A 7 year old female is brought to the ED with a chief complaint of abdominal pain. She vomited once and feels weak. Emesis occurred about 1 hour after eating saimin (a local soup/noodle dish, also called ramen) from a neighborhood lunch/snack truck (a small mom and pop type business). The pain is worse in the periumbilical region described as painful and somewhat intermittent. Her mother stated that this happened to her in the past and they waited too long before coming in to the emergency room.
During this previous episode, she was given IV fluids at which point, her symptoms largely resolved and she went home. Her mother didn’t want her to suffer as much as she did the last time, so she was brought in early this time, despite only vomiting once.
T36.7, HR 91, RR 24, BP 140/81. She is uncomfortable, but in no respiratory distress. She is alert and cooperative. Her oral mucosa is moist and her eyes are not sunken. Neck supple. Heart regular without murmurs. Lungs clear. Abdomen flat, soft, and non-tender. Bowel sounds are active. No masses are felt. No hernias and no CVA tenderness.
Laboratory studies were drawn and an IV infusion of Lactated Ringer’s was started because this was indirectly requested by her mother in the description of her past experience.
Additionally, the patient seemed so disproportionately uncomfortable despite her benign exam findings and a history suggestive of food poisoning.
CBC Hgb 15, Hct 45, WBC 14,000 without a left shift. Na 144, K 3.2, Cl 110, Bicarb 22, glucose 169.
The patient received a total of 400cc of Ringer’s Lactate and a phenergan suppository while in the E.D. At which time, her abdominal pain resolved. There was no further vomiting since her initial episode of emesis prior to arrival. She was not retching and she was feeling much better. She was sleeping and had to be awakened to go home. She ambulated briefly but became grumpy after awakening and wanted her mother to carry her. Her abdomen was non-tender.
She was discharged with a diagnosis of “Food Poisoning” with the usual vomiting instructions. She was instructed to return if worse.
You might wonder why a patient who is ill for only an hour had blood tests and IV fluids. Call it overkill or instinct.
Read on. . .
Six hours after discharge from the E.D. the patient returns because she it still vomiting, has pain, and feels her abdomen is distended. She has not had a bowel movement since a small one early in the morning before the onset of symptoms. Her mother administered an enema with only fluid return.
T37.0, HR 166, RR 48, BP 88/57, oxygen saturation 97% in room air. Her exam showed a distended abdomen, diffuse tenderness (more so periumbilical without rebound), no stool and no tenderness on rectal exam with a smear showing specks of heme positive material.
A repeat of her labs was done. CBC WBC 21,500, 65 segs, 20 bands, Hgb 12.4, Hct 36.4. Na 142, K 3.1, Bicarb 17.
Shortly after arrival she vomited 800cc of yellow fluid. An abdominal series was ordered.
This series of radiographs shows a large distended loop in the RUQ. There are other less dilated loops in the RLQ. The remainder of the abdomen is relatively gasless. The lateral decubitus view shows only a few small air fluid levels and the same distended loops.
What happened next?
A surgical consultation was sought. The patient received Ringers 500cc and was admitted to the hospital. She was observed and continued to receive fluid support but became progressively worse. She developed a fever and dropped her hemoglobin to 5.3. At surgery, approximately 24 hours after her initial presentation, she was found to have malrotation with a midgut volvulus.
The small bowel was infarcted and necrotic and required removal of her entire small intestine. In reviewing this case we see the initial presentation is entirely nonspecific. However, the rapidity of change in the patient’s vital signs, labs, and requirement for very aggressive fluid management point to the evolution of a serious problem.
The abdominal radiographs provided important information that could (should?) have been acted on sooner. The distended loops and absence of gas in the other areas of the abdomen in conjunction with the clinical findings of abdominal distention and bilious vomiting should raise the suspicion of a bowel obstruction.
Unfortunately in pediatrics, the radiographic diagnosis of a bowel obstruction may not be very obvious.
The aim (aaiimm) of this case is to consider the following in the differential diagnosis of a bowel obstruction using the mnemonic A-A-I-I-M-M: Adhesions Appendicitis Intussusception Inguinal hernia Malrotation Miscellaneous (Meckel’s, tumor, duplication, etc.) .
Try these x-rays….
Can you reach a diagnosis?
These radiographs show very little bowel gas. There is a small amount of gas on the left. Otherwise, the only significant air filled loop that is seen, is located in the RUQ. These findings are again non-specific, but they suggest the possibility of a bowel obstruction. This patient turned out to have a malrotation.
What is malrotation?
Malrotation of the intestine is the underlying abnormality which predisposes the bowel to volvulus (twisting) and subsequent ischemic necrosis. The term “malrotation” refers to an occurrence in fetal development at the point where the bowel returns to the abdominal cavity. After entering the midabdomen at 12 o’clock, the cecum rotates counterclockwise into the right lower quadrant at 7 o’clock. The true significance of the rotation is not so much that the cecum must be in the right lower quadrant, but the fact that the mesentery, containing the superior mesenteric artery, goes with it. The mesentery grows to fix the terminal ileum to the posterior abdominal wall. This produces a fan of mesentery securing the small bowel from the upper midabdomen just behind the duodenum to the right lower quadrant.
Note the broad fan of meseteric attachment of the small bowel making it difficult for a volvulus of the small bowel to occur. If the correct rotation does not occur, it is termed “malrotation”. This results in the failure of proper mesenteric development so that instead of a broad fan of mesenteric attachment, the entire midgut is attached to the posterior abdominal wall by a short, narrow stalk in the region of the duodenum. There may also be bands crossing the duodenum (Ladd’s Bands) which can cause duodenal obstruction.
Note the mesenteric attachment of the cecum. This narrow stalk is more prone to volvulus. Additionally, this stalk (Ladd’s bands) is capable of compressing the duodenum and obstructing it. In a malrotation, many meters of intestine are free to twist around this stalk, which, since it contains the superior mesenteric artery, is vulnerable to strangulation and ischemic necrosis. The occurrence of this twisting and strangulation results in the surgical emergency called midgut volvulus. Midgut volvulus should not be confused with cecal or sigmoid volvulus. Cecal and sigmoid volvulus generally occur in adults. Sigmoid volvulus involves the large bowel and can often be decompressed by barium enema or other non-surgical procedures.
In midgut volvulus, the majority of the small bowel is involved in the strangulation. Substantial small bowel necrosis occurs without prompt surgical intervention.
In malrotation, the cecum may be prone to twisting or kinking if it is excessively mobile. Cecal volvulus can occur in the absence of malrotation. This most often presents in adults rather than children.
Sigmoid volvulus is the most common site of colonic volvulus. It occurs most often in the elderly. It is associated with elongation of the descending colon making the sigmoid region hypermobile and prone to twisting. Midgut volvulus is a surgical emergency at risk of bowel infarction. Some neonatal examples of volvulus are shown below.
This radiograph of a 5-day old infant with vomiting shows a gasless abdomen except for the small air bubble in the stomach. Such a radiograph should be considered highly suspicious for any type of upper GI obstruction. Further studies on this infant showed a midgut volvulus and malrotation.
This radiograph of a 9-day old infant with vomiting looks relatively normal. It has a normal gas distribution with no air fluid levels or excessively dilated loops. Although this radiograph looks much more normal than the first neonatal radiograph, further studies on this infant also showed a midgut volvulus and malrotation. Thus, it is not possible to rule out a volvulus due to malrotation solely on plain films in some instances. Clinical suspicion should lead one to pursue more definitive radiographic studies. While sigmoid volvulus usually shows severely dilated loops of bowel and large air fluid levels on plain film radiographs, a midgut volvulus may show non-specific findings on plain films without the characteristic signs of an obvious bowel obstruction.
This is a barium enema of the infant above which shows the ascending colon and cecum in the wrong place. The cecum should normally be located in the right lower quadrant, but in this BE, most of the proximal large bowel is in the left upper quadrant. The cecum is in the central abdomen. In a patient who has a malrotation but is not experiencing strangulation, malrotation is usually identified on an upper GI series or barium enema. The UGI series can more definitively determine the presence of malrotation by identifying the position of the ligament of Treitz.
The BE can usually determine the presence of malrotation by noting the malposition of the cecum. It should normally be located in the right lower quadrant. If the cecum is located elsewhere, then malrotation is likely.
However, both of these studies can be deceiving at times. The ligament of Treitz may be close to the normal location in a malrotation and the cecum may occasionally be in the RLQ in a malrotation.
The classic presentation of malrotation is usually described as a volvulus, heralded by bilious vomiting in the first days of life. Less than half of the cases actually present in the neonatal period. Catastrophic midgut volvulus can present at any age. Lesser degrees of reversible ischemia (sometimes called intermittent volvulus), can produce intermittent pain, non-bilious vomiting, gastroesophageal reflux, malabsorption and failure to thrive. Patients with malrotation may be entirely asymptomatic with catastrophic volvulus occurring at any age. Neither the age of the patient, nor the chronicity of symptoms are predictive. All are at risk for severe complications (even adults).
The mortality of midgut volvulus in several series is 40 to 60%. As some of these series date prior to modern intensive care techniques, the current mortality is probably lower, but the survivors may lose so much bowel that they are totally dependent on parenteral nutrition. Due to this significant mortality and morbidity, even incidentally discovered malrotation should be surgically corrected. Intestinal obstruction is an uncommon cause of vomiting in the pediatric age group.
Most pediatric vomiting is caused by infectious agents, including viral gastroenteritis, but also associated with generalized non-intestinal infections such as URI, otitis media and pneumonia. Because of the relative preponderance of benign causes of vomiting, the serious causes must always be kept in mind and excluded or at least anticipated in discharge instructions. Vomiting in the neonatal period brings to mind sepsis, congenital anomalies or meconium ileus. In the first few months of life, pyloric stenosis, hernias and intussusception are important causes of obstruction. As the infant becomes mobile, foreign bodies and poisoning must be considered. Abdominal trauma, both intentional and accidental can produce vomiting. In addition to the above, remember A-A-I-I-M-M (AIM x2).
The diagnosis of appendicitis is sometimes obscure in the young patient. There are no reliable tests to adequately exclude early appendicitis; therefore, anticipation of the need for early reexamination or observation in the emergency department should be considered in any child with abdominal pain and vomiting.
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