GI Flashcards
Initial actions in a patient with abdominal pain?
- Primary survey (ABCs, 2 large bore IVs with immediate fluid resuscitation if hemodynamic instability)
- Pregnancy test in women of child-bearing age (use Foley to obtain urine if unstable or send blood)
- Blood products in unstable patients with suspected hemorrhage
- Bedside imaging in patients with concern for pneumo or hemoperitoneum (XR, US)
- Order ABX in the setting of sepsis, peritonitis, or perforation
- Analgesia
- Immediate surgical consultation in the setting of hemodynamic instability or a rigid abdomen
Abdominal pain + hemodynamic instability should alert the physician to what possibilities?
Hemorrhage, sepsis, perforated viscus, or necrotic bowel
Life- or organ-threatening diagnoses that must be considered in patients with abdominal pain?
Ectopic pregnancy Appendicitis AAA PID/TOA Biliary disease Bowel obstruction Perforated viscus Mesenteric ischemia Testicular (ACS)
Cholelithiasis occurs as a result of supersaturation of bile with ___ (70%), ___ such as bilirubin (20%), or both (10%), combined with delayed emptying of the gallbladder (stasis).
Cholesterol; bilirubin
What is choledocholithiasis?
Presence of gallstones within the common bile duct
What is acute cholecystitis?
Inflammation of the gallbladder related to the presence of gallstones in 90-95% of cases; acalculous cholecystitis occurs in <10% of cases and are more common in elderly, post-operative, or critically ill patients
What is cholangitis?
Inflammation of the bile duct, most often 2/2 polymocrobial bacterial infection
Classic presentation of biliary colic?
Episodic/intermittent/colicky burning/pressure-like/heavy RUQ or epigastric pain associated with N/V, may radiate to the back, R flank, or tip of the R scapula
May be related to ingestion of a fatty meal
Most resolve within 4-6 hours
Charcot’s triad?
Classic presentation of cholangitis - RUQ pain, fever, jaundice
Physical exam findings of biliary disease?
RUQ or epigastric tenderness
Murphy’s sign (good sensitivity, low specificity for acute cholecystitis)
Jaundice if biliary tree obstructed
Elevated temperature suggests cholecystitis and cholangitis
Lab work-up in biliary disease?
WBCs AST/ALT Bilirubin (conjugated) Alkaline phosphatase Amylase/lipase
Initial diagnostic test of choice for evaluation of biliary tract disease?
US
> 95% sensitivity for identification of cholelithiasis (mobile echogenic material casting posterior shadows)
<80% sensitivity for choledocholithiasis
Sensitivity 88-94% and specificity 78-80% for acute cholecystitis (gallstones, GB wall thickening - 5mm or greater, pericholecystic fluid, and/or positive sonographic Murphy’s sign)
Dilation of common bile duct (>6 mm adults, >8 mm in elderly)
Indications for HIDA scan?
If US is equivocal or negative for cholecystitis in the presence of a high clinical suspicion (90-94% sensitive for acute cholecystitis)
Positive HIDA study?
Lack of visualization of the gallbladder within 4 hours after injection
Indications for CT scan in evaluating biliary disease?
If US results are equivocal and HIDA scan is unavailable or if a broad differential is still being considered
Indications for ERCP in suspected biliary disease?
Useful for diagnosis and treatment of biliary and pancreatic duct diseases (MRCP or endoscopic US is better for diagnostics alone)
Risk factors for biliary disease?
Female >40 y/o Family history Obesity Multiparity Rapid weight loss Sickle cell or other hemolytic disorders (pigmented stones) DM (increased risk of cholecystitis)
Rx biliary disease
Biliary colic - symptom control (NSAIDs, fluids, anti-emetics), elective cholecystectomy
Choledocholithiasis - surgical or ERCP removal of stone
Cholecystitis and cholangitis - symptoms control with fluids, anti-emetics, and analgesics + broad-spectrum parenteral ABX, prompt cholecystectomy
Incidence of appendicitis peaks around which decades?
Around the 2nd and 3rd decades
Classic presentation of appendicitis?
Vague epigastric or periumbilical pain N/V and anorexia Abdominal tenderness, migrating then localizing to the RLQ Fever Leukocytosis
Discuss the sensitivity and specificity of physical exam findings in suspected appendicitis.
RLQ pain/guarding - high sensitivity (81%), low specificity
Abdominal rigidity - high specificity (83%), low sensitivity
Psoas, obturator, and Rovsing’s signs are all relatively poor predictors
NO SINGLE EXAM FINDING SHOULD BE USED TO RULE IN OR RULE OUT THE DISEASE
Work-up for appendicitis?
CBC (leukocytosis, though 10-20% will have a normal WBC count)
CRP (elevated CRP + elevated WBC has a combined sensitivity of 98%)
BMP
UA
US
CT
MRI
When is US indicated in appendicitis work-up?
Preferred imaging in children and pregnant patients
US findings suggestive of appendicitis?
Appendix >6-7 mm in diameter, non-compressible, increased wall thickness, periappendiceal stranding, fecalith, increased vascularity on Doppler
When is CT indicated in the work-up for appendicitis?
Adult males and non-pregnant females
IV contrast is recommended, though non-contrast is acceptable
When is MRI indicated in the work-up for appendicitis?
Pregnant patients with a non-diagnostic US
Rx appendicitis?
Prompt appendectomy
NPO, IV ABX (Amp-sulbactam, cefoxitin, combo metronidazole + ciprofloxacin, etc. if uncomplicated, carbapenem with pip/tazo if complicated)
IV fluids
Pain control
Antiemetics
Appendicitis ED dispo options?
OR for appendectomy
IR for percutaneous drainage of abscess
Obs in hospital for serial exam
Return in 24 hours for repeat exam
Patients with a rupture AAA may present to the ED with a CC of what?
Common misdiagnoses?
Abdominal, back, or flank pain
Renal colic, pancreatitis, bowel ischemia, diverticulitis, cholecystitis, bowel obstruction, MI, and MSK back pain
Classic presentation of ruptured AAA?
Pain (acute, severe, constant in the abdomen, back, or flank, can radiate to the chest, thigh, inguinal region, or scrotum)
Hypotension
Pulsatile abdominal mass (at or above the level of the umbilicus)
N/V, near-syncope, syncope, AMS
Continuous abdominal bruit and a palpable abdominal thrill suggest AV fistula; bloody stools can indicate an aortoenteric fistula
Initial actions and primary survey in suspected AAA?
If known or suspected ruptured AAA, consider unstable regardless of initial vitals and Hgb.
Manage ABCs -> 2 large bore IVs, type and cross-match blood
Target BP - 90-100 mmHg
Diagnostic testing in suspected AAA?
If unstable with known or suspected ruptured AAA - transfer to OR as soon as possible
Labs - H/H, coags, BMP, UA (lipase, LFTs if undifferentiated)
Imaging - US (ideal study), CT (extremely accurate), plain films (if no US/CT)
Rx AAA?
Crystalloid, blood products
Emergent surgical repair (vascular surgery)
Dispo AAA?
Acutely symptomatic - hospital admission and surgical repair
Unstable - emergent surgery
Stable, not cause of symptoms - refer to surgeon for OP work-up
Initial actions and primary survey in suspected mesenteric ischemia?
Consider in all elderly patients with abdominal pain Large bore IV access Fluid resuscitation Telemetry monitoring EKG (AFib?) Surgical consultation early Address ABCs
Classic presentation of mesenteric ischemia?
> 50 y/o
Sudden onset abdominal pain +/- N/V/diarrhea
Pain will initially be severe and diffuse without localization, out of proportion to exam (screaming in pain, benign exam), eventual abdominal distention with guarding, rebound, absence of bowel sounds, bloody diarrhea (late finding)
4 different etiologies of mesenteric ischemia?
Mesentery artery embolus
Mesentery artery thrombosis
Mesenteric vein thrombosis
Non-occlusive ischemia
Most common cause of mesenteric ischemia?
Mesenteric artery embolus (50% of cases)
Presentation of mesenteric ischemia 2/2 embolus?
Classic abdominal pain out of proportion to exam
Risk factors - arrhythmias (AFib), post-MI with mural thrombi, valvular heart disease, structural heart defects (R->L shunts)
Most common location of an embolus?
SMA due to the oblique angle of the SMA from the aorta
Usually lodges distal to the origin of the middle colic artery, sparing the duodenum and proximal jejunum (vs. thrombosis, which causes a more proximal blockage -> extensive ischemia)
Presentation of mesenteric ischemia 2/2 mesenteric artery thrombosis?
Patients with systemic atherosclerosis and old age
History of vague and insidious symptoms such as weight loss, abdominal angina (after meals), diarrhea, and fear of food -> chronic mesenteric ischemia, often confused with PUD
Slow progression of atherosclerosis until a certain level of blockage is obtained
Vasculature most likely to be involved in mesenteric artery thrombosis?
Celiac trunk, SMA
Least common cause of mesenteric ischemia?
Mesenteric vein thrombosis (10% of cases)
Presentation of mesenteric vein thrombosis?
Can occur acutely or over time Patients may be relatively younger Risk factors include hypercoagulable states, recent surgery, malignancy, cirrhosis, hx of DVT May have vomiting, diarrhea No postprandial pain or food fear
Most commonly involved vein in mesenteric vein thrombosis?
Superior mesenteric vein
Risk factors for mesenteric ischemia 2/2 non-occlusive ischemia?
Any condition associated with decreased CO -> cardiogenic shock, CHF, arrhythmias
Hospitalized sick patients
Sepsis, hypotensive states, drugs inducing mesenteric vasoconstriction -> digoxin, cocaine, alpha-agonists, beta-blockers
Labs to diagnose mesenteric ischemia?
WBC (commonly elevated)
Hemoconcentration
Elevated amylase
Metabolic acidosis
Elevated lactate -> sensitive late in the disease course
D-Dimer -> sensitive (higher than lactate)
Imaging to diagnose mesenteric ischemia?
Plain films - normal early, subtle signs later (bowel wall thickening, distended bowel loops)
Angiography (gold standard) - lateral view for origins of major vessels, AP views for visualization of distal mesenteric vessels
CTA (93% sensitive, 95% specific) - faster, less invasive, readily available compared to angiography
US, MRA - able to be used, but limitations
Initial Rx in mesenteric ischemia?
Stabilize and resuscitate:
2 large bore IVs with crystalloid fluids if hypotensive
Continuous vital sign monitoring
Insert triple lumen for CVP monitoring if needed to guide IV fluid Rx
Broad spectrum ABX
D/C meds with vasoconstrictive properties
If thrombosis suspected, anticoagulant like heparin can be started to stop propagation of thrombus
If angiography - papaverine during procedure to increase blood flow to bowel (decrease mesenteric vasoconstriction)
Rx ranges from non-operative management with medications, IV thrombolytics, percutaneous angioplasty, operative revascularization, bowel resection, combo of these
Rx of choice for mesenteric artery embolus?
Embolectomy + bowel visualization to assess for signs of necrosis
Another option - percutaneous treatment with thrombolytics infused into the artery with the embolus during angiography (no peritoneal signs or non-operative candidates)
Rx of choice for mesenteric artery thrombosis?
Start heparin as soon as diagnosis is made and prior to surgery
Same operative measures as embolectomy
Non-operative patients - percutaneous transluminal angioplasty
Rx of choice for mesenteric vein thrombosis?
Operative Rx if signs of infarction
Otherwise, thrombectomy with endarterectomy or distal bypass is first line
Anticoagulation to prevent thrombus reoccurrence, usually life-long
Rx non-occlusive mesenteric ischemia?
Rx undelrying cause
Papaverine to treat vasoconstriction of vessels to the mesentary
OR if peritoneal signs
Dispo in mesenteric ischemia?
Admitted, usually to ICU
Most common causes of SBO? Other causes?
Adhesions, followed by tumors and hernias. Strictures, intussusception, volvulus, Crohn disease, gallstones
Most common cause of LBO?
Malignancy
Describe the pathophysiology of SBO.
Begins when the normal luminal flow of intestinal contents is interrupted and the small intestine proximal to the obstruction dilates. Secretions are prevented from passing distally. As time progresses, the distention leads to N/V and an inability to take PO. Bacteria may ferment in the proximal intestine and cause feculent emesis. The bowel wall becomes more edematous and leads to a transudative loss of fluid into the peritoneal cavity, increasing the degree of dehydration and electrolyte abnormalities. Decreased urine output, tachycardia, azotemia, and hypotension can also be seen.
Define partial bowel obstruction.
Gas or liquid stool can pass through the point of narrowing (v. complete, when no substance can pass)
History consistent with SBO?
Abdominal pain, distention, vomiting, inability to pass flatus, N/V more prevalent in proximal obstruction
Possible diarrhea earlier during obstruction progressing to inability to pass flatus/obstipation
History of prior abdominal surgery, GI disorders like Crohn
Physical exam findings in SBO?
Abdominal distension (more prevalent in distal obstructions), hyperactive bowel sounds (early) or hypoactive bowel sounds (late)
Fever, tachycardia, peritoneal signs with strangulation
Inguinal hernia
Imaging in SBO?
Plain radiographs (upright chest - free air/perforation, upright abdominal - air fluid levels, supine abdominal - distended loops of bowel) - diagnosis made when multiple air fluid levels are seen with distended loops of small bowel, absence of air in colon/rectum (complete) vs. presence (partial)
Small bowel series - diagnosis and degree of obstruction (gold standard for determining partial or complete)
CT - replacing small bowel series as study of choice to differentiate partial vs. complete, and to identify strangulation early, can also differentiate between etiologies of SBO and diagnose other causes of abdominal pain (requires PO and IV contrast)
Define obstruction on CT.
Small-bowel loops >2.5 cm in diameter dilated proximal to a distinct transition zone of collapsed bowel <1 cm in diameter
Smooth beak - simple obstruction
Serrated beak - strangulation
Bowel wall thickening, pneumatosis, and portal venous gas all suggest strangulation
Lab work-up in SBO?
Generally not helpful in diagnosing SBO, but helpful in management (degree of dehydration, operative management) - CBC, BMP, T&S, coags
Lactic acid, LFTs, lipase, UA
Rx of SBO?
Initial management:
- Resuscitation and electrolyte replacement
- Identify severity and cause of obstruction
- GI decompression
- Symptomatic Rx
- Decide surgery or not
If acutely ill/peritoneal signs - emergent surgical consult, aggressive resuscitation (2L wide open with standard O2 and monitoring per protocol), PPx ABX if surgery acutely needed.
If stable, consult surgery to determine if operative management is warranted.
Non-operative: GI decompression with NG tube, IV fluids, bowel rest, symptomatic Rx
Frequent reassessment, IV pain/nausea medication
Difference between upper and lower GI bleed?
Ligament of Treitz crosses the small intestine at the duodenal-jejunal junction (anatomic dividing line)
Initial management of GI bleed?
Primary survey (ABCs) - initiate stabilizing care
IV access - minimum of 2 large bore IVs, consider transfusing un-crossmatched blood and IV fluids while type and cross is performed
If severe/uncontrolled, unstable vitals, no ability for emergent endoscopy, consider esophageal tamponade (1 balloon in stomach, 1 balloon in esophagus)
Lab evaluation in suspected GI bleed?
STAT CBC, BMP, coags, type and cross
Primary indication for blood transfusion in GI bleed?
Hemorrhagic shock despite IV fluid resuscitation
Subacute bleeding and a Hgb of 7
Symptomatic anemia (dyspnea, lightheadedness, chest pain) at a Hgb of 8 or 9
Massive upper or lower GI bleed (1000 mL maroon-colored thin liquid stools Q20-30 minutes or NG tube with constant output of blood)
Hgb dropping at a rate of 3 g/dL over 2-4 hours in the setting of active bleeding
Hgb <9 in active bleeding
Anemia induced end-organ injury
Considerations in a patient with GI bleed who is on anticoagulation or antiplatelet agent?
FFP or cryoprecipitate - warfarin, cirrhosis and likely variceal bleeding)
Platelets - ASA or clopidogrel
Consider reason for anticoagulation (risks and benefits)
Newer oral anticoagulations (dabigatran, rivaroxaban, apixaban) are more difficult to reverse
- Dabigatran can be dialyzed
- Prhtrombin complex concentrate may be effective with all 3 medications
What type of bleed is indicated by the following:
- Hematemesis
- Coffee ground emesis
- Melena
- Hematochezia
Hematemesis/coffee ground emesis - upper GI bleed
Melena (drak/tarry) - 70% upper, 30% lower
Hematochezia - LGIB or UGIB with significant bleeding/increased GI motility
How can the source of bleeding be located?
History NG tube if intractable emesis or if question about upper GI bleed, can be helpful to assess the rate, but is not without risks/vagueness Bleeding scan (moderate lower GI bleeding, stable patient, especially if recurrent GI bleeding with previously negative colonoscopy and endoscopy)
Pharmacologic management of GI bleed?
PPIs - first line for acid suppression in upper GI bleed
H2 blockers - second line, used to reduce acid production in outpatient setting as PI; only used in ED when PPIs are contraindicated
Somatostatins (octreotide) - known or highly suspected variceal bleed, causes splanchnic vasoconstriction -> decreased secretion of gastric acid and pepcin
ABX: history of cirrhosis (reduces mortality) - ceftriaxone (first line), ciprofloxacin (second line)
How are PPIs administered?
Low-risk patient who is likely to be admitted: empiric IV PPI (40 mg IV BID), continue until source identified
More severe/active bleed or with comorbidities that increase risk: IV bolus followed by continuous protonix infusion (80 mg bolus, 8 mg/hr drop)
Dispo GI bleed?
Mild (mild anemia, no active bleeding beside positive stool guaiac or blood-streaked emesis) - home with prompt follow-up for Hgb monitoring and GI referral as appropriate
Severe/acute - admission to floor or ICU based on vital signs, rate of bleeding, need for transfusion, potential for decompensation, comorbidities, need for procedures/sedation only available in ICU
DDx - GI bleed (upper)?
Gastric ulcer Duodenal ulcer Gastritis Esophagitis Gastroesophageal varices Mallory-Weiss tear Aortoenteric fistula Malignancy
DDx - GI bleed (lower)?
Diverticulosis Meckels diverticulum Angiodysplasia Malignancy Colitis (infection, ischemia, IBD) Anorectal (hemorrhoids, fissures)
DDx - perforated viscus (broad categories)
- Foreign body perforation
- Extrinsic bowel obstruction
- Intrinsic bowel obstruction
- Loss of GI wall integrity
- GI ischemia
- Infection
DDx - perforated viscus (foreign body perforation)
Penetrating trauma
Endoscopy/iatrogenic
Ingestion of foreign bodies
DDx - perforated viscus (extrinsic bowel obstruction)
GI stromal tumors Lymphoma Surgical adhesions Hernia Volvulus
DDx - perforated viscus (intrinsic bowel obstruction)
Phytobezoar Crohn's stricture Diverticulitis Appendicitis Intraluminal neoplasm
DDx - perforated viscus (loss of GI wall integrity)
- Peptic ulcer
- Crohn disease
- Tumor lysis syndrome
DDx - perforated viscus (GI ischemia)
- Shock/hypotension
- Thromboembolic event
- Visceral arterial sclerosis
- Portal vein thrombosis
DDx - perforated viscus (infection)
- Salmonella typhosa
- C. difficile
- CMV
Initial actions and primary survey in suspected perforated viscus?
- Cardiac monitoring, continuous pulse ox, large bore IV access
- Fluid resuscitation
- Focused H&P
- Broad spectrum ABX
- Rapid surgical consultation
Presentation of perforated viscus?
Severe sudden onset abdominal pain with rapidly worsening overall condition
May have a history of prior abdominal pain that is less severe due to the underlying cause
SIRS (fever, tachycardia, tachypnea, hypotension, septic shock) due to leakage of air, GI contents, and bacteria toxins into the peritoneal cavity
Ill/toxic
Presentation may be altered in patients with delayed presentation, immunocompromise, or elderly
Labs indicated in suspected perforated viscus?
CBC with diff CMP Lipase UA Urine pregnancy test Lactic acid VBG T&S/T&C Coags EKG
Imaging in suspected perforated viscus?
Plain radiograph - rapid, bedside, ideal for unstable patients, limited as it can miss free air in many patients
CT A/P - best test for free air, limited by longer time and if unstable
US - reliable for intra-abdominal fluid and AAA, free air if experienced operator
Rx perforated viscus
- Resuscitation
- Early ABX (common regimens include cipro + metronidazole, Pip/Tazo, or imipenem)
- Early surgical consult
