Hemolytic Uremic Syndrome is one of the commonest cause of acute renal failure in young children. It is characterized by triad of microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure.
Gasser first reported HUS as a fatal illness of childhood in 1955; subsequently it has been recognized as the leading cause of ARF in children in North America.
HUS mostly affects infants and children younger than 5 years of age
Two Principle types:-
- Typical/D+ve HUS - with diarrhea
- Typical/D+ve HUS - without diarrhea
D+ve HUS is usually associated with E. Coli O157:H7 (in developed countries) and Shigella dysentery type-1 (in Indian subcontinent).
Familial form has also been recognized, which may show either autosomal recessive or autosomal dominant pattern and is usually associated with Hypocomplementaemia and factor H abnormalities.
HUS may also be associated with a wide variety of conditions (i.e., Secondary HUS) such as bacterial and viral infection, malignancies, collagen vascular disease, renal transplantation and malignant hypertension.
The clinical picture of HUS usually mimic septicemia with DIC in young children.
Circulating bacterial toxin causes microvascular endothelial cell injury particularly in kidney, which further leads to platelet adhesion and activation of coagulation cascade.
Peripheral blood smear shows fragmented RBCs, tear drop and target cells along with high reticulocyte count, thrombocytopenia and neutrophilic leukocytosis.
There is no specific therapy for HUS. Management is essentially supportive and should be started as soon as possible. Early identification of the disease and etiological agent is the key factor in the outcome of HUS.
Renal support is essential. Prompt and early renal dialysis along with management of electrolyte imbalance is required if there is renal failure, to prevent grave renal sequelae. Various other recent measures have been studied in the management of HUS and found to be effective to prevent long-term renal sequelae and also for immediate survival of the patients. These measures include renal dialysis, plasma exchange, plasma phresis and plasma infusion.
Bad prognostic factor indicators are age of the child at presentation, degree and duration of leukocytosis, etiological agent, severity of GI symptoms, prolonged anuria for more than 8 day or oliguria 10-15 days or more.
