Non-Bilious Vomiting
The absence of bile indicates that the obstruction is located proximal to the entrance of the biliary tract into the intestinal lumen (the major duodenal papilla).
Main causes:
- Hypertrophic Pyloric Stenosis (Hypertrophic Pyloric Stenosis). This is the most common cause requiring surgical intervention in infants. The classic presentation is projectile vomiting.
- Gastric Obstruction. Rare. Includes a pyloric web, gastric atresia (easily visible on fluoroscopy), or pyloric atresia, which is frequently associated with epidermolysis bullosa.
- Microgastria. A rare anomaly with a hypoperistaltic esophagus and a small, tubular stomach, often associated with the VACTERL association.
- Enteric Duplication Cysts. Rare in the stomach. On ultrasound, they present with a characteristic gut signature (gut signature), where the inner echogenic layer corresponds to the mucosa and the outer hypoechoic layer to the muscularis propria.
- Gastric Volvulus (Gastric Volvulus). Organoaxial torsion (along the longitudinal axis) carries a minimal risk of ischemia. Mesenteroaxial torsion (perpendicular to the mesenteric axis) brings the cardia and pylorus close together, creating a high risk of necrosis and requiring emergency surgery.
Bilious Vomiting
Bilious vomiting indicates a pathology distal to the major duodenal papilla. This condition always requires immediate diagnostic imaging to rule out urgent surgical pathology—malrotation with volvulus.
Malrotation and Small Bowel Volvulus (Malrotation and Volvulus): Normally, the duodenojejunal flexure (DJF) is located to the left of the spine and the cecum to the right, forming a broad-based mesentery. In malrotation (a disruption of embryological midgut rotation), the mesenteric root narrows. This creates a narrow axis around which the bowel easily twists. Volvulus develops, impairing blood flow through the superior mesenteric vessels, which rapidly leads to ischemia and necrosis.
Plain abdominal radiographs show no specific signs, but may reveal partial duodenal obstruction (mimicking a "double bubble"), a "closed-loop" pattern, or a ominous "gasless" abdomen.
Contrast Studies and Imaging Findings
If the newborn is unstable or there are signs of perforation or peritonitis, imaging is limited to a plain radiograph, after which emergency surgery is indicated.
For other patients with partial obstruction, an upper gastrointestinal contrast study using barium or water-soluble contrast is performed. The main objective is to locate the duodenojejunal flexure (DJF). Normally, it is located to the left of the vertebrae at the level of the duodenal bulb. In malrotation, the flexure is displaced inferiorly and to the right.
Pathognomonic signs of volvulus:
- Corkscrew sign (corkscrew pattern) — the duodenum and jejunum spiral around the mesenteric vessels.
- Abrupt cut-off sign (abrupt cut-off) — a sharp cessation of contrast in the third part of the duodenum.
Important: Do not overfill the stomach with contrast, as the contrast pool can obscure the DJF. Evaluation must focus on the initial passage of barium.
Red Flag Symptoms
Regurgitation and vomiting can be manifestations not only of surgical pathology, but also of infections, neurological problems (increased intracranial pressure), or metabolic disorders.
Symptoms requiring mandatory further evaluation:
- Presence of bile or blood in the vomitus
- Persistent projectile vomiting
- Onset of symptoms after 6 months of age
- Failure to thrive, lethargy, fever
- Bulging fontanelle or seizures
- Abdominal tenderness, distension, hepatosplenomegaly
Note on GERD: Imaging modalities (fluoroscopy or ultrasound) are not used to diagnose gastroesophageal reflux disease, but serve only to rule out anatomical defects.
Briefly: answers to topical questions
What ultrasound criteria and measurements are used to diagnose hypertrophic pyloric stenosis?
The most reliable ultrasound criterion for diagnosing hypertrophic pyloric stenosis is the transverse thickness of the pyloric muscle. In true pathology, the transverse diameter of the pyloric muscle exceeds 3 mm regardless of the patient's age and weight. Borderline abnormal ultrasound findings should be evaluated in conjunction with this parameter. In case of questionable measurement results or high clinical suspicion, a repeat ultrasound examination is indicated.
What contrast agents are used for gastrointestinal studies in newborns and in what volume?
Barium and water-soluble contrast agents are used for gastrointestinal imaging, although the exact volume in milliliters for newborns is not specified in the literature.
- Barium (Barium) is the optimal choice for single-contrast upper GI examinations.
- Water-soluble contrast is preferred by surgeons when planning emergency surgery, and is also used prior to anastomosing a defunctionalized bowel loop to assess the caliber of distal segments.
For small bowel follow-through or enteroclysis, oral administration or pressure injection of a large volume of contrast is used.
Class and exam questions
Why is contrast imaging not performed in cases of bilious vomiting and signs of perforation on X-ray?
The presence of free gas (pneumoperitoneum) or a pattern of high-grade obstruction is a direct indication for emergency surgery. Further imaging will lead to a dangerous waste of time and may cause harm.
What are the risks of mesenteroaxial gastric volvulus?
Unlike organoaxial torsion, mesenteroaxial volvulus occurs around the transverse axis, bringing the cardia and pylorus into close proximity. This causes acute obstruction with a high risk of bowel wall ischemia.
What comorbidities are frequently associated with malrotation?
Malrotation is by definition associated with congenital diaphragmatic hernias, gastroschisis, and omphalocele. It is also associated with heterotaxy syndromes and Hirschsprung's disease.
What else to study on this topic
- Embryogenesis of the gastrointestinal tract and stages of midgut rotation
- Differential diagnosis of causes of pneumoperitoneum in newborns
- Technique of duodenography via an enteral tube
- Non-obstructive causes of vomiting: neurological and metabolic disorders
- Association of gastrointestinal anomalies with genetic syndromes (VACTERL, epidermolysis bullosa)
Master the entire topic in the "Diagnostic Radiology" course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Vomiting in Newborns" and 2,199 other pages of the curriculum
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 10 video lessons on the subject
Other Topics in "Pediatric Diagnostic Radiology"
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.