Widespread haemorrhages in infants post-shunting (WHIPS): clinical features, risk factors and neuroimaging characteristics of a rare and under-recognised phenomenon.

Purpose: Infants undergoing CSF shunting procedures face a rare complication which we propose to rename "Widespread Haemorrhages in Infants Post-Shunting" (WHIPS) to better capture this unique phenomenon specific to infants undergoing CSF diversion. Our objective is to analyse the risk factors for WHIPS development and provide a detailed neuroradiological description of these haemorrhages.

Materials and methods: A radiology information system (RIS) was searched using the search terms "shunt" and/or "catheter" and/or "drain" and/or "ventriculoperitoneal" and/or "VP" between September 2008 to January 2021 for patients < 12 months of age. Clinical data was compiled for each patient meeting the inclusion criteria. Included cases were reviewed by three radiologists for the presence of WHIPS with calculation of the bifrontal ratio and documenting haemorrhage number, morphology, location and lobar distribution.

Results: 51 patients met inclusion criteria, 8 WHIPS patients and 43 controls. There was a statistically significant correlation between a larger post-op head circumference and WHIPS (p = 0.04). WHIPS was associated with post-haemorrhagic hydrocephalus and post-infectious hydrocephalus (p = 0.009). WHIPS were identified in the cortico-subcortical regions, periventricular white matter, and deep white matter. Haemorrhages were either punctate, ovoid or confluent. Haemorrhages ranged from single to innumerable.

Conclusions: WHIPS represent a rare and under-recognised complication of CSF shunting unique to the infantile population. We postulate deep and superficial medullary venous haemorrhage as an underlying mechanism related to disordered intracranial hydrodynamics which are exacerbated in the infantile population due to underdeveloped arachnoid granulations and a compliant skull.