Assessment of nutritional status and fluid deficits in advanced cancer.

Malnutrition and cachexia are frequent manifestations of cancer and are major contributors to morbidity and mortality. The assessment of nutrition status in cancer patients can be easily accomplished. The first step is to record a complete medical history and to perform a thorough clinical examination to uncover signs of nutritional deficiency. Simple and inexpensive tests are available to assess the body composition, such as: anthropometric measurements, skinfold thickness, arm muscle circumference and area, and weight and body mass index (BMI). Biochemical measurements are also available, such as serum albumin, transferring, and prealbumin. Fluid deficit is divided into two categories based on pathophysiology (dehydration and volume depletion) and to three subtypes based on plasma sodium concentration (hyponatremic, hypernatremic, and isotonic). Dehydration (total water deficit, especially intracellular) is always hypernatremic, while volume depletion (intravascular water and sodium deficit) is either hyponatremic, hypernatremic, or isotonic. There are no clear clinical differences among the various categories, but a delay of capillary refill, tachycardia, and orthostatic hypotension is more common with volume depletion. Careful clinical assessment and laboratory tests, especially serum sodium, are the keystones for diagnosis and effective management. Bioelectrical impedance (BEI) is an easy way to assess both nutrition status and fluid deficits in advanced cancer and should be used more often than it currently is. This article reviews the subjective and objective methods of assessing fluid deficit and nutrition in advanced cancer.