Chapter 11: Diseases of the Small Intestine
Small bowel obstruction: See classic step ladder appearance of air-fluid levels: air, fluid, air, fluid
(step ladder appearance). When you have a hollow viscous that peristalsis, you get a certain
characteristically pain, called COLIC pain. It isn’t like a crampy pain with no painfree intervals;
colicky pain is when you have pain, a painfree interval, pain, and then a painfree interval. The
intervals are not consistent, sometimes you have a 15 min painfree interval, and other times if
may be longer or shorter. This is colicky pain; it means TOTAL small bowel obstruction. By the
way, the bile duct does not have peristalsis, therefore you do not get colicky pain, and instead
you get crampy pain. You have to have peristalsis to get colicky pain, it has to move. And
what’s it doing is trying to move against that obstruction and that’s causing the pain. B/c you
cannot perstalse you get stagnation of the food proximal to wherever the obstruction is, and get
air-fluid levels. Distal to the area of obstruction there is no air. In obstruction, there are two
things that can happen: constipation or obstipation. Constipation is where you have a problem
with stooling, which does not necessarily mean obstruction. Obstipation means that not only do
you have constipation you also have a problem passing gas, that means you have complete
obstruction. So you have to ask the pt whether they have passed any stools or gas. MCC of
obstruction: adhesions from previous surgeries. Slide: those are watermelon pits, with a
narrow lumen. But if the case read that this pt did not have pervious surgeries and had colicky
pain, this is due to the bowel being trapped in the indirect inguinal hernia. Example: there was
a weight lifter who developed colicky pain in the RLQ area, had no previous surgery, the most
likely cause is indirect inguinal hernia. Weight lifters often times create indirect inguinal hernias.
Side note: there was a pic of Down’s syndrome kid. Trisomy 21 (abnormal number of chromosomes) is
due to nondisjunction (unequal separation during the first stage of meiosis I) but not all down’s have
trisomy 21. But if the kid had normal 46 chromosomes, this is due to Robertsonian translocation. In
this case, they would have 46 chromosomes but on one of those chromosomes 21, will be another
chromosome attached to it. They will have three functional chromosome 21. The two GI diseases that
are MC’ly seen in Down’s are duodenal atresia (double bubble sign) and Hirschsprung dz.
Hirschsprung dz: the nerves are there but the ganglionic cells are missing. So, what happens if it’s
missing in the rectum, the stools cannot get by, even when there is an opening, b/c there is no
peristalsis. So the stools just stay there. So, the dilation of the proximal colon has ganglionic
cells, and there peristalsis occurring and you can’t get the stools thru the rectal area. So this
means that the rectal ampulla has no stools in it. Example: if you have a child that didn’t pass
the meconium in 24 hours and a rectal exam was performed. If there was NO stools that came
out on exam it means Hirschsprung dz. If on exam, there was stools on the finger, it means
tight sphincter. This is a dz of the colon.
Intussusception: most occur in children, and it’s when the terminal ileum intussuscepts goes into
the cecum. There will be colicky pain b/c you are obstructing, and not only that, you are
compromising blood flow, so you get the bleeding. They will say: a 2 y/o kid, with colicky pain
and bloody stools. They might way there is an oblong mass in the RUQ. In some kids, it
spontaneously comes out, but if not, then the radiologists will do barium enema, and put a little
pressure there, and he reverts it. So you get complete bowel obstruction and infarctions.
Volvulus: Twisting of the colon around the mesentery b/c there’s too much of it causing complete
obstruction and infractions due to compromising blood flow. Gallstone ileus usually seen in older people, more women, and have signs of colicky pain, and
obstruction. The gallbladder stone falls thru the fistula and settles into the ileocecal valve and
causes obstruction. See a flat plane of the abdomen that produced air in the biliary tree. Boom,
there’s your Dx. There is a fistula that is communicating the gallbladder with the small bowel
therefore air can get in the small bowel and the biliary tree. Air in the biliary tree with colicky
pain is gallstone ileus. Dz of gallbladder.
Meconium Ileus = cystic fibrosis Whipple’s
An infection of the small infection due to an organism that you cannot gram stain. T. whippelii
only seen with EM; cannot be cultured. See flat blunted villi and foamy macrophages (look like
Niemann pic bubbly macrophages; can also be from an HIV “+” b/c it looks like Whipple’s, but
isn’t). The macrophages have distinctive PAS-positive stains.
HIV positive pt and acid fast stain – pt with helper T cell count of 100. Have an acid fast stain
with the foamy macrophages – due to MAI (this is more common that TB), and can cause
Whipple like dz with malabsorption.
Whipple’s, being an infection, has systemic signs and symptoms: fever, lymphadenopathy,
polyarthritis, generalized pain