Microalbuminuria: Nature, importance, significance, and limitations

SS Emara 
 Department of Surgery, Plastic Surgery Unit, Al-Hada Military Hospital, Taif, Saudi Arabia

Correspondence Address:
Dr. S S Emara
Department of Surgery, Plastic Surgery Unit, Al-Hada Military Hospital, Taif
Saudi Arabia

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The article by Bhadade and colleagues is an important article [1] elucidating the value of microalbuminuria (MAU) in the field of the care of critically ill patients. We have been investigating MAU for the last seven years in our Burn Intensive Care Unit (ICU) and we believe that it is a good tool when used appropriately. Microalbuminuria simply refers to the excretion of pathologically significant amounts of normal molecular weight albumin in the range of 30-299 mg/L. [2] In sepsis, there is a generalized capillary leak with the same effect occurring in the renal glomeruli and tubular cells., [3] This leads to leakage of significant amounts of albumin into the urine. Thus, the term MAU is misleading, and a more accurate term would be hypoalbuminuria (HAU), as it represents diminution in the amount and not the size of the protein molecule. [4]

Hypoalbuminuria is the only simple, noninvasive, bedside, immediate, and cost-effective test to indicate the occurrence of the systemic inflammatory response syndrome (SIRS) - if the other variables are stabilized. It can be measured with every urine void or even every minute, with a catheter in place. It represents a useful tool in developing countries with limited resources. [4]

Hypoalbuminuria is a consistent finding in inflammatory states, including an ischemia-reperfusion injury, pancreatitis, SIRS, sepsis, and certain metabolic syndromes. [4] Transient HAU has also been associated with surgical stress. [5] In addition, HAU is an early indicator of acute respiratory distress syndrome (ARDS), sepsis, and mortality in critical illness. [6]

Some limitations are usually confronted. On a review of the literature, we know now that that there is no accepted basis on which studies can be pursued. HAU can be affected with alcohol or drug intoxication, [2] nephrotoxic antibiotics, and body mass index. [7] It is interesting to know that the prevalence of MAU in the general population is in the range of 5 to 7%; this is according to several large cohort studies. [8] All these indicate that we need to address the issue of MAU to set appropriate protocols for its management.

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