When your sodium is normal, but you are dehydrated.
Dehydration does cause the serum creatinine to rise and the estimated glomerular filtration rate (eGFR) will, accordingly, fall. The degree of change is generally proportional to the degree of dehydration. Severe dehydration can actually cause acute kidney injury and may lead to a need for dialysis therapy.
National Kidney Foundation.
Water, water, every where,
And all the boards did shrink;
Water, water, every where,
Nor any drop to drink.
The Rime of the Ancient Mariner (text of 1834) Samuel-Taylor-Coleridge
Within the support groups there is always talk about dehydration being a sign of crisis, or impending crisis (or pre-crisis if that’s what you prefer to call it). To decide if you are in crisis, your electrolytes are checked. The standard sign is low sodium of <135 and/or high potassium of >5.2. The problem is when you don’t fit this criteria.
I hear many times, people believe they are in crisis, they feel horrible, they feel sick, they feel dehydrated, but when they present at ED they have their bloods taken, and are told they are “normal”, they aren’t dehydrated and therefore they can’t be in crisis.
What is being tested is sodium and potassium. I don’t often hear talk about creatinine.
Yet creatinine is the better teller of dehydration. Derek has had 3 crisis since diagnosis. The first two I didn’t get the blood test results for.
The 3rd one, because it was 18 months after diagnosis, I knew Derek’s normal blood levels. I was recording them on OneNote so I had them with me wherever I was, whenever bloods were taken. So I asked the Dr what Derek’s blood results were.
She insisted they were “all fine”. I kept pushing requesting very firmly that she told me the levels. She kept saying she couldn’t remember them, but they were fine. After pushing more and explaining that I knew what his normal was, so I would like to compare them, she finally told me that one was creatinine. She remembered this number because it was high, which meant his kidney function was low.
When I pointed out that it was changed and higher than his normal level she actually argued with me that it was better than the one she compared it to. I asked the date of that one. It was compared to when he was in hospital suffering CAPS and his worst and most life threatening Adrenal Crisis, before diagnosis. She wasn’t interested.
She was a Resident, which means she was learning how to be a Dr, she was a first year resident, so some basic knowledge should still have been in her brain.
Although at that time I knew Derek’s numbers, what I didn’t know was what those numbers meant.
After some more toing and froing we finally got Derek some SoluCortef, but still no fluid because his sodium had come back in the higher end of normal. I have since learned that his potassium was just above range and higher than normal for him.
The next day when the General Medical Consultant did ward rounds, his first comment was “So, pneumonia and adrenal crisis, and you are dehydrated.”
He had looked very quickly at a vein in Derek’s neck to confirm, but he was also looking at the blood results.
After I got home I started investigating what it was, when sodium was normal, that told him Derek was dehydrated, and why drinking water hadn’t helped.
Here’s what I found out.
Why Sodium and Water may not help. A very simple explanation.
Although Sodium can be a sign of dehydration, when you are on fludrocortisone sodium can be kept within range, but it won’t stop the kidneys from functioning below par.
When creatinine is higher, and therefore eGFR is lower than YOUR normal, it is a commonly known indicator of dehydration. The lower the eGFR number the more dehydrated you are.
But why don’t sodium and fluids help?
If you are really suffering low cortisol then that same low cortisol stops your body absorbing fluids so you not only need sodium, but you need cortisol, to keep you from becoming dehydrated. This is where Blood Pressure comes in. When you are first dehydrated, your body kicks in with a lot of other system mechanisms, to keep your blood volume up, hence you don’t suffer low BP immediately. It is the dehydration that determines when your blood pressure lowers.
The reason HC works to lower your BP is because it helps your body absorb the fluids it needs to increase blood volume, and thereby reduce the other mechanisms from activating, to try and balance things out. This won’t necessarily stop the crisis, but it will help you long enough to get more help.
So if you are told you can’t be dehydrated because your sodium isn’t low, ask what your creatinine (or eGFR) is. If they don’t know, ask them to find out. If they still argue, ask them what anti-diuretic hormone does, and the effect of that when you have low cortisol. It is one of a number of the mechanisms in your body to keep your blood volume up when dehydrated.
Generally, a high serum creatinine level means that your kidneys aren’t working well. Your creatinine level may temporarily increase if you’re dehydrated, have a low blood volume, eat a large amount of meat or take certain medications. – Mayo Clinic Website.
Back to Derek
When Derek is dehydrated he slips from Stage 2 to Stage 3 CKD. We have to monitor it regularly. IF you don’t know what your normal is perhaps you should find out when you are feeling healthy. This could save you a lot of medical issues when you are sick. And check out my post on “know your own normal” because sometimes, it too can save you.
One thing I remember is when Derek was in hospital in crisis before diagnosis, after 3 days they had to stop the fluids as his body was swelling up, and wasn’t absorbing the fluids. His kidney’s were failing, his blood pressure had started going down, and fluids were not working as he was just absorbing into tissue, his blood volume was going down.
A number of people have asked why they get fluids and fee better, before they are in crisis. these people still appear to have a very small amount of cortisol production. It may be that it’s enough to help absorb the fluids. Derek has no production, so at the time his body had nothing, including aldosterone, to help.