Lower Gastrointestinal Disorders Flashcards
What is an “obstructive series”
Upright PA and lateral CXR, and flat and uptright abdominal radiograph
Why do patients with SBO typically present with contraction alkalosis and hypokalemia?
When patients have SBO they tend to vomit because of bowel back up. This results in loss of H2O, Na+, H+ and Cl- with an overall decrease in plasma volume from H20 loss and an increase in pH due to H+ loss…giving you alkalosis. Hypovolemia and alkalosis causes the kidneys to retain more Na+ and H+…thus giving you hypokalemia.
How do you correct a contraction alkalosis in a patient with SBO?
IVF containing Na and K usually does the job
When is it appropriate to d/c a patient w/SBO
Pain and distention resolution w/toleration of food after NG removal.
Differential diagnosis for SBO in a patient with no prior abdominal surgeries?
Adhesions can still form regardless of surgical history. Hernia, bowel tumors or inflammatory processes can also cause SBO.
A patient presents with nausea, vomiting, abdominal distention and tenderness to palpation of the abdomen. She says that she has had symptoms for the past 2 days and only has passed small amounts of diarrhea. What do you need to do in your assessment of this patient?
Typically complete SBO presents with no BMs. Small amounts of diarrhea can indicate constipation and you need to check for fecal impaction. Gastroenteritis and partial SBO should also be in your differential.
What is the most common tumor metastasis in the intestine?
Melanoma, it frequently manifests as SBO that does not resolve with nonoperative management. Even if the tumor is not resectable, surgical measures should be taken to relieve the obstruction.
A patient presents with SBO and a PHMx significant for ovarian cancer. What is at the top of your differential?
Recurrent ovarian cancer can happen locally or as peritoneal studding, resulting in obstruction.
How can breast cancer affect the bowel?
Breast cancer mets can manifest as SBO
What is a good physical exam finding that tells you this patient needs surgical exploration for SBO?
Localized tenderness, markedly elevated temperature, localized pain around hernia, free air under diaphragm on CXR and marked leukocytosis can indicate closed loop obstruction, perforation, ischemia or abscess. Metabolic acidosis is suspicious for ischemia or necrotic bowel and depending on the patients status and imaging mertis either urgent surgical exploraiton or mesenteric arteriography before exploration to check for arterial occlusion.
Post-op plan for pt that underwent LOA to correct SBO
NPO w/NG tube until bowel function returns. Once patient tolerates food d/c.
What is a second look operation in regards to surgery for SBO?
If the SBO was due to a closed loop obstruction and it was questionable if the bowel would still be viable, you re-explore the abdomen in 24 hours to assess for viability and resect any ischemic or necrotic bowel followed by anastamosis. Don’t just send the patient home because ischemic bowel will present several days later and make the patient much sicker.
Management of a patient with SBO due to hernia.
Exploration through hernia incision if patient is stable. Exploration through midline abdominal incision if patient appears ill to more thoroughly inspect the entire bowel for ischemia and necrosis. Repair the hernia and resect non-viable bowel.
Management of accidental enterotomy during intra-abdominal procedure
If small, primary repair is fine. If large, resection and anastomosis are required. Either way, the patient will be at risk for small bowel fistulas and leaks post-op.
A patient presents with heart failure, COPD and urinary sepsis. The sepsis is resolved in the hospital, but he has SBO now. After NG drainage and NPO treatment, the patient still cannot tolerate solids. You are unsure if the obstruction is mechanical or from paralytic ileus due to his many comorbidities. How do you determine if you need to do surgery or not?
Upper GI series w/small bowel follow through. Note that constipation can be seen on radiographs and in upper GI series the Barium will still find its way through the impacted stool.
Work up of a patient with possible mesenteric ischemia
Pain out of proportion to PE, nonspecific ileus on radiographs, hydrate/oxygenate/perfuse, sigmoidoscopy to check for ischemia, mesenteric angiogram if sigmoidoscopy is negative. If the patient looks really sick and you suspect necrotic bowel you can go straight to the OR.
This patient presents with 1 day hx of nausea, vomiting and sever abdominal pain. PE shows abdominal distention and tenderness. Her pain seems much more severe than her abdominal findings. Sigmoidoscopy shows ischemic bowel. Mesenteric angiogram is shown below. How do you tx this patient?
Revascularization of SMA due to risk of recurrence, necrosis and a much worse episode. Also put the patient on aspirin.
When can you go directly to the OR for a patient with suspected ischemic bowel?
Significantly worsening pain over acute time period, markedly elevated WBC/markedly decreased WBC in elderly or metabolic acidosis
When is an angiogram an acceptable next step before taking a patient with mesenteric ischemia to the OR?
Hx of a-fib, hx of abdominal bruit (looking for stenotic celiac/SMA) and hx of thoracic aortic dissection.
A patient presents with symptoms of mesenteric ischemia. His hct is 55%, how do you manage this patient?
Most common cause of polycythemia is dehydrate, so rehydrate the patient. If the patient has polycythemia vera the patient needs phlebotomy, rehydration, angiography and surgery if angiography indicates significant occlusion. If the patient has COPD, he needs a pulmonology consult to improve ventilation which will decrease RBC load.
A patient presents with sx of mesenteric ischemia and hx of CHF. How do you manage this patient?
Ischemia may be due to low flow nonocclusive state, confirmed by angiogram. Tx involves direct mesenteric infusion of papaverine (PED10A inhibitor) to vasodilate and meds to improve cardiac output. If necrosis is likely go to the OR, where you will likely see small punctate areas of necrosis, indicating a low flow state. Post-op hemodynamic optimization and second look is a reasonable approach without immediate resection.
Next step in a patient with suspect mesenteric ischemia and bloody diarrhea?
Sigmoidoscopy, if full-thickness necrosis is present then send for surgery. If only mucosal necrosis, optimize hemodynamics, give abx and admit for observation.
How do you treat a patient with mesenteric necrosis from the ligament of Treitz to the transverse colon?
Let the succumb to the disease and die. In younger individuals you may consider surgical resection and reanastaomosis followed by chronic TPN or small bowel transplant due to short bowel syndrome.
How do patients present if they develop short bowel syndrome from multiple bowel resections?
Deficiencies in vitamins A (night blindness, xerophthalmia, xerosis, Bitot spots and keratinization of the skin and mucous membranes), D (muscle aches, muscle weakness, bone pain, osteomalacia and hypocalcemia), E (mild hemolytic anemia and nonspecific neurologic deficits), K (easy bruisin/bleeding), B9 (macrocytic anemia), and B12 (macrocytic anemia + posterior column deficits), calcium,magnesium, iron, and zinc.
