Pyramidal system

Clinic

• Pyramidal tracts are a system of efferent nerve fibers that carry signals from the cerebral cortex to either the brain-stem or the spinal cord.
• It divides into two tracts:
  1. Corticospinal tract: It starts at Primary motor cortex / Premotor areas and terminates on LMN / Spinal cord Interneurons.
  2. Corticobulbar / corticonuclear tract: It connects motor cortex to the medullary pyramids

Sign / Symptoms

• Pyramidal tracts are part of the UMN system. Pyramidal signs are:
  • Spasticity
  • Weakness
  • Slowing of rapid alternating movements
  • Hyper reflexia
  • Positive Babinski sign

These symptoms are all characteristic of an upper motor neuron lesion. However, certain symptoms are specific to a pyramidal tract lesion.

• More on lower extremities than upper ones.
• In presence of asymmetrical findings, ALS should be considered.

Clinical significance

• Parkinsonian-Pyramidal syndrome (PPS) is a combination of both pyramidal and parkinsonian signs

• Pyramidal tract lesions can occur from any type of damage to the brain or spinal cord such as meningitis, multiple sclerosis, or trauma.

• ALS: It causes symptoms of both upper and lower motor neuron syndrome.

• MS: In early MS stages, corticospinal tract integrity is already affected in the absence of WM lesions or brain atrophy.
• Central Pontine Myelinolysis: It is a condition that involves damage to nerve cells in the pons.

Entity / Miasms

I suggest the same Entities / Miasms of UMN entity which are GSS, JE, CJD, NVCJD, HTLV-1 and WEE/ EEE.