Duke University Medical Center, North Carolina virtual meeting

One of the impacts of the Covid-19 pandemic over the past year has been the switch of scientific conferences and medical teaching courses from in-person to virtual meetings. This course, titled “Headache: The Highs & Lows of CSF Pressure Problems”, was no different, taking place virtually over two days in March 2021.

The meeting was hosted by the radiology department at Duke University in North Carolina, USA. Duke is one of the three major centres in the USA which have a dedicated team who manage patients with cerebrospinal fluid (CSF) leaks and have published a number of the scientific articles on this condition. The speakers included neuroradiologists, neurologists, and neurosurgeons from Duke and other centres in the USA.

Whilst the meeting did cover other conditions which can cause high or low CSF pressure, the majority of the meeting was dedicated to the diagnosis and treatment of spontaneous intracranial hypotension (SIH) due to spinal CSF leak.

The first step in the pathway of a patient with SIH is the recognition that their symptoms may be caused by this condition. Dr Simy Parikh gave the first talk, which covered the clinical symptoms of SIH, of which the most common is orthostatic headache (headache which is provoked by becoming upright and relieved by lying flat).

A later talk by Dr Vincent Martin discussed the importance of considering other conditions which can cause orthostatic headache. This is particularly important as some of the investigations used in SIH such as myelography involve high doses of radiation, and risk of actually causing a CSF leak by puncturing the meninges (the protective membrane which covers the brain and spinal cord and keeps CSF in its usual place). One of the more common mimics, Postural orthostatic tachycardia syndrome (PoTS), was also covered in a separate talk by Dr Jeremy Cutsforth-Gregory, a specialist in autonomic nervous system disorders. He outlined the management of PoTS, which includes a number of lifestyle measures and sometimes medications to slow the heart rate or increase blood pressure.

A series of talks on the first day by Dr Michael Malinzak, Dr Peter Kranz, and Dr Pat Luetmer, discussed the various types of scans which are used to identify CSF leaks. This is one area which has developed significantly in the last few years. The development of new myelography techniques in particular has meant that in some patients a leak can now be seen which was not visible on the scans available a few years ago. One of the major developments in this field in the last decade has been the discovery of some patients with a CSF-venous fistula. This is not a typical “leak” of CSF, but an abnormal connection where CSF drains to a nearby vein.

An eye-opening talk by Dr Ian Carroll discussed spinal CSF leaks which are caused by medical interventions such as lumbar punctures and epidural injections. He presented a series of studies which showed that many patients with post-dural puncture headaches continue to experience disabling headaches months to

years afterwards. In a “back-of-the-envelope” calculation he estimated that there may be as many as 15000 chronic CSF leaks per year following epidurals in the USA.

The second half of the conference moved on from the diagnosis to the treatment of SIH. The most commonly used treatment of SIH is non- targeted epidural blood patching. Although most people working in this field agree that blood patching is the cornerstone to management of SIH, a talk by Dr Timothy Amrhein highlighted that there is actually a lack of high-quality evidence for the treatment of SIH with blood patches. This is one area which would benefit from a high- quality clinical trial.

Dr Linda Gray Leithe gave a talk on targeted treatment for CSF leaks with targeted blood and fibrin glue patching. This was followed by Dr Waleed Brinkijki presenting a newly developed minimally invasive treatment for CSF venous fistulas involving passing a device through the veins to close the fistula. In the second half of the first day, there were a series of talks on the advantages and disadvantages of different surgical approaches to treating CSF leaks.

There were a number of interesting discussions during the Q&A sessions throughout the course. As a neurologist in training, many of the clinical questions which have come up when seeing patients with suspected SIH in my own hospital were echoed by panel members: How to define orthostatic headache? Which patients to send for invasive imaging? How to assess response to epidural blood patches? I am positive that radiologists and neurosurgeons attending the meeting will have felt similarly about the imaging and surgical aspects of SIH.

It is clear that there is still much that we do not know about this condition, but a talk given by Dr Jill Rau towards the end of the second day highlighted a number of new publications in the last couple of years, which show that the understanding of this condition is advancing faster than at any other time in history.

It was great to hear from so many specialists who are working on CSF leaks, and attending certainly galvanised my own interest in this condition. Hopefully courses like these will spark an even wider interest among other healthcare professionals, with aims that align well with the aims of the CSF Leak Association in raising the profile of CSF leaks, increasing access to information, and facilitating research into better understanding the causes, symptoms, diagnosis and treatment of CSF leaks in the UK.

Dr Sanjay Cheema

Clinical research fellow

UCL Queen Square Institute of Neurology, London.