Early treatment critical in aHUS to prevent lasting kidney damage
Case shows heart function can recover, but kidneys may not
Written by |
A previously healthy young man in Greece who later developed atypical hemolytic uremic syndrome (aHUS) improved rapidly after being treated with the complement inhibitor Soliris (eculizumab), which helped his heart function recover over time, but delayed therapy was linked to permanent kidney failure requiring dialysis.
“This case emphasizes the importance of timely recognition of the disease and initiation of therapy,” researchers wrote in “Early recognition of atypical hemolytic uremic syndrome to prevent irreversible kidney injury: cardiac failure and refractory hypertension as critical clues in young patients,” published in CEN Case Reports.
aHUS damages small blood vessels and can affect multiple organs
Symptoms of aHUS appear due to damage in small blood vessels caused by an overactive complement system, a part of the immune system that normally helps fight infection. This damage can lead to blood clots that reduce the flow of oxygen to organs and cause injury. The disease primarily affects the kidneys but can also involve other organs, including the heart.
Here, the researchers describe the case of a 27-year-old man with no previous health problems. Over two weeks, he developed shortness of breath and swelling in his legs. When he arrived at the hospital, he had extremely high blood pressure, known as a hypertensive crisis, along with low oxygen levels.
The doctors found that he had acute decompensated heart failure, meaning a sudden episode of severe heart failure symptoms, associated with fluid buildup in his lungs, known as pulmonary edema. An ultrasound of the heart showed a very low ejection fraction of 27% from the main pumping chamber. Ejection fraction refers to how much blood the heart pumps with each beat.
Blood tests revealed severe anemia (low hemoglobin, the protein that carries oxygen in red blood cells) and thrombocytopenia (a low number of platelets, which help form blood clots). A blood smear showed schistocytes, which are fragmented red blood cells, a sign that blood vessels may be damaged. Another marker of red blood cell destruction, lactate dehydrogenase, was markedly elevated. Further tests showed low C3, a sign of complement system activation.
Although kidney function was normal about one year before, creatinine, a waste product normally filtered by the kidneys, was now very high, indicating a sudden loss of kidney function. A kidney biopsy, in which a piece of tissue is collected for examination under the microscope, confirmed thrombotic microangiopathy, or damage due to blood clots in small blood vessels. This finding was consistent with aHUS and helped confirm the diagnosis.
Standard treatments failed to improve heart and kidney function
Despite intensive treatment, including medications to reduce blood pressure, diuretics to remove excess fluid, corticosteroids to reduce inflammation, dialysis to filter the blood when the kidneys cannot, and repeated plasma exchange given while doctors evaluated possible causes of his condition, the man did not improve. His problems with the heart, kidneys, and blood pressure remained severe.
The doctors then prescribed Soliris, which inhibits the complement protein C5 and prevents the formation of the membrane attack complex that contributes to organ damage. After starting Soliris, the man’s blood pressure and clinical condition stabilized, and his heart function began to improve rapidly after treatment began.
Over the following months, his heart fully recovered. By six months, his ejection fraction returned to normal, showing that the heart damage was reversible in this case. However, his kidneys did not recover. He remained dependent on dialysis and was listed for a kidney transplant.
“This case underscores the paramount importance of early recognition of [aHUS] and prompt initiation of complement inhibition therapy. These measures are crucial to halting disease progression and preventing irreversible organ damage,” the researchers wrote, noting that Soliris can “lead to full recovery” of heart function, but “fail to reverse” advanced kidney damage in cases like this.
