Letter to the Editor. Shunt dysfunction and constipation.

TO THE EDITOR: We appreciated the article by Morais et al.2 describing a 6-year-old shunt-treated spina bifida patient in the emergency department, presenting with mixed symptoms of shunt malfunction and abdominal pathology (Morais BA, Cardeal DD, Andrade FG, et al: Reversible ventriculoperitoneal shunt dysfunction and chronic constipation: case report. J Neurosurg Pediatr 22:147–150, August 2018). The authors demonstrate concomitant ventricular dilatation and abdominal constipation, which resolved with nonsurgical management. The discussion included the possibility that intracranial hypertension could cause bowel dysfunction. At our institution, we frequently observe the clinical phenomenon of transient shunt malfunction related to constipation. Here, we provide 3 recent cases, which expand the scope of the problem. The first case involved a 16-year-old boy with neonatal posthemorrhagic hydrocephalus, ventriculoperitoneal (VP) shunt surgery, epilepsy, and history of chronic constipation, who presented to the emergency department with refractory vomiting and headache over a 24-hour period. MRI revealed ventricular enlargement, and an abdominal radiograph showed increasing colonic burden of stool (Fig. 1). A shunt tap was performed with brisk flow, low opening pressure, and good distal runoff. The patient was hospitalized for medical management. Over the next day, his symptoms and radiographic changes remitted (Fig. 1). In our second case, a 16-year-old boy with spina bifida, cervicothoracic syrinx, and shunted hydrocephalus, the patient presented to the clinic for routine follow-up, with no symptoms of shunt malfunction. However, the patient’s mother noted very hard stools and decreased frequency of bowel movements. MRI of the brain and spine was remarkable for simultaneous increase in his ventricular size as well as caliber of his cervical syrinx (Fig. 1). Given these findings, he was scheduled for an elective shunt revision if imaging findings did not improve after outpatient bowel regimen. Follow-up imaging at 2 weeks revealed his ventricular size had returned to baseline (Fig. 1), and no surgical intervention was pursued. Our third recent case was a 13-year-old boy with history of congenital hydrocephalus that had been shunted as an infant. He presented to the clinic for annual follow-up without symptoms of shunt malfunction. Abdominal radiographs revealed increasing stool burden. MRI revealed increased ventriculomegaly (not pictured). He was started FIG. 1. The first patient’s asymptomatic baseline imaging is shown (A and D), along with evidence of ventricular enlargement and increased stool burden (B and E), with resolution after medical management of constipation (C and F). The second patient’s asymptomatic baseline imaging is also shown (G and J). Ventricular enlargement along with increased caliber of cervical syrinx was seen (H and K), that resolved with aggressive bowel regimen (I).