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Mrs. P is a 42-year-old woman who arrives at the emergency department via ambulance with abdominal pain and syncope. She was in her usual state of health until the morning of admission when increasing left lower quadrant abdominal pain developed. The pain increased in intensity and became quite severe. Upon standing, she lost consciousness and collapsed to the floor. She recovered quickly and was helped to a chair by her husband. When she stood several minutes later, she briefly lost consciousness again. The patient reports that her abdominal pain is much better. She has no chest pain or dyspnea. Her vital signs are BP, 105/60 mm Hg; pulse, 85 bpm; temperature, 37.0°C; and RR, 18 breaths per minute. Her cardiac and pulmonary exams are normal, and abdominal exam reveals mild left lower quadrant tenderness. Her ECG is normal and her HCT is normal at 36.0%.

image At this point, what is the leading hypothesis, what are the active alternatives, and is there a must not miss diagnosis? Given this differential diagnosis, what tests should be ordered?


As noted in Figure 31-1 the first step ascertains whether Mrs. P suffered from syncope or some other transient loss of consciousness. The history of abrupt onset and rapid recovery without intervention strongly suggests syncope. The next step considers whether this is likely due to reflex syncope, orthostatic syncope, or cardiac syncope (Figure 31-2). Several features of Mrs. P’s syncope are noteworthy. First, her syncope occurred in association with abdominal pain raising the possibility of vasovagal syncope. Second, she had 2 episodes of syncope upon standing. This pivotal clue raises the possibility of orthostatic syncope from either dehydration, hemorrhage, medications, or autonomic dysfunction. Finally, cardiac syncope should be considered in all patients with syncope. Fortunately, Mrs. P has no prior history of heart disease that would increase the likelihood of cardiac syncope. Additionally, she has no suggestive symptoms (syncope with chest pain, syncope with exertion, syncope while sitting or supine, palpitations, or dyspnea), or signs (significant murmur, gallop, or JVD) to suggest cardiac syncope. Her ECG is also normal. The combination of the lack of underlying heart disease or suggestive symptoms of cardiac syncope, coupled with recurrent syncope immediately after standing makes orthostatic syncope likely and cardiac syncope unlikely. Table 31-9 lists the differential diagnosis.

Table 31-9.Diagnostic hypotheses for Mrs. P.

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