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Emergency and Acute Medicine – Evaluation and Management of Abdominal Pain
Overview and Pain Mechanisms
Abdominal pain originates from several distinct physiologic processes. Parietal pain occurs when the peritoneum becomes inflamed by irritating substances. It is conveyed through somatic nerves, intensifies with movement or changes in abdominal wall tension, and is typically sharp, well defined, and associated with rebound tenderness and involuntary guarding.
In contrast, visceral pain arises from internal organs and is transmitted through autonomic afferent pathways. This pain is often vague and poorly localized, reflecting embryologic origin rather than precise anatomy. Pain from foregut organs is perceived in the epigastrium, midgut pain around the umbilicus, and hindgut pain in the suprapubic region. It commonly results from distention of hollow organs, stretching of organ capsules, or smooth muscle spasm, and may be constant or colicky.
As inflammation progresses and involves the parietal peritoneum, localized tenderness develops. Ischemic pain, frequently due to vascular emergencies, is characteristically severe and diffuse. Referred pain is experienced at a site distant from the affected organ because of shared neural pathways. Abdominal wall pain is usually persistent and aching, often accompanied by muscle spasm and involvement of nearby muscle groups.
Causes of Abdominal Pain
Etiologies are broad and include peritoneal irritation from gastric acid, fecal contamination, pus, blood, bile, or pancreatic enzymes. Obstructive processes may affect the small or large bowel, gallbladder, ureters, or kidneys, and may be complicated by ischemia of intestinal, renal, or splenic tissue. Inflammatory conditions include appendicitis, inflammatory bowel disease, cholecystitis, hepatitis, peptic ulcer disease, pancreatitis, pelvic inflammatory disease, and pyelonephritis. Additional considerations include abdominal wall pathology and referred pain from extra-abdominal sources such as intrathoracic disease.
Clinical Assessment: History and Symptoms
A thorough history is critical. Important features include the onset, timing, duration, and progression of pain; its initial and current location; radiation; and quality (sharp, dull, cramping). Clinicians should assess aggravating and relieving factors and associated symptoms such as anorexia, nausea, vomiting (including bilious or coffee-ground material), malaise, syncope, respiratory complaints, changes in bowel habits or stool color, hematuria, urinary symptoms, trauma, gynecologic or obstetric history, recent surgery, family history of vascular disease, alcohol intake, and medication use, particularly NSAIDs or aspirin.
Physical Examination Findings
General examination may reveal fever, tachycardia, tachypnea, hypotension, jaundice, or abnormal peripheral pulses. Abdominal evaluation should include inspection for distension, auscultation for altered bowel sounds, and palpation for masses or tenderness. Signs of peritoneal irritation such as guarding and rebound tenderness are key. Specific maneuvers—including Rovsing, psoas, obturator, McBurney point tenderness, Murphy sign, and Carnett sign—help localize pathology. Rectal and pelvic examinations may identify tenderness, masses, cervical motion tenderness, or occult blood. Genitourinary assessment includes evaluation for flank pain, dysuria, costovertebral angle tenderness, testicular pain, and suprapubic tenderness. Skin findings such as jaundice, ecchymosis, rashes, or vesicular lesions may provide diagnostic clues.
Initial Workup
Pregnancy testing is mandatory in women of reproductive age. In many cases, ultrasonography serves as the first-line imaging study, with CT scanning reserved for situations in which ultrasound is nondiagnostic or when more detailed evaluation is required.
Investigations and Interpretation
Laboratory studies typically include a complete blood count, serum electrolytes, renal function tests, glucose, inflammatory markers, liver function tests, lactic acid, serum lipase, urinalysis, stool studies when indicated, and pregnancy testing.
Imaging is guided by clinical suspicion and may include ECG for possible cardiac causes, abdominal radiographs, upright chest radiograph to assess for free air, ultrasonography for biliary disease, hydronephrosis, free fluid, aneurysm, or torsion, and CT scanning tailored to suspected pathology. CT angiography is essential when mesenteric ischemia or abdominal aortic aneurysm is suspected. MRI may be considered when radiation exposure or contrast nephrotoxicity is a concern.
Differential Diagnosis
Abdominal pain encompasses a wide differential including gastrointestinal, vascular, genitourinary, gynecologic, metabolic, infectious, and referred causes. Examples include bowel obstruction, appendicitis, cholecystitis, pancreatitis, diverticulitis, ectopic pregnancy, ovarian torsion, renal colic, ischemic bowel, myocardial infarction, pneumonia, abdominal wall disorders, and herpes zoster. Pediatric considerations vary by age and include intussusception, volvulus, incarcerated hernia, Meckel diverticulitis, and sickle cell crisis.
Management in the Emergency Department
Initial management focuses on stabilization and symptom control. This includes bowel rest, nasogastric decompression when indicated, intravenous fluids, correction of electrolyte abnormalities, and antiemetics. Adequate analgesia should be provided promptly and not delayed. Blood typing and cross-matching are required in unstable patients, and early surgical consultation is crucial when a surgical cause is suspected.
Pharmacologic Therapy
Pain control commonly involves opioids such as fentanyl or morphine. Nausea and vomiting are treated with antiemetics including ondansetron, prochlorperazine, or promethazine.
Disposition and Follow-Up
Hospital admission is indicated for patients with suspected surgical pathology, peritoneal signs, inability to tolerate oral intake, uncontrolled pain, serious medical causes such as myocardial infarction or diabetic ketoacidosis, or the need for intravenous antibiotics.
Discharge may be appropriate when serious pathology has been excluded, pain is well controlled, oral intake is tolerated, and the patient can comply with clear return instructions.
Discharge Advice and Safety Netting
Patients should be advised to return immediately for worsening or persistent pain, ongoing vomiting, blood in vomitus or stool, jaundice, fever or chills, or lack of improvement within 8–12 hours.
Clinical Pearls
Older adults often present atypically and are at higher risk for life-threatening conditions. Constipation should not be diagnosed solely by the absence of stool in the rectum. When vomiting precedes the onset of abdominal pain, a surgical cause is less likely.
Overview and Pain Mechanisms
Abdominal pain originates from several distinct physiologic processes. Parietal pain occurs when the peritoneum becomes inflamed by irritating substances. It is conveyed through somatic nerves, intensifies with movement or changes in abdominal wall tension, and is typically sharp, well defined, and associated with rebound tenderness and involuntary guarding.
In contrast, visceral pain arises from internal organs and is transmitted through autonomic afferent pathways. This pain is often vague and poorly localized, reflecting embryologic origin rather than precise anatomy. Pain from foregut organs is perceived in the epigastrium, midgut pain around the umbilicus, and hindgut pain in the suprapubic region. It commonly results from distention of hollow organs, stretching of organ capsules, or smooth muscle spasm, and may be constant or colicky.
As inflammation progresses and involves the parietal peritoneum, localized tenderness develops. Ischemic pain, frequently due to vascular emergencies, is characteristically severe and diffuse. Referred pain is experienced at a site distant from the affected organ because of shared neural pathways. Abdominal wall pain is usually persistent and aching, often accompanied by muscle spasm and involvement of nearby muscle groups.
Causes of Abdominal Pain
Etiologies are broad and include peritoneal irritation from gastric acid, fecal contamination, pus, blood, bile, or pancreatic enzymes. Obstructive processes may affect the small or large bowel, gallbladder, ureters, or kidneys, and may be complicated by ischemia of intestinal, renal, or splenic tissue. Inflammatory conditions include appendicitis, inflammatory bowel disease, cholecystitis, hepatitis, peptic ulcer disease, pancreatitis, pelvic inflammatory disease, and pyelonephritis. Additional considerations include abdominal wall pathology and referred pain from extra-abdominal sources such as intrathoracic disease.
Clinical Assessment: History and Symptoms
A thorough history is critical. Important features include the onset, timing, duration, and progression of pain; its initial and current location; radiation; and quality (sharp, dull, cramping). Clinicians should assess aggravating and relieving factors and associated symptoms such as anorexia, nausea, vomiting (including bilious or coffee-ground material), malaise, syncope, respiratory complaints, changes in bowel habits or stool color, hematuria, urinary symptoms, trauma, gynecologic or obstetric history, recent surgery, family history of vascular disease, alcohol intake, and medication use, particularly NSAIDs or aspirin.
Physical Examination Findings
General examination may reveal fever, tachycardia, tachypnea, hypotension, jaundice, or abnormal peripheral pulses. Abdominal evaluation should include inspection for distension, auscultation for altered bowel sounds, and palpation for masses or tenderness. Signs of peritoneal irritation such as guarding and rebound tenderness are key. Specific maneuvers—including Rovsing, psoas, obturator, McBurney point tenderness, Murphy sign, and Carnett sign—help localize pathology. Rectal and pelvic examinations may identify tenderness, masses, cervical motion tenderness, or occult blood. Genitourinary assessment includes evaluation for flank pain, dysuria, costovertebral angle tenderness, testicular pain, and suprapubic tenderness. Skin findings such as jaundice, ecchymosis, rashes, or vesicular lesions may provide diagnostic clues.
Initial Workup
Pregnancy testing is mandatory in women of reproductive age. In many cases, ultrasonography serves as the first-line imaging study, with CT scanning reserved for situations in which ultrasound is nondiagnostic or when more detailed evaluation is required.
Investigations and Interpretation
Laboratory studies typically include a complete blood count, serum electrolytes, renal function tests, glucose, inflammatory markers, liver function tests, lactic acid, serum lipase, urinalysis, stool studies when indicated, and pregnancy testing.
Imaging is guided by clinical suspicion and may include ECG for possible cardiac causes, abdominal radiographs, upright chest radiograph to assess for free air, ultrasonography for biliary disease, hydronephrosis, free fluid, aneurysm, or torsion, and CT scanning tailored to suspected pathology. CT angiography is essential when mesenteric ischemia or abdominal aortic aneurysm is suspected. MRI may be considered when radiation exposure or contrast nephrotoxicity is a concern.
Differential Diagnosis
Abdominal pain encompasses a wide differential including gastrointestinal, vascular, genitourinary, gynecologic, metabolic, infectious, and referred causes. Examples include bowel obstruction, appendicitis, cholecystitis, pancreatitis, diverticulitis, ectopic pregnancy, ovarian torsion, renal colic, ischemic bowel, myocardial infarction, pneumonia, abdominal wall disorders, and herpes zoster. Pediatric considerations vary by age and include intussusception, volvulus, incarcerated hernia, Meckel diverticulitis, and sickle cell crisis.
Management in the Emergency Department
Initial management focuses on stabilization and symptom control. This includes bowel rest, nasogastric decompression when indicated, intravenous fluids, correction of electrolyte abnormalities, and antiemetics. Adequate analgesia should be provided promptly and not delayed. Blood typing and cross-matching are required in unstable patients, and early surgical consultation is crucial when a surgical cause is suspected.
Pharmacologic Therapy
Pain control commonly involves opioids such as fentanyl or morphine. Nausea and vomiting are treated with antiemetics including ondansetron, prochlorperazine, or promethazine.
Disposition and Follow-Up
Hospital admission is indicated for patients with suspected surgical pathology, peritoneal signs, inability to tolerate oral intake, uncontrolled pain, serious medical causes such as myocardial infarction or diabetic ketoacidosis, or the need for intravenous antibiotics.
Discharge may be appropriate when serious pathology has been excluded, pain is well controlled, oral intake is tolerated, and the patient can comply with clear return instructions.
Discharge Advice and Safety Netting
Patients should be advised to return immediately for worsening or persistent pain, ongoing vomiting, blood in vomitus or stool, jaundice, fever or chills, or lack of improvement within 8–12 hours.
Clinical Pearls
Older adults often present atypically and are at higher risk for life-threatening conditions. Constipation should not be diagnosed solely by the absence of stool in the rectum. When vomiting precedes the onset of abdominal pain, a surgical cause is less likely.
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