ACUTE GASTRIC OUTLET OBSTRUCTION DUE TO AN IATROGENIC CAUSE

Purpose: Ultrasound features in acute gastric outlet obstruction caused by prostaglandin infusion.

Methods and Materials: Mucosa hyperplasia is an uncommon cause of gastric outlet obstruction in neonatal period. The main etiologic factor of this disorder is long-term prostaglandin E1 (PGE1) infusion. PGE1 administration is used to maintain the patency of the ductus arteriosus in neonates with ductal-dependent cyanotic congenital heart diseases. The treatment although life saving is limited with possible side effects. The pathophysiology of prostaglandin induced gastric mucosa hyperplasia is based on delayed senescence and exfoliation of foveolar cells. Supposition of this disorder is possible on the basis of some clinical features, results of chest radiographs, contrast gastrointestinal imaging or ultrasound examination. We present two cases of neonates with tetralogy of Fallot, pulmonary trunk hypoplasia and PDA hospitalised in Pediatric Cardiology Departament of Medical University in Gdansk, for who prostaglandin E1 therapy was started on the second day of life. After around 3–3,5 weeks of these treatment clinical features of acute gastric outlet obstruction were noticed. Therefore ultrasound examination was carried out using Unit GE Logiq 500, with microconvex transducer 3–7MHz and linear transducer 8,2–11,0MHz.

Results: In both cases features of acute gastric outlet obstruction due to mucosa hyperplasia were found. Ultrasound examination results indicated gastric mucosa foveolar hyperplasia due to PGE 1 infusion. The problems with feeding receded after stomach tube insertion and reduction of PGE1 infusion.

Table:

Ultrasound findings:

Neonate	Gastric wall	Antrumdiameter	Antrummucosa layer	Antrummuscular layer	Pyloric canallength	CumulativePGE 1 dosage
D.J. female25 days old	4,6–5,5mm	14,0mm	2,5mm	3,0–3,5mm	17,0mm	1650µg/kg
S.N. female22 days old	5,7–5,9mm	17,0mm	2,0mm	3,5–3,7mm	23,6mm	1512µg/kg

Conclusions:

• Suspecting acute gastric outlet obstruction in neonates with PGE 1 infusion following sonographic features should be fulfilled:

• • increased height of the mucosal layer corresponds to the papillary hyperplasia of the gastric foveolae,

  • alternate hyperechoic and hypoechoic pattern of the gastric mucosa represent dilated mucosal glands in the thickened foveolae and interfoveolar mucin products,

  • thickness of the muscular layer is in the normal range.

• Ultrasonography should be the first and final method in diagnosing almost all cases post prostaglandin gastric mucosa foveolar hyperplasia.