Are shunt series and shunt patency studies useful in patients with shunted idiopathic intracranial hypertension in the emergency department?

• Shunt series rarely showed new shunt pathology or affected management.
• Shunt series should be used with impending visual loss or worsening papilledema.
• Risk of foregoing shunt series is related to clinical risk of having an abnormality missed.
• Shunt patency studies considered with other inconclusive diagnostic findings.

ObjectivesShunt series and shunt patency studies can be performed in the emergency department (ED) to evaluate for shunt malfunction in patients with idiopathic intracranial hypertension (IIH). Here, we examine the utility of these studies in this specific patient population.MethodsWe retrospectively reviewed the ED visits of all shunted patients diagnosed with IIH from 2003 to 2014. ED visits for symptoms not related to the patient's IIH were excluded from the study. Collected variables included demographics, symptoms, IIH diagnosis and treatment history, imaging findings, and management changes.ResultsTwenty-five (81%) patients had a total of 105 visits involving a shunt series, with four (3.9%) showing problems with the catheter. The majority of shunt series (n = 101, 96%) showed no catheter pathology. Based on results of the shunt series alone, in 3 instances, management changes in the form of shunt revision or shunt reprogramming occurred. Of the 105 visits with a shunt series, 17 (16%) resulted in a change in management as compared to 12 out of 66 (18%) visits without a shunt series (p = 0.83). Nine patients had a total of 10 visits involving a shunt patency study: five were normal, four were abnormal, and one was inconclusive. Based on findings on the shunt patency study alone, changes in management leading to shunt adjustment or revision occurred in 4 instances. Of the 10 visits with shunt patency studies, 5 resulted in a change in management as compared to 24 out of 161 visits without a shunt patency study (p = 0.014).ConclusionsShunt series detected catheter pathology only 3.9% of the time, and there was no difference in the rate of management changes between those patients who underwent a shunt series and those who did not. There was a significant difference in the rate of management changes in patients who received shunt patency studies as compared to those who did not. Shunt series may not be a useful screening tool to be used universally to diagnose shunt malfunction in IIH patients in the ED, and should be utilized when there is concern for impending visual loss. Shunt patency studies should be reserved for patients with inconclusive diagnostic imaging and clinical findings to decide whether to proceed to surgical exploration and revision.