Abdominal pain, vomiting, diarrhea, and constipation are exceedingly common symptoms. In 2007, 10.8 million cases presented to emergency departments with gastrointestinal complaints, representing 9.2% of ED visits.¹ Twenty-one to forty-one percent of these patients, despite a full complement of diagnostic testing, leave the ED without a clear diagnosis.² There is diagnostic complexity in differentiating benign self-limited disease versus serious life-threatening conditions when evaluating these common gastrointestinal complaints. Patients arriving via EMS transport are more likely to require hospital admission, suggesting that EMS providers will encounter a sicker subset of the overall ED population.³ Evaluation of these patients is often a challenge as is the provision of education and medical oversight to the EMS provider and system.

Differentiating the seriousness of gastrointestinal complaints begins at the time of dispatch. Dispatch protocols often attempt to address severity of illness and consideration of pathology originating from an alternate organ system when determining the response to the “sick” or “abdominal pain” call types. It has been suggested that dispatch protocols relying on age and gender classification alone result in significant overtriage.⁴ Potential overuse of advanced life support (ALS) must be weighed against the benefits of ALS response: early electrocardiogram (ECG) interpretation, intravenous fluids, and medication administration. The diagnostic complexity of gastrointestinal complaints requires providers to approach them with a high level of suspicion and thorough evaluation, especially in higher risk populations such as the elderly, immunocompromised, women of childbearing age, and individuals with chronic disease.

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  Discuss the assessment of gastrointestinal emergencies.

  
  
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  Understand common causes of gastrointestinal symptoms.

  
  
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  Identify life-threatening gastrointestinal conditions.

  
  
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  Discuss appropriate out-of-hospital management.

  
  
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  Identify life-threatening nongastrointestinal conditions that commonly present with gastrointestinal symptoms.

  
  
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  Discuss the use of ultrasound and other point-of-care testing in the prehospital environment.

  
  
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  Discuss the use of narcotics for abdominal pain in the prehospital environment.

  
  
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  Discuss the use of antiemetics for nausea or vomiting in the prehospital environment.

Patients often present with one or more complaints, typically abdominal pain with associated symptoms such as nausea, vomiting, anorexia, diarrhea, or constipation. Atypical presentations of gastrointestinal conditions such as alterations in mental status, syncope, or jaundice with or without abdominal pain are responsible for some of the diagnostic uncertainty. The key to the appropriate diagnosis comes with a history and physical examination that is as complete as possible. Consideration of past medical and surgical history can significantly impact the differential diagnosis. The provider should complete the history with full awareness of time of onset, duration of the pain, the quality of the pain, the region or radiation of the pain, factors that provoke or palliate, and the severity of the symptoms. Utilization of a rapid assessment mnemonic such as OPQRST is helpful and should be encouraged (Table 41-1).

Symptoms with an acute onset are of great concern in the practice of emergency medicine but gastrointestinal disease associated with high morbidity and mortality may have a more indolent presentation. An acute onset of symptoms of abdominal pain may increase concern for perforated viscous or nongastrointestinal causes such as abdominal aortic aneurysm, aortic dissection, ruptured ectopic pregnancy, or testicular/ovarian torsion. A slower onset of symptoms may indicate an inflammatory or infectious process such as appendicitis or colitis. Understanding the quality of painful symptoms is helpful in determining visceral versus somatic types of pain. Visceral symptoms tending more toward dull, aching pains with somatic symptoms often described as sharp, well-localized pain. Visceral pain is often referred to other locations and difficult to pinpoint. The location where the patient feels referred visceral pain is determined during fetal development and therefore subject to some variation. Classically, referred pain to the right shoulder is attributed to gallbladder disease. Pancreatic, aortic and renal colic often refers to the back.

Provoking factors may include oral intake as in the case of biliary disease, gastric ulcers, or mesenteric ischemia; pain with sudden movements may indicate peritoneal irritation as with appendicitis or peritonitis. Palliating factors may alternatively include oral intake, rest, or medications. Severe symptoms would heighten concern though the presence of even mild symptoms especially in the elderly, young, immunocompromised, and chronically ill may indicate serious disease. These populations warrant special consideration in the assessment of gastrointestinal symptoms.

The past medical and surgical history will direct the development of the differential and are therefore important pieces of information to obtain. Knowledge of a previous history of peptic ulcer disease in the patient with sudden onset, severe abdominal pain would increase concern for a ruptured viscous. A history of abdominal surgery would raise the diagnosis of a bowel obstruction higher on the differential.

The physical examination is of the most benefit when a clear differential is in mind when performing the examination. The patient’s general appearance will provide insight into the severity of illness. Identification of the “sick” patient is a vital skill for any clinician. Special attention should be paid to the level of discomfort, mental status, color, and respiratory pattern. The absence of severe pain is not unexpected in elderly or immunocompromised patients. An alteration in mental status may indicate a serious metabolic derangement such as acidosis, uremia, or hyperammonemia though it may also be a result of poor perfusion and shock. Jaundice or pallor would be of a concern in patients at risk for liver failure, hepatitis, or severe anemia. Kussmaul-type respiratory pattern may be an indicator of acidosis.

Inspection of the abdomen yields important information especially in patients who are unable to provide a reliable history. A distended abdomen from ascites or obstruction is notable. Chronic changes such as the caput medusa may indicate the presence of liver disease. Cullen or Grey Turner sign would raise concern for intraperitoneal bleeding. The presence or absence of surgical scars should be noted as this may have significant impact on the differential diagnosis.

Auscultation can be difficult in the prehospital environment and the presence or absence of bowel sounds is of limited clinical utility. The presence of hyperactive bowel sounds may be noted in patients with bowel obstruction. The utility of percussion in the prehospital environment is also of limited clinical utility. Environmental factors will make it difficult to differentiate the tympany associated with bowel obstruction versus the shifting dullness associated with ascites.

Most of the information from the abdominal examination is yielded from palpation. Tenderness to palpation in specific locations or quadrants may focus the differential. Voluntary guarding is a protective mechanism that is often found with focal tenderness. Rebound tenderness is indicative of peritoneal inflammation with rigidity on physical examination indicating diffuse peritoneal inflammation and a potential “surgical abdomen” (Table 41-2).

Point-of-care testing (POC) is possible in the prehospital arena but its use is generally limited to response with urban search and rescue (USAR) or disaster medical assistance teams (DMAT); however, some advanced POC has been done in the standard prehospital setting.^5–16 Hemoglobin and hematocrit have utility in the assessment of gastrointestinal hemorrhage. The metabolic panel, blood gas, and lactate are useful tools to assess the patient’s metabolic state and as part of the evaluation for mesenteric ischemia or in the evaluation of patients with extra abdominal causes of gastrointestinal complaints such as diabetic ketoacidosis, hypercalcemia, hyponatremia, or acute kidney injury.

The 12-lead electrocardiogram should be utilized to assess patients with gastrointestinal complaints at risk for potential cardiac pathology such as an acute coronary syndrome or arrhythmia. Elderly patients, women, and diabetics are more likely to present with atypical symptoms of an acute coronary syndrome. The ECG may also be used to assess for metabolic derangements resulting from gastrointestinal illness or causing gastrointestinal symptoms such as hypokalemia or hypercalcemia.

There is no reported data regarding the utilization of radiographs in the prehospital setting but as with point-of-care testing the equipment may be available especially in the setting of an extended disaster response. While using these tools in the prehospital setting is a foreign concept during normal working conditions, the EMS physician must be aware of their availability and utility. Radiographs are of limited utility but may be helpful in the evaluation for free air in the abdominal cavity, the presence of pleural effusion/infiltrate, or to evaluate for a bowel obstruction.¹⁷

The use of ultrasound has become the standard of practice in emergency medicine for a variety of applications.¹⁸ Prehospital ultrasound in military, ground, and aeromedical applications has been shown to be of some utility in smaller studies focused primarily on the evaluation of trauma using the Focused Assessment Sonography in Trauma (FAST) examination.^19–22 The utility of prehospital ultrasound by paramedics is an area of significant interest.^23–30 In a majority of the studies on prehospital ultrasound, emergency physicians performed the scan or reviewed images remotely.^31–32 ALS providers have demonstrated the ability to perform and interpret FAST and abdominal aortic (AA) examinations in the field though further validation is necessary.³³ Larger studies to determine whether prehospital ultrasound could affect clinical outcomes are needed (Table 41-3).