aHUS triggered by pancreatitis in man, 49: Case report

Man had MCP mutation, but no symptoms before pancreas inflammation

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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The case of a 49-year-old man with atypical hemolytic uremic syndrome (aHUS) that manifested after he developed pancreatitis was described in a recent report.

Genetic testing showed the man had a mutation in the MCP gene, a known risk factor for aHUS. The fact that he hadn’t had any aHUS-like symptoms before having pancreatitis supports the idea that genetic risk factors alone don’t cause aHUS and that other triggering events are needed for the disease to manifest.

“This case supports the “multiple hit theory” that several factors are required for the manifestation of aHUS,” the researchers wrote in “A Case of Atypical Hemolytic Uremic Syndrome Triggered by Acute Pancreatitis in a Patient with a Membrane Cofactor Protein (CD46) Genetic Variant,” in Internal Medicine.

In aHUS, a part of the immune system called the complement cascade becomes overactive, driving inflammation and blood clotting in small blood vessels, especially the kidneys.

Most people with aHUS have a mutation in the genes that help regulate the complement cascade; MCP being one such gene. It’s thought that, in most cases, these mutations don’t cause the disease outright. Instead, they merely set the stage for the complement cascade to go awry in response to other triggers, such as infections, autoimmune disorders, and other conditions.

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aHUS symptoms follow pancreas inflammation

The man had a pancreas biopsy due to suspected pancreatic disease. The biopsy was negative, but he soon complained of abdominal pain. Lab tests suggested the biopsy had triggered inflammation in the pancreas.

To manage the pancreatitis, the man was initially given supportive care, including fasting and pain medicine. In the days that followed, he began showing signs of kidney damage, including high levels of proteins and blood in the urine. He also became anemic and lab tests indicated hhis red blood cells were being destroyed. His platelet counts also dropped.

Since kidney damage, red blood cell destruction, and low platelet counts are characteristic signs of aHUS, clinicians ordered genetic tests to look for complement-related mutations. These revealed a mutation in MCP, a complement-related gene that’s associated with aHUS.

While the man had had the mutation his entire life, he had no prior history of aHUS-like disease. Researchers speculated pancreatitis likely served as a trigger for the disease to manifest, which it’s known to do. Thiecase “shows that several triggers, not just genetic mutations, are involved in the development of aHUS,” the researchers wrote. The patient was treated with hemodialysis and plasma exchange, which effectively managed his condition.