Severe tick-borne infection leads to aHUS in woman: Case report

Babesiosis from infected tick can result in life-threatening complications

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by Andrea Lobo |

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A woman in her 60s developed atypical hemolytic uremic syndrome (aHUS) as a result of severe babesiosis, a tick-borne parasitic infection, according to a recent U.S. case report.

Babesiosis is caused by a parasite that infects red blood cells. The disease is transmitted from the bite of an infected tick and may result in life-threatening complications, including hemolytic anemia and kidney failure, both hallmark symptoms of aHUS.

“This case … emphasises the importance of maintaining a high clinical suspicion for Babesiosis, and the significance of blood smear examination in achieving a definitive diagnosis,” researchers wrote. “An individualized and timely approach to patient management is crucial, as demonstrated by the successful outcome achieved through antimicrobial therapy along with supportive therapy alone in our case.”

The case was described in a study, “Atypical haemolytic uremic syndrome in a patient with severe Babesiosis,” published in the journal Haematology.

aHUS is a rare disease marked by the abnormal activation of the complement cascade, a part of the immune system. This results in the formation of blood clots inside small blood vessels that may damage internal organs, particularly the kidneys.

The disease is characterized by three main symptoms: hemolytic anemia, which happens when red blood cells are destroyed faster than they can be made (hemolysis); low levels of platelets (cell fragments that help the blood to clot); and acute kidney failure.

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Favorable clinical outcome due to rapid diagnosis, prompt aggressive treatment

Here, researchers described the case of an East Asian woman in her 60s with severe babesiosis who developed aHUS and had a favorable clinical outcome due to rapid diagnosis and prompt aggressive treatment.

The woman, who had a previous history of tongue cancer that was now in remission, was admitted to the emergency department with vomiting, diarrhea, and decreased urine production over the past four days. She also reported having fever, chills, abdominal and back pain, and yellow discoloration in the eyes and skin for two days.

Her initial evaluation revealed she had a low fever and low blood pressure. Her heart rate, respiratory rate, and oxygen saturation levels were within the normal range.

Initial blood work indicated she had low hemoglobin and platelet levels, and high levels of creatinine, a marker of kidney dysfunction. Of note, hemoglobin is the protein in red blood cells that’s responsible for oxygen transport.

A urine analysis revealed the presence of blood and proteins, indicative of kidney dysfunction. Further blood tests showed the patient had high levels of lactate dehydrogenase, a marker of hemolysis, and a higher-than-normal percentage of reticulocytes (immature red blood cells). These observations led researchers to suspect aHUS.

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Patient had traveled to northeastern US, where babesiosis is more prevalent

Considering the patient’s recent travel to the northeastern region of North America, where babesiosis is more prevalent, and an analysis of a blood smear that was consistent with the presence of a parasitic infection, the researchers suspected babesiosis as the underlying cause of aHUS.

The patient started on medications to help raise her blood pressure, as well as hemodialysis, a type of treatment that replaces the kidneys’ natural function of filtering the blood. Moreover, while waiting for test results for the Babesia parasite, she was given antibiotics and anti-parasitic treatment. Results came back positive for the parasite, with an initial load of 22%.

On the second day, her blood pressure normalized. Two days after starting anti-parasitic treatment, the parasite burden had decreased to 3% and urine production increased. After eight days of treatment, she showed no signs of the parasitic infection.

However, she still showed signs of hemolysis, and her hemoglobin levels were frequently low, requiring intermittent blood transfusions.

Her kidney function recovered, leading her to stop hemodialysis, and she was discharged 20 days after being admitted. At a two-month follow-up visit, she remained asymptomatic, with normal hemoglobin levels and no signs of hemolysis, and had returned to her daily activity and work.

“This is the first reported case of aHUS following Babesiosis infection,” the researchers wrote. “Emphasis should be made on carrying out a holistic approach based on the clinical status of the patient rather than relying solely on extent of parasitemia or chemical markers when treating severe Babesiosis.”