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During the 3rd week of intrauterine life there is a communication between the intraembryonic gut and the yolk sac. As the development proceeds this communication narrows into a tube known as the vitellointestinal duct (VID). With the establishment of placental nutrition this duct usually becomes obliterated by the end of the 7th week of intrauterine life. In about 2% of humans this duct persists and gives rise to a group of anomalies of which Meckel's diverticulum is the commonest and complete patency of the duct is the rarest.1
We report a case of a 4-month-old infant who presented with umbilical polyp, discharge from the umbilicus, significant dehydration and failure to thrive because of complete patency of the VID
An infant with umbilical polyp can rarely have underlying complete patency of the VID and because of continuous fluid and electrolyte losses can present with severe dehydration and may fail to thrive. An umbilical granuloma must be differentiated from a polyp. Umbilical polyp is a rare abnormality resulting from persistence of all or part of the VID. The polyp is a red, firm, mass with mucoid discharge. Though the commonest anomaly of VID is Meckel's diverticulum, the complete patency of this duct is a rarity. If the polyp is communicating with the ileum or bladder, small amounts of fecal material or urine may be discharged intermittently. Histologically, the polyp consists of intestinal or urinary tract mucosa.2
A 4-month-old male infant presented with the history of a red mass protruding and some discharge from the umbilicus since birth. The parents were concerned that the infant was not gaining weight adequately.
This baby was delivered vaginally and weighed 4 kg at birth.
At the time of admission he weighed 3.98 kg, his length was 59.0 cm and the head circumference 37.5 cm. (All the parameters were less than 3rd percentile for the age.)
This baby was dull and was significantly dehydrated. The heart rate was 100/min, the respiratory rate was 48/min and the breathing was acidotic.
He had a polyp protruding from the umbilicus and through a visible opening in it there was fluid discharge causing excoriation of the surrounding skin (figure 1).
The rest of the physical examination was unremarkable.
Haemoglobin was 8.5 g/dl, MCV 57.8, RDW 15.4% and MCH 20.2; TLC 27 000/mm3, polymorph 58%, lymphocytes 36%, eosinophils and monocytes 3% each. Blood urea was 17.5 mmol/litre and creatinine 85 μmol/litre. Serum sodium on admission was 128 mmol/litres and 2 days later it was 133 mmol/litre. Serum potassium was 3.7 mmol/litre and subsequently 4.5 mmol/litre. Ionic calcium was 1.40 mmol/l. Total serum proteins were 5.00 g/dl, albumin 2.25 and globulin 2.75 g/dl. Venous blood gas: pH 7.187, base excess; −15.4 mmol/litre, anion gap 14 mmol/litre.
Water soluble contrast was injected through the opening in the polyp and showed the dye in the intestine (figure 2).
The hydration was restored using 0.45% N with 5% dextrose and 40 mmol/litre potassium and, following this, 0.2% N with 5% dextrose was used as maintenance fluid.
After stabilising the baby, on the 5th hospital day he was taken up for surgery (figure 3). The patent VID was excised and end-to-end ileo-ileal anastomosis was done. The procedure went well and she is on the way to recovery.
The incidence of a completely patent VID is reported to be 0.0063–0.067%.1 Of all the anomalies of the VID, complete patency of the duct is the rarest. The condition is mostly seen either in neonates or in infants.
The omphalomesenteric duct connects the yolk sac to the gut in a developing embryo and provides nutrition until the placenta is established. Between the 5th and 7th week of gestation, the duct attenuates and separates from the intestine. Just before this involution, the epithelium of the yolk sac develops a lining similar to that of the stomach. Partial or complete failure of involution of the omphalomesenteric duct results in various residual structures. Meckel's diverticulum is the most common of these structures and is the most frequent congenital gastrointestinal anomaly occurring in 2–3% of all infants. Other omphalomesenteric duct remnants occur infrequently, including a persistently patent duct, a solid cord, or a cord with a central cyst or a diverticulum associated with a persistent cord between the diverticulum and the umbilicus.3
The omphalomesenteric duct may remain patent throughout its course, producing an enterocutaneous fistula between the distal small intestine and the umbilicus. This condition presents with the passage of meconium and mucus from the umbilicus in the first few days of life. Persistence of the distal end of the omphalomesenteric duct results in an umbilical polyp, which is a small excrescence of omphalomesenteric ductal mucosa at the umbilicus. Such polyps resemble umbilical granulomas except that they do not disappear after silver nitrate cauterisation4 (figure 4).5
This child presented with significant fluid and electrolyte losses resulting in dehydration and dyselectrolytemia. Surgical excision of the patent duct is the treatment of choice, which was offered to this child.
Competing interests None.
Patient consent Obtained.