In the latest Case Record of the Massachusetts General Hospital, a 10-month-old girl was seen in the emergency department because of vomiting and episodes of unresponsiveness, which had begun suddenly 7 hours earlier. She gradually became somnolent. Vital signs, a physical examination, and brain imaging were normal.
The immediate approach to a child who presents to the emergency department with altered mental status is twofold. The first principle of emergency management is evaluation of the ABCs (airway, breathing, circulation). Added to this evaluation should be the letter D: dextrose (an initial glucose measurement), disability (degree of neurologic compromise), and drugs (overt toxidromes due to ingestion or exposure). After the ABCDs are secured, we turn to investigating the causes of impaired mental status. Mechanisms of such alterations in mental status include compression or increased intracranial pressure, vascular changes or disease, metabolic derangement, toxin exposure, abnormal neuronal discharges (i.e., seizures), and temperature irregularities.
• What are the gastrointestinal causes of unresponsiveness in an infant?
The major gastrointestinal causes of unresponsiveness are those associated with an acute abdomen. In an infant with nonbilious vomiting, the most likely cause of acute abdomen would be intussusception. Pyloric stenosis is also in the differential diagnosis, typically presenting in the first several months of life. Intestinal malrotation or volvulus are possible but are associated with bilious vomiting. An incarcerated hernia may be ruled out by the presence of a normal abdominal examination. Porphyria can present with altered mental status and abdominal pain, but is a rare consideration in infancy. Sandifer’s syndrome — the occurrence of dystonic posturing of the head and upper limbs after eating — is associated with reflux or hiatal hernia, but is not accompanied by altered mentation.
• What is neurologic intussusception?
This is a term used to describe an acute abdomen due to intussusception with syncope. Numerous case reports, retrospective studies, and clinical reviews document prominent neurologic features in the absence of common gastrointestinal symptoms of intussusception. Although lethargy is most common, other neurologic symptoms include apathy, listlessness, hypersomnolence, impaired reaction to painful stimuli, and fluctuating levels of consciousness. Neurologic intussusception is particularly common in infants. The pathophysiology of neurologic intussusception is not well understood. Proposed mechanisms include release of neuropeptides from strangulated bowel, absorption of toxic metabolites, dehydration and electrolyte imbalance as a result of vomiting, and progressive bowel obstruction. It is also possible that neurologic impairment is simply a normal behavioral reaction of an infant to severe abdominal pain.
Morning Report Questions
Q: How does intussusception typically present and how is it diagnosed?
A: There are many commonly described clinical symptoms of intussusception, including a palpable right-sided abdominal mass, vomiting, bloody or “currant jelly” stools, colicky or intermittent abdominal pain, drawing up of the legs toward the abdomen, and intermittent or inconsolable crying. Nonetheless, fewer than a quarter of patients present with the classic triad of clinical symptoms of vomiting, abdominal pain, and bloody stools. Intussusception is a common pediatric abdominal emergency, second only to appendicitis as the cause of acute abdomen, and the most common cause in children such as this one who are under the age of 2. It may be diagnosed on plain abdominal radiography. Features suggestive of intussusception would include decreased air in the right colon, with a masslike lesion surrounded by radiolucent fat (“target sign”). Lack of gas in the cecum is the most important sign; sensitivity of the radiograph for detecting this can be increased by positioning the patient left side down (left decubitus), and the addition of a film taken in the prone position. Abdominal ultrasonography is more accurate than radiography for the diagnosis of intussusception.
Q: How is intussusception treated?
A: A therapeutic enema is typically performed to reduce the intussusception. Therapeutic enemas can be done with either air (pneumatic) or fluid (hydrostatic). Contraindications for a therapeutic enema are peritonitis, shock, and perforation of the bowel, none of which were present in this case. Nonetheless, a surgical consultation is always required; the surgeon needs to know that the patient is in the hospital in case the reduction is unsuccessful, or if there is a complication. Small-bowel obstruction makes it more difficult to reduce the intussusception, but this is not a contraindication.