Small Intestine Diseases Symptoms, Diagnosis, Treatment
The small intestines are the main center of digestion and absorption of food. However, the small intestines are the body's largest endocrine organ and the largest part of the immune system (due to the abundance of hormone-producing cells and immune system cells in the intestine). The small intestines are also the largest surface of our body that opens to the outside. Although the small intestines are very long, small intestine diseases are quite rare compared to stomach and colon diseases. Common diseases of the small intestine are intestinal obstructions due to adhesion (adhesion-surgery), inflammatory bowel diseases (especially Crohn's disease), mesenteric ischemia (intestinal ischemia). Small bowel cancers are rare. Other small intestine diseases; intestinal fissures, radiation enteritis, Meckel's diverticulum and short bowel syndrome.
Small Intestine Anatomy
Small intestine; It consists of duodenum, jejunum and ileum. Duodenum is 20-30 cm long. The mesenteric small intestine is 2.5 m (jejunum = 100 cm (40%) + ileum = 150 cm (60%)). The meaning of mesenteric small intestine is the length of the small intestine measured while the small intestine mesus is still in the living organism. If the mesentery of the small intestine is removed from the edge of the small intestine and the small intestine is extended on the table, its length is 6 meters (actual length). The length of the column is 135-180 cm. The small intestine wall consists of 4 layers (serosa, muscularis, submucosa, mucosa). There are mucosal folds called plicae circulares or valvulae conniventes on the inner surface of the small intestine. Pilica circularis expand the surface area of the small intestine and are not found in the large intestine. In the small intestine mucosa, there are villi that expand the surface area (villi, microscopic finger-like projections). There are also cavities called Lieberkühn crypts in the small intestine mucosa, where new small intestine mucosa cells are produced, it is the most dynamic tissue of the body. Artery of the small intestines; superior mesenteric artery, vein; It is the superior mesenteric vein. The lymphatics of the small intestine (from the edge of the intestine to the center) is as follows: Marginal (peripheral lymph nodes) > intermediate lymph nodes > mesenteric (central) lymph nodes > cisterna chile > ductus thoracicus sinister.
Small Intestine Obstruction (Mechanical)
The two most common causes of mechanical small bowel obstruction are postoperative adhesions (adhesions due to previous abdominal surgery) and incarcerated-strangulated (stuck) hernias. The small intestines proximal to the obstruction become dilated (accumulation of fluid and gas), while the small intestines and colon after the obstruction are empty. If small bowel obstruction continues, dilatation increases and strangulation develops in the small intestine (perfusion-blood supply is impaired). Strangulation causes necrosis, and necrosis causes perforation.
Causes of Mechanical Small Intestine Obstruction
• Obstruction of the intestinal lumen
Polypoid (vegetative, eccentric) tumor
Intussusception (intussusception)
gallstone ileus
Petrified stool, meconium
bezoar
Phytobezoar (Plant fiber)
Trichobezoar (Hair)
• Intestinal wall origin
congenital
Atresia, stenosis, duplication
Stricture (narrowing)
Scirrhous (concentric) tumor
Crohn's
Anastomosis
Radiation
• Lesions outside the intestine
Adhesion (Previous operation, inflammation)
external hernia
internal hernia
congenital
postoperative
tumor compression
volvulus
Symptoms and Signs of Small Intestine Obstruction:
Classic findings are sudden onset of colicky abdominal pain, nausea, vomiting, abdominal distension, inability to pass gas and stool, widespread abdominal tenderness, increased bowel sounds and metallic sound. After 24 hours, the patient develops dehydration and associated findings are added (tachycardia, hypotension, oliguria (decrease in urine output)). If the nutrition (blood supply) of the intestine is impaired (strangulation), the following four more findings are added; fever, tachycardia, localized tenderness-defense, leukocytosis.
Diagnosis of Small Intestine Obstruction:
A preliminary diagnosis of small bowel obstruction is made with the above signs and symptoms. However, it is necessary to confirm this preliminary diagnosis, determine the cause of obstruction, and understand whether strangulation (ischemia-necrosis) has developed. For this purpose, direct radiographs (mostly standing direct abdominal radiography (sometimes lying down and lateral decubitus radiographs)) and computed tomography (CT) with IV contrast are used.
Treatment of Small Intestine Obstruction:
Many patients have an indication for surgery (laparotomy, laparoscopy). Classical approach to small bowel obstruction; examination → fluid resuscitation → laparotomy (laparoscopy). If there is one of the four strangulation findings in the examination, laparotomy should be performed without waiting (Strangulation findings are: fever, tachycardia, localized tenderness-defense, leukocytosis). During the examination phase, the etiology of small bowel obstruction is also investigated (tumor, adhesion, hernias, etc.). Fluid resuscitation; If 24 hours have passed since the onset of symptoms, fluid resuscitation should be administered. Adhesive partial obstruction may resolve within 24 hours with NG and medical observation (monitoring may be done first). Obstructions due to intra-abdominal malignancy cannot be resolved with medical monitoring. In the following cases, medical monitoring is not appropriate and laparotomy should be performed:
• If there is obstruction in those who have not had abdominal surgery before
• Incarcerated external hernia
• Peritonitis findings
• Strangulation findings
For more detailed information, you can read our article titled "Intestinal Obstructions".
Ileus (Paralytic, Adynamic Ileus)
Paralytic ileus, or simply ileus, is an intestinal obstruction that occurs due to paralysis (paralysis) of the intestinal muscles (peristalsis stops). A certain level of paralytic ileus occurs in almost all open abdominal surgeries. Other common causes of paralytic ileus are peritonitis (inflammation of the abdominal lining), hypokalemia, abdominal trauma, intestinal ischemia, anticholinergic and morphine use. Symptoms and Diagnosis of Paralytic Ileus: Distension (swelling) develops in the intestines, as seen in mechanical intestinal obstruction. In mechanical bowel obstruction, gas and distension are not seen distal to the obstruction, whereas in paralytic ileus air is also seen in the colon and rectum. Additionally, no evidence of mechanical bowel obstruction is detected on computed tomography (CT) in paralytic ileus. Paralytic Ileus Treatment: Oral food is stopped, nasogastric decompression (catheter) is applied, fluid - electrolyte therapy (K+) is applied. If paralytic ileus is due to peritonitis, laparotomy is already required.
Intestinal Pseudo-Obstruction
Intestinal pseudo-obstruction is a chronic condition characterized by recurrent abdominal distension. Abdominal distension may be accompanied by nausea, vomiting and diarrhea. Pseudoobstruction usually occurs more in the colon than in the small intestine, and acute colonic pseudoobstruction is called Ogilvie syndrome. No mechanical cause can be found, and often (70%) these patients were operated on for previously unexplained bowel obstruction.
Crohn's Disease
Crohn's disease is one of two diseases called inflammatory bowel disease (the other being ulcerative colitis). Crohn's disease can occur in all parts of the gastrointestinal tract, from the mouth to the anus (perineum). The inflammatory reaction is transmural (i.e., inflammation is present in all layers of the intestinal wall). Crohn's disease is also called terminal ileitis. Small intestine involvement is found in 80% of people with Crohn's disease, only terminal ileum involvement is 30%. There is 50% hatsan ileocolitis (colon +ileum involvement). In 20% of people with Crohn's disease, the disease is limited to the colon. Symptoms of Crohn's Disease: Crohn's symptoms are in the form of attacks (exacerbations, episodes) that appear and disappear. During a Crohn's attack, crampy abdominal pain (most commonly in the lower right quadrant) and diarrhea (usually bloodless) occur. Weight loss and fever may also be present. Diagnosis of Crohn's Disease: After considering the preliminary diagnosis of Crohn's disease with the above complaints, a colonoscopy is first requested. On colonoscopy, the diagnosis of terminal ileitis and ileocolitis is easily made (ulcered areas and solid areas are seen in the mucosa, cobblestone appearance in advanced cases). Treatment of Crohn's Disease: Type of treatment; It varies depending on the location and severity of the disease, the treatment of the acute attack and the purpose of remission. The main drugs used are:
• Oral 5-aminosalicylates (sulfasalazine, mesalamine)
• Steroids (prednisone, budenoside)
• Immunomodulators (azothiopyrine, 6-mercaptopurine, methotrexate)
• Biological treatments (infliximab, adalimumab, certolizumab etc.)
• Antidiarrheals (loperamide, cholestyramine)
• Probiotics
• Antibiotics (metronidazole, ciprofloxacin)
Small Intestinal Fistulas (Intestinal-Enteric Fistulas)
Enteric fistulas are abnormal connections (tracts) between the gastrointestinal or other hollow organs or between the skin and the chest cavity. Fistulas are serious diseases because the mortality rate is up to 25%. Most fistulas develop after abdominal surgery. 20-30% of intestinal fistulas are due to Crohn's disease (spontaneous or after resection). Intestinal (Enteric) Fistula Types
• External fistula (fistula opens into the skin)
• Enteroatmospheric fistula (it is a complication of an open abdomen; let alone the fistula, even the intestine where the fistula is located is exposed)
• Internal fistula (fistula opens into the gastrointestinal tract, vagina, bladder, thorax)
• Gastric fistula
• Biliary fistula
• Pancreatic fistula
• Upper gastrointestinal tract (including duodenal fistulas)
• Colonic fistula
• Aortoenteric fistula
• Low flow fistula: 200 mL/day
• Medium flow fistula: 200-500 mL/day
• High flow fistula: > 500 mL/day
• Controlled fistula (no signs of peritonitis and sepsis)
• Uncontrolled fistula (there are signs of peritonitis and sepsis)
Symptoms of Small Intestine Fistulas:
Symptoms may differ depending on the type of fistula.
• Drainage from drain
• Drainage from the surgery site (incision)
• Diarrhea (entero-enteric fistula, e.g. gastro-jejuno-colic fistula)
• Fecaluria (gas and stool from urine, for example rectovesical fistula)
• Gas and stool discharge from the vagina (for example, rectovesical fistula)
Treatment of Small Intestine Fistulas:
Initial treatment includes liquid-electrolyte therapy, treatment (drainage) of infection and abscess, and skin protection by stopping oral nutrition if necessary. If the fistula can be resected with surgery, it is of course the most definitive solution. If the fistula cannot be resected or if it is thought to improve with conservative treatment: Antidiarrheals (Lopermide (loperamide), Lomotil (diphenoxylate-atropine)) and somatostatin analogues can be used as drugs to reduce the flow of the fistula. Negative pressure therapy (VAC, vacuum assisted closure) is extremely effective in protecting the skin, accelerating the development of granulation tissue, shrinking (contraction) of the wound, and drainage of fistula, and reduces hospital stay and mortality in many patients.
Small Intestinal Neoplasms (Tumors)
Common small intestine cancers; adenocarcinoma, carcinoid, lymphoma and sarcomas. Common benign small intestine tumors are; adenoma, leiomyoma and lipoma. Since small bowel tumors are very rare and show nonspecific symptoms, diagnosis is difficult and delays are common.) Symptoms of Small Intestine Tumors: Abdominal pain (44-90%), weight loss (24-44%), nausea-vomiting (17-64%), bleeding (23-41%), obstruction (22-26%), perforation (6-9%). Diagnosis of Small Intestinal Tumors: Computed tomography (CT), small intestine passage radiography, enteroclysis, double-balloon endoscopy, capsule endoscopy are imaging methods that can be used. Treatment of Small Intestinal Tumors: Treatment of adenocarcinomas is wide resection (with meso). Adenocarcinomas in the duodenum require pancreaticoduodenectomy.
Radiation Enteritis
Some damage may occur when gastrointestinal organs enter the radiotherapy area and are exposed to radiation. Two types of radiation damage occur; acute radiation enteritis (occurs immediately after radiotherapy), chronic radiation enteritis (occurs 8-12 months after radiotherapy). Radiation
Symptoms of Enteritis:
• Acute radiation enteritis is due to the direct effect of radiation on the intestinal mucosa (shedding of the epithelium). Acute radiation enteritis causes cramping (colic) abdominal pain, nausea, loss of appetite, and diarrhea.
• In chronic radiation enteritis, small arteries leading to the intestine gradually narrow (endarteritis). As a result, atrophy (narrowing, thinning) and ulcers develop in the intestine. As a result, obstruction, bleeding, fistula and malabsorption develop in the small intestines.
Treatment of Radiation Enteritis:
• Treatment of acute radiation enteritis is symptomatic.
Antispasmotic and analgesic for abdominal cramps
Opiates and other antidiarrheal medications for diarrhea
IV fluid replacement, discontinuation of oral feeding if necessary
buffered aspirin
• Treatment of chronic radiation enteritis (after 8-12 months).
Small bowel obstruction most commonly develops.
Oral intake is stopped, IV fluids and NG decompression.
If there is no clinical improvement, surgery.
Malabsorption.
Gluten-free diet.
Low-carb, lactose-free, fat-free diet.
Cholestyramine (binds to bile salts and prevents diarrhoea).
TPN.
Obstruction (most common), fistula, perforation and bleeding are indications for surgery.
Meckel's Diverticulum and Diverticulitis
Meckel's diverticulum is a remnant (complete closure) of the vitelline duct (ompholomesenteric duct). Meckel's diverticulum is the most common congenital gastrointestinal system anomaly. It is a true diverticulum (includes all layers of the intestinal wall). Meckel's diverticulum has its own mesosome and vein.
Rule of Twos in Meckel's Diverticula
• It is seen in 2% of the population.
• Approximately 2 inches (5 cm) long
• The distance from the ileocecal valve is 2 feet (70 cm).
• Male / Female = 2
• Symptoms occur most often at the age of 2 years.
• Complications develop in 2-4% of those with diverticula (lifetime).
• 2 types of heterotropic mucosa are common; pancreas and stomach (sometimes colon)
Complications of Meckel's Diverticula
• Bleeding (stomach mucosa)
• Ileus (volvulus, intussusception, Littre hernia)
• Meckel's diverticulitis
• Perforation
• Fistula
Meckel Diverticula Treatment: Surgery is required in case of complications. While wedge resection is sufficient in diverticulitis (segmental small intestine resection if necessary), segmental resection + anastomosis to the small intestine is required in bleeding (for complete removal of the heterotropic gastric mucosa). If it is detected incidentally during laparotomy, resection should be performed in the following cases; Patient younger than 40 years of age, diverticulum longer than 2 cm, connection to the umbilicus or mesentery by a fibrous band.
Mesenteric Ischemia
Mesenteric ischemia is the development of gangrene in the small intestines due to interruption of small intestine blood supply. Mesenteric ischemia is fatal. There are actually two mesenteric arteries (superior and inferior mesenteric artery). The artery referred to in mesenteric ischemia is the superior mesenteric artery, which supplies the entire small intestine and the right hemicolon (until the middle of the transverse colon). The inferior mesenteric artery is rarely occluded, and even if it is occluded, it rarely causes ischemia (it is asymptomatic). Mesenteric ischemia can be acute (intestinal necrosis) or chronic (angina abdominalis). Causes (Types) of Mesenteric Ischemia
• Acute superior mesenteric artery embolism (50%)
• Acute superior mesenteric artery thrombosis (15-25%)
• Non-occlusive mesenteric ischemia (Heart failure, hemodynamic disorder) (20-30%)
• Mesenteric venous thrombosis (5%)
• Chronic mesenteric ischemia
• Colonic ischemia
In acute mesenteric ischemia, the median age is 70 and most patients are women. In acute mesenteric artery embolism, the source of the embolism; atrial fibrillation, heart valve diseases, akinetic left ventricular wall (previous acute myocardial infarction). The embolism usually sits within the superior mesenteric artery, where the middle colic artery originates. Therefore, small bowel ischemia begins approximately 50 cm after Treitz and continues until the middle of the transverse colon. Acute mesenteric artery thrombosis develops in patients with generalized atherosclerosis. These patients are hypertensive patients. Intestinal ischemia develops insidiously in these patients, and more than half of them have angina abdominalis (postprandial abdominal pain and weight loss).
Symptoms of Acute Mesenteric Ischemia:
The patient's extreme suffering and complaints are inconsistent with the physical examination (acute visceral ischemia). Initially, the abdomen is soft and there is slight tenderness. As ischemia progresses, sensitivity increases, defense develops, and bowel sounds disappear (wooden abdomen). If necrosis develops, leukocytosis develops rapidly.
Diagnosis of Acute Mesenteric Ischemia:
While in the past the standard imaging method was angiography (aortagraphy and selective SMA angiography), today CT angiography is at the forefront. Treatment of Acute Mesenteric Ischemia: Embolectomy is performed in superior mesenteric artery embolism, and aortomesenteric bypass is performed using saphenous vein graft or synthetic graft in superior mesenteric artery thrombosis.
Short Bowel Syndrome
Short bowel syndrome, as its name suggests, is a syndrome that occurs due to the shortness of the intestine (food cannot be absorbed); There are malabsorption, malnutrition, diarrhea, steatorrhea and electrolyte disorders. The most common causes of short bowel syndrome are; trauma, mesenteric ischemia, midgut volvulus, Crohn's disease, tumor, necrotizing enterocolitis. Normally, the approximate length of the small intestine is 600 cm. If it remains shorter than 200 cm, short bowel syndrome develops.
