widow envenomation
Diabetic ketoacidosis
Familial Mediterranean fever
Glaucoma
Heavy metal poisoning
Hereditary angioedema
Hyperthyroidism
Poisoning/overdose (iron, others)
Pneumonia
Streptococcal pharyngitis
Sickle cell vaso‐occlusive crisis
Shingles (Zoster herpticus)
Uremia
Vasculitis
Pathologic states may cause different types of pain: visceral, somatic, or referred pain. Luminal or capsular distention will typically produce visceral pain by stimulation of nerves surrounding a hollow or solid organ. Because the innervation of organs is sparse and multisegmented, this pain is usually dull and poorly localized. When caused by an obstructive process, the pain is typically intermittent or colicky. Distention of a solid organ tends to produce more constant pain (e.g., hydronephrosis, hepatitis). Visceral pain is typically associated with other autonomic phenomena such as anorexia, nausea, and vomiting.
Somatic abdominal pain typically results from irritation of the parietal peritoneum from infection or inflammation. The pathologic process stimulates peripheral nerves, and the pain tends to be more intense and distinct than visceral pain. The evolution of acute appendicitis involves both visceral and somatic pain. Early obstruction and distention of the appendix generates dull, poorly localized pain around the umbilicus. As inflammation progresses, the parietal peritoneum becomes involved and the pain becomes localized to the right lower quadrant.
Referred pain is at a site not directly involved with the disease process. Visceral and somatic nerves from different areas converge at the spinal cord allowing for misinterpretation of location by the brain. An example is irritation of the diaphragm by blood in the peritoneal cavity as might be seen following a ruptured ectopic pregnancy. This is perceived as shoulder pain because both the diaphragm and the skin near the shoulder share the C4 sensory level. Other common sites of referred pain are indicated in Table 19.1.
History and physical examination
An organized assessment must be applied to any patient with a presenting complaint of abdominal pain. A careful history will yield an appropriate list of potential etiologies in most patients.
Box 19.3 Etiologies of abdominal pain by anatomical location
Right upper quadrant
Cholelithiasis/cholecystitis
Acute hepatitis
Acute pancreatitis
Renal colic
Duodenal ulcer
Right lower lobe pneumonia
Myocardial infarction
Right lower quadrant
Acute appendicitis
Cecal diverticulitis
Colitis (Inflammatory bowel disease)
Renal colic
Abdominal aortic aneurysm
Inguinal hernia
Testicular/ovarian torsion
Ectopic pregnancy
Pelvic inflammatory disease
Ovarian cyst
Endometriosis
Left upper quadrant
Pancreatitis
Renal colic
Gastric ulcer
Gastritis
Splenic enlargement/infarction
Left lower lobe pneumonia
Myocardial infarction
Left lower quadrant
Sigmoid diverticulosis
Colitis (i.e., inflammatory bowel disease)
Renal colic
Abdominal aortic aneurysm
Inguinal hernia
Testicular/ovarian torsion
Ectopic pregnancy
Pelvic inflammatory disease
Ovarian cyst
Endometriosis
Table 19.1 Common sites of referred abdominal pain
| Etiology | Region of perceived pain |
|---|---|
| Biliary colic/cholecystitis | Right scapula |
| Renal colic | Testicle, labia, inguinal region |
| Pancreatitis | Midback |
| Gastric or bowel perforation | Shoulder |
| Ruptured ectopic pregnancy | Shoulder |
| Rectal or prostate disorder | Lower back |
Useful historical data may be obtained directly from the patient or from a parent or other care provider. Emphasizing a SAMPLE history is encouraged. The OPQRST mnemonic (Box 19.4) highlights important questions regarding signs and symptoms. Ask the patient about allergies prior to medication administration and consider anaphylactic reactions as a source of abdominal discomfort. EMS clinicians
