SESAP ALIMENTARY II Flashcards
Mirizzi syndrome
obstructive jaundice due to extrinsic compression of the common hepatic duct (CHD) caused by a stone impacted in the neck of the gallbladder or cystic duct.
Up to 25% of patients have an increased risk of gallbladder cancer.
Because the stone is characteristically in either the neck of the gallbladder or the cystic duct, previous cholecystectomy does not rule it out as a possible diagnosis
Four factors contribute to development of Mirizzi syndrome:
(1) The cystic duct must be anatomically parallel to the CHD
(2) a stone must become impacted in the cystic duct or gallbladder neck,
(3) the CHD must be obstructed by the stone or by the secondary inflammatory response,
(4) the longstanding obstruction must cause intermittent or constant jaundice with occasional cholangitis.
treatment of Mirizzi syndrome
One study suggested that laparoscopic cholecystectomy can be successful with type 1 Mirizzi syndrome
or
external compression of the CHD by a stone impacted in the cystic duct or Hartmann pouch,
but the authors cautioned that open cholecystectomy is the method of choice for type 2 Mirizzi syndrome, a fistula between the gallbladder and common duct from inflammation and erosion.
Another retrospective study indicated that of 14 patients who underwent laparoscopic surgery, 11 required conversion to an open procedure.
Gastrin is a hormone secreted by
G cells in the gastric antrum.
the action of gastrin
It acts on parietal cells to stimulate hydrochloric acid after ingestion of food.
Patients who have a gastrinoma as their source of uninhibited gastrin secretion usually present with
peptic ulcers secondary to acid hypersecretion.
unopposed gastrin secretion in response to achlorhydria typically occurs in patients with
atrophic gastritis or who take proton pump inhibitors.
Hypergastrinemia occurring with gastritis related to Helicobacter pylori infection is caused by
the decreased somatostatin release by D cells due to increased pH and circulating cytokines around D cells.
Gastric carcinoid tumors also termed
neuroendocrine tumors (NETs),
gastric carcinoid tumors subclassified into 3 distinct groups:
type 1
associated with chronic atrophic gastritis/pernicious anemia (; 70–80%),
type 2
associated with multiple endocrine neoplasia type I (MEN I) Zollinger-Ellison syndrome (ZES; ; 5%),
type 3
sporadic NETs of the stomach ( 15–20%).
treatment of gastric carcinoid tumors
Because type 1 and 2 NETs of the stomach generally pursue an indolent course, tumors smaller than 2 cm (up to 6 in number) should be resected endoscopically, with subsequent interval follow-up.
require more aggressive management, and local surgical resection is recommended:
when greater than 2 cm,
or those with recurrent tumors,
or those with more than 6 tumors generally
type 1 NETs of the stomach arising in the setting of chronic atrophic gastritis, antrectomy may be performed to eliminate the source of gastric production.
Antrectomy results in tumor regression in such cases.
treatment of gastric carcinoid tumors In patients with type 2 NETs of the stomach secondary to ZES/MEN I syndrome,
treatment with somatostatin analogs may be initiated and result in tumor regression.
treatment of sporadic (type III) gastric carcinoid tumors
type 3 isolated sporadic NETs of the stomach requires more aggressive surgery,
partial gastrectomy and lymph node dissection.
associated findings with gastric carcinoid tumor
anemia, hypergastrinemia, and atrophic gastritis consistent with type 1 gastric carcinoid.
5% of patients with pernicious anemia, an autoimmune condition in which antibodies are directed against parietal cells.
The destruction of parietal cell mass results in atrophic gastritis, a loss of acid production, hypergastrinemia, and macrocytic anemia from the loss of intrinsic factor and Vitamin B12 absorption.
Roux-en-Y gastric bypass effects on hormones
ghrelin, glucagon-like peptide-1, and peptide YY that influence eating behaviors and body weight.
Roux-en-Y gastric bypass physiologic effects
fat malabsorption:
After RYGB, the secretion of bile and lipolytic enzymes is reduced, because lipids never pass through the duodenum.
Undigested fat passes into the colon, producing fat malabsorption and steatorrhea.
protein intolerance:
Intolerance of protein-rich foods, such as meat and dairy products, is common. For this reason, many patients fail to meet the daily recommended protein intake, which should average 60–120 g/day.
CCK stimulation and effects
Under physiologic conditions, fat passes into the duodenum and stimulates cholecystokinin (CCK).
CCK stimulates the gallbladder and pancreas to release bile and lipolytic enzymes.
Vitamin deficiencies of Roux-en-Y
iron, Vitamin B12, calcium, Vitamin D, folate (Vitamin B9), and thiamine (Vitamin B1) is recommended.
In addition, iron, calcium, and thiamine are absorbed primarily in the duodenum, which is precluded with RYGB.
Iron stores decline after gastric bypass procedure, making iron-deficient microcytic anemia very common.
Vitamin C supplementation should also be added to increase iron absorption and ferritin levels.
Oral iron supplements can decrease absorption of calcium, magnesium, and zinc, so these should be taken at different times of the day.
RYGB procedure alters the absorption of Vitamin B12 by isolating the source of intrinsic factor, the distal stomach, from the alimentary stream.
However, substantial deficiencies in Vitamin B12 do not occur until at least 1 year after the surgery. Deficiency can result in macrocytic anemia and neuropathy.
calcium deficiency and bone loss.
The loss of fat absorption is believed to contribute to Vitamin D deficiency because it is a fat-soluble vitamin.
This is believed to increase bone turnover and to decrease bone mass. However, calcium deficiency and loss of bone density can occur in the presence of normal Vitamin D and parathyroid hormone (PTH) levels.
An increase in serum PTH levels is indicative of negative calcium balance or Vitamin D deficiency. If deficient, Vitamin D can be supplemented with ergocalciferol or cholecalciferol.
When performing LAR resections for cancer, division of the inferior mesenteric artery (IMA) at its origin from the aorta (high ligation) is often performed to
remove the lymph node basin at risk for metastasis and provide adequate mobilization of the proximal bowel for a tension-free anastomosis.
arterial flow occurs through collateral vessels.
Sudeck point
junction of the colon and rectum
when the LIMA was divided at its origin at the aorta how it is perfusion maintained with descending colon rectal anastomosis
The arc of Riolan
The arc of Riolan
is an inconstant artery
connects the proximal SMA or 1 of its primary branches to the proximal IMA or 1 of its primary branches.
It is classically described as connecting the middle colic branch of the SMA with the left colic branch of the IMA.
It forms a short loop that runs close to the root of the mesentery.
It is an important connection between the SMA and IMA in the setting of arterial occlusion or significant stenosis such as proximal SMA occlusion.
The marginal artery of Drummond is the anastomoses
The marginal artery of Drummond is the anastomoses of the SMA:
the terminal branches of the ileocolic,
right colic,
middle colic arteries
and of the IMA:
left colic
sigmoid branches
These form a continuous arterial circle or arcade along the inner border of the colon known as the marginal artery of Drummond.
The marginal artery is an important connection between the SMA and IMA and provides collateral flow in the event of occlusion or significant stenosis.
The junction of the SMA and IMA territories is at the splenic flexure.
where is the marginal artery of Drummond the weakest
the splenic flexure, hence “the marginal artery” at this point,
known as the Griffiths point