I'm so sorry to hear the news of your recent episode and hospitalization, rnuara! Despite the scare, consider yourself extremely lucky to have suffered, yet again, no harm to your extremities or organs.
You are in the tiny minority of SCLS patients who have defied the odds, namely, you have survived this life- and limb-threatening illness for nearly a quarter of a century; you've had episodes only once every 3-4 years on average, but without ever sustaining permanent damage; and for the most part you have taken no medication to prevent the episodes, except that lately you've been taking Terbutaline and Theophylline, as per your Profile page.
So now you face a choice that many of us never had the luxury to contemplate, because we had frequent and damaging episodes which Terbutaline and Theophylline were unable to prevent -- so we HAD to go on an IVIG therapy because otherwise we were surely going to die, as many before us had died before the news of IVIG's benefits arrived.
I don't envy you. On the one hand, you can keep playing Russian Roulette, hoping that future episodes will likewise be infrequent and benign. To be brutally frank, almost all the patients I've known who went for this choice ended up dead -- sooner or later. And in a scientific article published in 2011 describing the experience of French doctors with 28 different SCLS patients over many years, they came to the same conclusion: 7 of their 8 patients who died were taking no medications prior to the episode that killed them, and the 8th had only been taking medications for just 3 weeks.
On the other hand, you can go on an IVIG therapy, which has proven highly effective in stopping all episodes over many years except in a couple of patients that we know of, both members of this community: one in Canada, see _Josephite_, and another one in France, _Bruno_, who died last year of a severe episode -- despite being on IVIG and episode-free for several years. However, receiving IVIG is inconvenient and time-consuming; some patients have had to fine-tune the dosage and the time interval between infusions; and some others have had allergic or other reactions.
Good luck to you!