Page 158 - Color Atlas Of Pathophysiology (S Silbernagl Et Al, Thieme 2000)

Disorders After Stomach Surgery
Gastric tumors are treated surgically by re- moglobin in food or for absorption of fat in-
moving the stomach (gastrectomy [GE]) and cluding the fat-soluble vitamin D (see below).
replacing it with jejunal loops, or by gastric ! High concentrations of carbohydrate and
resection (Billroth I or II, or Roux). Treat- especially sugar (e.g., marmelade) in chyme
ment-resistant gastric ulcers have also been also cause symptoms because the rapid ab-
treated with selective vagotomy (VT). Non- sorption of glucose causes a high hyperglyce-
selective VT is often unavoidable in tumor mia peak that 90–180 minutes after food in-
operations or when bleeding occurs. These take followed by reactive hypoglycemia due
procedures may result in undesirable func- to the release of insulin (confusion, loss of
tional disorders (→ A): consciousness), the so-called late dumping
Liver disordered accommodation and receptive re- syndrome.
Surgical reduction of gastric volume and
! Rapid gastric emptying also exceeds the
Stomach, Intestines, wall tension when ingesting a normal meal; tine. Moreover, VT results in a halving of pan-
digestive capacity of the upper small intes-
laxation reflexes after VT increase gastric
this leads to feeling full, nausea, and vomiting
creatic secretion, and in Billroth II the upper
duodenum does not receive the flow of
as well as premature satiety. A serious conse-
chyme, so that there is no physiological stim-
quence is too rapid gastric emptying. This is
ulus for secretin and CCK secretions. As a re-
due to: 1) an absent accommodation reflex
ach to small intestine; 2) the “apportioning”
the digestion and absorption of nutrients. Its
chemoreceptors are intensively involved in
antrum and pylorus are absent; and 3) gas-
6 that raises the pressure gradient from stom- sult, the distal small intestine takes part in
tric emptying into the small intestine is no initiating reflexes and hormonal signals that
longer inhibited. The latter is especially true bring about the feeling of premature satiety
in VT (no vagovagal reflex) and in gastric re- (see above), so that these patients eat too lit-
section after Billroth II or Roux, in which tle and lose weight. Deficient chyme prep-
chyme circumvents the duodenal chemore- aration is partly responsible for the distal
ceptors. shift of digestion and absorption. After distal
Consequences of too rapid gastric empty- gastric resection, the pieces of food leaving
ing are (→ A, bottom): the stomach are too large (> 2 mm). As one
! Too high a chyme volume per unit time third of iron in food comes from hemoglobin
distends the intestinal wall and, via hor- (in meat), incomplete digestion of oversized
mones and neurotransmitters, brings about food particles diminishes the availability of
nausea, vomiting, cramps, and pain as well as heme-iron.
vasomotor reactions with cutaneous vascu- Billroth II (but not Roux-Y) gastrectomy
lar dilation (flush), tachycardia, palpitations, can lead to the blind loop syndrome (→ p. 34
and abnormal orthostatic regulation. This and 152).
+
early dumping syndrome (occurring 30– Reduced H secretion in the stomach de-
60 min after food intake) is also in part due creases the liberation of iron in food and the
to: absorption of Fe(II). Loss of the sources of
! Hypertonicity of chyme that is emptied iron will ultimately lead to iron-deficiency
too quickly. Via osmotically obliged water se- anaemia (→ p. 38).
cretion into the intestinal lumen, this chyme Additionally, when the number and activ-
also: 1) increases intestinal distension; 2) re- ity of the parietal cells is diminished, the se-
sults in diarrhea; and 3) leads to further car- cretion of intrinsic factor is also reduced. If it
diovascular reactions that are initiated by the falls below 10% of ist normal value, cobala-
resulting hypovolemia. min absorption is affected so that (long-
! Furthermore, the secreted water dilutes term) cobalamin deficiency can arise and
the enzymes and bile salts in the intestinal lu- the anemia is further aggravated (→ p. 34).
148 men. This dilution can be critical, for exam- Osteomalacia will ultimately result from
ple, for the liberation of heme-iron from he- Ca 2+ and vitamin D deficiency (→ p.132).
Silbernagl/Lang, Color Atlas of Pathophysiology © 2000 Thieme
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