops, anastomoses or diverticula 55
  56. 56. Vitamin B12 deficiency • Present with limb paraesthesia, subacute gait disorder with sensory ataxia and/or spasticity • Examination shows signs of dorsal column impairment, including loss of proprioception and vibration as well as the combination of sensory ataxia and spastic paraparesis. • Length-dependent peripheral neuropathy often coexists – May manifest as depressed lower limb reflexes with stocking sensory loss 56
  57. 57. Vitamin B12 deficiency • MR scan of spine may show increased T2 signal, most commonly in the dorsal cervical and thoracic cord • May have normal or borderline B12 level • Helpful tests to confirm the diagnosis – Increased serum levels of homocysteine and methylmalonic acid 57
  58. 58. Copper deficiency • Under-recognised cause of neurological and haematological abnormalities Risk factors for copper deficiency • Previous upper gastrointestinal surgery • Zinc overload from zinc supplementation or ingestion of denture cream – Competes with copper for absorption 58
  59. 59. Copper deficiency • Clinical picture is often clinically and radiologically indistinguishable from vitamin B12 deficiency • Anaemia (microcytic, macrocytic, or normocytic), leucopenia and, rarely, thrombocytopenia. Plasma copper, caeruloplasmin levels and urinary copper levels are all reduced • Neurological syndrome is incapacitating and frequently irreversible, especially if treatment is delayed – Early diagnosis and treatment with copper supplementation is therefore essential 59
  60. 60. HIV infection • Can cause vacuolar myelopathy • Causes symptoms in about 10% of patients with AIDS, although half show pathological evidence at autopsy. • Often occurs in the late stages of HIV infection • Commonly parallels the development of AIDS dementia complex 60
  61. 61. HIV infection • Slowly progressive painless spastic paraparesis, sensory ataxia and sphincter dysfunction • MR scan of the spine usually normal although there may be non-specific tract hyperintensities 61
  62. 62. Tabes dorsalis • In late-stage or tertiary neurosyphilis • Degeneration of the dorsal columns of the spinal cord and sensory nerve roots • Lancinating or lightning-like pains, progressive sensory ataxia, proprioceptive loss and positive Romberg’s sign • Also by diabetes mellitus, vitamin B12 deficiency, and other diseases that involve the posterior roots or dorsal root ganglia 62
  63. 63. Hepatitis C infection • May cause transverse myelopathy • Sensory ataxia may be its only manifestation 63
  64. 64. Compressive and demyelinating disorders Cervical myelopathy • Painful stiff neck, upper limb paraesthesia and gait and balance disturbance Other compressive pathologies (eg, meningioma) • Cause sensory ataxia if there is predominant involvement of the posterior columns • Spastic weakness in limbs, impaired joint position and vibration sense as well as a positive romberg sign 64
  65. 65. Compressive and demyelinating disorders Multiple sclerosis • Can cause sensory ataxia if demyelination involves the central sensory pathways 65
  66. 66. DDs Of Sensory Ataxia 66 Due to Thalamus lesions • Involvement of the VPL and VPM nuclei of the thalamus • Usually because of a vascular lesion, less often because of a tumor • Position sense is affected more frequently than any other sensory function
  67. 67. DDs Of Sensory Ataxia 67 Due to Parietal lesions •Loss of proprioceptive sensation, or to lack of spatial orientation •Due to the destruction of the parietopontine fibres destined for the cerebellum •Can occur without any sensory loss
  68. 68. Inherited causes of sensory ataxia Complete absence of SNAPs in someone with no positive sensory symptoms strongly suggests a genetic cause • Friedreich’s ataxia • Ataxia with vitamin E deficiency • Abetalipoproteinaemia • Spinocerebellar ataxia with neuropathy • Mitochondrial neuropathies 68
  69. 69. Role Of Neurophysiology • Slowing and reduced amplitude of SNAP – Lesions of nerve or sensory ganglion • Severe sensory loss with preserved sensory nerve action potentials indicates a radiculopathy • Suggest the pathological process, Axonal Versus Demyelination. • Neurophysiology can and should be repeated if the clinical syndrome progresses or alters 69
  70. 70. Role Of Neurophysiology Dorsal root ganglionopathy • SNAPs may be more affected in the upper than the lower limbs • Non-length-dependent axonal degeneration helps to distinguish DRG from the more common dying-back axonal neuropathies Sensory root involvement, as in chronic immune sensory polyradiculopathy • Normal nerve conduction, but often abnormal somatosensory- evoked potentials 70
  71. 71. To Detect And Diagnose Sensory Ataxias • Initial differentiation relies heavily on a careful and targeted clinical examination • Subsequently detecting correct cause of sensory ataxia by adopting a logical anatomical approach • Requires neurophysiology – into anatomical (nerve, dorsal root ganglion, etc.) and pathological (demyelinating vs axonal) subsets 71
  72. 72. Other investigations Aetiology Ancillary investigations Miller Fisher syndrome Anti-GQ1b antibodies, CSF, NCS Sensory variant of GBS Anti-ganglioside antibodies, CSF, NCS Lyme disease Lyme serology Neurosarcoidosis CSF, NCS, ACE, chest X ray, HPE CIDP NCS, CSF Paraproteinaemia Electrophoresis, anti-MAG Diabetes mellitus Plasma glucose. Coeliac disease Anti-tTG antibodies Vitamin E deficiency Serum vitamin E level 72
  73. 73. Other investigations Aetiology Ancillary investigations HIV, HTLV-1, HCV Serology Paraneoplastic Anti-Hu, CRMP-5, Relevant imaging Pyridoxine intoxication History of exposure; pyridoxine levels Chemotherapeutic agents History of exposure Sjögren’s syndrome ENA (Anti-SSA/SSB) Abs, Lip biopsy Chronic active hepatitis RF, ANA, ASMA, hepatitis serology 73
  74. 74. Other investigations Aetiology Ancillary investigations CISP NCS, SSEP, CSF, MRI Vitamin B12 deficiency Serum B12, Schilling’s test Copper deficiency Serum copper and ceruloplasmin level. Tabes dorsalis Syphilis serology Cervical myelopathy Neuroimaging 74
  75. 75. 75
  76. 76. Thank you 76
  77. 77. Clinical Approach To Ataxia • First step is to distinguish cerebellar, sensory and vestibular ataxia 77

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