Abdominal Surgery: Small and Large Intestine Part I Lecture/Onlinemeded/amboss

Question 1

Many things can cause small bowel obstruction (SBO), but they are most commonly caused by…

Answer 1

adhesion and hernias of the abdomen

Question 1

What will you see on Xray for SBO?

Answer 1

Abdominal X-rays(lying and standing) will show distended loops of bowel (lying) and air-fluid levels (standing).

Question 2

A diagnostic procedure in which _______, a nontoxic, water-soluble contrast agent, is ingested and visualized on fluoroscopy to evaluate the integrity of the esophagus or eval SBOs.

Answer 2

gastrografin test

Question 3

With increased demand comes ischemia. The intestines work harder to absorb food. Thus, patients will present with pain after eating and avoid eating (to avoid the pain), resulting in weight loss. They will have the typical risk factors—hypertension, diabetes, dyslipidemia, cigarettes, age—and maybe even evidence of vascular disease elsewhere (CVA, CAD, PLI).

Answer 3

Chronic mesentery ischemia

Question 4

presents with pain out of proportion to the physical exam, elevated lactic acid,and, if allowed to go on long enough, bloody diarrhea because the mucosa is farthest from the blood supply, so it infarcts first and sloughs off. By the time there are peritoneal findings,

Answer 4

Acute mesenteric ischemia

Question 5

How do we work up transmural infarct of the mesentery?

Answer 5

Diagnose with CT angiography and treat by relieving the blockage (stent or bypass) or removing the infarcted bowel

Question 6

t are other etiologies of mesenteric ischamia aside from thrombus/embolus?

Answer 6

Acute mesenteric ischemia can also occur unrelated to atherosclerosis if the blood vessels become compressed, such as in volvulus, intussusception, or strangulated hernia. In these cases the underlying pathology needs to be corrected.

Question 7

Answer 7

Chronic mesentery ischemia

Question 8

Answer 8

acute mesenteric ischemia

Question 9

Bowel that herniates through the inguinal ring will be within the spermatic cord along with the testicular blood vessels, lymphatics, and nerves. The inguinal ring is lateral to the epigastric blood vessels and superior to the inguinal ligament.

Answer 9

indirect hernia

Question 10

maleadult hernia subtype, caused by increased intra-abdominal pressure (straining, lifting heavy things) and the area of weakened abdominal wall known as the inguinal triangle. This is a region where no abdominal muscle supports the abdominal wall, only the fascia of the transversalis muscle. The inguinal triangle is medial to the epigastric vessels and superior to the inguinal ligament. Entering the inguinal canal without going through the inguinal ring results an inguinal hernia that is outside the spermatic cord.

Answer 10

direct hernia

Question 11

Femoral hernia

Answer 11

If bowel herniates under the inguinal ligament, it will exit into the anterior thigh, within the femoral triangle where the femoral nerve, artery, vein, some space, and lymphatics are found (NAVEL). Women get this type of hernia often because there is no inguinal canal or spermatic cord to herniate through. Pain and a bulge are elicited in the anterior thigh.

Question 12

If bowel herniates under the inguinal ligament, it will exit into the anterior thigh, within the femoral triangle where the femoral nerve, artery, vein, some space, and lymphatics are found (NAVEL). Women get this type of hernia often because there is no inguinal canal or spermatic cord to herniate through. Pain and a bulge are elicited in the anterior thigh.

Answer 12

Femoral hernia

Question 13

are herniations anywhere other than the groin or femoral triangle, anywhere there is an anterior abdominal wall. Most are iatrogenic, a consequence of surgery, called incisional hernias (caused by skin and fascia closing and healing well, but not the abdominal muscles).

Answer 13

ventral hernias

Question 14

What kind of hernia is not reducible?

Answer 14

Incarcerated

An incarcerated hernia is not reducible, and the bowel cannot be pushed back in through the defect. As long as there are no signs of obstruction or ischemia, even an incarcerated hernia can be managed electively. But the symptom to watch out for is small bowel obstruction, escalating the severity to urgent.

Question 15

small bowel perf shows as what on XR?

Answer 15

Free air under diaphragm

Question 16

Perf of retroperitoneal organs/ascending and descening colon will show what on XR?

Answer 16

Air outlining the retroperitoneal organs (especially the kidney and blood vessels) indicates that there has been a retroperitoneal perforation (ascending and descending colon).

Question 17

A radiographic finding of gas within the wall of the intestine. The etiology varies from benign conditions to life-threatening gastrointestinal diseases. In newborns, the finding is considered diagnostic for necrotizing enterocolitis (NEC), resulting from intramural gas-producing bacteria.

Answer 17

Pneumatosis intestinalis

Question 18

Answer 18

Pneumatosis intestinalis

Question 19

are small, slow-growing neuroendocrine tumors. They are most commonly located in the gastrointestinal tract and can synthesize a variety of hormones (especially serotonin).

Answer 19

Carcinoid tumors

Question 20

Elevated 5-HIAA in the urine helps to establish the diagnosis.

Answer 20

Carcinoid tumor, we use 5-HIAA b/c its a serotonin metabolite and carcinoid tumors tend to produce serotonin

Question 21

Why do many carcinoid tumors go asymptomatic?

Answer 21

They are most commonly located in the gastrointestinal tract and can synthesize a variety of hormones (especially serotonin). Most carcinoids are asymptomatic because most of the hormones they produce are metabolized by the first-pass effect in the liver.

Question 22

What does carcinoid symdrome present with and when do we see it?

Answer 22

Carcinoid syndrome – characterized by diarrhea, flushing, dyspnea, and wheezing – may occur if a serotonin-producing tumor has metastasized to the liver, bypassing first-pass metabolism.

Question 23

What heart problems can arise from carcinoid tumors?

Answer 23

Endocardial fibrosis that especially affects the right heart
Tricuspid insufficiency and/or pulmonary stenosis
Symptoms of right-sided heart failure

Question 24

How may you be able to discern strangulated versus incarcertaed inguinal hernia on presentation?

Answer 24

Strangulated= sick as shit

Question 25

When dealing with a SBO question, when do you pick NG tube over CT w/contrast?

Answer 25

If not peritoneal or refractory shock, when managing a small bowel obstruction a diagnosis should be confirmed with a CT scan with IV contrast, then treated conservatively with NG tube, IV fluids, and serial abdominal exams. An NG tube decompression may come before the CT scan, but not when the NG tube is part of an answer choice that represents conservative management only.

Question 26

What does the red arrow hilight on this CT view?

Answer 26

This hilights a thrombus in the superiror mesenteric artery

Question 27

Where the arrow is, what is this sign called and what is it indicative of?

Answer 27

Its called pneumonatosis intestinitis, this tells you that there is are in the bowel wall (you have black air surround grey fluid in the intestin), this can be from a number of etiolofies from necrotizing enterocolitis, acute mesenteric ischemia/perforation, or from an obstruction of other causes.

Question 28

most common congenital gastrointestinal tract anomaly

Answer 28

Meckel diverticulum

Question 29

Incomplete obliteration of the omphalomesenteric duct → persistence of the proximal (intestinal) segment of the duct → _____________________

Answer 29

Meckel diverticulum

omphalomesenteric duct is also called the vitelline or vitellointestinal duct

Question 30

How does meckel diverticulum present?

Answer 30

Male more common than female, can be asymptomatic. Symptomatic one would present with:
Lower gastrointestinal bleeding (most common feature)
Presence of ectopic gastric mucosa or pancreatic tissue → acid or enzyme secretion within the diverticulum → ileal ulceration → bleeding
Can manifest as:
Hematochezia
Tarry stools
Abdominal pain (typically in the right lower quadrant)

Question 31

What test to we do to dx meckel diverticulum?

Answer 31

Meckel scintigraphy scan (Meckel scan): a noninvasive nuclear medicine imaging technique using radiolabelled technetium (99mTc), which is preferentially absorbed by the gastric mucosa and can identify ectopic gastric mucosa

Question 32

________________________ is a temporary disturbance of peristalsis in the absence of mechanical obstruction

Answer 32

Functional bowel obstruction, or paralytic ileus, is a temporary disturbance of peristalsis in the absence of mechanical obstruction

Question 33

_____________________- is the most common cause of SBO and _____________ is the most common cause of LBO.

Answer 33

Postoperative bowel adhesion is the most common cause of SBO and malignancy is the most common cause of LBO.

Question 34

Regardless of the cause, bowel obstruction typically manifests with

Answer 34

Regardless of the cause, bowel obstruction typically manifests with nausea, vomiting, abdominal pain, abdominal distention, and constipation or obstipation.

Question 35

A type of mechanical bowel obstruction in which the proximal and distal ends of the obstructed loop are closed (e.g., volvulus, obstructed inguinal hernia, obstructing colon cancer with a competent ileocecal valve).

Answer 35

Closed-loop bowel obstruction which can rapidly lead to ischemia and perforation and typically necessitates surgical intervention.

Question 36

List some causes of small bowel obstruction

Answer 36

adhesions
meckel diverticulum
strictures (crohn disease)
tumors
gallstone ileus
SMA syndrome
Hernia

Kiddos:
Congenital intestinal atresia (e.g., duodenal atresia, jejunal atresia)
Intussusception (e.g., secondary to Meckel diverticulum)
Congenital strictures and bands (e.g., Ladd bands in intestinal malrotation)

Question 37

What are some causes of large bowel obstruction?

Answer 37

Tumors
diverticulitis
volvulus
adhesions
strictures
fecal impaction

in kiddos
Hirschsprung disease
Congenital strictures and bands (e.g., Ladd bands in intestinal malrotation)
Meconium ileus
Rectal atresia

Question 38

How does intraluminal air appear in a complete bowel obstruction?

Answer 38

Complete bowel obstruction: minimal or no air distal to the obstruction

Question 39

Answer 39

Small bowel dilatation

Question 40

Answer 40

SBO mechanical

Question 41

Answer 41

X-ray abdomen (AP view; supine position) of a patient with a history of distal colonic obstruction

Question 42

Answer 42

Distal large bowel obstruction (1/2)

X-ray abdomen (AP view; supine position)

Question 43

Answer 43

Bird beak sign: in volvulus

this is a barrium enema or water coluable enema

Question 44

Answer 44

Apple core sign: in colonic malignancy

Question 45

Temporary impairment of peristalsis in the absence of a mechanical obstruction

Answer 45

Paralytic ileus

Question 46

What are the risk factors for Paralytic ileus?

Answer 46

Recent abdominal surgery
Atherosclerotic disease
Abdominal infections or inflammatory conditions
Certain medications (opioids, anticholinergics, antiparkinsonian agents)

Question 47

What are some findings that can help differentiate a mechanical bowel obstruction from a paralytic ileus?

Answer 47

mechanical:
High-pitched, tinkling bowel sounds (early)
Absent bowel sounds (late)

PAralytic ileus:
Absent bowel sounds

Question 48

Diagnosis is based primarily on characteristic endoscopic features (ulcerations, skip lesions, cobblestone appearance) and evidence of intestinal inflammation on imaging.

Answer 48

Crohn

Question 49

What would you see on endoscopy for crohn disease?

Answer 49

ulcerations, skip lesions, cobblestone appearance

Question 50

age of onset for crohn

Answer 50

Typical age of onset: bimodal distribution with one peak at 15–35 years and another one at 55–70 years

Question 51

Risk factors for crohn

Answer 51

Familial aggregation

Genetic predisposition (e.g., mutation of the NOD2 gene, HLA-B27 association)

Tobacco smoke

Smoking tobacco is the primary modifiable risk factor for CD. Therefore, smoking cessation is especially important in patients with CD.

Question 52

________________ most commonly affects the terminal ileum and colon, but involvement of any part of the GI tract (from mouth to anus) is possible.

Answer 52

CD most commonly affects the terminal ileum and colon, but involvement of any part of the GI tract (from mouth to anus) is possible.

Question 53

________________________most commonly affects the terminal ileum and colon, but involvement of any part of the GI tract (from mouth to anus) is possible. In contrast to ___________________, rectal involvement is uncommon.

Answer 53

CD most commonly affects the terminal ileum and colon, but involvement of any part of the GI tract (from mouth to anus) is possible. In contrast to ulcerative colitis, rectal involvement is uncommon.

Question 54

What are often the first signs of Crohn?

Answer 54

Perianal fistulas and abscesses are often the first signs of CD.

Question 55

What are some extraintestinal symptoms of crohn?

Answer 55

Joint involvment: Enteropathic arthritis
e.g., sacroiliitis, spondylitis, inflammation of peripheral joints

Uveitis
Cholethiasis
Urolithiasis (remember increased risk of calcium oxalate stones)
Erythema nodosum
pyoderma gangrenosum

Question 56

A rare oral condition strongly associated with inflammatory bowel disease (especially ulcerative colitis). Manifests with slightly elevated, yellow-white, round mucosal lesions with a characteristic snail-track appearance. Most commonly affects the labial and buccal mucosae, gingivae, and palate.

Answer 56

Pyostomatitis vegetans

A rare oral condition strongly associated with inflammatory bowel disease (especially ulcerative colitis). Manifests with slightly elevated, yellow-white, round mucosal lesions with a characteristic snail-track appearance. Most commonly affects the labial and buccal mucosae, gingivae, and palate.

Question 57

What serologic marker is elevated in CD more than in UC?

Answer 57

↑ Anti-Saccharomyces cerevisiae antibodies (ASCA): more commonly elevated in CD than in UC

pANCA: more commonly elevated in UC than in CD

Question 58

Treatments for CD

Answer 58

steroids

Thiopurine analogs (azathioprine, 6-mercaptopurine)

Anti-p40 antibodies (e.g., ustekinumab)

Alpha 4 integrase inhibitors (e.g., natalizumab, vedolizumab)

Anti-TNF-α antibodies: e.g., adalimumab, infliximab, certolizumab

Question 59

Crypt abscesses are seen in

Answer 59

ulcerative colitis

Question 60

UC or CD: primary sclerosing cholangitis

Answer 60

UC

Question 61

UC or CD: transmural inflammation

Answer 61

CD

Question 62

macrocytic, megaloblastic anemia in a pt with crohn is concerning for…

Answer 62

vitamin B12 deficiency

Question 63

This patient with chronic abdominal pain, bloody diarrhea, significant weight loss, proctitis (evidenced by pain on defecation with an unremarkable rectal examination), anemia, and positive p-ANCA most likely has

Answer 63

ulcerative colitis (UC)

Question 64

Confluent inflammation of the colonic mucosa with edema, fibrin-covered ulcers, and loss of vascular pattern

Answer 64

ulcerative colitis (UC)

Question 65

Five days after undergoing open distal pancreatectomy and splenectomy for a complex pancreatic cyst, a 65-year-old man notes a gush of salmon-colored fluid from his wound while getting out of bed. What is the most likely problem?

Answer 65

Dehiscence

The drainage of clear pink fluid from this patient’s incision a few days after open abdominal surgery is most likely peritoneal fluid tinged with blood, which is consistent with fascial dehiscence.

Question 66

What may predispose a pt to poor wound healing and subsequently wound/fascial dehiscence?

Answer 66

history of type 2 diabetes mellitus and smoking are big ones

Question 67

CT scan of the abdomen shows an edematous appendix with a 5-cm periappendiceal fluid collection. The patient is placed on bowel rest and started on IV fluids. In addition to administering intravenous antibiotics, what is the most appropriate next step in management?

Answer 67

Percutaneous drainage.

Patients with large (> 4 cm) periappendiceal abscesses should be managed with nonoperative measures (i.e., IV antibiotics, fluids, and bowel rest) and percutaneous drainage of the abscess. Although appendectomy can be considered in patients whose appendiceal abscess is not eligible for percutaneous drainage and in patients with small abscesses, emergency appendectomy should generally be avoided in patients with appendiceal abscesses because of the high risk of surgical complications due to acute inflammatory reaction in the area around the abscess.

Question 68

What is considered a large periappendiceal abscess?

Answer 68

over 4 cm

Question 69

uniform distribution of gas in small bowel, colon, and rectum suggest paralytic ileus.

Answer 69

uniform distribution of gas) suggest paralytic ileus.

Question 70

This is the most common cause of acute abdomen in pregnancy.

Answer 70

appendicitis

Question 71

How does appendicits present in pregnancy?

Answer 71

presents with dull abdominal pain, vomiting, fever, leukocytosis, and mild pyuria. Pregnant patients may present with pain in the upper quadrants/RUQ because appendix is displaced/

Although appendicitis pain classically localizes to the RLQ (McBurney point), in pregnant patients the gravid uterus can displace the appendix towards the right upper quadrant or the flank. Sterile pyuria is a common finding in appendicitis and can occur if part of the urinary tract (usually the right ureter) is within close proximity of the inflamed appendix, causing ureteric irritation and/or inflammation. Graded compression abdominal ultrasound is the best initial imaging modality for suspected appendicitis in pregnancy.

Question 72

Biopsy results showing granulomatous inflammation/noncaseating granulomas of the colonic mucosa are diagnostic of _____________

Answer 72

Crohn disease

Question 73

findings of ulcers and polyps (likely inflammatory pseudopolyps) with crypt abscesses on biopsy are characteristic features of ___________________

Answer 73

ulcerative colitis (UC)

Question 74

UC or CD: colonic granulomas

Answer 74

CD