When You Think It’s the Shunt Causing a Problem, What’s the Most Cost-Effective Way to Know That? :

When a child with an intracranial shunt comes into the ED more irritable than normal, one cannot help but worry if the shunt has become blocked or disconnected. So how do you know? What is the best way to diagnose an intracranial shunt problem?  Pershad et al. (10.1542/peds.2016-4263) decided to compare the cost-effectiveness of several imaging modalities including CT scan, fast sequence MRI and ultrasound of optic nerve sheath diameter.  The authors share the results of four diagnostic imaging strategies, including CT alone, MRI alone, ultrasound first followed by CT or ultrasound first followed by MRI. All models were preceded by a plan shunt series and the short and long-term costs of radiation–induced malignancy up the road were factored into their model.  The results of this modelling study suggest that if a plain film series is inconclusive, an ultrasound measurement of optic nerve sheath diameter is the best way to go and if that suggests a problem or if the shunt series suggests a concern, then fast sequence MRI is the preferred most cost effective imaging test rather than CT.  Is this sequence what you or your pediatric neurosurgeon uses to screen for a shunt problem in your patients?  Will it be what you do going forward after reading this study?  We won’t apply pressure and force you to read this study, but you will be heads up above your colleagues and be of great help to families of patients who do have intracranial shunts if you do review the information on cost-effective imaging so you have a sound approach the next time this problem occurs.