Complications of Hemolytic Uremic Syndrome (HUS)

HUS can cause extensive extrarenal damage, some of which may be life-threatening. However, with advancements in treatment, the mortality rate has decreased to below 10%, and only about 5% of survivors experience persistent and severe long-term extrarenal sequelae.

1. ‌Gastrointestinal System‌
   In addition to intestinal manifestations, complications include:
   • ‌Pancreatic Disorders‌: Thrombotic microangiopathy (TMA) can affect the pancreas, leading to insufficient exocrine or endocrine function. While clinical pancreatitis is rare, 4%–15% of patients may develop transient or permanent diabetes.
   • ‌Hepatic Disorders‌: Hepatomegaly and elevated liver enzymes may occur, with occasional cholestatic jaundice. Chronic liver damage or liver failure has not been reported. Liver biopsies may reveal microthrombi without necrosis.
   • ‌Gallbladder Disorders‌: Gallstones may develop, potentially due to rapid hemolysis leading to bilirubin-calcium salt deposits.
2. ‌Central Nervous System (CNS) Damage‌
   Manifestations range from irritability, drowsiness, and anxiety to hallucinations, delusions, stupor, or coma. Neurological signs include tremors, seizures, hyperreflexia, ataxia, positive Babinski sign, and cranial nerve deficits. Increased cerebrospinal fluid protein levels may be observed. CT or MRI can identify the nature and location of lesions.
3. ‌Cardiovascular System‌
   Complications include myocarditis, myocardial infarction, and heart failure.
4. ‌Respiratory System‌
   Pulmonary edema or hemorrhagic infiltrates may occur. Autopsy findings often reveal pulmonary microthrombi, even in patients without overt clinical lung involvement.
5. ‌Other Complications‌
   Skin ecchymoses and oral herpes may develop. Autopsies of HUS patients have identified microthrombi in the adrenal glands, thyroid, thymus, lymph nodes, bladder, and ovaries. However, no organ dysfunction directly linked to these anatomical lesions has been reported.