A moderate normochromic or slightly hypochromic anemia is usually present, with normal red blood cell size.  Iron and folate deficiencies, intestinal parasites, malaria, and other chronic infections exacerbate the anemia.  However, iron stores are present in the liver.

Immune system

• Immune impairment and infections are usually associated with marasmus.  Thymus atrophy is a characteristic manifestation of marasmus, but all T lymphocyte-producing tissues are affected.  However, B-lymphocyte tissues, such as Peyeri plaques, the spleen and the tonsils, are relatively preserved.  Cellular immunity is most affected, with a characteristic tuberculin anergy.  However, antibody production is maintained.  In marasmus, a general acquired immunodeficiency occurs, with a decrease in secretory immunoglobulin A and an impairment of the nonspecific local defense system such as mucosal integrity and lymphokine productions.

Brain and nervous system

• Cerebral tissue is usually preserved during marasmus.  Brain atrophy with impairment of cerebral functions is only present in severe forms of marasmus.   Effects on the brain are more important if malnutrition takes place during the first year of life or during fetal life.  The permanent developmental consequences of marasmus are difficult to evaluate, but several ongoing studies are evaluating these long-term consequences as well as the benefit of nutritional supplementation with various vitamins and minerals

Cardiovascular system

• Cardiac muscle fiber is thin, and the contractility of the myofibrils is impaired.  Cardiac output is decreased in the same proportion as the weight loss.