Describe the pathophysiology of malabsorption.
Lack of chyme stimulation → ↓ pancreatic enzyme levels → protein and carbohydrate maldigestion → fat-soluble vitamin deficiency and weight loss
Loss of parietal cells → ↓/absent intrinsic factor production → vitamin B12 deficiency → pernicious anemia
Critical reduction of the absorptive surface → ↓ time for chyme absorption → ↓ iron absorption → iron deficiency anemia
How should malabsorption be managed?
Diet modifications
Increased protein intake
Supplementation of medium-chain triglycerides
Low carbohydrate diet
Supplementation of pancreatic enzymes and deficient nutrients (e.g., vitamin B12, iron, fat-soluble vitamins)
Define small intestinal bacterial overgrowth (SIBO).
a pathologically increased growth of bacteria in the small intestine
List causes of SIBO.
Anatomic causes
Short bowel syndrome
Blind loop syndrome: bacterial overgrowth in the bypassed intestinal segment (blind loop) that occurs as a result of gastrectomy
Small bowel diverticulosis
Inflammatory bowel disease
Motility disorders
Irritable bowel syndrome
Diabetes mellitus
Scleroderma
Describe the pathophysiology of SIBO.
all resulting from bacterial overgrowth
↓ Absorption of vitamin B12, fat-soluble vitamins, zinc, and iron
↑ Production of folate
↑ Deconjugation of the bile acids
Describe the clinical features of SIBO.
Diarrhea, steatorrhea
Weight loss, malabsorption
Which diagnostics should be carried out in SIBO?
Jejunal aspirate cultures collected during endoscopy
Positive lactulose breath test
Describe the management of SIBO.
Antibiotic therapy
Parenteral supplementation of vitamins and proteins
In some cases, surgical treatment
Define efferent loop syndrome.
kinking or anastomotic narrowing of the efferent loop that causes emesis and/or a feeling of fullness
Describe the management of efferent loop syndrome.
Acute abdomen requires immediate surgical treatment.
In uncomplicated cases: watch and wait
Define afferent loop syndrome.
Biliary and pancreatic obstruction due to stenosis, kinking, or incorrect anastomosis of the afferent loop
Chyme enters the afferent loop instead of the efferent loop and causes loss of appetite, a feeling of fullness, and bilious vomiting with subsequent relief of nausea.
Which patients are affected by afferent loop syndrome?
Afferent loop syndrome only affects patients undergoing Billroth II gastric resection, which is usually not used to treat gastric cancer.
What is the management of afferent loop syndrome?
Surgical management
Define dumping syndrome.
rapid gastric emptying as a result of defective gastric reservoir function, impaired pyloric emptying mechanisms, or anomalous postsurgery gastric motor function
Describe the pathophysiology of early dumping.
dysfunctional or bypassed pyloric sphincter → rapid emptying of undiluted hyperosmolar chyme into the small intestine → fluid shift to the intestinal lumen → small bowel distention → vagal stimulation → increased intestinal motility
What are clinical features of early dumping?
Occur within 15–30 minutes after meal ingestion
Include nausea, vomiting, diarrhea, and cramps
Vasomotor symptoms such as sweating, flushing, and palpitations
Describe the management of early dumping.
Dietary modifications: small meals that include a combination of complex carbohydrates and foods rich in protein and fat
30–60 min of rest in the supine position after meals
Beta blockers may be helpful to ease tachycardia arising from hypovolemia.
Describe the pathophysiology of late dumping.
dysfunctional pyloric sphincter → rapid emptying of glucose-containing chyme into the small intestine → quick reabsorption of glucose → hyperglycemia → excessive release of insulin → hypoglycemia and release of catecholamines
Describe the clinical features of late dumping.
Occur hours after meal ingestion
Include signs of hypoglycemia (e.g., hunger, tremor, lightheadedness)
GI discomfort
Describe the management of late dumping.
Dietary modifications
Second-line treatment: octreotide
Third-line treatment: surgery
When should late dumping be suspected?
Suspect late dumping syndrome in a patient with previous gastric surgery and hypoglycemia.
Define remnant gastric cancer.
the development of carcinoma in the remnant stomach after gastrectomy, regardless of the initial gastric condition or its duration
Describe the pathophysiology of remnant gastric cancer.
Studies suggest that duodenogastric reflux, chronic irritation due to biliary or pancreatic secretions, and the denervation of gastric mucosa after surgery result in chronic inflammation of the remnant mucosa.
Describe the management of remnant gastric cancer.
total gastrectomy with Roux-en-Y anastomosis and radical lymph node dissection
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