Dependence of Symptoms on Lab Results

Although the symptoms of chronic renal failure are well known and are believed to be the consequence of chemical abnormalities of the body fluids, there have been few attempts to relate these symptoms to specific abnormalities.

In an effort to see if symptoms can be correlated with lab results, Ramesh Mazhari and I conducted a study based on the symptoms of 167 patients with chronic kidney disease (renal failure or the nephrotic syndrome). They were graded as to the severity of the disease, based on their biochemical abnormalities, and the severity of their anemia. We chose four symptoms to analyze in detail: fatigue, muscle cramps, itching, and nausea and vomiting. When we placed most of these patients on dietary treatment, in many cases symptoms improved or disappeared. In the second analysis, we documented the level of each of the lab measurements we used to determine severity of kidney failure when, during follow-up and worsening of their renal failure, these same symptoms reappeared (or appeared for the first time). Thus we obtained two estimates of how these symptoms depend on the abnormalities seen in blood tests.

We were disappointed to find that none of the abnormalities in the tests predicted the common symptoms of kidney failure. The main conclusion from this study is that common blood test indicators cannot explain the symptoms of chronic renal failure.

In a similar study in a smaller number of patients, Birgitta Klang and Naomi Clyne found that the degree to which the body fluids had become abnormally acid, as indicated by how much the level of serum bicarbonate was reduced below normal, was correlated with both leg cramps and itching. This finding is of particular interest because the bicarbonate level was 18 mM or higher in their patients, and some laboratories consider such levels to be within normal limits. (see Chapter 10.)

Another surprise in our study was that nausea and vomiting were correlated only with hematocrit level; thus anemia seemed to be the strongest determinant of nausea and vomiting. Conventional wisdom would have predicted that the severity of renal failure, measured as serum urea or creatinine, or glomerular filtration rate, would have been the principal determinant of nausea and vomiting. Klang and Clyne, by contrast, found that nausea and vomiting were correlated with the concentration of albumin in the serum.

Perhaps most surprising in both studies was that serum levels of calcium, phosphate, and iron were not correlated with any of these symptoms, even though these levels often were often abnormal.

In the next chapter we'll take a look at ways of coping with kidney failure.

part ii

How to Treat Kidney Failure

0 0

Post a comment