Protein Energy Malnutrition: Types & related Diseases
Protein Energy Malnutrition
Protein Energy Malnutrition (PEM) describes a spectrum of clinical conditions with varying feature and biochemical findings. At one end is Marasmus (protein-calorie malnutrition), a syndrome related chronic dietary restriction of energy, protein and other nutrients.
Marasmus is associated with diseases such as anorexia nervosa, GI cancer, chronic illness, and old age.
Marasmic patients often appricachectic as a result of a slow, progressive loss from adipose and muscle tissue.
At the other end, Kwashiorkor (protein energy malnutrition) develops as a result of a prolonged deficit dietary protein intake accompanied by adequate energy intake.
Dietary intake is primarily in the form of carbohydrates. Kwashiorkor is associated with fad diets, partial obstruction of the upper GI tract, and prolonged use of protein-free dextrose intravenous solutions.
Patient presenting with protein energey malnutrition may not appear malnourished and may actually be obese. Kwashiorkor may be overlooked unless a careful assessment of laboratory data is made.
Table-1 provides generally accepted findings that differentiate these two basic types of malnutrition.
Between these two extremes are many mixed disorders, which have features characteristic of both Marasmus and Kwashiorkor.
A mixed disorder represents a transition of degrees of protein and energy deficiencies in addition to depletion of electrolytes, minerals, and vitamins.
It is the result of a stressful event being superimposed upon chronic undernutrition and necessitates aggressive nutritional support.
Thus, PEM is a complex pathologic process that requires a comprehensive approach to accurately assess nutritional status and plan for nutritional intervention.
Assessment of nutritional status includes a comprehensive appraisal of medical, dietary, and medication histories, patient appearance upon physical examination, pertinent laboratory indices, and anthropometric measures of body composition.
Evaluation and correlation of these parameters will substantiate PEM, with early indications of patients at nutritional risk including:
- patients with histories of alcoholism and chronic diseases,
- patients experiencing >= 10% weight loss from premorbid weight, and
- patients who are NPO (nothing by mouth) or receiving standard intravenous fluids for 5 or more days.
Anthropometric measurements such as triceps skinfold and midarm muscle circumference related subcutaneous fat stores and lean body mass to known standards for healthy individuals of comparable sex and age.
Laboratory indices such as serum albumin and transferrin, in conjunction with determinations of nitrogen balance comparing nitrogen intake to urine urea nitrogen excretion serve as biochemical markers of nutritional status and metabolic expenditure.
Screening patients for drug-induced taste disorders and drug-induced nutrient deficiencies will complete the assessment profile.
A thorough nutritional assessment will provide a foundation from which to plan nutrition support and evaluate the need for a more aggressive approach.
Peoples who need nutritional support
Aggressive nutritional support is utilized in patients when normal dietary intake is not possible.
Nutritional therapy via either enteral or the parenteral route may be indicated in the following situation:
- Patients who cannot eat
- Patients who will not eat
- Patients who should not eat
- Patients who cannot eat enough
In general, nutrition support is provided by enteral means (oral, feeding tube) when GI function is intact and use of this route is not contraindicated.
When adequate nourishment cannot be provided by the enteral route, consideration is given to the TPN (total parenteral therapy) therapy.
Enteral nutrition (EN) with feeding tubes can be utilized for nutritional support when adequate oral nutrient intake is not achievable but the gastrointestinal (GI) tract is functional.
Total parenteral nutrition (TPN) is indicated only when adequate nutritional intake cannot be provided by the GI tract.
Patients suffering from GI disease or injury, those requiring complete bowel rest, and patients who refuse enteral support are potential candidates for TPN therapy.
Some of the diseases or conditions when EN and TPN therapy may be indicated are given below:
Diseases Related to Enteral and Parenteral Nutrition :
- GI cancer (P)
- Gastric outlet obstruction (P)
- Enterocutaneous fistulas (P)
- Short bowel syndrome (P)
- Inflammatory bowel disease (P)
- Acute or chronic pancreatitis (P)
- Bowel obstruction (P)
- Radiation Enteritis (P)
Increased nutritional demand
- Thermal Burns (EP)
- Sepsis (EP)
- Trauma (EP)
- Anorexia nervosa (EP)
- Renal Failure (EP)
- Hepatic failure (EP)
- Cardiac cachexia (EP)
- Cancer (EP)
- Prolonged unconsciousness (E)
- Ventilation (EP)
- Preterm infant (EP)
[ Note: P = parenteral, E = enteral, EP = both or either]
Constituents of nutritional solutions
To maintain energy balance and tissue synthesis, a human being requires adequate sources of protein, carbohydrates, fats, electrolytes, vitamins, minerals, and water.
Components of EN and TPN solutions are listed in the following, which reflect commercially available sources of the required nutrients.
Factors considering during Nutritional Support
|Energy||Dextrose; sucrose*; maltose*; glucose polymers*; fat emulsions|
|Nitrogen||Crystalline amino acids; protein hydrolysate*; intact proteins*|
|Electrolytes||Salts of sodium, potassium, magnesium, calcium, chloride, phosphate, acetate|
|Vitamins||Fat-soluble (A, D, E, K) and water soluble (B1, B2, B6, B12, C, nicotinic acid, pantothenic acid, biotin, folic acid)|
|Trace minerals||Commercially available or extemporaneous preparations, including iron, zinc, copper, manganese, chromium, iodide, selenium|
|Water||Sterile water for injection (USP); tap water*; sterile water for irrigation*|
|Table-1||*used in EN formulas only|
Energy Provision during Nutritional Support
The provision of sufficient energy is critical to the success of EN and TPN therapy.
Generally, carbohydrates are the main energy sources and glucose is the most commonly used energy substrate for TPN. But fat is a concentrated caloric source providing 9 kcal/gm.
Nitrogen in Nutritional Solutions
Nitrogen is an essential component of every tissue and organ system. One gram of nitrogen is contained in each 6.25 gm of protein or amino acids.
A 70-kg adult will require between 9 and 17 gm of nitrogen per 24 hrs. The actual protein requirements will depend upon factors such as age, degree of stress, and organ function.
It is generally believed that adult patients with normal renal and hepatic function require 12-16% of the total administered calories in the form of protein (protein supplies approximately 3 kcal/gm).
Electrolyte Considerations during EN and TPN
Electrolytes must be administered concurrently to patients receiving nutritional support in order to supply daily-metabolic needs and correct any deficit.
Electrolyte requirements are based upon the patient’s cardiovascular, renal, hepatic, and fluid status.
Vitamins & Trace Minerals
Vitamins & Trace Minerals are normally obtained from food or EN products; however, in patients who are dependent on TPN, the enteric source for vitamins is not available.
Consequently, parenteral vitamin supplementation during TPN is necessary.
Role of a Pharmacist
Nutritional support with enteral and parenteral nutrition affords tremendous opportunities for clinical pharmacy involvement.
The pharmacist may participate in establishing nutritional needs, formula design, and compounding, and assist in the delivery and monitoring of the therapy.
Additionally, the clinical pharmacist’s knowledge of drug therapy can be invaluable when the complex interrelationships between drugs and nutritional therapy are evaluated.
With an ever-increasing number of hospitalized patients receiving EN and TPN therapy, the opportunities for pharmacy involvement are almost unlimited.