Investigations
1st investigations to order
clinical diagnosis
Test
Kwashiorkor is primarily a clinical diagnosis; there is no specific diagnostic test for the condition. Specific investigations are generally unnecessary for the vast majority of children and are only required to look for underlying co-existing conditions, to exclude other differentials of oedema, and to assess complications.
Result
clinical features of kwashiorkor
Investigations to consider
urine dipstick
Test
This is used to exclude common differentials of oedema; nephrotic syndrome and glomerulonephritis (GN).
Result
no proteinuria or haematuria
full blood count (FBC)
Test
Malnourished children often have a low haemoglobin (Hb), typically 80-100 g/L (8-10 g/dL) or less, but severe anaemia can also be responsible for oedema without kwashiorkor. A Hb of <50 g/L (5 g/dL) is indicative of severe anaemia.
Result
variable; may have anaemia
serum electrolytes
Test
Serum electrolytes may be variably abnormal. There is a profound reduction in whole body potassium to ≤35 mmol/kg (44 mmol/kg is normal). 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 hypokalaemia, and hypophosphataemia may occur with re-feeding in severe cases. Although hyponatraemia occurs, total body sodium is elevated.[43]
Result
variable; may have hypokalaemia, hyponatraemia, or hypophosphataemia
serum protein
Test
Usually normal or low. If the serum protein is raised, HIV infection should be considered.
If serum protein is very low, consider a diagnosis of nephritis, protein-losing enteropathy, or burns.
Result
normal or low
serum albumin
Test
Usually low in kwashiorkor, but a normal result does not preclude the diagnosis. If markedly low, an alternative diagnosis should be considered. Management is through feeding, not replacement.
If serum protein is very low, consider a diagnosis of nephritis, protein-losing enteropathy, or burns.
Result
low or normal
blood glucose
Test
Hypoglycaemia should be corrected and re-checked with commencement of regular feeding as soon as possible.
Result
<3 mmol/L (54 mg/dL) with hypoglycaemia
chest x-ray (CXR)
Test
Tuberculosis (TB) may co-exist with kwashiorkor.
Pneumonia is less obvious on CXR in malnourished children.
Result
may show upper zone cavitation and lymphadenopathy with concurrent TB infection
urine culture
Test
A common source of intercurrent infection.
Result
positive with urine infection
blood culture
Test
Concurrent infection is common in patients with kwashiorkor.
Results may help tailor antibiotic therapy.
Result
positive growth with bacteraemia
stool culture
Test
May identify gastrointestinal (GI) pathogens if diarrhoea is a predominant feature.
Positive growth may identify specific pathogens such as Giardia cysts.
Result
positive with GI infection
tuberculosis (TB) skin testing
Test
This provides evidence of TB exposure. A positive test is determined by the size of the skin reaction, but interpretation of a positive result depends on what other risk factors for TB are present.
TB skin testing may be unreliable in endemic areas; if resources are available, specific testing for TB such as cultures or polymerase chain reaction-based testing can be considered.
Result
positive result indicates TB exposure
HIV serology/polymerase chain reaction (PCR)
Test
More likely when 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 old). Needs careful consideration and counselling with family members.
In general, all malnourished children should be tested for HIV in endemic areas where resources permit and testing is feasible.
Result
positive with underlying HIV infection
malaria screen
Test
Malaria screen is not always required, but is useful in endemic areas or in the presence of severe anaemia. This may predispose to kwashiorkor.
Result
positive with concurrent malarial infection
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