New onset weakness in the face and arm

Dear editor,

I enjoyed reading the case presentation by Brites et al., 2020 titled "new onset weakness in the face and arm". The good outcome with immunosuppression supports the diagnosis of systemic lupus erythematous (SLE) with central nervous system vasculitis. However, as a newly qualified F1 doctor, I was unclear why the alternative differential of anti-phospholipid syndrome was not considered more seriously.

The comment "no...history of thrombotic events or obstetric complications" suggests there was no previous history of anti-phospholipid syndrome, acknowledging it as a consideration, but it does not exclude a possible new diagnosis. Furthermore, there are some investigation findings that support it as a very plausible possible alternative.

Namely, the normal (non-inflammatory) CSF analysis [benign, protein free] and normal serum complement (you would expect reduced C3/C4 due to immune complex formation in active SLE) . Furthermore, it can be difficult to reliably distinguish between inflammatory changes and thrombus on cerebral imaging. And finally, the treatment would differ greatly, anticoagulation as opposed to steroid/immunosuppression treatment.

In support of this, Goswami et al., 2013 present the typical CSF findings in SLE with cerebral involvement and discuss the diagnostic conundrums of cerebral imaging in an article titled "two case reports indicating the dilemma in diagnosing lupus cerebritis".

It is pleasing to read the positive outcome but ... could there be an argument for using both treatment approaches initially in difficult cases such as this?

Again, many thanks for the thought provoking case!