Magnesium homeostasis is brought about mainly by kidneys and intestines. To a moderate extent bones also contribute to magnesium balance.
AdvertisementsThe renal reabsorption and excretion of magnesium is highly adaptable. The kidneys can eliminate excess of magnesium in the blood by increased excretion. In chronic kidney disease (CKD), with the decline of renal function the ability to regulate magnesium deteriorates.
In the initial and moderate stages of chronic kidney disease the fractional excretion of magnesium is increased to maintain its homeostasis. The increased excretion compensates for the decline in glomerular filtration rate. As the CKD progresses the increased excretion is inadequate to compensate the steadily increasing serum magnesium levels. With the creatinine clearance falling below 30 mL/min, the symptoms of hypermagnesemia set in.
Chronic kidney disease is the progressive deterioration of renal function over a period of several months. The known contributing factors of CKD are, high blood pressure, diabetes mellitus, glomerulonephritis and familial predisposition.
Initial and moderate CKD may be asymptomatic. The CKD is diagnosed by measuring creatinine clearance and serum creatine levels. High level of serum creatinine indicates decline in glomerular filtration rate. As the CKD advances the creatinine clearance declines and serum creatinine, magnesium (Mg2+), potassium (K+) and phosphate levels increase. Urinalysis will reveal red blood cells and proteins in the urine.
The increased P+, phosphate and Mg2+ and the resultant hyperkalemia, hyperphosphatemia and hypermagnesemia lead to many cascading effects causing diseases like hypocalcemia, secondary hyperparathyroidism, renal osteodystrophy, vascular calcification, metabolic acidosis, iron deficiency anemia, impaired cardiac function and atherosclerosis. The end stage chronic kidney disease, apart from causing excess Mg2+ related symptoms, causes fluid retention in the body. In certain studies, it was found that low serum levels of magnesium had lead to decline in the kidney function.