Acute Abdomen
Adult-Gerontology Acute Care Practice Guidelines
Definition
A.Acute abdomen is defined as pain, which arises suddenly and is usually less than 48 hours duration. Acute abdomen sometimes requires urgent surgical intervention, but not always.
B.Nontraumatic pain in the abdominal region with an onset of less than a few days and has worsened progressively until presentation.
C.Conditions categorized under acute abdomen.
1.Abdominal aortic aneurysm (AAA).
2.Acute cholecystitis.
3.Acute mesenteric ischemia.
4.Acute pancreatitis.
5.Appendicitis.
6.Diverticulitis.
7.Ectopic pregnancy/ovarian torsion.
8.Intestinal obstruction.
9.Perforated duodenal ulcer.
Incidence
A.Acute abdomen accounts for approximately 5% to 10% of all ED visits.
B.Approximately 20% of these patients will have small bowel obstruction, 14% will be diagnosed with appendicitis, 5% with cholecystitis, and less than 1% with perforated peptic ulcer. Another 25% will not be able to be diagnosed and will be discharged from the ED.
Pathogenesis
A.Acute abdomen depends on the origin of the pain: Ischemia, distension, obstruction, ulceration, or inflammation in the affected area.
Predisposing Factors
A.Previous abdominal surgery.
B.Diverticulitis.
C.Constipation.
D.History of gallstones.
E.Abdominal cancers.
F.Peptic/duodenal ulcers.
G.Crohn’s disease or ulcerative colitis.
H.Severe endometriosis or ectopic pregnancy.
I.Medications including nonsteroidal anti-inflammatory drugs (NSAIDS), steroids.
J.Alcohol abuse.
1.Age greater than 50.
Subjective Data
A.Common complaints/symptoms.
1.Right upper quadrant (RUQ).
a.Cholecystitis: Colicky, intermittent waves of pain that come and go. The pain may radiate to back, cause nausea, and worsen after a fatty meal. Pain improves with rest.
b.Peptic ulcer disease: Pain worsens after a meal.
c.Pancreatitis: Diffuse, burrowing, stabbing pain radiates to mid back.
2.Right lower quadrant (RLQ).
a.Appendicitis: Starts in mid abdomen, becoming more acute in RLQ. Sometimes nausea and vomiting occur.
3.Left lower quadrant (LLQ).
a.Diverticulitis.
B.Common/typical scenario.
1.AAA: If ruptured, patients who do not die immediately present with abdominal or back pain, hypotension, and tachycardia. They may have a recent history of straining (such as lifting a heavy object), and most will also have a history of hypertension.
2.Acute cholecystitis: Abrupt, severe, constant, aching pain in RUQ with radiation to the back and right shoulder lasting 24 hours or more, associated with nausea and vomiting.
3.Acute mesenteric ischemia: Patients are usually greater than 50 years old.
a.Arterial: Sudden onset of severe pain out of proportion to physical findings (abdomen soft; little or no tenderness) in patients at risk (coronary artery disease, atrial fibrillation, generalized atherosclerosis, low flow states). Patients may have a history of post prandial pain suggesting intestinal angina. However, many patients have no identifiable risk factors.
b.Venous: Similar symptoms to arterial, but with a more gradual onset.
4.Acute pancreatitis: Steady, piercing, upper abdominal pain, severe enough to require intravenous (IV) opioid pain management. Pain radiates to the back in some patients. Patients may find pain reduction by sitting up and leaning forward. Nausea and vomiting may be present. The pain develops suddenly in gallstone pancreatitis. In alcoholic pancreatitis, pain usually develops over several days.
5.Appendicitis: In about 50% of patients, epigastric or periumbilical pain is followed by nausea, vomiting, then pain shifting to the RLQ. Direct and rebound tenderness at McBurney’s point is present. In other patients, pain may not be localized or may be diffuse.
6.Diverticulitis: Pain or tenderness in the LLQ with fever. Rebound or guarding, nausea, vomiting, and abdominal distention occur if concurrent bowel obstruction is present.
7.Ectopic pregnancy: Sudden, severe pelvic pain and/or vaginal bleeding followed by syncope and signs of hemorrhagic shock in females of reproductive age.
8.Intestinal obstruction.
a.Small bowel: Cramping near epigastrium, vomiting (with some relief in pain), and, if complete obstruction, obstipation. Range of bowel sounds on auscultation from high pitched peristalsis in early presentation to no BS in later presentations.
b.Large bowel: Gradual development of constipation, then abdominal distention, lower abdominal cramps, and borborygmi (loud prolonged bowel sounds).
9.Perforated duodenal ulcer—sudden agonizing pain usually in patients with history of peptic ulcer disease or NSAID therapy. Frequently occurs in the elderly (60 to 70 year age group). Pain occurs initially in the upper abdomen then becomes diffuse. Patients lay still, in a knee to chest position, breathe shallowly, and are tachycardic. Hypotension and fever are late findings. Abdomen appears nondistended with board-like rigidity.
C.Family and social history.
1.Smoking.
2.Alcohol abuse.
3.Low fiber or fatty diet.
4.Obesity.
5.Family history may increase risk.
D.Review of systems.
1.SOCRATES acronym.
a.Site: Ask about location of pain.
b.Onset: Inquire about exact time and mode of pain. Did it occur suddenly or gradually?
c.Character: How is the pain characterized? Is it confined to one area or all around? Is the pain dull or sharp?
d.Radiation or referral of pain: Does the pain stay in one place or does it move around?
e.Associated symptoms: Is there any weight loss, nausea, vomiting, diarrhea, constipation, pain on urinating, skin discoloration, vaginal bleeding?
f.Time course: Is the pain continuous or intermittent?
g.Exacerbating/relieving factors: Does it hurt to cough, eat, or does it feel better to vomit?
h.Severity: Can the pain be measured on a scale from 1 to 10, 10 being the worst pain ever felt?
Physical Examination
A.Vital signs: Check postural VS to assess for hypovolemia or bleeding.
B.Inspection: From nipples to knees.
1.Distention.
2.Scars.
3.Ecchymosis such as Grey Turner sign.
C.Auscultation.
1.Bowel sounds (hyperactive/hypoactive/absent?).
2.Bruit.
D.Palpation.
1.Rebound tenderness.
2.Ask patient to cough to ascertain peritonitis.
3.Guarding.
4.Organomegaly.
5.Hernia.
6.Rectal, pelvic, testicular examination.
E.Diagnosis: Specific findings.
1.AAA.
a.Abdomen rigid or distended, very tender.
b.Shock-like symptoms (pallor, diaphoresis, tachycardia).
2.Ectopic pregnancy.
a.Appears toxic and shock-like symptoms.
b.Lower abdominal tenderness.
3.Appendicitis: Guarding and rebound tenderness, prefers fetal position.
4.Diverticulitis: LLQ pain.
5.Biliary colic cholecystitis: RUQ pain with Murphy’s sign.
6.Renal colic: Severe pain, costovertebral angle tenderness on affected side.
7.Pancreatitis.
a.Epigastric tenderness, abdominal distention, fever, and tachycardia.
b.Signs of jaundice.
c.May develop Cullen or Grey Turner sign.
8.Special abdominal examination maneuvers: Prior to the advent of radiologic imaging, several clinical maneuvers were utilized to differentiate abdominal pain diagnoses. While most of these tests will be followed by imaging studies today to confirm findings, they are still utilized.
a.Iliopsoas sign: Have the patient roll on his/her left side and hyperextend the right hip joint. If pain is present, the test is positive and suggests irritation of the iliopsoas muscle by appendicitis.
b.Obturator sign: With the patient supine, passively flex the thigh and rotate inward. If pain is elicited, the obturator muscle is inflamed because of pathology such as appendicitis, diverticulitis, pelvic inflammatory disease, or ectopic pregnancy.
c.Rovsing sign: Apply pressure to the LLQ. If pain is referred to McBurney’s Point (RLQ), the test is positive and appendicitis is suspected.
d.Murphy’s sign: Ask the patient to take a deep breath while palpating the RUQ. If the patient abruptly stops inspiration, the sign is positive and suggests acute cholecystitis.
e.Cullen and Grey Turner signs: Both Cullen and Grey Turner signs are associated with ecchymosis on the abdomen.
i.Cullen sign is superficial edema and bruising in the subcutaneous tissue around the umbilicus. This is associated with ruptured ectopic pregnancies but can be seen in other conditions as well such as pancreatitis or trauma.
ii.Grey Turner sign is bruising along the flank associated with retroperitoneal bleeding or intraabdominal bleeding.
Diagnostic Tests
A.Ordered based on differential diagnosis, but can include:
1.In all women of childbearing age, assume the woman is pregnant unless proven otherwise; use HCG test, or possibly transvaginal ultrasound (US).
2.Complete blood count (CBC) with differential.
3.Metabolic panel.
4.Electrolytes.
5.Amylase and lipase.
6.Consider blood culture in elderly with fever or hypothermia for suspected sepsis.
7.Urinalysis.
8.Abdominal x-ray.
9.Chest x-ray.
10.EKG to rule out cardiac cause of pain.
11.Consider abdominal US.
12.Consider CT abdomen with PO and IV contrast.
13.Consider endoscopic retrograde cholangiopancreatography (ERCP) to visualize distal common bile duct.
14.Helicobacter pylori testing.
15.Endoscopy.
16.Stool guaiac.
17.Colonoscopy.
Differential Diagnosis
A.Location and duration of abdominal pain can often help in narrowing.
1.RUQ pain.
a.Acute cholecystitis and biliary colic.
i.Biliary tract—Increased serum amylase.
ii.Ascending cholangitis presents with fever and jaundice.
iii.In acute cholecystitis, pain radiates to scapula associated with nausea, vomiting, and fever. Murphy’s sign (inspiratory arrest in response to deep RUQ palpation) may be seen.
b.Perforated duodenal ulcer: Accompanied by increased serum amylase.
c.Acute pancreatitis.
i.Bilateral right and left upper quadrant pain.
ii.Accompanied by increased serum amylase.
d.Myocardial infarction.
e.Pulmonary pathology.
2.RLQ pain.
a.Appendicitis: Dull, steady periumbilical pain and nausea, which then localizes to the RLQ at McBurney’s point.
b.Abdominal aneurysm.
c.Ruptured ectopic pregnancy/ovarian cyst.
d.Incarcerated inguinal hernia.
e.Diverticulitis.
3.LUQ pain.
a.Acute pancreatitis: Epigastric pain which radiates to the back and is associated with nausea.
b.Splenic enlargement infarction or aneurysm.
c.Myocardial ischemia.
d.Left lower lobe pneumonia.
4.LLQ pain.
a.Diverticulitis.
b.Aortic aneurysm.
c.Ruptured ectopic pregnancy/ovarian cyst.
5.Must not miss diagnoses.
a.Small bowel obstruction.
b.Large bowel obstruction.
c.Nonspecific bowel pain.
i.Appendicitis.
ii.Perforated ulcer.
iii.Acute cholecystitis.
6.Common abdominal pain culprits.
a.Acute pancreatitis.
b.Diverticulitis.
c.Acute pyelonephritis.
Evaluation and Management Plan
A.General plan.
1.Determine if patient is hemodynamically stable and if peritoneal signs are present.
2.Obtain imaging studies and treat based on suspected condition.
a.AAA.
i.If rupture is suspected, attempts at hemodynamic stability are begun as the patient is optimized for surgery. An US provides bedside results to assist in diagnosis (without treatment, mortality rate approaches 100%).
ii.Patients who present in shock will need fluid resuscitation but mean arterial pressure should not exceed 65 mmHg to prevent further bleeding.
iii.If the patient is stable, abdominal CT or computed tomography angiography (CTA) can more precisely characterize aneurysm size and anatomy to assist with surgical intervention if necessary.
1)Surgical options include endovascular stent grafting VS open repair.
2)Medical management if AAA less than 5 mm includes repeat imaging every 6 to 12 months to monitor for size increase greater than 5 mm or to assess for rapid growth. Both are indications for elective surgical repair.
b.Acute cholecystitis.
i.On examination, RUQ pain to palpation with inspiratory arrest (+ Murphy’s sign).
ii.US (showing presence of stones, gallbladder wall thickening, or enlargement) is the study of choice and can often establish the diagnosis.
iii.Management.
1)Medical—single episode may not warrant surgery. Counsel patient to avoid fatty foods, fasting, or starvation diets and to see provider for recurrent pain. Tylenol PRN for pain. Actigall decreases amount of cholesterol produced by the liver and absorbed by intestines and may be helpful.
2)Surgical management—laparoscopic cholecystectomy. Conversion to open procedure occurs approximately 5% of the time.
3)Surgical cases a need liver and pancreatic enzyme levels assessed, as elevated levels may show common duct stones.
c.Acute mesenteric ischemia.
i.Clinical diagnosis is more important than testing due to time delay. Increased mortality is observed once intestinal infarction occurs. Intestinal infarction can occur as soon as 10 hours after the onset of symptoms. Untreated, mortality approaches 90%.
ii.Proceed directly to surgery for diagnosis and treatment in patients with peritoneal signs. CTA is used if diagnosis is unclear.
iii.Support blood pressure (BP) with IV fluids (avoid vasopressors), adequate oxygenation, broad spectrum antibiotics, and adequate pain control. Consider anticoagulation.
iv.Treatment involves surgical embolectomy and revascularization with possible bowel resection. Angiographic vasodilators (papaverine) or thrombolytics may be used.
v.Depending on the severity of bowel ischemia, the patient may require a long inpatient hospital stay, maintaining nil per os (NPO) status, and supporting nutrition with total parenteral nutrition.
vi.Find and treat predisposing causes.
vii.Plan for long-term anticoagulation.
d.Acute pancreatitis: Condition ranges from mild abdominal pain and vomiting to severe with systemic inflammatory response syndrome (SIRS) response, shock, and multiorgan failure.
e.Mortality rates are as high as 40% to 50% of cases. Important to assess the severity of illness on admission utilizing tools (Ranson criteria, others) that predict mortality risk. Early recognition of severe pancreatitis improves outcomes by risk stratification and correct admission placement of the patient.
i.Diagnose based on clinical suspicion, especially in patients with a history of gallstones or chronic heavy alcohol abuse and noting elevated amylase and lipase.
ii.Urine dipstick for trypsinogen-2 has sensitivity and specificity of greater than 90%. WBC elevation range is 12 to 20,000. Imaging with plain abdominal film shows calcifications within pancreatic ducts and gallstones. Obtain US if gallstone pancreatitis is suspected. CT abdomen with contrast is usually done to identify necrosis, fluid collection, or cysts once condition is diagnosed.
iii.Treatment includes fluid resuscitation (up to 8 L/day), maintaining NPO status (until tenderness subsides, amylase WNL), pain control, antibiotic therapy if pancreatic necrosis, and drainage of collections.
f.Appendicitis.
i.Surgical management: Appendectomy.
ii.Medical management: Antibiotics may be used to treat uncomplicated, nonsurgical appendicitis; however, there are recurrences. More studies need to be done in order to determine the efficacy of antibiotic therapy alone.
g.Diverticulitis.
i.Typical presentation is with LLQ pain with or without peritonitic findings; an absence of vomiting; fever; and leukocytosis with left shift. May also complain of back pain, flatulence, borborygmi (loud prolonged bowel sounds), diarrhea, or constipation.
ii.A C-reactive protein greater than 50 mg/L, along with LLQ pain and absence of vomiting, is highly predictive of acute colonic diverticulosis.
iii.CT scan of abdomen and pelvis is the current gold standard in confirming the diagnosis of acute diverticulitis if the clinical picture is unclear.
iv.US is fast becoming an additional modality in diagnosis of the disease.
v.Management.
1)Medical: Bowel rest. nil per os (NPO). NG tube placement to low suction, IV fluid replacement therapy. Antimicrobial therapy covering gram negative organisms and anaerobes should be initiated when associated with systemic manifestations of infection. If relapse, same regimen × 1 month.
2)Surgical resection for abscess, peritonitis, obstruction, fistula, failure to improve after several days, or recurrence.
3)Nonsurgical cases should be referred for a colonoscopy 4 to 6 weeks after the event.
h.Ectopic pregnancy.
i.Urine pregnancy test (beta-hcg) is 99% sensitive for ectopic and uterine pregnancy. If positive, follow with serum beta-hcg and transvaginal pelvic US. Diagnostic laparoscopy may be necessary for confirmation.
ii.Surgical resection is usually necessary to treat. If possible, salpingotomy is done to conserve the tube. Salpingectomy indicates when ectopic pregnancies are greater than 5 cm, when tubes are severely damaged, or when no future childbearing is planned.
iii.Resuscitate if hemodynamically unstable or in hemorrhagic shock and prepare for immediate surgery.
iv.Methotrexate may be an option if unruptured tubal pregnancy is less than 3 cm, no fetal heart activity is heard, and beta-hcg level is less than 5,000. Follow-up within 1 week for repeat beta-hcg level.
i.Intestinal obstruction.
i.Supine and, if possible, upright abdominal x-rays are usually adequate to diagnose obstruction, showing a coiled spring sign in a series of distended small bowel loops or right colon. Large bowel obstruction shows distention of the colon proximal to the obstruction.
ii.Treatment for both small and large bowel obstruction includes NG decompression and resuscitation with IV crystalloid fluid administration and IV antibiotics covering gram negative and anaerobes if bowel ischemia is suspected.
iii.Complete obstruction of small bowel is treated with early laparotomy.
iv.Obstructing colon cancers can be treated with resection and anastomosis, with or without a colostomy or ileostomy.
j.Perforated duodenal ulcer.
i.Upright chest x-ray reveals free air. Upper GI film with water-soluble contrast is also helpful to diagnose perforation and if it has healed spontaneously.
ii.Leukocytosis and elevated amylase usually present.
iii.In approximately 50% of cases, the perforation self-heals. Those who are poor surgical candidates or who present more than 24 hours after perforation and who are stable may be admitted. Provide careful observation for clinical deterioration, IV fluids, NG suction, and broad spectrum antibiotics. Low threshold for surgical repair if condition deteriorates.
1)H. pylori infection is implicated in 70% to 90% of all perforated ulcers. Medical therapy for peptic ulcer disease includes the combination of omeprazole 20 mg BID, plus clarithromycin 500 mg BID, plus metronidazole 500 mg TID × 14 days; for non-PCN allergic patients.
B.Patient/family teaching points.
1.Do not take laxatives, use enemas, or take medications, food, or liquids until consulting a healthcare provider for suspected abdominal pain and the following:
a.Increased or unusual looking vomit or stool.
b.Hard, swollen abdomen.
c.Lump in scrotum, groin, or lower abdomen.
d.Missed period or suspected pregnancy.
2.Engage in activity as tolerated. Abdominal pain with nausea and vomiting, fever, or pain that lasts more than 3 hours which halts daily activities should be reported to a healthcare provider.
3.Eat regular foods as tolerated. Do not eat food or drink liquids until a healthcare provider is consulted if pain occurs with nausea and vomiting, fever is present, or pain lasts longer than 3 hours.
C.Pharmacotherapy.
1.Regardless of the cause, early use of analgesia before diagnosis is associated with improved diagnosis and treatment.
a.Acetaminophen 1,000 g IV recommended regardless of pain severity.
b.IV narcotic analgesics can be added depending on the severity of pain. Morphine and opioids such as fentanyl can be considered in cases of acute abdomen.
c.NSAIDs are effective for colic of biliary tract and ureteral stones.
2.If abdominal infections are suspected, blood cultures should be obtained and antimicrobial agents administered (within 1 hour in cases of suspected septic shock). Coverage of gram negative organisms is prudent. Broad antibiotic coverage is used if concern for sepsis.
3.When surgery is necessary, antimicrobial agents should be given just prior to the start of surgery (ideally within 30 minutes), which significantly reduces the risk of surgical site infection.
D.Discharge instructions.
1.Surgery instructions depend on the procedure and surgeon preference, if applicable.
2.Stress the importance of follow-up, adherence to prescription instructions, and to call the healthcare provider with questions.
Follow-Up
A.If surgical intervention, perform as per surgeon instructions.
Consultation/Referral
A.Consultation/referral depends on the underlying cause of acute abdomen.
1.Surgery.
2.Medicine (anticoagulation, antibiotic therapy management).
3.Nutrition.
4.Oncology.
5.Gynecology.
6.Counseling.
7.Geriatric medicine.
Special/Geriatric Considerations
A.Consider that obesity distorts the abdominal examination, making organ palpation or pelvic examination difficult.
B.Men over 40 and women over 50 should warrant a high suspicion of cardiac origin of pain when epigastric.
C.Geriatric patients have a higher incidence of:
1.Biliary disease.
2.Ischemic disease.
3.Mortality.
4.Hospital admission and complication rates.
5.Reliable history and physical can be difficult as findings in other age groups are often absent in the elderly.
6.Elderly individuals may have a vague or atypical presentation of pain, varying in location, severity, and presentation of fever or nonspecific findings. Classical presentation of peritonitis rebound tenderness and local rigidity occur less often. Urinary tract infection (UTI) symptoms are more likely to be frequency, dysuria, or urgency. Abdominal pathology may advance to a dangerous point prior to symptom development, and altered mental status may play a role in assessment.
7.Aortic abdominal aneurysm (AAA) occurs most often in the elderly. Maintain a high level of suspicion in patients presenting with symptoms suggestive of renal colic or musculoskeletal back pain (approximately 65% of men older than 65 years have AAA).
8.Patients older than 65 have a 30% to 50% risk of gallstones and may not present with significant pain.
9.Fever and elevated white blood cell (WBC) count occur in less than half of elderly patients with diverticulitis.
10.Presence of peptic ulcer disease (PUD) is more common in the elderly due to NSAIDs. The most common presenting symptom of PUD in the elderly is melena.
Bibliography
Banks, P. A., & Freeman, M. L. (2006). Practice guidelines in acute pancreatitis. The American Journal of Gastroenterology, 101, 2379–2400. Retrieved from https://journals.lww.com/ajg/Citation/2006/10000/Practice_Guidelines_in_Acute_Pancreatitis.31.aspx
Barkley, T. W., & Meyers, C. M. (2015). Practice considerations for adult-gerontology acute care nurse practitioners (Vol. 1, 2nd ed.). West Hollywood, CA: Barkley & Associates.
Cartwright, S. L., & Knudson, M. P. (2008). Evaluation of acute abdominal pain in adults. American Family Physician, 77(7), 971–978.
Cash, J. C., & Glass, C. A. (2017). Family practice guidelines (4th ed.). New York, NY: Springer Publishing Company.
Cervellin, G., Mora, R., Ticinesi, A., Meschi, T., Comelli, I., Catena, F., & Lippi, G. (2016). Epidemiology and outcomes of acute abdominal pain in a large urban emergency department: Retrospective analysis of 5,340 cases. Annals of Translational Medicine, 4(19), 362. doi:10.21037/atm.2016.09.10
Chey, W. D., Leontiadis, G. I., Howden, C. W., & Moss, S. F. (2017). ACG clinical guideline: Treatment of Helicobacter pylori infection. American Journal of Gastroenterology, 112, 212–239. Retrieved from https://journals.lww.com/ajg/Abstract/2017/02000/ACT_Clinical_Guideline__Treatment_of_Helicobacter.12.aspx
DeStigter, K. K., & Keating, D. P. (2009). Imaging update: Acute colonic diverticulitis. Clinics in Colon and Rectal Surgery, 22(3), 147–155. doi:10.1055/s-0029-1236158
El-Garem, H., Hamdy, E., Hamdy, S., El-Sayed, M., Elsharkawy, A., & Saleh, A. (2013). Use of the urinary trypsinogen-2 dipstick test in early diagnosis of pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP). Open Journal of Gastroenterology, 3, 289–294. doi:10.4236/ojgas.2013.36049
Hardy, A., Butler, B., & Crandall, M. (2013). The evaluation of the acute abdomen. In L. Moore, K. Turner, & S. Todd (Eds.), Common problems in acute care surgery (pp. 17–30). New York, NY: Springer Publishing Company.
Kendal, J. L., & Moreira, M. (2018). Evaluation of the adult with abdominal pain in the emergency department. In J. Grayzel (Ed.), UpToDate. Retrieved from https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain-in-the-emergency-department
Macaluso, C. R., & McNamara, R. M. (2012). Evaluation and management of acute abdominal pain in the emergency department. International Journal of General Medicine, 5, 789–797. doi:10.2147/IJGM.S25936
Malbrain, M. L., Chiumello, D., Pelosi, P., Bihari, D., Innes, R., Ranieri, V. M., … , Gattinoni, L. (2005). Incidence and prognosis of intraabdominal hypertension in a mixed population of critically ill patients: A multiple-center epidemiological study. Critical Care Medicine, 33(2), 315–322. doi:10.1097/01.CCM.0000153408.09806.1B
Mayumi, T., Yoshida, M., Tazuma, S., Furukawa, A., Nishii, O., Shigematsu, K., & Hirata, K. (2016). The practice guidelines for primary care of acute abdomen 2015. Japanese Journal of Radiology, 34, 80–115. doi:10.1007/s11604-015-0489-z
Murray, H., Baakdah, H., Bardell, T., & Tulandi, T. (2005, October 11). Diagnosis and treatment of ectopic pregnancy. Canadian Medical Association Journal, 173(8), 905–912. doi:10.1503/cmaj.050222
Musson, R. E., Bickle, I., & Vijay, R. (2011). Gas patterns on plain abdominal radiographs: A pictorial review. Journal of Postgraduate Medicine, 87, 274–287. doi:10.1136/pgmj.2009.082396
Saccomano, S. J., & Ferrara, L. R. (2011). Evaluation acute abdominal pain. The Nurse Practitioner, 38(11), 46–53. doi:10.1097/01.NPR.0000433077.14775.f1
Stollman, N., Smalley, W., & Hirano, I. (2015, December). American Gastroenterological Association Institute guideline on the management of acute diverticulitis. Gastroenterology, 149(7), 1944–1949. doi:10.1053/j.gastro.2015.10.003
Vaidyanathan, S., Wadhawan, H., Welch, P., & El-Salamani, M. (2008). Ruptured abdominal aortic aneurysm masquerading as isolated hip pain: An unusual presentation. Canadian Journal of Emergency Medicine, 10(3), 251–254. doi:10.1017/S1481803500010186