HUS: Why the Increase?
HUS: Why the Increase?
Medscape: Can you describe early management? Many primary care and emergency care providers will involve infectious disease and nephrology specialists early on; is there general agreement regarding management?
Dr. Bichu: The management of HUS is essentially supportive care. This includes managing anemia, renal failure, nutrition, and the etiology itself (especially if it is atypical HUS). Involving nephrology and infectious disease specialists early on is a good idea. Early initiation of nutritional support in some form is very important. It is generally agreed that there is no role for plasmapheresis, plasma therapy, or immunosuppression in management of HUS.
Most HUS disease episodes are associated with some level of complication, and as we know, renal failure is a part of it. We definitely recommend some high level of care; this may be observation in the hospital for a day or more to monitor for any critical complications, which should be managed in a timely manner. We have seen multiorgan failure with HUS, which is unfortunately associated with a high level of mortality.
As I mentioned earlier, avoiding antibiotics and antimotility agents both during the interval while awaiting confirmation of the etiology, and if EHEC is confirmed, is important. Good infection control while awaiting stool results is very important. If not hospitalized, these children should definitely not be in day care. Until cultures confirm or rule out an STEC infection, parents must continue to provide hydration, manage nutrition, and keep in touch with the primary care provider for follow-up.
Medscape: What is the long-term outlook for these children? Can you discuss the role of the primary care provider in ongoing monitoring of children after STEC HUS?
Dr. Bichu: The long-term outlook for HUS patients is generally favorable. Most kids needing dialysis will recover and be weaned off dialysis. Some of them may develop renal scarring and will have some degree of chronic kidney disease, in the form of decreased renal function or proteinuria. Some children may continue to need medication to manage hypertension for a long time, because high blood pressure may worsen kidney function that is already compromised. Ongoing proteinuria is not just an indicator of compromised renal function, but also a risk factor for worsening kidney function; we therefore tend to monitor that very closely as well, to ensure that kidney function improves or remains stable and does not deteriorate.
Primary care providers play a crucial role in closely monitoring for high blood pressure, proteinuria, renal failure, and nutritional status in these patients. Moreover, the period of monitoring for these signs and symptoms after HUS will vary for each child.
It is important also to recognize that HUS can recur and that the diagnosis of STEC HUS may not rule out an underlying genetic cause, which predisposes the child to HUS. With the initial episode, genetic testing for complement deregulation in children with typical STEC HUS presentation may not be indicated. Unfortunately, we do not know who among these kids will have recurrent HUS.
We are seeing more indicators that Shiga toxin itself works through complement-mediated damage to the vasculature or endothelium. So there have been suggestions that Shiga toxin could be a trigger for an underlying complement-mediated dysfunction, which could then trigger HUS. If we consider this hypothesis, there may be a chance that some percentage of these kids fall into this category and experience relapse because of complement deregulation abnormalities. In these children, Shiga toxin is the inciting event, and that could happen again in their life and produce a relapse. But it's so difficult to differentiate this episode from any other episode of HUS that occurs in a child without any abnormalities.
Managing HUS
Medscape: Can you describe early management? Many primary care and emergency care providers will involve infectious disease and nephrology specialists early on; is there general agreement regarding management?
Dr. Bichu: The management of HUS is essentially supportive care. This includes managing anemia, renal failure, nutrition, and the etiology itself (especially if it is atypical HUS). Involving nephrology and infectious disease specialists early on is a good idea. Early initiation of nutritional support in some form is very important. It is generally agreed that there is no role for plasmapheresis, plasma therapy, or immunosuppression in management of HUS.
Most HUS disease episodes are associated with some level of complication, and as we know, renal failure is a part of it. We definitely recommend some high level of care; this may be observation in the hospital for a day or more to monitor for any critical complications, which should be managed in a timely manner. We have seen multiorgan failure with HUS, which is unfortunately associated with a high level of mortality.
As I mentioned earlier, avoiding antibiotics and antimotility agents both during the interval while awaiting confirmation of the etiology, and if EHEC is confirmed, is important. Good infection control while awaiting stool results is very important. If not hospitalized, these children should definitely not be in day care. Until cultures confirm or rule out an STEC infection, parents must continue to provide hydration, manage nutrition, and keep in touch with the primary care provider for follow-up.
Medscape: What is the long-term outlook for these children? Can you discuss the role of the primary care provider in ongoing monitoring of children after STEC HUS?
Dr. Bichu: The long-term outlook for HUS patients is generally favorable. Most kids needing dialysis will recover and be weaned off dialysis. Some of them may develop renal scarring and will have some degree of chronic kidney disease, in the form of decreased renal function or proteinuria. Some children may continue to need medication to manage hypertension for a long time, because high blood pressure may worsen kidney function that is already compromised. Ongoing proteinuria is not just an indicator of compromised renal function, but also a risk factor for worsening kidney function; we therefore tend to monitor that very closely as well, to ensure that kidney function improves or remains stable and does not deteriorate.
Primary care providers play a crucial role in closely monitoring for high blood pressure, proteinuria, renal failure, and nutritional status in these patients. Moreover, the period of monitoring for these signs and symptoms after HUS will vary for each child.
It is important also to recognize that HUS can recur and that the diagnosis of STEC HUS may not rule out an underlying genetic cause, which predisposes the child to HUS. With the initial episode, genetic testing for complement deregulation in children with typical STEC HUS presentation may not be indicated. Unfortunately, we do not know who among these kids will have recurrent HUS.
We are seeing more indicators that Shiga toxin itself works through complement-mediated damage to the vasculature or endothelium. So there have been suggestions that Shiga toxin could be a trigger for an underlying complement-mediated dysfunction, which could then trigger HUS. If we consider this hypothesis, there may be a chance that some percentage of these kids fall into this category and experience relapse because of complement deregulation abnormalities. In these children, Shiga toxin is the inciting event, and that could happen again in their life and produce a relapse. But it's so difficult to differentiate this episode from any other episode of HUS that occurs in a child without any abnormalities.
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