Approach
Kwashiorkor is primarily a clinical diagnosis; there is no specific diagnostic test for the condition. Edema is the defining characteristic. The history of living in chronic poverty with food insecurity should alert the clinician to this possibility. Children at highest risk are those ages 1-3 years. Availability of testing will determine which investigations can be carried out, as the condition is found predominantly in the developing world.
History
A dietary history of a monotonous single cereal-based diet with inclusion of animal-source foods less than once per week should raise suspicion of kwashiorkor. Diets based on maize, cassava, and rice are most commonly associated with kwashiorkor.
Cessation of breastfeeding in the few months before presentation is a common finding, classically due to the birth of a younger sibling. There may be a history of preceding diarrhea or measles infection. A child may complain of eye symptoms such as photophobia or eye soreness, which can be a sign of xerophthalmia. Poor social and economic conditions may contribute to food insecurity and the development of kwashiorkor.
Kwashiorkor edema starts in the feet and develops over a few days. If untreated, it either progresses to increasing edema with clinical deterioration or, if mild, may resolve without treatment.
Refusing to eat when spoon-fed and general lethargy are often connected to concomitant infection or maternal deprivation.[Figure caption and citation for the preceding image starts]: Nigerian civil war refugee showing manifestations (swollen feet, thin and shiny skin over knees) of kwashiorkor.From CDC Public Health Image Library/ Dr Lyle Conrad, 1968 [Citation ends].
Anthropometry
Accurate measurements, using correct age- and sex-specific growth charts, are mandatory to make a correct diagnosis. Care must be taken to plot the height and weight based on the child's actual chronological age. Children who are >2 years old and >85 cm tall and who are able to stand can have their height measured. Otherwise, length can be measured. Premature infants should have their growth plotted on charts designed to account for their gestational age (i.e., until 24 months for weight, 40 months for length, and 18 months for head circumference). Measurements of weight, height (or length), and mid-upper arm circumference (MUAC) can be used to determine the severity of malnutrition and confirm the diagnosis of kwashiorkor. The following classifications are useful:
World Health Organization (WHO) classification of malnutrition in children 6-59 months of age[1]
Moderate malnutrition
No symmetric edema
A weight for height z-score between -2 and -3 or MUAC of 11.5 cm to 12.4 cm defines moderate wasting (also called moderate acute malnutrition)
Height for age z-score between -2 and -3 defines moderate stunting.
Severe malnutrition (includes kwashiorkor, a form of severe acute malnutrition)
Symmetric edema defines kwashiorkor, regardless of other anthropometric parameters
A weight for height z-score of <-3 or MUAC <11.5 cm defines severe wasting (also known as marasmus, a form of severe acute malnutrition)
Height for age z-score of <-3 defines severe stunting.
The standard deviation score (or z-score) is defined as the deviation of the value from the median of the reference population, divided by the standard deviation of the reference population.[2]
Exam
The aim of examination is to determine the severity and presence of associated complications. It is also important to exclude alternative causes for edema.
Edema associated with kwashiorkor is bilateral, pitting, and dependent. Predominant facial edema suggests nephropathy. Ascites is not a typical feature of kwashiorkor. Edema is tested by applying pressure for 3 seconds, causing persistent visible indentation of the skin. Edema is graded + if confined to the foot and lower anterior shin; ++ if also extending to the hands or lower arms; and +++ if generalized to include feet, hands, arms, and face.
Temperature should be assessed when resources exist. Hypothermia in children with kwashiorkor is not uncommon. A fever may be present with concurrent infection. Common sources include gastrointestinal, chest, and urinary sepsis. However, malnourished children may not display fever in the presence of infection.
The level of hydration should be recorded. Dehydration is overestimated and over-diagnosed in malnourished children. However, in severe cases, the pulse rate may be rapid with a poor urine output; the child may be thirsty and lethargic, with a skin pinch slow to return, absent tears, and dry eyes and mouth.
Mental status should be assessed and recorded. The child may be irritable, lethargic, drowsy, or have a decreased level of consciousness and thus initially require facility-based care. The child's appetite for therapeutic foods must be assessed.
Dermatosis is classically seen as areas of hyperpigmentation, beginning as spots that become hard and scaly and then fuse, followed by desquamation and cracking of the skin. It may also present as dry, thin, shiny, or wrinkled skin because of atrophy of the basal layers of the epidermis with hyperkeratosis. Ulcerations may appear in the genital and perianal regions, in body creases, and on exposed surfaces.
Infection is common in malnourished children presenting with kwashiorkor, and there may be signs of gastrointestinal, respiratory, or urinary sepsis with fever.[40] White plaques of candida are commonly seen on the tongue or hard palate, particularly with underlying HIV infection. Even without specific signs of infection, all children with kwashiorkor should be treated empirically for bacterial infection, and strong consideration be given to other infections such as malaria.
Hair may be thin and sparse, and easily falls out. Black hair may lose pigmentation to become orange or reddish-brown, and features of anemia may be present, such as pale conjunctiva and pale mucous membranes.
Xerophthalmia can result in dry eyes with thickened conjunctiva and ultimately corneal ulceration and blindness if left untreated.
Some physical signs are suggestive of an alternate cause for edema, such as the presence of jaundice that may be because of liver failure or a hemolytic anemia. Auscultation of the heart may identify a gallop rhythm because of heart failure or a cardiac murmur with valve pathology.[41] Lymphadenopathy may also suggest an alternative or underlying cause, such as lymphoma, tuberculosis, or Kaposi sarcoma associated with HIV.
Diagnostic workup
Kwashiorkor is a clinical diagnosis and specific investigations are generally unnecessary for the vast majority of children. Investigations are limited by local resources, as kwashiorkor is predominantly a disease of the developing world, and are only required to look for underlying coexisting conditions such as infection, HIV, or tuberculosis (TB), to exclude other differentials of edema and to assess complications.
Hemoglobin level and packed cell volume: malnourished children often have a low hemoglobin, typically 8-10 g/dL or less, but severe anemia can also be responsible for edema without kwashiorkor.
Blood glucose to diagnose hypoglycemia: this is defined as a blood glucose <3 mmol/L (<54 mg/dL).
Serum electrolytes may be variably abnormal. There is a profound reduction in whole body potassium to ≤35 mmol/kg (44 mmol/kg is normal).[42] This corresponds to the loss of intracellular potassium. Management should be based on predicted whole-body electrolyte status rather than blood results as profound, life-threatening hypokalemia and hypophosphatemia may occur with refeeding in severe cases. Although hyponatremia occurs, total body sodium is elevated.[43]
Serum protein and albumin are usually normal or low in kwashiorkor. The presence of very low serum protein and albumin suggests an alternative diagnosis such as nephritis, protein-losing enteropathy, or burns. If the serum protein is elevated, HIV infection should be considered.
Chest x-ray (CXR) and TB skin testing if underlying TB is suspected. CXR may show upper zone cavitation and lymphadenopathy. Pneumonia is less obvious on CXR in malnourished children. TB skin testing may be unreliable in endemic areas; if resources are available, specific testing for TB such as cultures or polymerase chain reaction (PCR)-based testing can be considered.
Blood and urine cultures if sepsis is suspected; results may help tailor antibiotic therapy.
Stool cultures may identify gastrointestinal pathogens if diarrhea is a predominant feature.
Malaria screen is not always required but useful in endemic areas or in the presence of severe anemia.
HIV should be suspected in HIV-prevalent areas and when kwashiorkor presents outside the normal age range (e.g., in babies still breastfeeding or in children over 5 years), but testing is advised only after discussion and counseling with family members. In general, all malnourished children should be tested for HIV in endemic areas where resources permit and it is feasible.
Urine dipstick to assess for proteinuria, hematuria, and nephrotic syndrome or nephritis as a cause of edema.
Echocardiography is not routine, but where it is available, small pericardial effusions can help differentiate kwashiorkor from cardiac causes of edema if there is diagnostic uncertainty.
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