Thickened Pituitary Stalk
Joseph Junewick, MD FACR
over 6 years ago
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Joseph Junewick, MD FACR
|Diagnostic Category: Developmental or Congenital
|Created: over 4 years ago
|Updated: over 4 years ago
6 week old male with projectile vomiting.
US – 1) Fluid filled aperistaltic duodenal sweep with a beak-like termination, 2) dilated fluid filled closed loop obstruction, 3) Color Doppler of the mesenteric artery and vein demonstrated the whirlpool sign.
As the embryologic process of normal counterclockwise rotation is completed, the bowel supplied by the SMA becomes fixed and stabilized in its final position by the mesentery and peritoneum. The normal mesentery has a broad base, extending from the duodenojejunal junction to the cecum. The failure to complete rotation results in a narrow base of the mesentery, which can predispose the neonate to volvulus.
Midgut volvulus is a life-threatening emergency that can occur in the intestinal tract of a neonate. If not promptly diagnosed and treated, it leads to death or a lifelong dependence on total parenteral nutrition in survivors with short bowel syndrome. Although usually seen in the neonatal period, it may also occur later in life. Bile-stained emesis and occasional bloody stools are the main presenting clinical indicators.
Findings on abdominal radiographs are a jejunal gas pattern on the right, variable degrees of duodenal obstruction due to peritoneal bands or a volvulus and gasless right lower quadrant. Barium enema studies have fallen out of favor as the preferred diagnostic modality for malrotation, since the cecum may be normally positioned in as many as 20% of patients with malrotation. On upper GI, the duodenum demonstrates partial or complete obstruction, low and rightward deviation of the duodenojejunal junction, and corkscrew descent of distal bowel.
Ultrasound should not be the primary means of diagnosis of volvulus although some clinical overlap with pyloric stenosis makes knowledge of the ultrasound diagnosis is necessary. Leftward orientation of the superior mesenteric vein relative to the superior mesenteric artery is seen with malrotation; the whirlpool sign is seen with volvulus.
Epelman M. The Whirlpool sign. Radiology (2006); 240: 910-911.