(2) Non-mechanical obstruction is the result of physiological disturbances.
(a) Electrolyte imbalances.
(b) Neurogenic disorders (such as spinal cord lesions).
(c) Paralytic (adynamic) ileus, developing as a result of abdominal
surgery, trauma, or infection.
c. Signs and symptoms of small bowel obstruction.
(1) Small bowel obstruction is characterized by colicky pain, constipation,
nausea, and vomiting.
(2) If the small bowel obstruction is complete, the peristaltic waves become
quite vigorous, assuming reverse direction and propelling intestinal contents toward the
mouth rather than the rectum. The patient vomits stomach contents first, then the
bilious contents of the duodenum, and finally the fecal contents of the ileum.
(3) In later stages, dehydration and plasma loss result in hypovolemic
shock. (As much as 10 liters of fluid can collect in the small bowel, causing a drastic
reduction in plasma volume.)
d. Signs and symptoms of large bowel obstruction.
(1) Symptoms of large bowel obstruction differ from those of small bowel
obstruction because the colon is able to absorb its fluid contents and distend well
beyond normal size.
Constipation may be the only symptom for several days.
Eventually, the distended colon loops will be visible on the abdomen.
Nausea and cramps, abdominal pain will occur.
(5) Vomiting is absent at first, but when obstruction becomes complete,
fecal vomiting will occur.
(6) If the obstruction is only a partial one, any of the above symptoms may
occur in a less severe form. Additionally, liquid stool may leak around the obstruction.