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Missed Appendicitis Cases Share Similar Features
There are many things that factor into missing a diagnosis of appendicitis, says William Sullivan, DO, JD, FACEP, director of emergency services at St. Mary's Hospital in Streator, IL.
Four features are often present in missed cases of appendicitis, according to a recent study. These are lack of distress, absence of rebound tenderness, a discharge diagnosis of "gastroenteritis," and lack of timely follow-up.1 Here are Sullivan's recommendations to reduce risks:
Absence of rebound tenderness. "This is one of the classic signs of appendicitis, so it would make sense that doctors would consider appendicitis less likely if patients do not have rebound tenderness," says Sullivan. "There isn't much we can do to change the atypical presentations."
Documenting that a patient does not have rebound tenderness is a good idea, says Sullivan. "but obviously doesn't exclude the diagnosis of appendicitis."
Discharge diagnosis of gastroenteritis. Sullivan says that care should be taken when discharging a patient with a diagnosis of gastroenteritis. "If a patient doesn't have the triad of vomiting, diarrhea, and crampy abdominal pain, physicians may want to reconsider their gastroenteritis diagnosis," he says.
The problem with providing a definitive diagnosis when patients have a vague presentation is that the diagnosis may cause premature "closure" of the problem. "It may cause a patient not to seek further evaluation for continuing or worsening symptoms," says Sullivan. "In the patient's minds, they have a self-limiting disease because that was what the doctor diagnosed."
If the pain worsens, instead of seeking care, the patient may just consider the pain as part of the course of the "gastroenteritis" when the pain may actually represent a worsening appendicitis.
"If doctors aren't sure about their diagnosis, make sure that the patient is aware that the diagnosis is uncertain, and that follow-up is important so that the patient can be re-evaluated," says Sullivan. "A diagnosis of 'undifferentiated abdominal pain' or 'abdominal pain–etiology undetermined' helps to illustrate the uncertainty of the patient's symptoms."
Lack of timely follow-up. "Re-evaluation is an underutilized method of diagnosing abdominal pain," says Sullivan. If a stable patient with improving or minimal abdominal pain does not warrant admission to the hospital, it is perfectly acceptable to have that patient return to the ED in eight to 12 hours for a repeat examination, he says.
Overreliance on normal white blood cell counts is also another problem that may lead to a missed diagnosis of appendicitis. "Depending on the study cited, between 10% and 60% of patients with appendicitis have a normal white blood cell count," says Sullivan.
Radiologic testing has significantly improved the ability to diagnose appendicitis, says Sullivan. He notes that CT scans are 95% to 97% accurate in diagnosing appendicitis, and depending on the experience of the technician, ultrasound scans are up to 90% sensitive in diagnosing appendicitis.
"Note that both tests still have a false negative rate of 3% to 10%, though," says Sullivan. '
Another problem to watch out for is a radiologist's report that does not mention the appendix. If the report does not state that the appendix was visualized and was normal, contact the radiologist, clarify the report, and ask for an updated report reflecting the normal appendix in writing.
"If the appendix cannot be visualized, then admission or additional testing may be warranted," says Sullivan.
1. Vissers RJ, Lennarz WB. Pitfalls in appendicitis. Emerg Med Clin N Am 2010; 28:103-118.