Mr. C is a 22-year-old man who complains of diffuse abdominal pain.
|What is the differential diagnosis of abdominal pain? How would you frame the differential?|
Abdominal pain is the most common cause for hospital admission in the United States. Diagnoses range from benign entities (eg, irritable bowel syndrome [IBS]) to life-threatening diseases (eg, ruptured abdominal aortic aneurysms [AAAs]). The first pivotal step in diagnosing abdominal pain is to identify the location of the pain. The differential diagnosis can then be narrowed to a subset of conditions that cause pain in that particular quadrant of the abdomen (Figure 3–1 and Summary table of abdominal pain by location at the end of the chapter). The character and acuity of the pain are also pivotal features that help prioritize the differential diagnosis.
The differential diagnosis of abdominal pain by location.
Other important historical points include factors that make the pain better or worse (eg, eating), radiation of the pain, duration of the pain, and associated symptoms (nausea, vomiting, anorexia, inability to pass stool and flatus, melena, hematochezia, fever, chills, weight loss, altered bowel habits, orthostatic symptoms, or urinary symptoms). Pulmonary symptoms or a cardiac history can be clues to pneumonia or myocardial infarction (MI) presenting as abdominal pain. In women, sexual and menstrual histories are important. The patient should be asked about alcohol consumption.
A few points about the physical exam are worth emphasizing. First, vital signs are just that, vital. Hypotension, fever, tachypnea, and tachycardia are pivotal clinical clues that must not be overlooked. The HEENT exam should look for pallor or icterus. Careful heart and lung exams can suggest pneumonia or other extra-abdominal causes of abdominal pain.
Of course, the abdominal exam is key. Inspection assesses for distention (often associated with bowel obstruction or ascites). Auscultation evaluates whether bowel sounds are present. Absent bowel sounds may suggest an intra-abdominal catastrophe; high-pitched tinkling sounds and rushes suggest an intestinal obstruction. Palpation should be done last. It is useful to distract the patient by continuing to talk with him or her during abdominal palpation. This allows the examiner to get a better appreciation of the location and severity of maximal tenderness. The clinician should palpate the painful area last. The rectal exam should be performed, and the stool tested for occult blood. Finally, the pelvic exam should be performed in adult women and the testicular exam in men.