Claude and Arturo, thankyou.
I will gladly expand, as it is perplexing.
I have been having fortnightly IVIG for the past 4 years. There have been times that I have extended the interval to 19 days, without incident. At all times, I have checked my 'trough' level of serum IgG, and the lowest it has been is 20g/l. So, I was led to believe that as long as I received my standard IVIG dose within 19 days, I would be safe.
However, this October, I took a small break, and on day 16 after my standard dose, I came down with the attack described. (More later). The only difference was that, in those 16 days, I also received antibiotics and steroids for a chest infection. I was taken to a small rural health centre where my IgG level was 18g/l, whereas 16 days prior it was 24g/l. So issue #1 is, why did my IgG level drop suddenly?, and what (if known) is a safe level? I have always believed in the assumption that anything over 12-14g/l was safe, and certainly over 16g/l would be ok. Thus I search for an answer. Now we know that steroids drop the serum level of IgG,over time, but is this significant? i am not convinced. Issue #2 is, "What is the role in the use of steroids during an acute episode? ". I have always taken 50mg prednisolone while waiting for the ambulance, but feel silly doing so as it doesn't act in a short time period, and it's action may well be adverse. I will continue to take the steroids while waiting for the ambulance though.
The third issue relates to the episode itself. What has become apparent over time is that the presenting symptoms vary so much. Some will present with oedema, while others shock etc. My first episode started with myalgia, but rapidly progressed to shortness of breath as the pulmonary oedema took over. With subsequent episodes, I recognised the myalgia, and called for help early. The pattern has a sudden onset and cessation. This episode woke me at 5am with muscle pain. By 5.05, I couldn't stand unaided, and we had called the ambulance. Every muscle in my body was in spasms. My masseter jaw muscles cramped, and I could only talk through my teeth. I was unable to hold my cell phone. My wife helped me to the car where I got the most relief from the heated car seats. As this was in a rural setting, the ambulance had some 120km to travel, and the delay was difficult. My oximeter was reading 85% and falling. I didn't have my sphygmomanometer with me. However when the paramedics arrived at 6.30, the attack was nearly over. I have an A6 laminated crib sheet which gives a treatment plan, names and numbers of relevant Physicians, medicare numbers, allergies etc. (I carry this everywhere on my smart phone). The obverse also details what investigations and blood tests need to be ordered. Essentially, I get an IV line with minimal crystalloids. (This time was 1l over 5 hrs), high flow O2 or CPAP if available, pain relief, and antibiotics. By 7am the attack was over from my point of view. My breathing was normal, the pain had gone, and I was able to sit up in ED and tell them my BP, pain, and Sats had turned the corner. My wife has got used to this, but everybody else is very sceptical for the next 24 hrs! Just a side issue here is that I was a 2-3 hour flight to the next tertiary hospital, and the threat of acute pulmonary oedema demanded a pressurised cockpit! Road transport over bumpy rural roads is not on my agenda. Somehow, I feel this makes the condition worse.
Claude, you seem to be bionic! Do you fluoresce at night? I do confess that my dosage rate appears higher than many, but I loathe to try a change. It does however point to a multifactorial origin, -that there is not single cause. I have discussed with my physicians the possibility that in my case, the IVIG works through a hyperosmolar effect. I am heartened by your tolerance of the steroids.
Arturo, in all my 4 episodes, I have never had IVIG during an acute attack, as it seems to be self-limiting every time. My first attack had severe shock, pulmonary oedema, sats 65%, Hb 220, low albumin, and lasted from 6.15am to 10.45am, before I new I was coming right. At 11am, I still needed CPAP, and volume expansion for hypotension, but I could tell the episode was over.. I stay in ICU afterwards to prevent the resorption phase, and ensure renal function is OK
So, thankyou kind folk. I am reassured by the steroid situation, puzzled by the Hydra that is SCLS, and have only this to offer.... That a treatment plan worked well for me.. Either laminated or on the phone.