Efficient nutrition management in marasmus has a significant impact on the outcome and prognosis. Marasmus is a severe form of malnutrition, specifically undernutrition, where a deficiency of all macronutrients (carbohydrate, fat and protein) causes severe muscle and fat wasting. 

Keep reading to learn more about the causes, the role of nutritional treatment, the management of treatment-related complications, and how to prevent this life-threatening condition.

Prevalence 

Malnutrition is a global concern, with 282 million people in 59 countries experiencing increased levels of acute hunger. According to the 2024 Global Report on Food Crises a sharp increase of almost 24 million people from the year before.¹ It’s thought that current political climates, wars, ongoing recovery from the pandemic and climate change resulting in a rising cost of living have led to increased food insecurity and people facing hunger.² There are well-researched links between poverty and childhood undernutrition,³ meaning those living in low and lower-middle-income countries are worst affected,⁴ with children under 5 facing the highest risk of death related to undernutrition.⁵

Malnutrition is an overarching term with specific conditions under its umbrella. Malnutrition, or ‘poor nutrition’, refers to an imbalance of nutrients which can cause various symptoms. There are numerous forms of malnutrition which include undernutrition (lower intake of nutrients), micro-nutrient related (inadequate intake of vitamins and minerals) overweight and obesity (excessive intake of nutrients) and diet-related non-communicable diseases (stroke, cardiovascular disease, diabetes, and some types of cancers). Without early interventions, malnutrition can affect health, growth, and development.^6,7

Malnutrition is a social, environmental and economic problem that has become the leading cause of poor health and death, with the reports from the Food Security Information Network and United Nations stressing that global collaboration is required to tackle injustices and disparity in food and health systems.^1,2

Defining undernutrition?

Undernutrition is a term often used interchangeably with malnutrition..

Malnutrition can have many causes and may be either:

Primary

Due to an inadequate intake of nutrients and calories

Secondary

• Malabsorption
• Increased nutritional requirements 
• Impaired metabolism or metabolic demands 
• Excess losses of nutrients due to diarrhoea and vomiting 

Malnutrition can progress depending on cause, risk factors and period of inadequate nutrition. Slow progression of undernutrition is seen in cases where food intake is reduced due to food access/insecurity or anorexia, and progression can occur due to metabolic disturbances seen in disease-related cachexia. 

There are numerous risk factors in development and progression, including but not limited to:

• Reduced access to food and food preparation facilities
• Food insecurity
• Disease-related malabsorption
• Poor mental health
• Alcohol and substance misuse
• Poverty
• Age
• Location
• Long-stay hospital admission⁸
• Social isolation
• Poor nutritional knowledge

As mentioned, the predominant cause is inadequate nutritional intake. This can either be when the diet is primarily deficient in energy (calories) and all nutrients or when the diet is sufficient in energy and other nutrients but severely deficient in protein. For this reason, undernutrition is now commonly termed protein-energy malnutrition (PEM)

What is PEM?

PEM can be mild, moderate, or severe depending on the progression and consequences, and categorised as either:

• Acute: short periods resulting in underweight and wasting
• Chronic: recurrent periods resulting in stunted growth and development

Chronic PEM can begin in the womb if the mother is malnourished during pregnancy.

PEM can affect people of any age, e.g. older hospitalized adults or people with anorexia, but children under 5 are most at risk because of increased calorie requirements for growth and development. Breastfed infants tend to have some protection for 6 months when solid foods are given to provide nutrients, unless the mother is malnourished herself.

Similarly, whilst it frequently affects children in lower-income countries, cases are rising in higher-income countries, particularly in areas of low socio-economic status, those with chronic diseases or hospitalized for long.⁹

There are three known sub-forms of PEM:

• Marasmus: inadequate intake of energy + protein
• Kwashiorkor: inadequate intake of protein
• Marasmic-kwashiorkor: a manifestation of both

The most extreme form is starvation, which occurs when there is a total lack of nutrients for an extended period when food is often unavailable, e.g., during a famine or when people choose to fast. Starvation can be fatal in as little as 8-12 weeks, so classic symptoms of PEM do not always have time to develop.

How is Marasmus diagnosed?

Marasmus is an acute form of malnutrition that typically occurs due to a relatively short period of insufficient nutrition. It is often easy to diagnose and differentiate from Kwashiorkor due to physical characteristics.

Oedema (fluid accumulation) in the hands, feet, face and abdomen occurs in Kwashiorkor due to protein deficiency.

In comparison, Marasmic-kwashiorkor has features of both conditions (wasting + oedema).

Physical examination and diet history help to diagnose marasmus. It includes measuring the mid-upper arm circumference and checking height for weight and head circumference. The stool blood test helps to determine the severity and complications and nutritional deficiencies. It helps to guide safe treatment.

Symptoms

If left untreated it can affect linear growth, resulting in infants experiencing altered growth and altered neurological, cognitive, and behavioural milestones.

It often presents as:

• Severely low body weight for age
• Loss of muscle mass resulting in a frail appearance with protruding bones and sunken eyes
• Fatigue, boredom, generalised weakness
• Irritability, apathy, poor attention
• Delayed developmental milestones 

Marasmus is the most common form of PEM in countries with higher rates of food insecurity, water contamination, poverty, and limited access to healthcare.

Marasmus has slightly better outcomes and prognosis compared to Kwashiorkor. It leads to severe complications due to fluid imbalance and organ failure. In addition, oedema makes it difficult to identify malnutrition early as it often masks weight loss.

Nutritional intervention and complications

Appropriate treatment depends on the type and the cause of malnutrition. Marasmus can be fatal if left untreated due to infection, dehydration, electrolyte imbalances and heart failure. Marasmus is treatable and is reversible, though long-term consequences from stunting and vitamin deficiencies may remain.

Treatment is in three steps- clinical, nutritional, and educational. It requires input from a team of doctors, nurses, dietitians, pharmacists, specialist therapists and ideally social workers if there are housing concerns.

Clinical

The clinical aim is to rehydrate, minimise infections of progression to life-threatening sepsis and avoid complications of refeeding syndrome.

Refeeding syndrome can occur if the reintroduction of food happens too quickly after starvation.¹⁰ Fluid and electrolyte shifts following aggressive nutritional treatment can cause life-threatening problems such as cardiac arrythmia, fluid in the lungs, high blood sugar, swelling of the brain and cardiac failure.

To manage refeeding syndrome effectively and safely in marasmus, nutrition must be carefully reintroduced. The preferred route is oral and in mild-moderate cases can be treated as an outpatient. In cases where people are unable to eat or there are complications such as infection, treatment in a hospital or clinic may be needed and Nutrition and fluids are given directly into the stomach by the nasogastric tube at a slow rate or intravenously if, unable to absorb nutrients.

Replacement of depleted electrolytes, and supplements must be given before feeding. Thiamine (vitamin B1) and multivitamin-mineral supplements should also be given to minimise the risk of further electrolyte imbalances whilst refeeding.

Thiamine is an essential nutrient required for the nervous system to convert energy from food and drinks into a form the body can use. Thiamine deficiency can cause brain, heart and circulatory damage. Thiamine replacement should be oral if possible unless there are concerns for Wernicke’s encephalopathy. 

Nutritional

Once acute complications are treated, nutritional rehabilitation may begin.

This stage is identified by appetite improvement, l electrolyte correction and signs of improvement in infection e.g. temperature is restored and blood tests improve. As appetite increases the nasogastric tube may be weaned and oral diet encouraged and optimised with calorie-rich foods and drinks. At this point calorie intake can be increased and physical activity reintroduced.

In children, parental bonding encourages developmental delay.¹¹ Evidence that mild cognitive impairments in adults due to malnutrition may be potentially reversed or slowed with early intervention, though current studies are focused on older adults.^12,13

Educational

As there is often a high relapse risk, educating caregivers on nutritional needs, appropriate food sources and supplementation, cooking skills, breastfeeding if needed, recognition of symptoms and how to seek medical help is of utmost importance.

Adequate food and clean water supplies, access to healthcare, public education on nutritional screening and food supplementation may help reduce the prevalence of severe malnutrition.

Summary

Marasmus is a severe form of acute malnutrition that manifests as wasting because of total energy and protein deficiency in the diet resulting in long-term growth, neurological and cognitive deficits and death if left untreated. E Treatment reverses the impact of the disease. Care and education can help reduce the risk of relapse however global strategies and collaboration are needed to reduce prevalence and effects.