COVID-19 triggers aHUS in boy, 13, case report details
Treatment with plasma exchange therapy helped teen recover
COVID-19 triggered atypical hemolytic uremic syndrome (aHUS) in a 13-year-old boy with a genetic predisposition to the syndrome, a recent case study reports.
Treatment with plasma exchange therapy, a type of blood-cleansing procedure, was effective, and the boy fully recovered.
“This case highlights the potential of COVID-19 to trigger aHUS, particularly in individuals with underlying genetic predispositions,” the researchers wrote.
The report, “Atypical hemolytic uremic syndrome with a C3 variant following COVID-19: a case report,” was published in Frontiers in Pediatrics.
aHUS is a rare type of thrombotic microangiopathy (TMA), a group of diseases characterized by the formation of blood clots in the body’s small vessels. In aHUS, the abnormal activity of the complement system, a component of the body’s immune system, causes blood clots to form in small blood vessels, leading to organ damage.
COVID-10 triggers onset of aHUS symptoms
While most people with aHUS have mutations in genes involved in complement regulation, these mutations alone are typically not sufficient to cause the disease on their own. Usually, the onset of symptoms is triggered by an immune-activating stimulus, such as an infection.
Here, researchers at the Gifu University Hospital in Japan described the case of a 13-year-old boy infected with SARS-CoV2, the virus that causes COVID-19, leading him to develop aHUS.
The boy had a headache and sore throat for two days, which progressed into cough and diarrhea. His urine also had traces of blood, a condition known as hematuria. He was positive for SARS-CoV2 and blood work revealed he had low platelet counts, or thrombocytopenia. Platelets are tiny cell fragments involved in blood clotting.
The next day, at his local hospital, his platelet counts were even lower, and he had signs of microangiopathic hemolytic anemia, anemia driven by the destruction of red blood cells associated with the obstruction of small blood vessels.
Due to suspicions of TMA, he was transferred to the Gifu hospital. Upon arrival, his vital signs were normal, and he was fully conscious and well oriented.
Blood work showed signs of hemolytic anemia, including high levels of lactate dehydrogenase, a marker of cell and tissue injury. The levels of creatinine, a marker of kidney dysfunction, also were elevated, and he presented severe thrombocytopenia and hematuria.
The activity of the ADAMTS13 enzyme was normal (85%) indicating he did not have a TMA called thrombocytopenic purpura (TTP), in which the enzyme’s activity is severely reduced.
Complement analysis was normal, with the exception of a slight decrease in the levels of the C3 complement protein. The boy also tested negative for Shiga toxin, a compound that can indicate the presence of typical HUS.
After three days, his anemia and thrombocytopenia worsened, accompanied by a rise in creatinine levels. Because the results of the ADAMTS13 activity tests were still pending, he began treatment with plasma exchange therapy. Also known as plasmapheresis, this procedure replaces a person’s plasma — the liquid portion of blood — and is believed to be helpful for patients with aHUS and TTP.
The boy recovered fully after undergoing plasma exchange and was discharged after 18 days. He remained free of relapses in the year following.
Genetic testing revealed the boy had a disease-causing mutation in one of the copies of the C3 gene, confirming the diagnosis of aHUS. His father, who had a medical history of unexplained TMA, also carried the same mutation.
This case reinforces the notion that COVID-19, even in the absence of severe respiratory symptoms, can trigger aHUS, particularly in individuals with genetic predisposition to develop the disease.
“Clinicians should be vigilant for signs of aHUS in children with COVID-19, especially those with a family history of TMA or complement system abnormalities, as early diagnosis and intervention can lead to favorable outcome,” they wrote.
About the Author
