Acute Abdominal Pain Case File

Acute Abdominal Pain Case File

Eugene C. Toy, MD, Barry C. Simon, MD, Terrence H. Liu, MD, MHP, Katrin Y. Takenaka, MD, Adam J. Rosh, MD, MS

Case 18

You are working in the emergency department (ED) of a 15-bed rural hospital without CT scan capabilities, and a 25-year-old, previously healthy, woman presents for evaluation of abdominal pain. The patient describes her pain as having been present for the past 3 days. The pain is described as constant, exacerbated by movements, and associated with subjective fevers and chills. She denies any recent changes in bowel habits, urinary symptoms, or menses. Her last menstrual period was 6 days ago. The physical examination reveals temperature of 38.4°C (101.1°F), pulse rate of 110 beats per minute, blood pressure of 112/70 mm Hg, and respiratory rate of 18 breaths per minute. Her skin is nonicteric. Cardiopulmonary examination is unremarkable. The abdomen is mildly distended and tender in both right and left lower quadrants. Involuntary guarding and localized rebound tenderness are noted in the right lower quadrant. The pelvic examination reveals no cervical discharge; cervical motion tenderness and right adnexal tenderness are present. The rectal examination reveals no masses or tenderness. Laboratory studies reveal white blood cell count (WBC) of 14,000 cells/mm³, a normal hemoglobin, and a normal hematocrit. The urinalysis reveals 3 to 5 WBC/high-power field (HPF), few bacteria, and trace ketones.

⯈ What are the most likely diagnoses?

⯈ How can you confirm the diagnosis?

ANSWER TO CASE 18:

Acute Abdominal Pain

Summary: A 25-year-old, previously healthy, woman presents with a 3-day history of lower abdominal pain and subjective fever. Her examination indicates the presence of fever and lower abdominal tenderness (right > left). The rectal examination is unremarkable. Her laboratory studies indicate leukocytosis.

• Most likely diagnosis: Likely diagnoses include complicated acute appendicitis, pelvic inflammatory disease (PID), ovarian torsion, or other pelvic pathology.
• Confirmatory studies: Begin with pregnancy test and pelvic ultrasonography to evaluate for possible ovarian and pelvic pathology. If these suggest pelvic source of pathology, then strong consideration should be given to perform exploratory laparoscopy or laparotomy.

ANALYSIS

Objectives

1. Learn the relationships between symptoms, findings, and pathophysiology of the various types of disease processes capable of producing acute abdominal pain.
2. Learn to develop reasonable diagnostic and treatment strategies based on clinical diagnosis, resource availability, and patient characteristics.
3. Learn the diagnosis and severity stratification for acute pancreatitis.

Considerations

This is a healthy young woman, who presents with acute pain in the lower abdomen. Based on patient age and location of pain, acute appendicitis and gynecological pathology are the most likely sources of pathology, and additional history and diagnostic studies may help to differentiate these possibilities.

Pertinent gynecological history should include history of sexual contacts, menstrual pattern, previous gynecological problems, and the probability of pregnancy. A pregnancy test should be obtained early during the evaluation process to verify the presence or absence of pregnancy, and if the history and physical examination suggest the source of pathology to have originated from the pelvic organs, a pelvic ultrasound should be obtained.

In the event that the patient is pregnant, an ultrasound should be performed to verify intrauterine gestational sac and estimate the gestational age. If an intrauterine gestational sac is not visualized by ultrasound, the possibility of ectopic pregnancy should be considered and an immediate referral should be made for a gynecologic evaluation and possible operative intervention. Whereas, if the pregnancy test is negative and pelvic pathology is strongly suspected, the initial priority would be to identify potential life-threatening and fertility-reducing processes, including tuboovarian abscesses, pelvic inflammatory diseases, and ovarian torsion.

Pelvic ultrasonography would be very valuable as the initial study to identify or rule out these processes. In the event that the pelvic ultrasound does not identify any pelvic pathology, a computed tomography (CT) scan of the abdomen and pelvis may be useful. The management approach for patient with abdominal pain varies depending on resource and expertise availability. For this patient at a 15-bed facility without CT capability, the general surgeon should be consulted early regarding the potential need for transfer to another facility or further evaluation by laparoscopy or laparotomy.

Approach To:

Abdominal Pain

DEFINITIONS

ACUTE ABDOMEN: “Acute abdomen” describes the recent onset of abdominal pain. Patients with acute abdomen require urgent evaluation and not necessarily urgent operations.

FOREGUT: Foregut extends from oropharynx to mid-duodenum, including liver, biliary tract, pancreas, and spleen.

HINDGUT: Hindgut extends from distal transverse colon to rectum.

MIDGUT: Midgut extends from distal duodenum to mid-transverse colon.

REFERRED PAIN: This pain usually arises from a deep structure to a remote deep or superficial structure. The pattern of referred pain is based on the existence of shared central pathways between the afferent neurons of cutaneous dermatomes and intra-abdominal structures. Frequently, referred pain is associated with skin hyperalgesia and increased muscle tone. (Classic example of referred pain occurs with irritation of the left hemidiaphragm from ruptured spleen that causes referred pain to the left shoulder because of shared innervation by the same cervical nerves.)

SOMATIC PAIN: This pain arises from the irritation of the parietal peritoneum. This type of pain is mediated mainly by spinal nerve fibers supplying the abdominal wall and is perceived as sharp, constant, and generally localized to one of four quadrants. Somatic pain may arise as a result of changes in pH and temperature (infection and inflammation) or pressure increase (surgical incision).

VISCERAL PAIN: This pain is generally characterized as dull, crampy, deep, or aching. Normal embryological development of abdominal viscera results in symmetrical bilateral autonomic innervations leading to visceral pain being perceived in the midline location. Visceral stimulation can be produced by stretching and torsion, chemical stimulation, ischemia, or inflammation. Visceral pain from gastrointestinal (GI) tract structures correlate with pain location based on their embryonic origins, where foregut pain is perceived in the epigastrium, midgut pain is perceived in the periumbilical region, and hindgut pain is perceived in the hypogastrium.

CLINICAL APPROACH

Abdominal pain is a common chief complaint of patients seen in the ED, comprising approximately 5% to 8% of total visits. Overall, 18% to 25% of patients with abdominal pain evaluated in the ED have serious conditions requiring acute hospital care. In a recent series, the distribution of common diagnosis of adult ED patients with abdominal pain were listed as the following: 18% admitted, 25% undifferentiated abdominal pain (UDAP), 12% female pelvic, 12% urinary tract, and 9.3% surgical gastrointestinal. Approximately 10% of patients required urgent surgery, and most patients with UDAP were young women with epigastric symptoms who did not progress to develop significant medical problems.

Understanding of disease pathophysiology, epidemiology, clinical presentations, and the limitations of laboratory and imaging studies are important during evaluation of patients with abdominal pain in the ED. Abdominal pain can be initially categorized as “surgical” or “nonsurgical”; alternatively, pain may be approached from an organ-system approach. Overall, the surgical causes are encountered more commonly than nonsurgical causes when considering all comers with acute abdominal pain.

Surgical causes (or causes that may require surgical corrections) may be categorized by mechanism into (1) hemorrhagic, (2) infectious, (3) perforating, (4) obstructive, (5) ischemic, and (6) inflammatory. Hemorrhagic conditions causing abdominal pain include traumatic injuries to solid and hollow viscera, ruptured ectopic pregnancy, tumor rupture/hemorrhage (eg, hepatic adenomas and hepatocellular carcinomas), and leaking or ruptured aneurysms. Infectious conditions may include appendicitis, cholecystitis, diverticulitis, infectious colitis, cholangitis, pyelonephritis, cystitis, primary peritonitis, and pelvic inflammatory disease. Perforations causing abdominal pain can occur from peptic ulcers, diverticulitis, esophageal perforations, and traumatic hollow viscus injury. Obstructive processes leading to abdominal pain can occur from small intestinal obstruction, large bowel obstruction, ureteral obstruction, and biliary obstructions (see Figure 18-1 for radiograph). Ischemic causes are subcategorized as microvascular or macrovascular. Macrovascular ischemic events can occur from mechanical causes, including torsion (intestines and ovaries are most common), vascular obstruction from thrombosis, embolism, and non-occlusive low-flow states, and these can include small bowel and colonic ischemia. Microvascular ischemic events are uncommon and can occur from causes such as cocaine intoxication. Inflammatory conditions causing abdominal pain may include acute pancreatitis and Crohn disease; the mechanism of pain production associated with acute pancreatitis is not clearly known but is likely related to the local release of inflammatory mediators. Although, not all patients with abdominal pain produced by the above listed surgical causes need surgical interventions, the potential for surgical or other forms of invasive interventions are high in these patients; therefore, early surgical consultation is advisable.

Nonsurgical causes of acute abdominal pain are less common and occur most frequently in patients with history of prior endocrine, metabolic, hematologic, infectious, or substance abuse history. The endocrine and metabolic causes of abdominal pain may include diabetic ketoacidosis, Addisonian crisis, and uremia. Hematologic causes of abdominal pain include sickle cell crisis and acute leukemia.

Figure 18–1. Abdominal radiographs in the supine (A) and upright (B) positions show a dilated

small bowel with air-fluid levels. (Reproduced, with permission, from Kadell BM, Zimmerman P, Lu

DSK. Radiology of the abdomen. In: Zinner MJ, Schwarz SI, Ellis H, et al, eds. Maingot’s Abdominal

Operations. 10th ed. New York, NY: McGraw-Hill; 1997:24.)

Systemic infectious causes of abdominal pain can include acute meningitis, TB peritonitis, acute hepatitis, and varicella zoster infections. Because the differences between surgical and nonsurgical causes of abdominal pain are often subtle, it is advisable to consult a surgical colleague for all patients with acute abdominal pain. In addition, because of the potential for complications development in some of the patients with initially nonsurgical causes of abdominal pain, surgical consultations and follow-up are essential for the management of these complex patients.

Patient evaluations should be directed toward identifying potentially serious medical conditions. Analgesia including narcotics should not be withheld in patients with pain. In the event that a diagnosis is not identified following a thorough evaluation, it may be appropriate to discharge the patient with the diagnosis of “abdominal pain of uncertain etiology.” Usually, individuals still under the effect of analgesia without a diagnosis should not be discharged. For patients whose abdominal pain etiologies are not clearly determined, it is important to provide them with the reassurance that the pain most likely would improve and resolve; however, because of the broad overlap in the early manifestation of serious disease, the patient need to be instructed to seek early follow-up if symptoms do not resolve. Furthermore, the use of narcotic pain medications should be withheld in the individuals without clear diagnosis or follow-up.

Abdominal Pain in Women

Women make up approximately 75% of all patients evaluated in the ED with abdominal pain. Women of childbearing age represent a complex patient population from the diagnostic standpoint, because of a broader differential for pain. Acute appendicitis, biliary tract disease, urinary tract infection, and gynecological problems are the most common sources of abdominal pain in childbearing-age women. The history obtained from each patient should include details of menstrual history, sexual practices, gynecological and obstetrical history, and surgical history. For most individuals, the initial history and physical examination can help to direct the workup toward an organ system or body region. Laboratory evaluations, including CBC with differential, serum amylase, urinalysis, pregnancy test, and liver functions test, may provide additional information to help rule in or rule out certain diagnoses. When indicated, imaging such as ultrasonography and CT scans can be helpful in assessing for biliary tract and pelvic pathology, and for acute appendicitis. Because overreliance on laboratory and/or imaging can contribute to misdiagnoses, laboratory and imaging results should always be interpreted within the proper clinical context; clinical judgment should be exercised regarding the acquisition of consultation and/or observation.

Abdominal Pain in Elderly Patients

Elderly patients (age >65) account for approximately 15% of all ED visits, and about one-third of these visits result in inpatient admissions. In comparison to young adults, elderly patients with abdominal pain evaluated in the ED generally have increased prevalence of serious diseases causing abdominal pain, where the frequency of illnesses requiring surgical intervention has been estimated to be as high as 30%. Furthermore, the mortality rate associated with abdominal pain is increased in this population as a consequence of the increase in catastrophic illnesses (including mesenteric ischemia, leaking or ruptured aneurysm, and myocardial infarction). Common diagnoses among elderly patients include biliary tract disease (23%), diverticular disease (12%), bowel obstruction (11%), and undetermined (11%).

Due to various reasons that include atypical clinical presentations and difficulty with communications, abdominal pain in the elderly is associated with high frequency of inaccurate diagnosis (up to 60%). Inability to accurately diagnose the cause of abdominal pain contributes to delayed treatment and increased morality, as elderly patients whose abdominal pain were not accurately diagnosed in the ED have been shown to have a 2-fold increase in mortality when compared to elderly patients whose causes of abdominal pain were accurately diagnosed.

For most elderly patients, the evaluation should be broadened to help identify cardiac, pulmonary, vascular, neoplastic, and neurologic causes of abdominal pain. Often symptoms in this population are attributable to an underlying medical comorbidity. It is important to bear in mind that medications taken by many elderly patients may contribute to abdominal problems, as well as alter the clinical presentations (eg, β-blockers may blunt pulse rate response to stress). When indicated, ancillary testing should be applied to assist in establishing the diagnosis; however, it is important to remember that the diagnostic accuracy of any test is dependent on the pretest probability, specificity, sensitivity, and disease prevalence of the test population. Because abdominal pain in the elderly population is more frequently associated with serious pathology, appropriate consultations should be sought out and a liberal policy regarding inpatient or ED observation should be applied whenever causes cannot be clearly identified.

Patients With Acute Pancreatitis (AP)

Acute pancreatitis is an acute inflammatory condition of the pancreas that can affect adults of all ages, and in its severe forms, AP can affect all organ systems in the body. Patients are said to have severe AP when the process is associated with organ dysfunction, APACHE II scores ≥8, Ranson scores ≥3, or presence of local complications based on contrast-enhanced CT scans (eg, pancreas necrosis, pseudocysts, or peripancreatic fluid collections). Severe AP is reported in 15% to 20% of patients with AP. Mortality rates associated with mild AP is approximately 5%, whereas severe AP is associated with mortality rates up to 25%. The diagnosis of pancreatitis should be suspected when patients present with persistent abdominal or back pain associated with elevated levels of serum lipase and/or amylase. In the emergency department setting, the etiology of AP can be assessed by clinical history (these should include inquiries regarding gallstones, alcohol use, medications, infections, metabolic and autoimmune disorders, family history, and history of trauma), and laboratory studies that include liver function tests, calcium, and triglyceride levels. In approximately 80% of the patients with AP, the cause can be determined based on the clinical history and initial clinical evaluation. Identifying AP cause is generally not critical during the initial management of patients in the emergency center, but could have implications in the prevention of future disease recurrences. Severity stratification for patients is helpful during the initial evaluation, as it may help direct the triage of patients to intensive care units or specialty care facilities.

Early management of patients is directed toward the recognition and prevention of organ dysfunction in those patients with severe AP. Prompt repletion of intravascular volume is essential in the prevention of renal dysfunction. When patients do not respond appropriately to their initial fluid management, central venous pressure monitoring, pulse-oximetry monitoring, and urine-output monitoring should be considered to help direct these efforts and avoid fluid overloading patients.

Disease recurrences are common among patients with AP, especially when the cause is alcohol, metabolically-induced, or produced by anatomic abnormalities such as pancreas divisum and periampullary duodenal diverticulum. It is important to identify patients with AP that are gallstone-related, because most recurrences in these patients can be prevented by cholecystectomies.

CT scan of the abdomen is not necessary for the diagnosis or confirmation of AP. CT scans in the emergency center setting may be indicated to help confirm the diagnosis of AP when the clinical picture and/or biochemical values are not sufficient for the confirmation of diagnosis. In addition, CT scan may help identify patients with significant pancreas necrosis, which often correlates with disease severity and regional pancreatic complications (Table 18–1). CT scan with intravenous contrast performed in intravascular volume depleted patients with severe AP could contribute to acute kidney injuries and further injuries to the pancreas; therefore, these studies should be withheld until the patients’ volume depletions have been corrected.

Patients with severe pancreatitis determined either by the presence of end-organ dysfunction, APACHE II >8, Ranson score >3, or CT demonstrating pancreas necrosis may benefit from close monitoring, therefore admissions to intensive care units. Over the past several years, there has been a continued trend toward the

nonoperative or delayed-operative (>14 days) management of patients with severe AP. Critically ill patients with AP would still benefit from early consultation by a surgical specialist because other intra-abdominal processes that would require surgical interventions could mimic AP or develop as the result of severe AP.

Patients With Chronic or Recurrent Abdominal Pain

Patients with chronic or recurrent abdominal pain represent one of the most difficult diagnostic and management challenges for emergency medicine physicians. The dilemma facing ED physicians during encounters with these patients include establishing the accurate diagnosis, determining appropriate use of diagnostic studies, determining the appropriateness of analgesic medications, and follow-up.

Similar to the approach taken toward patients with acute abdominal pain, the evaluation of chronic abdominal pain should begin with a thorough history. Events and activities that trigger or alleviate the symptoms may be helpful in identifying the organ systems of pain origin. Furthermore, detail description of the patterns and location of pain are helpful for categorization of pain as visceral pain, somatic pain, or referred pain, and based on these determinations, organ system and anatomical sources of abdominal pain also may be delineated.

The physical examinations in these patients should be focused to help sort out the differential diagnosis formulated on the basis of history, and not a search for pathology. Unfortunately, the physical examination findings are sometimes difficult to interpret because of psychologic and personality changes, especially if the pain has been chronic, recurrent, and severe.

Unfortunately, no specific laboratory or imaging studies are completely sensitive or specific for the diagnosis of abdominal pain. As a general rule, diagnostic studies should be selected only if results of the studies will lead to specific additional evaluations or treatment. The CBC might be helpful in identifying leukocytosis, which may indicate an inflammatory or infectious condition, whereas the presence of anemia might help to verify the presence of ischemic colitis, GI tract malignancy, or inflammatory bowel disease. Abnormalities within the liver functions panel may help identify choledocholithiasis, stenosing papillitis, and periampullary malignancy. Serum amylase elevation is generally seen in the setting of chronic or acute pancreatitis. Elevation in erythrocyte sedimentation rate may suggest the presence of autoimmune processes or collagen vascular disorders.

Frequently, even after the completion of extensive, appropriate evaluations the patient’s condition may remain unrecognized. If possible, the results of the evaluation and diagnostic studies should be discussed with the patient’s primary care physician, so that the patient may be provided with additional testing and follow-up. For those patients without primary care physicians, evaluation and consultation by an appropriate primary care physician or specialist should be obtained prior to discharge from the ED.

COMPREHENSION QUESTIONS

18.1 A 30-year-old woman presents with epigastric pain that developed following dinner. The patient describes having similar pain prior to the current episode, but previous episodes were less severe. The patient was diagnosed as having gastroesophageal refl ux disease by her primary care physician and prescribed a proton pump inhibitor, which has been ineffective in resolving her pain. The current pain episode has been severe and persistent for 3 hours. The patient has a temperature of 38°C (100.4°F), heart rate of 100 beats per minute, respiratory rate of 20 breaths per minute, and blood pressure of 130/90 mm Hg. The abdominal examination reveals no abdominal tenderness. The administration of 30 mL of antacids and 4 mg of morphine sulfate resulted in some relief of pain. Which of the following is the most appropriate next step?

A. Obtain CBC, amylase, liver function tests, and ultrasound of the gallbladder. Discuss with surgical consultants regarding admission to the hospital.

B. Follow up with her primary care physician in 2 weeks.

C. Admit the patient to the hospital for upper GI endoscopy.

D. Prescribe antacids and discharge the patient from the ED, with follow-up by her primary care physician.

E. Obtain an ultrasound of the gallbladder, prescribe oral antibiotics, analgesics, and arrange for an outpatient follow-up with her primary care physician.

18.2 Which of the following features best characterizes somatic pain?

A. Midline location

B. Sharp, persistent, and well-localized pain in the left lower quadrant

C. Intermittent pain

D. Pain is improved with body movement

18.3 For which of the following patients is CT of the abdomen contraindicated? 

A A 60-year-old man with persistent left lower quadrant pain, fever, and a tender mass

B. A 45-year-old alcoholic man with diffuse abdominal pain, WBC 18,000 cells/mm³, and serum amylase of 2000

C. A nonpregnant 18-year-old woman with suprapubic and right lower quadrant pain, fever, right lower quadrant mass, and WBC of 15,000 cells/mm³ 

D. A 70-year-old man with abdominal pain and distension, a 10-cm pulsatile mass in the epigastrium, and blood pressure of 70/50 mm Hg

E. A 24-year-old man with a new finding of painful, irreducible umbilical hernia who presents with 12-hour history of abdominal distension and vomiting

ANSWERS

18.1 A. This patient has recurrent epigastric pain, which is attributed to gastroesophageal reflux disease. However, the fact that her symptoms have been poorly controlled with proton pump inhibitors in the past suggests that the diagnosis is probably inaccurate. Her recurrent symptoms are likely caused by biliary tract disease, and her current presentation is highly suspicious for complicated biliary tract disease such as acute cholecystitis. Choice A represents testing for the evaluation of biliary tract disease, which is appropriate in this setting. Because of her fever, outpatient management approach described in choice E is inappropriate.

18.2 B. Somatic pain is generally associated with irritation of the parietal peritoneum, resulting in localized, persistent, and sharp pain. This type of pain is aggravated by movement and can produce spasm in the overlying abdominal wall musculature, which is manifested as involuntary guarding.

18.3 D. The patient in “D” is hemodynamically unstable and possesses signs and symptoms suggestive of ruptured abdominal aneurysm. A CT scan would likely delay his care and is contraindicated in this situation. The patient described in choice A likely has diverticulitis, where CT may be appropriate for severity staging. The patient described in choice B likely has acute pancreatitis, where CT is helpful for the stratification of disease severity. The patient described in choice C may have complicated appendicitis or some other complicated GI or gynecological process, where CT can be useful for differentiation. The patient described in choice E has an incarcerated umbilical hernia with signs and symptoms of intestinal obstruction related to this finding. Surgical intervention is indicated based on his presentation alone.

CLINICAL PEARLS

⯈ Most patients with the diagnosis of “undifferentiated abdominal pain” determined after thorough ED evaluation will have spontaneous resolution of pain.

⯈ Narcotic medications will affect the characteristics and intensity of all abdominal pain, regardless of etiology.

⯈ Up to one-third of elderly patients with abdominal pain evaluated in the ED have conditions that may require surgical intervention.

References

Delrue LJ, De Waele JJ, Duyck PO. Acute pancreatitis: radiologic scores in predicting severity and outcome. Abdom Imaging. 2009;35:349-361. 

Gravante G, Garcea G, Ong SL, et al. Prediction of mortality in acute pancreatitis: a systematic review of the published evidence. Pancreatology. 2009;9:601-614. 

McNamara R, Dean AJ. Approach to acute abdominal pain. Emerg Med Clin N Am. 2011;29:159-173. 

Pezzeilli R, Zerbi A, DiCarlo V, et al. Practice guidelines for acute pancreatitis. Pancreatology. 2010;10: 523-535. 

Privette Jr TW, Carlisle MC, Palma JK. Emergencies of the liver, gallbladder, and pancreas. Emerg Med Clin N Am. 2011;29:293-317.

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