SACD Of Cord/Tropical Ataxic Neuropathy

Question 1

What is Subacute Combined Degeneration (SCD) of the spinal cord?

Answer 1

A condition affecting the posterior and lateral spinal cord columns caused by vitamin B12 deficiency.

Question 2

Which spinal cord tracts are affected in SCD?

Answer 2

Posterior columns (vibration and proprioception) and lateral corticospinal tracts (voluntary motor control).

Question 3

Why is vitamin B12 important for the spinal cord?

Answer 3

B12 is needed for myelin synthesis; deficiency leads to increased methylmalonic acid, causing myelin damage.

Question 4

What is the earliest pathology seen in SCD?

Answer 4

Degeneration of long, myelin-rich spinal cord tracts.

Question 5

What are the sensory symptoms of SCD?

Answer 5

Numbness and tingling in a glove and stocking pattern, ataxia, and positive Romberg sign.

Question 6

What are the motor symptoms of SCD?

Answer 6

Spasticity, brisk reflexes, and Babinski sign.

Question 7

What are the late neurological features of SCD?

Answer 7

Cognitive and mood changes.

Question 8

What hematological findings are seen in SCD?

Answer 8

Macrocytic anemia and hypersegmented neutrophils on CBC.

Question 9

Which biomarkers are elevated in vitamin B12 deficiency?

Answer 9

Methylmalonic acid and homocysteine.

Question 10

Which MRI finding is characteristic of SCD?

Answer 10

T2-weighted MRI shows an inverted ‘V’ sign in the posterior columns.

Question 11

Who are at risk of developing SCD?

Answer 11

Vegans, elderly, patients with pernicious anemia, Crohn’s disease, or history of gastric surgery.

Question 12

Which substances or deficiencies can mimic or contribute to SCD?

Answer 12

Nitrous oxide abuse and copper deficiency.

Question 13

What is the preferred treatment for SCD?

Answer 13

Intramuscular hydroxocobalamin.

Question 14

When is oral B12 treatment appropriate?

Answer 14

If there is no gastrointestinal malabsorption.

Question 15

What determines the prognosis of SCD?

Answer 15

Early treatment leads to recovery, while late diagnosis may cause permanent damage.

Question 16

What is the spinal cord?

Answer 16

Extension of the CNS below the skull, housed by the vertebral canal and covered by pia, arachnoid, and dura mater.

Question 17

Where is cerebrospinal fluid (CSF) located in the spinal cord?

Answer 17

In the subarachnoid space between pia and arachnoid mater.

Question 18

What is the conus medullaris?

Answer 18

The tapered end of the spinal cord at L2.

Question 19

What is the cauda equina?

Answer 19

Cluster of lower lumbar and sacral nerve roots below the conus medullaris, within the lumbar cistern.

Question 20

Why is there a discrepancy in spinal cord and vertebral spine length?

Answer 20

Due to continued growth of the vertebral column after the spinal cord stops growing in fetal development.

Question 21

How is the spinal cord segmented?

Answer 21

Cervical (8 roots), thoracic (12), lumbar (5), sacral (5), coccygeal (1).

Question 22

What is a dermatome?

Answer 22

An area of skin supplied by a specific spinal nerve.

Question 23

What is a myotome?

Answer 23

A group of muscles supplied by two adjacent spinal segments.

Question 24

Where are the spinal cord enlargements located?

Answer 24

At cervical and lumbosacral levels.

Question 25

What are signs of pyramidal tract disruption?

Answer 25

Paraparesis or paraplegia, hypertonia, hyperreflexia.

Question 26

What results from extrapyramidal tract disruption?

Answer 26

Loss of coordination, tremors.

Question 27

What sensory deficits occur with spinothalamic tract damage?

Answer 27

Loss of pain, temperature, deep touch, and pressure.

Question 28

What sensory loss occurs with dorsal column disruption?

Answer 28

Loss of fine touch, vibration, and joint position sense.

Question 29

What autonomic dysfunction can occur with spinal cord compression?

Answer 29

Erectile dysfunction, constipation, urinary/stool incontinence.

Question 30

What does tropical neuropathy include?

Answer 30

Myelopathy, cerebellar signs, optic atrophy, deafness, dementia, and symmetrical polyneuropathy.

Question 31

Where is tropical neuropathy described?

Answer 31

Southern Nigeria and Tanzania, in cassava-consuming communities.

Question 32

What are possible causes of tropical neuropathy?

Answer 32

Chronic cyanide intoxication and vitamin B deficiencies.

Question 33

What is the typical age of onset for tropical neuropathy?

Answer 33

Most common in the 5th decade, rare in the 1st.

Question 34

What are polyneuropathy symptoms in tropical neuropathy?

Answer 34

Paresthesiae, dysthesiae, sensory ataxia, stocking and glove loss, absent ankle reflexes, foot drop.

Question 35

What are dorsal column signs in tropical neuropathy?

Answer 35

Sensory ataxia, proprioceptive loss, positive Romberg's sign.

Question 36

What pyramidal tract signs are seen in tropical neuropathy?

Answer 36

Limb weakness, exaggerated reflexes, extensor plantar response.

Question 37

What extrapyramidal/cerebellar signs are found?

Answer 37

Truncal ataxia, intention tremors, Parkinsonism.

Question 38

What other neurological signs are seen?

Answer 38

Bilateral optic atrophy, sensorineural deafness, dementia.

Question 39

What vitamin B deficiency signs may be present?

Answer 39

Angular stomatitis, glossitis.

Question 40

What are differential diagnoses for tropical neuropathy?

Answer 40

Neurosyphilis, beriberi, pellagra, diabetic neuropathy, subacute degeneration of SC, etc.

Question 41

What are key investigations for tropical neuropathy?

Answer 41

Nerve conduction studies, nutritional tests, blood films, FBC, HIV serology.

Question 42

What is the treatment approach for tropical neuropathy?

Answer 42

Identify and treat the underlying cause.