Hemolytic Uremic Syndrome: 6 Q & A's

Getting your head around this deadly syndrome

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WHAT IS HEMOLYTIC UREMIC SYNDROME (HUS) 

The word "hemolysis" implies destruction of red blood cells (which can happen for various reasons). "Uremic" pertains to kidney failure.  Hence, the term hemolytic uremic syndrome refers to an entity where destruction of red blood cells (for various reasons, which leads to them clumping together in to tiny clots) leads to blood vessels inside the kidneys' filters (glomeruli) getting clogged, and eventual kidney failure.

Here is a video that will help you understand it in a more visual form

HOW COMMON IS HEMOLYTIC UREMIC SYNDROME AND WHO IS AT RISK 

Although, all age groups can be affected, the disease is most often seen in children. Those under 5, and those with a positive family history are especially high risk.  However, it is not a very common disease. Hemolytic uremic syndrome has an overall incidence of about 2 cases per 100,000.

HOW DOES ONE DEVELOP HEMOLYTIC UREMIC SYNDROME AND WHAT CAN CAUSE IT 

Traditionally, hemolytic uremic syndrome was divided into two categories, typical, and atypical. However this classification is now being challenged since it does not necessarily divide the disease into two classes based on its pathophysiology, but rather on arbitrary parameters which might not help with treatment (a type of blood protein called "complement" is involved in both situations). The new classification systems are beyond the scope of this article.

 However, here are the common causes:

​WHAT ARE THE SIGNS/SYMPTOMS OF HEMOLYTIC UREMIC SYNDROME AND WHY IS IT A BIG DEAL

Initially, most patients will complain of non-specific symptoms like fatigue, shortness of breath, headache etc.

They might look pale. Fever and change in mental status might be present, and can progress to coma in severe cases.The urine may be dark in color because of the presence of hemoglobin. Decreased urine output or edema might be apparent. Seizures are possible in severe cases. Vomiting with bloody diarrhea may be seen in typical HUS, although you can see it in the so-called atypical HUS as well.

Since the underlying problem affects the blood vessels (where tiny blood clots cut off the blood supply to organs), problems with any organ system may be seen.

The following signs might be apparent on blood and urine tests:

HOW CAN YOU DIAGNOSE HEMOLYTIC UREMIC SYNDROME 

Diagnosis of hemolytic uremic syndrome requires a high index of suspicion where the clinical picture needs to be correlated with the information obtained from the above-mentioned blood and urine tests. If a diagnosis is in doubt, other invasive diagnostic procedures like a kidney biopsy might be necessary.

CAN YOU TREAT HEMOLYTIC UREMIC SYNDROME

Hemolytic uremic syndrome is a serious illness requiring  aggressive treatment. In the absence of timely intervention, hemolytic uremic syndrome can often have catastrophic consequences.

The underlying principal is to treat the immediate complications like bleeding, dehydration, etc in addition to basic life support measures that would be required in any critically ill patient. In parallel to that, treating the underlying cause of the hemolytic uremic syndrome is also essential. Supportive measures like dialysis might be required at least temporarily until the kidneys recover.

Lately, a new medication called eculizumab has shown great promise in treatment of some cases of HUS. Please see here for details

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