Urinary retention is the most frequent finding in cauda equina syndrome. It is usually due to what kind of herniation?

Urinary retention is the most frequent finding in cauda equina syndrome. It is usually due to what kind of herniation?

• A. Small foraminal herniation
• B. Massive centrally herniated disc
• C. Urinary tract infection
• D. BPH

Answer: (B)

Urinary retention in cauda equina syndrome comes from compression of the sacral nerve roots (S2–S4) that innervate the bladder. A large, central disc herniation presses into the thecal sac and pinches multiple cauda equina roots, including these sacral fibers, leading to detrusor dysfunction and loss of bladder control. When the herniation is massive and centrally located, it disrupts these sacral roots on both sides, producing the characteristic bladder symptoms seen in cauda equina syndrome. In contrast, a small foraminal herniation tends to compress a single exiting nerve root, causing localized radicular pain rather than the widespread sacral nerve involvement needed for bladder dysfunction. Urinary tract infection or BPH are not causes of acute cauda equina compression.

Urinary retention in cauda equina syndrome comes from compression of the sacral nerve roots (S2–S4) that innervate the bladder. A large, central disc herniation presses into the thecal sac and pinches multiple cauda equina roots, including these sacral fibers, leading to detrusor dysfunction and loss of bladder control. When the herniation is massive and centrally located, it disrupts these sacral roots on both sides, producing the characteristic bladder symptoms seen in cauda equina syndrome.

In contrast, a small foraminal herniation tends to compress a single exiting nerve root, causing localized radicular pain rather than the widespread sacral nerve involvement needed for bladder dysfunction. Urinary tract infection or BPH are not causes of acute cauda equina compression.