Protein-Energy Malnutrition (PEM) is Another Term for Protein Calorie Malnutrition

December 28, 2025 •

4 min read

Globally, over 150 million children under the age of five are estimated to be affected by stunting, a major consequence of chronic undernutrition. A significant contributor to this is protein calorie malnutrition, a serious condition with several alternative names and manifestations.

Quick Summary

Protein calorie malnutrition (PCM) is also known as protein-energy malnutrition (PEM), a nutritional disorder stemming from an inadequate intake of protein and/or calories. It includes the severe forms of Kwashiorkor and Marasmus.

Key Points

Another Name: Protein-energy malnutrition (PEM) is the modern and medically preferred term for what was previously known as protein calorie malnutrition (PCM).
Primary Forms: Severe PEM manifests in two primary forms: Kwashiorkor (protein deficiency causing edema) and Marasmus (combined calorie and protein deficiency causing severe wasting).
Global Prevalence: PEM is a significant global health issue, most commonly affecting children in developing regions due to factors like poverty, poor sanitation, and infection.
Varied Causes: The condition can be caused by inadequate diet, underlying chronic illnesses, malabsorption disorders, or increased metabolic demand from infections or trauma.
Distinct Symptoms: Kwashiorkor is characterized by swelling and fluid retention, while Marasmus is defined by extreme emaciation and muscle wasting.
Careful Treatment: Nutritional rehabilitation must be implemented cautiously to prevent refeeding syndrome, a potentially life-threatening complication in severely malnourished patients.
Diagnosis Indicators: Diagnosis relies on clinical signs like BMI and physical wasting, combined with laboratory tests measuring serum albumin and electrolyte levels.
Prevention Focus: Prevention requires addressing the socioeconomic and educational factors that contribute to nutritional deficiencies, particularly among infants and young children.

What is Protein-Energy Malnutrition (PEM)?

Protein-energy malnutrition (PEM), also referred to as protein-calorie malnutrition (PCM), is a severe form of malnutrition caused by a deficiency of dietary protein and energy (calories) in varying proportions. While the two terms are often used interchangeably, PEM is the more modern and widely accepted designation. This condition encompasses a range of clinical states, from mild deficiencies to life-threatening starvation, and disproportionately affects children in resource-limited settings. It can be either primary, resulting from insufficient nutrient intake, or secondary, caused by underlying diseases or conditions that interfere with nutrient absorption or metabolism.

The Clinical Spectrum of Protein Calorie Malnutrition

Depending on the specific combination and severity of protein and calorie deficiency, PEM can manifest in several distinct ways. The two most classic and severe presentations are Kwashiorkor and Marasmus. A combined form, Marasmic-Kwashiorkor, also exists.

Kwashiorkor: This type is primarily a result of severe protein deficiency, often occurring when a child is weaned from protein-rich breast milk and given a diet high in carbohydrates but low in protein. A key feature of Kwashiorkor is edema, or fluid retention, which can mask the true extent of wasting and lead to a distended abdomen. Other symptoms include hair discoloration, skin lesions, and apathy.
Marasmus: Marasmus is caused by a severe deficiency of both total calories and protein. It most commonly affects infants and young children and is characterized by extreme emaciation and muscle wasting. Unlike Kwashiorkor, edema is not present in Marasmus, and the child appears visibly skeletal with loose, wrinkled skin.
Marasmic-Kwashiorkor: This is the most severe form of PEM, where the patient exhibits features of both Marasmus and Kwashiorkor, including significant wasting alongside edema.

Kwashiorkor vs. Marasmus Comparison


Feature	Kwashiorkor	Marasmus
Primary Deficiency	Severe protein deficiency with relatively adequate calorie intake.	Severe deficiency of both calories and protein.
Appearance	Swollen abdomen and limbs due to edema (fluid retention).	Extremely emaciated, with severe muscle wasting and loss of subcutaneous fat.
Fluid Retention	Present and prominent.	Absent, leading to a thin, skeletal appearance.
Skin & Hair	Dry, peeling skin; sparse, discolored, or brittle hair.	Dry, loose, and wrinkled skin; hair is sparse and dry.
Key Characteristic	Edema often masks the muscle wasting.	Severe wasting gives a "skin and bones" appearance.
Appetite	Often poor or lacking.	Variable; may be hungry initially.
Age of Onset	Typically appears after weaning, around 1 to 4 years of age.	Often seen in infants under 1 year of age.

Causes and Risk Factors

The causes of PEM are multi-faceted, involving a combination of socioeconomic, environmental, and health-related factors.

Inadequate Dietary Intake: The most common cause worldwide is a lack of sufficient food, particularly protein and calorie-rich foods, often due to poverty, famine, or poor weaning practices.
Medical Conditions: Various diseases can lead to secondary PEM by impairing nutrient absorption, increasing metabolic requirements, or decreasing appetite. Examples include chronic renal failure, HIV infection, cancer, and gastrointestinal issues like diarrhea.
Increased Metabolic Demand: Conditions such as severe infections, burns, or trauma can significantly increase the body's need for calories and protein, leading to malnutrition if not met.
Social and Behavioral Factors: Issues such as eating disorders, alcohol use disorder, abuse, neglect, or even fad diets can contribute to PEM in both children and adults. The elderly are also at risk due to reduced appetite and absorption with age.

Diagnosis and Management

Diagnosing PEM involves a comprehensive assessment that goes beyond simple observation. Healthcare providers perform a physical exam, take a dietary history, and order laboratory tests.

Physical Examination: This includes anthropometric measurements, such as height, weight, mid-upper arm circumference, and calculating Body Mass Index (BMI). Obvious signs of wasting, edema, skin changes, and hair changes are also noted.
Laboratory Tests: Blood tests measure levels of serum albumin and other markers to determine the severity and type of malnutrition. Electrolyte levels are also checked, as imbalances are common complications.

Treatment for PEM requires a careful, multi-step approach, especially in severe cases, to prevent refeeding syndrome, a potentially fatal complication. The World Health Organization (WHO) outlines a phased treatment plan.

Stabilization: The initial phase focuses on addressing immediate threats, such as hypoglycemia, hypothermia, dehydration, and infections. Fluid and electrolyte imbalances are carefully corrected.
Rehabilitation: Once stable, the patient is gradually fed a high-calorie, high-protein diet to promote weight gain and catch-up growth. This can involve specialized formulas, oral nutritional supplements, or feeding tubes in severe cases.
Follow-Up: Long-term recovery involves addressing the root cause of the malnutrition and providing ongoing nutritional counseling and support.

For more detailed clinical guidelines, information is available from reputable sources like the MSD Manuals.

Conclusion

While the term "protein calorie malnutrition" was once common, the current clinical standard is "protein-energy malnutrition" (PEM). Understanding this condition involves recognizing its various forms, namely Kwashiorkor and Marasmus, and the critical differences between them. With complex causes ranging from socioeconomic disparities to underlying medical issues, proper diagnosis and a cautious, multi-phase treatment plan are essential for recovery. The long-term prevention of PEM requires systemic changes that address food insecurity, improve access to healthcare, and provide nutritional education to vulnerable populations worldwide.

Key Takeaways: PEM is the correct term, and its two main forms present with distinct physical symptoms related to specific deficiencies.

Frequently Asked Questions

Protein energy malnutrition (PEM) is the current and broader term for what was previously known as protein calorie malnutrition (PCM). Both refer to a deficiency of protein and/or energy (calories), but PEM is the medically accepted terminology.

The two main types are Kwashiorkor, which results from severe protein deficiency and causes edema, and Marasmus, which stems from a severe deficiency of both calories and protein and causes extreme wasting.

Kwashiorkor is primarily caused by a severe dietary protein deficiency. It often occurs in children who are abruptly weaned from protein-rich breast milk and put on a carbohydrate-heavy diet lacking sufficient protein.

An individual with Marasmus appears extremely thin and emaciated due to severe muscle wasting and the loss of subcutaneous fat. Their skin may look loose and wrinkled, and their ribs and facial bones are often prominent.

Yes, while most common in children, PEM can also affect adults, particularly the elderly, those with chronic diseases like cancer or renal failure, or conditions that impair nutrient absorption.

Diagnosis is based on a combination of clinical signs, dietary history, physical examination (including measuring height, weight, and BMI), and laboratory tests to check for low serum albumin levels and other deficiencies.

Refeeding syndrome is a potentially fatal metabolic disturbance involving fluid and electrolyte shifts that can occur in severely malnourished patients during nutritional rehabilitation. It requires careful, medically supervised management.

Treatment involves a phased approach, starting with stabilizing the patient by correcting fluid and electrolyte imbalances and treating infections. This is followed by a gradual increase in nutritional intake to achieve catch-up growth and weight gain.