Severe childhood malnutrition

Abstract

The main forms of childhood malnutrition occur predominantly in children <5 years of age living in low-income and middle-income countries and include stunting, wasting and kwashiorkor, of which severe wasting and kwashiorkor are commonly referred to as severe acute malnutrition. Here, we use the term 'severe malnutrition' to describe these conditions to better reflect the contributions of chronic poverty, poor living conditions with pervasive deficits in sanitation and hygiene, a high prevalence of infectious diseases and environmental insults, food insecurity, poor maternal and fetal nutritional status and suboptimal nutritional intake in infancy and early childhood. Children with severe malnutrition have an increased risk of serious illness and death, primarily from acute infectious diseases. International growth standards are used for the diagnosis of severe malnutrition and provide therapeutic end points. The early detection of severe wasting and kwashiorkor and outpatient therapy for these conditions using ready-to-use therapeutic foods form the cornerstone of modern therapy, and only a small percentage of children require inpatient care. However, the normalization of physiological and metabolic functions in children with malnutrition is challenging, and children remain at high risk of relapse and death. Further research is urgently needed to improve our understanding of the pathophysiology of severe malnutrition, especially the mechanisms causing kwashiorkor, and to develop new interventions for prevention and treatment.

Figure 1. Organ system involvement in severe malnutrition.

Severe malnutrition can affect several organ systems. The functional impairments in these systems have been characterized, but the underlying mechanisms have not been fully elucidated.

Figure 2. Prevalence of wasting.

The prevalence of wasting as a percentage of the population (part a) and the number of individuals (thousands; part b). Data from the Global Targets Tracking tool, version 3 (http://www.who.int/nutrition/trackingtool/en/; May 2017).

Figure 3. Metabolic changes in severe malnutrition.

Reduced secretion of insulin contributes to a catabolic state in both kwashiorkor (part a) and severe wasting (part b). In severe wasting, the reduced secretion of insulin leads to a lipolytic and proteolytic response and the release of free fatty acids (FFAs) and amino acids into the bloodstream. FFAs are taken up by muscle tissue for oxidation. Both FFAs and amino acids are also partially taken up by the liver and are used for ATP production and the synthesis of essential proteins and glucose. In kwashiorkor, this adaptive response is disturbed, which causes a reduced release of FFAs from adipose tissue and amino acids from muscle tissue. Mitochondrial damage in the liver is associated with increased reactive oxygen species (ROS) production and reduced glutathione. Arrow thickness represents the amount of metabolites in that pathway. TGs, triglycerides.

Figure 4. Assessment of oedema.

Oedematous swelling of the lower extremities with skin changes in a child with kwashiorkor.

Figure 5. Overview of management of severe and moderate malnutrition.

The first step in the treatment of malnutrition is to determine the severity. Moderate malnutrition is typically treated with the use of supplementary foods, which are administered in addition to the child’s normal diet. Uncomplicated severe malnutrition is usually treated with ready-to-use therapeutic foods (RUTFs), which are given instead of the child’s normal diet, in addition to a course of oral antibiotics and along with other treatments, such as deworming and treatment for other non-life-threatening infections. The management of complicated severe malnutrition requires admission to an inpatient facility with adequate paediatric emergency care facilities and a nutritional rehabilitation care programme. Children with complicated malnutrition can be discharged from inpatient facilities when serious complications have resolved, and subsequently entered into outpatient management programmes. Management includes the use of therapeutic foods and antibiotics and the treatment of other infections. After the completion of treatment for severe malnutrition, children are transitioned from RUTFs to their home diet, which is a potential point of faltering. However, aside from standardized supplementary feeding, strategies to decrease this risk have not been assessed in trials.

Figure 6. Detailed management of complicated severe malnutrition.

The challenges associated with the management of children with complicated severe malnutrition require the integration of structured, high-quality paediatric care and nutritional support, which must happen in parallel and in a multidisciplinary manner. Paediatric care focuses on the identification and treatment of the most immediately life-threatening problems, as laid out in the WHO Emergency Triage and Treatment guidelines. Nutritional support focuses first on helping to restore physiological processes to a normal state and then on achieving rehabilitation. Initially, use of the ‘ABCD’ mnemonic can help focus attention on the assessment and maintenance of the airway (A) and breathing (B), circulation (C) and disability (coma, convulsion and dehydration (D)). Children with complicated severe malnutrition remain exceptionally vulnerable during treatment and can deteriorate rapidly without clear prior warning signs. Accordingly, monitoring and frequent re-evaluation are essential. When prevalent, comorbidities such as tuberculosis and HIV should be actively tested for. If community-based management of uncomplicated severe malnutrition is available, the decision to discharge children from hospital is based on their appetite and the resolution of complications rather than on anthropometric parameters, and should be decided by nutritional and clinical staff. The treatment process in hospital and after discharge should be explained to parents and caregivers, and they should know what help is available to them and what is expected of them. RUTFs, ready-to-use therapeutic foods.