Infratentorial superficial siderosis (of the central nervous system)

This page aims to provide information about Infratentorial superficial siderosis (iSS) for patients living with this condition, their families, carers and physicians.

Infratentorial superficial siderosis (iSS) is a rare but sometimes disabling neurological disorder for which awareness among medical professionals is low; iSS has received very little research attention, so understanding and treatment options are limited. A dedicated multidisciplinary team at UCL are researching iSS in more depth. Additional resources related to understanding iSS and some of the research undertaken by our group can be found on our research pages.

iSS results from the leakage of blood into the fluid that bathes the brain and spinal cord (the cerebrospinal fluid, or CSF); as the blood is broken down an iron-containing compound called haemosiderin is deposited over the surfaces of the brain, spinal cord, and some nerves. On MRI, haemosiderin appears as dark areas which can be seen here over the cerebellum and brainstem (arrows).

Haemosiderin appearance as dark areas and rims over cerebellum and brainstem

iSS is a chronic disorder, meaning that it continues for a long time rather than being a sudden or acute illness; this means it often slowly progresses. iSS can involve any part of the brain or spinal cord (and sometimes nerves) so the symptoms can be varied; however, the most common ones are hearing and balance problems. There is often history of spinal or brain surgery or trauma, which is thought to be the underlying cause of bleeding into the CSF in most cases. However, not everyone who has spinal or brain surgery or trauma goes on to develop iSS, while some people can develop iSS without any such history. While further research is needed why this happens, for individuals who are diagnosed and living with iSS, there are major daily challenges.

Here, our patients share their experience of being diagnosed and living with iSS: patients' narratives