Volume 5, Case 16
Richard Lichenstein, MD
Philip Haney, MD
Kapiolani Medical Center For Women And Children
University of Hawaii John A. Burns School of Medicine
This is a five year old male who was struck by an automobile four weeks ago, sustaining a right femur fracture. He was placed in a spica cast and hospitalized for a week without complications. He was discharged in the spica cast. Over the past 10 days, he began vomiting everyday (without blood or bile), usually one hour after meals. Although he says he "can't keep anything down", his urine output has been reported as normal. His mother says that he has had fevers ranging from 39 to 40 degrees. He continues to have 1-2 normal formed bowel movements per day without diarrhea. He has complained of intermittent leg pain and headache although there are no current complaints. He has not complained of any abdominal pain.
His past history is significant for attention deficit disorder and modest developmental delays.
Medications include methylphenidate and acetaminophen.
Exam: VS T36.5, HR 86, BP 84/54, RR 20. He is alert, apprehensive at first but cooperative with time, in no distress. Moist mucous membranes. Clear pharynx, conjunctiva, and tympanic membranes. Neck supple without significant lymphadenopathy. Cardiac exam normal. Lungs clear to auscultation. His abdomen is difficult to fully examine because of the spica cast. His limited abdomen is soft and non-tender without masses. Skin turgor good. No rashes. Extremities symmetric with good pulses and brisk capillary refill. No neurological deficits are noted.
Labs: Na 141, K 3.9, Cl 106, bicarb 25, BUN 6, creatinine 0.3, amylase 39, calcium 10, albumin 4.2. UA: specific gravity 1.023, trace protein otherwise dip negative.
An abdominal flat-plate is ordered.
View abdominal film.
Discussion
If you diagnosed the cast syndrome, you correctly identified the clinical signs consistent with this syndrome. This is due to an extrinsic compression of the third portion of the duodenum by the superior mesenteric artery. This syndrome is also referred to as superior mesenteric artery (SMA syndrome) or acute gastric dilatation. This radiograph shows a dilated gas-filled stomach suggesting a partial gastric outlet obstruction.
Cast syndrome is common in the second decade of life which may be attributable to the increased flexibility of the spine in young adults. Truncal casting can increase lumbar lordosis. This can change the take-off of the superior mesenteric vessels which crosses the horizontal part of the duodenum. Patients with the cast syndrome may have mesenteric vessels with a more acute angle and a shorter distance from the take-off to the duodenum.
Many cases of cast syndrome are observed in patients with spinal disease. Most commonly it involves fractures of the pelvis or femur. Other patients with this syndrome may have congenital deformities or have experienced rapid weight loss. Handicapped children may also develop this type of functional obstruction perhaps related to poor fat mass, hypotonicity and skeletal distortion as has been reported in one child with cerebral palsy.
Clinical signs include intermittent or continuous nausea, vomiting and abdominal distention. Sequelae include dehydration, metabolic alkalosis and shock. Fatalities have been reported when recognition or treatment has been delayed. Symptoms may begin immediately after casting or up to 12 weeks thereafter.
Compression of the duodenum by the cast is one mechanism postulated for the cast syndrome. Another contributory factor may be weight loss and associated loss of fat in the mesentery. Retroperitoneal fat may keep the duodenum from being compressed by the superior mesenteric trunk or the spine. The diagnosis can be confirmed by a flat plate of the abdomen which may reveal dilatation of the stomach and duodenum. The diagnosis can be confirmed by an upper gastrointestinal series.
View UGI series.
This view from the UGI series shows a narrowing in the third portion of the duodenum due to external compression. The nasojejunal tube failed to negotiate the duodenum and coiled on itself.
A duodenal hematoma may result in a similar obstruction. However, this would occur during the initial trauma, or soon after.
Treatment includes IV replacement therapy, electrolyte maintenance, a nasogastric tube to decompress the stomach and duodenum, along with replacement of the cast.
References