Her past medical history is unremarkable. She’s never had any surgical procedures. She’s not been taking any medications beyond antipyretics for her fever. No one else in the family has been ill but several of her classmates at school have been vomiting (no surprise there).
On first glance, she looks ill but not toxic. Her eyes are somewhat sunken, her mucous membranes are tacky and her tongue is coated. Her CR is about 2 seconds. She’s febrile to 39.1, and somewhat tachycardic. The rest of her exam is unremarkable until you get to her abdomen. It’s mildly distended and tympanitic with diminished bowel sounds. She has diffuse, poorly localizing pain across the lower abdomen. Her belly is soft and she doesn’t have guarding or rebound, but she doesn’t like you pressing deeply.
Ok, you’ve finished your initial assessment. Your patient is dehydrated with a distended, somewhat tender belly and a fever. This could be from gastroenteritis, but she looks a bit sicker than the other kids you’ve been seeing all evening. You order some IV fluids and Zofran, of course. But you also add some labs and abdominal films, looking for obstruction or ileus.
You get busy and move on to other patients. In about an hour the labs are back. Her chemistries are not particularly remarkable, her amylase and lipase are normal. Her urine is concentrated and has ketones, which you would expect from several days of poor dietary intake, but there’s no evidence of infection. Her white count is 18,000 with a left shift. She doesn’t feel all that much better from the fluids and antiemetic. You run by radiology to check on her film.
Now this is interesting – the child looks like she has a small bowel obstruction. She has dilated loops and air-fluid levels. This doesn’t look like the typical ileus you can get with gastroenteritis. Her colon is not distended. No it’s dilated small bowel all right. But why?
When the bowel develops obstruction, gas distal to the blockage gets passed within hours, leaving an airless region distally. OK, looking at her films (particularly the upright), it appears that the region sans gas starts in the right lower quadrant. And what lives in the right lower quadrant? The appendix, for starters. Could this be an atypical presentation of appendicitis? What else could give you this picture? Gastroenteritis can give you an ileus, but the colon should be involved. Electrolyte disturbances (hypokalemia, hypercalcemia), ditto – besides her chemistries weren’t all that off. Mechanical obstruction would look more like this, but what would cause it in a previously healthy child? She’s never had surgery so it’s unlikely that she’d have adhesions. She’s a bit old for an intussuception. Perhaps a duplication or mass? It’s time to pass an NG to decompress this child, hook it up to some low intermittent suction, and pursue other imaging.
You elect to get a contrasted abdominal CT. Sure enough, she’s got a perforated appendix with abscess formation.
As you phone the pediatric surgeon, you reflect on the key points of evaluating abdominal distention in kids. It’s either gas, fluid, an enlarged solid organ or mass. The flat and upright got you quickly to gas. The next question is localized or generalized? This gas was localized, suggesting obstruction. The next question – where does the air stop, got you to the right lower quadrant and helped narrow your differential to the point where you could reasonably pursue the work-up and get the information you needed. Age and history are important too – in a younger child with episodic pain this would have been a likely film for intussuception. In that case, a CT would not be your next step, you’d have gone for the air contrast enema.
Isn’t it typical for appendicitis to be atypical? Keep up your guard.
Amy Levine, MD, is an associate professor of pediatric EM at UNC Chapel Hill