Protein-calorie malnutrition: Clinical sciences

Protein-calorie malnutrition occurs when someone loses weight, due to inadequate protein and calorie intake. Diagnosis and management of protein-calorie malnutrition are crucial, particularly in the elderly, as it is associated with poor outcomes.

The most common causes of protein-calorie malnutrition are chronic conditions, oropharyngeal conditions, gastrointestinal malabsorption, anorexia nervosa, as well as social functional barriers.

When a patient presents with chief concerns suggesting protein-calorie malnutrition, the first step is to perform a focused history and physical exam. The most important history findings typically include reduced food intake, weight loss, weakness, and fatigue.

Your patient may also have a background of chronic diseases, such as chronic kidney disease, COPD, congestive heart failure, or malignancy.

Their physical examination will show thin, dry skin; hair thinning or loss; temporal wasting; muscle atrophy, and generalized muscle weakness.

Additionally, there might be peripheral edema due to a decrease in serum albumin and a subsequent drop in oncotic pressure. If your patient presents with these symptoms and signs, you should suspect protein-calorie malnutrition.

Your next step is to obtain the patient’s weight to calculate their Body Mass Index or BMI. If the patient’s unable to stand on the scale, such as patients using a wheelchair, you should estimate the patient’s muscle mass by measuring the circumference of your patient’s upper arm.

Now, here’s a high-yield fact to keep in mind! Mean upper arm circumference, or MUAC for short, is measured at the patient’s left upper arm. You can use it to track the patient’s muscle mass loss or gain, just as you can use their weight to follow their weight loss or gain. An upper arm circumference of less than 22 cm for women and less than 23 cm for men suggests malnutrition.

Okay, your next step is to assess if your patient meets the diagnostic criteria for protein-calorie malnutrition. One handy tool you can use is the Global Leadership Initiative on Malnutrition, or GLIM, which is a screening survey used in primary care to identify patients who are at risk of malnutrition.

The GLIM criteria are grouped into two main categories called phenotypic and etiologic criteria. Phenotypic criteria include unintentional weight loss greater than 5 percent within the past 6 months, or greater than 10 percent beyond 6 months; a BMI of less than 20, if your patient is less than 70 years old, or less than 22 if your patient is greater than 70 years old; and evidence of reduced muscle mass.

On the flip side, etiologic criteria include reduced food intake for more than 2 weeks; having a condition that reduces caloric absorption; or having a chronic illness that causes chronic or recurrent inflammation, like chronic kidney disease, COPD, congestive heart failure, and malignancy.

If your patient meets no phenotypic and etiologic criteria, the GLIM criteria for malnutrition are not met, so you should consider alternative diagnoses. On the other hand, if your patient has one or more phenotypic criteria, and one or more etiologic criteria, you can diagnose protein-calorie malnutrition.

Once you diagnose protein-calorie malnutrition, you should assess the underlying cause. Underlying causes include; chronic disease, oropharyngeal condition, gastrointestinal malabsorption, anorexia nervosa, and social or functional barriers.

Let's start with chronic diseases. If your patient has a history of known chronic illness, such as advanced dementia, malignancy, autoimmune disease, COPD, chronic kidney disease, or AIDS, diagnose your patient with protein-calorie malnutrition due to an underlying chronic disease.

In such cases, treatment includes optimizing the management of the underlying disease, adding dietary supplementation such as whey powder or high protein drinks, and loosening any dietary restrictions that might be inhibiting adequate caloric intake.