The duodenum is the first stretch of small intestine, just past the stomach. When it’s blocked, food and fluid back up and come back out as vomiting. In newborns the cause is almost always a problem in how the gut formed, while in adults something presses on or narrows a gut that was once normal. Babies typically need one corrective operation, whereas adults may be treated with feeding support, a stent, or bypass surgery, depending on the cause.
Causes in Newborns and Children
Duodenal atresia means the duodenum is closed off at birth. Duodenal stenosis means it is open but too narrow. Together they are one of the more common gut defects in newborns.1PubMed Central. Congenital duodenal obstruction associated with Down’s syndrome presenting with hematemesis More than half of affected babies have at least one other birth difference, such as a heart defect.2PubMed Central. Congenital duodenal obstruction associated with Down’s syndrome presenting with hematemesis For babies with atresia alone, no specific genetic cause has been found.3National Organization for Rare Disorders. Duodenal Atresia or Stenosis – Symptoms, Causes, Treatment
Atresia isn’t one shape. The duodenum can end in a solid cord, in two separate blind ends, or in a thin membrane stretched across the inside, and the surgeon sees which during the operation. A membrane, or web, can bulge and stretch with food, so it may block only partly and be found later than a complete closure. That difference largely decides when symptoms start: a complete closure shows up within the first feeds, while a narrowing may let some milk through.
Early in pregnancy the gut is briefly a solid cord of cells that normally hollows out into an open tube. Atresia is thought to reflect a problem in that process, though the exact cause isn’t settled. Nothing a parent did or didn’t do during pregnancy is known to cause it in a typical case.
Roughly 25% to 40% of babies with duodenal atresia have Down syndrome.4PubMed Central. Congenital duodenal obstruction associated with Down’s syndrome presenting with hematemesis Seen the other way, about 1 to 5 in 100 babies with Down syndrome have duodenal atresia, making it their most common gut defect.5PubMed Central. Congenital duodenal obstruction associated with Down’s syndrome presenting with hematemesis The risk isn’t tied to the mother’s age, ethnicity or the baby’s sex.6PubMed Central. Congenital duodenal obstruction associated with Down’s syndrome presenting with hematemesis For parents, a duodenal finding on a scan often leads doctors to offer genetic testing. Most babies with atresia do not have Down syndrome, but because other defects are common, a heart scan is usually advised.
A blockage can also come from outside the gut wall. In annular pancreas, part of the developing pancreas wraps around the duodenum instead of rotating past it, squeezing it like a ring.7Applied Radiology. Annular Pancreas When the bowel doesn’t rotate into place before birth, bands of tissue can press on the duodenum.8PubMed Central. A rare case of Ladd’s band causing duodenal occlusion in an adult with intestinal malrotation Those bands occasionally aren’t found until adulthood.9PubMed Central. A rare case of Ladd’s band causing duodenal occlusion in an adult with intestinal malrotation
Causes in Adults
A duodenal ulcer can block the passage suddenly when the area swells and the gut stops pushing food along.10International Surgery Journal. A rare cause of gastric outlet obstruction Over time, ulcers can heal with scar tissue that narrows the passage permanently.11International Surgery Journal. A rare cause of gastric outlet obstruction
A form of pancreatitis that inflames the groove between the pancreas and duodenum can thicken and scar the duodenal wall.12PubMed Central. Acute pancreatitis associated with duodenal obstruction induced by groove pancreatitis That scarring usually narrows the second part of the duodenum.13PubMed Central. Acute pancreatitis associated with duodenal obstruction induced by groove pancreatitis It can also narrow the bile ducts and trigger pancreatitis attacks.14Journal of Pediatric Surgery Case Reports. Groove pancreatitis treated by duodenal and biliary bypass
People with pancreatic cancer that can’t be removed often develop a blocked duodenum, blocked bile ducts, or both as the disease progresses.15PubMed. Palliation of biliary and duodenal obstruction in patients with unresectable pancreatic cancer: endoscopy or surgery? The tumor grows into the duodenum, which sits wrapped around the head of the pancreas.16PubMed Central. The Malignant Obstruction Caused by Pancreatic Cancer Within the Uncinate Process in the Third Portion of the Duodenum Blocked bile ducts cause jaundice, yellowing of the skin and eyes.17PubMed Central. The Malignant Obstruction Caused by Pancreatic Cancer Within the Uncinate Process in the Third Portion of the Duodenum
In superior mesenteric artery (SMA) syndrome, a major gut artery squeezes the third part of the duodenum against the aorta.18PubMed Central. Superior mesenteric artery syndrome: Diagnosis and management Losing weight shrinks the fat pad that normally cushions the space between the two vessels, narrowing the angle.19PubMed Central. Superior mesenteric artery syndrome: Diagnosis and management Significant weight loss from illness, an eating disorder or surgery can set it off. It can become a vicious cycle: the blockage makes eating painful and causes vomiting, eating less causes more weight loss, and more weight loss shrinks the fat pad further and tightens the squeeze.
Rarely, a large gallstone erodes into the gut through an abnormal channel and lodges in the duodenum.20PubMed Central. Bouveret’s syndrome: revisiting gallstone obstruction of the duodenum It accounts for only 1% to 3% of gallstone blockages of the bowel and follows long-standing gallstones.21PubMed Central. Bouveret syndrome in a young patient: A case report and review of literature
Which cause is likely depends on the person, and timing offers one clue among several. Swelling from an active ulcer or a flare of pancreatitis tends to cause a blockage that comes on over days and may ease as inflammation settles. Scar tissue, a tumor or an artery squeeze tends to produce symptoms that build over weeks or months and don’t go away without treatment.
When the duodenum narrows, the stomach can’t empty normally, so it stretches and fills with food, fluid and acid. That’s why the main complaint is fullness and vomiting rather than diarrhea. Bile and pancreatic juices enter partway along, so the location of the narrowing decides whether vomit contains bile. Long-lasting vomiting costs the body fluid and acid, so people with a stubborn blockage can become dehydrated and have abnormal blood salts, which is part of why hospital care is often needed.
Symptoms to Watch For
The classic sign is green, bile-stained vomiting.22Journal of pediatric and neonatal individualized medicine. Delayed presentation of congenital intrinsic duodenal obstruction in children with non-bilious vomiting: a diagnostic dilemma Most blockages sit below where bile enters the duodenum, so bile usually comes up with the vomit; a blockage above that point causes vomiting that isn’t green.23PubMed Central. Neonatal Duodenal Obstruction: A 15-Year Experience Some children with a partial blockage have recurrent plain vomiting and are first misdiagnosed with stomach bugs.24Journal of pediatric and neonatal individualized medicine. Delayed presentation of congenital intrinsic duodenal obstruction in children with non-bilious vomiting: a diagnostic dilemma
In a newborn, vomiting starts within the first day or two of feeds, and the upper belly may look swollen while the lower belly stays flat. Green vomit in a baby is always an emergency.
Adults feel full after a few bites and may vomit undigested food hours after eating. As it continues, weight loss and dehydration follow.
A child with a narrowing rather than a complete closure may feed, grow slowly, and vomit only now and then, so the pattern can go unnoticed for months or even years. These habits are easy to read as picky eating, but poor weight gain alongside repeated vomiting should prompt a closer look.
Vomiting blamed on a stomach bug that keeps returning deserves imaging. If you’ve had weight loss or jaundice, mention them to your doctor.
How Doctors Find It
On ultrasound or X-ray, a blocked duodenum shows a “double bubble”: a swollen stomach and a swollen duodenum. On a prenatal scan the clue often comes late in pregnancy, together with extra amniotic fluid, because the baby can’t pass swallowed fluid along the gut. In one series, every baby with a double bubble on a pregnancy scan was confirmed to have duodenal atresia at surgery, though a scan finding still needs confirming after birth.25PubMed Central. The Double Bubble Sign: Duodenal Atresia and Associated Genetic Etiologies
After birth, an X-ray showing air in the two bubbles and little or none beyond suggests a complete blockage, while some air farther down points to a partial one. A double bubble alone doesn’t say which type it is, so the surgeon confirms the exact cause during the operation. Meanwhile, a tube through the nose drains the stomach to stop vomiting, fluids go through a drip, and surgery usually follows within days.
In adults, a CT scan can show where the blockage is, whether it’s inside, in the wall, or pressing from outside, and any complications.26PubMed. CT of gastro-duodenal obstruction A barium swallow X-ray is sometimes used but misses some cases.27PubMed Central. Duodenal imaging on the spotlight: from A to Z
Surgery for Babies and Recovery
The operation joins the swollen duodenum above the blockage to the bowel below it, letting food bypass the blocked spot. The baby is under general anesthesia, and the surgeon usually opens the belly through a small cut or uses keyhole instruments, depending on the baby and the surgeon’s experience. The surgeon first checks the whole bowel, because other blockages further down or a twisted gut can occur alongside atresia and would need fixing in the same operation. Surgery is generally done in the first days of life, once the baby is stable and other problems, such as a heart defect, have been assessed. A diamond-shaped join let babies start feeds in about 4 days and go home in about 16, versus 8 to 10 days and 24 to 28 days with older joins.28PubMed. Duodenal atresia: a comparison of techniques of repair
The gut is slow to restart, so the stomach tube keeps draining green fluid for days, and that is expected rather than a sign of failure. Pain is treated with medicine, and the baby is watched for fever, a swelling belly or renewed vomiting, which could signal infection or a leak at the join.
Some babies need nutrition by vein while the gut wakes up.29PubMed. The role of parenteral nutrition following surgery for duodenal atresia or stenosis Babies fed by vein had more suspected infections, 41% versus 14%.30PubMed. The role of parenteral nutrition following surgery for duodenal atresia or stenosis Feeding through a thin tube passed beyond the join hasn’t clearly shortened time to full feeds.31PubMed Central. Postoperative feeding in neonatal duodenal obstruction
In a typical stay, the stomach tube comes out once drainage slows, tiny feeds start and build up, and the baby goes home once taking full feeds and gaining weight. About 95% survive, with higher risk when a baby has a major heart defect or was born prematurely.
Treatment for Adults
For SMA syndrome, treatment starts with restoring weight, leaving surgery for when that fails.32PubMed Central. Increase body weight to treat superior mesenteric artery syndrome Regained fat widens the angle and frees the duodenum.33PubMed Central. Laparoscopic Duodenojejunostomy for Treatment of Superior Mesenteric Artery Syndrome Nutrition may be by tube past the blockage or by vein, depending on how blocked it is.34Nutrición Hospitalaria. The two sides of superior mesenteric artery syndrome treatment: conservative or surgical management? Lying on the left side or in a knee-chest position during meals helps about half of patients.35Nutrición Hospitalaria. The two sides of superior mesenteric artery syndrome treatment: conservative or surgical management? This approach succeeds in about 83% of cases.36Nutrición Hospitalaria. The two sides of superior mesenteric artery syndrome treatment: conservative or surgical management? If there’s no improvement after 3 to 4 weeks, surgery bypasses or frees the duodenum.37Nutrición Hospitalaria. The two sides of superior mesenteric artery syndrome treatment: conservative or surgical management?
Weight restoration works best when the cause of the weight loss, such as an eating disorder, surgery or a chronic illness, is treated at the same time, otherwise the squeeze can return. Small, frequent meals and avoiding lying flat after eating can ease symptoms while weight returns, though they support recovery rather than cure it. When surgery is needed, the bypass connects the duodenum to the bowel beyond the squeezed spot.
For cancer blockages, a stent is a mesh tube placed through a scope to prop the passage open. Bypass surgery instead connects the stomach to bowel beyond the blockage.38PubMed. Comparison of gastrojejunostomy to endoscopic stenting for gastric outlet obstruction: An updated Systematic Review and Meta-analysis Both relieve symptoms about equally well.39PubMed. Comparison of gastrojejunostomy to endoscopic stenting for gastric outlet obstruction: An updated Systematic Review and Meta-analysis Stents mean shorter stays, around 1.5 days versus 11 after surgery.40PubMed Central. Stenting versus gastrojejunostomy for management of malignant gastric outlet obstruction: comparison of clinical outcomes and costs In pancreatic cancer, stented patients ate again in 3 days versus 5, and started chemotherapy in 14 days versus 32.41PubMed. Endoscopic duodenal stent placement versus gastrojejunostomy for unresectable pancreatic cancer patients with duodenal stenosis before introduction of initial chemotherapy (GASPACHO study): a multicenter retrospective study Bypass surgery blocks again less often and needs fewer repeat procedures.42PubMed. Comparison of gastrojejunostomy to endoscopic stenting for gastric outlet obstruction: An updated Systematic Review and Meta-analysis Survival was about 6 months either way in pancreatic cancer.43PubMed. Endoscopic duodenal stent placement versus gastrojejunostomy for unresectable pancreatic cancer patients with duodenal stenosis before introduction of initial chemotherapy (GASPACHO study): a multicenter retrospective study
A stent suits people wanting fast relief and quick chemotherapy, while bypass suits those expected to live longer. After a stent, people typically start with liquids and move to soft foods, aiming to eat enough to keep strength up for further treatment. A stent can become blocked again as a tumor grows through or over the mesh. Bypass is a larger operation with a longer recovery, and for someone very weak or with a short life expectancy, that cost can outweigh the benefit.
A newer technique creates the stomach-to-bowel connection using a scope guided by ultrasound, without open surgery.44Clinical Endoscopy. Endoscopic ultrasound-guided gastroenterostomy, with focus on technique and practical tips It works in roughly 70% to 100% of patients.
Other causes are treated differently. Ulcer swelling is treated with acid-lowering drugs and stomach drainage, scarring may need stretching with a balloon or surgery, and a lodged gallstone is removed by scope or surgery.
Long-Term Problems After Childhood Repair
In one surgical series, 70% of children had a complication after surgery.45PubMed. Complications associated with surgical treatment of congenital intrinsic duodenal obstruction The most frequent were a stretched, sluggish duodenum or bile reflux into the stomach (22%), jaundice (17%) and acid reflux (17%).46PubMed. Complications associated with surgical treatment of congenital intrinsic duodenal obstruction About 18% needed another operation.47PubMed. Complications associated with surgical treatment of congenital intrinsic duodenal obstruction Problems such as ulcers and gut movement issues can appear months or years later.48PubMed. Duodenal atresia and stenosis: reassessment of treatment and outcome based on antenatal diagnosis, pathologic variance, and long-term follow-up
A stretched duodenum means the part above the old blockage stays wide and pumps poorly. Food sits there and bacteria overgrow, and a narrowing operation can fix it.
Even a technically good repair can leave a duodenum that moves food poorly, so problems may appear only as the child eats a more varied diet. Families should report vomiting that returns months after surgery, poor weight gain, or belly pain or swelling after meals.