Neuro8 Spinal Cord Lesions

Question 1

Poliomyelitis

Answer 1

Caused by poliovirus, which is transmitted by the fecal-oral route. Replicates in the oropharynx and small intestine before spreading through the bloodstream to the CNS, where it leads to the destruction of cells in the anterior horn of the spinal cord, leading in turn to LMN destruction.

Malaise, headache, fever, nausea, abdominal pain, sore throat. Signs of LMN lesions-muscle weakness and atrophy, fasciculations, fibrillation, and hyporeflexia.

CSF with lymphocytic pleocytosis with slight elevation of protein (with no change in CSF glucose). Virus recovered from stool or throat.

Question 2

Werdnig-Hoffman disease

Answer 2

Also known as infantile spinal muscular atrophy. Autosomal-recessive inheritance ; presents at birth as a “floppy baby,” tongue fasciculations; median age of death 7 months. Associated with
degeneration of anterior horns. LMN involvement only.

Question 3

Amyotrophic lateral sclerosis

Answer 3

Associated with both LMN and UMN signs; no sensory, cognitive, or oculomotor deficits. Can be caused by defect in superoxide dismutase 1 (SOD 1) . Commonly presents as fasciculations and eventual atrophy; progressive and fatal. Riluzole treatment modestly lengthens survival by decreasing presynaptic glutamate release.

Commonly known as Lou Gehrig’s disease. Stephen Hawking is a well-known living patient (highlighting the lack of cognitive
deficit) .

Question 4

Tabes dorsalis

Answer 4

Degeneration of dorsal columns and dorsal roots clue to 3° syphilis, resulting in impaired proprioception and locomotor ataxia. Associated with Charcot’s joints, shooting (lightning) pain, Argyll Robertson pupils (reactive to accommodation but not to light), absence of DTRs, positive Romberg, and sensory ataxia at night.

Argyll Robertson pupils are also known as “prostitute’s pupils” because they accommodate but do not react.

Question 5

Friedreich’s ataxia

Answer 5

Autosomal-recessive trinucleotide repeat disorder (GAA) in gene that encodes frataxin. Leads to impairment in mitochondrial functioning. Staggering gait, frequent falling, nystagmus, dysarthria, pes cavus, hammer toes, hypertrophic cardiomyopathy (cause of death). Presents in childhood with kyphoscoliosis.

Friedreich is Fratastic (frataxin) : he’s your favorite frat brother, always stumbling, staggering, and falling.

Question 6

Brown-Sequard syndrome

Answer 6

Hemisection of spinal cord. Findings:
l . Ipsilateral UMN signs (corticospinal tract)
below lesion
2. Ipsilateral loss of tactile, vibration,
proprioception sense (dorsal column)
below lesion
3. Contralateral pain and temperature loss
(spinothalamic tract) below lesion
4. Ipsilateral loss of all sensation at level of
lesion
5. LMN signs (e.g., flaccid paralysis) at level
of lesion
If lesion occurs above Tl, presents with Horner’s
syndrome.

Question 7

Horner’s syndrome

Answer 7

Sympathectomy of face:
l . Ptosis (slight drooping of eyelid : superior
tarsal muscle)
2. Anhidrosis (absence of sweating) and
flushing (rubor) of affected side of face
3. Miosis (pupil constriction)
Associated with lesion of spinal cord above
Tl (e.g., Pancoast tumor, Brown-Sequard
syndrome [cord hemisection] , late-stage
syringomyelia).

PAM is horny (Horner’s).

The 3-neuron oculosympathetic pathway projects from the hypothalamus to the intermediolateral column of the spinal cord, then to the superior cervical (sympathetic) ganglion, and finally to the pupil, the smooth muscle of the eyelids, and the sweat glands of the forehead and face. Interruption of any of these pathways results in Horner’s syndrome.