Megacystis microcolon intestinal hypoperistalsis syndrome

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS), also known as Berdon syndrome, is a rare congenital disorder characterized by a dilated non-obstructive urinary bladder and hypoperistalsis of the gastrointestinal tract.

Epidemiology

There is a recognized strong female predilection.

Associations

• polyhydramnios: can be present in ~25% of cases

• omphalocele

• intestinal malrotation ¹⁰

Pathology

The disorder is thought to arise from defects primarily affecting the gastrointestinal and renal tracts ¹¹. It is suggested that intestinal smooth muscle myopathy is responsible for the hypofunctioning intestine. Reduced actin level, degeneration of vacuoles and reduction in cytoskeleton protein have also been described.

Genetics

The disease carries an autosomal recessive inheritance ^2,3 with the gene locus at 15q24 ⁸ although some authors suggest a sporadic occurrence in certain cases ^ref.

Radiographic features

Fluoroscopy

On an upper GI study, features can include:

• dilated stomach and duodenum

• very poor or absent peristaltic motion

• intestinal malrotation

On a contrast enema, a microcolon is initially demonstrated. However, this is typically transient and the bowel loops may later be normal or dilated ¹⁵.

Antenatal ultrasound

Direct sonographic findings can include:

• fetal megacystis

• fetal megaureter

• fetal renal pelvic dilatation

• dilatated segments of bowel (including stomach): fetal bowel dilatation

Ancillary sonographic features include:

• presence of polyhydramnios 

• presence of normal amniotic volumes in the context of the above renal tract findings

In the context of obstructive-like renal findings, the presence of normal to elevated amniotic fluid volumes may suggest the diagnosis. 

Treatment and prognosis

The overall prognosis is considered to be poor and treatment has been shown to be generally ineffective ⁶. It is usually lethal within the first year of life ³.

History and etymology

First described by W E Berdon in 1976 ⁴.

Differential diagnosis

For antenatal hydronephrosis with hydroureter consider:

• prune belly syndrome: tends to be associated with oligohydramnios

• posterior urethral valves: also tends to be associated with oligohydramnios