Sarcoidosis Revealed as Culprit in Rare Blood Disorder: Case Report
Example illustrates need to consider condition in uncommon cases of organ impairment
Sarcoidosis led to thrombotic microangiopathy (TMA), a rare blood disorder, and associated severe kidney damage and blood-related abnormalities in a 31-year-old man, a case study reported.
This rare case emphasizes the importance of considering sarcoidosis in uncommon cases of multiple organ dysfunction, as well as early intervention by a multidisciplinary team to ensure the best possible treatment, the researchers noted.
The case study, “A case of thrombotic microangiopathy and acute sarcoidosis,” was published in Chest Journal.
A feature of sarcoidosis is chronic inflammation that leads to small clumps of immune cells — granulomas — in several tissues and organs, ultimately affecting their function. The most commonly affected organs and tissues are the lungs and lymph nodes, which act as business centers of immune responses.
While lung, heart, and neurological manifestations of sarcoidosis “are encountered frequently in clinical practice,” kidney and blood-related complications “are less well described,” the researchers wrote.
Man presents symptoms rarely associated with sarcoidosis
Kidney problems may be associated with granulomas or disrupted calcium balance. Blood-related symptoms, such as anemia and low platelet counts, are typically mild and temporary, while hemolytic anemia — the destruction of red blood cells — is “rare and has only been described in a small number of case reports,” wrote researchers in Cambridge, England who described a case of a 31-year-old man in whom sarcoidosis caused kidney failure and blood-related problems due to TMA.
TMA is a group of rare disorders marked by hemolytic anemia, low levels of platelets (small blood cell fragments involved in blood clotting), and blood clots forming in small blood vessels that can lead to organ damage.
The patient was admitted to the emergency room with stomach pain, nausea, overall discomfort, and fatigue. About three weeks before, he’d had intense diarrhea that was treated with proper medication.
“He was a current smoker, working as a delivery driver, with no significant medical history and no regular prescribed medications,” the researchers wrote.
Lab tests indicated acute kidney damage, with the presence of blood and proteins in urine, and increased levels of amylase, a marker of inflammation of the pancreas (pancreatitis).
Imaging chest scans showed infiltrates, substances denser than air, were widespread in his lungs, even though he had no difficulty breathing and didn’t need oxygen supplementation.
He started into-the-vein treatment with fluids and medications to stop nausea and vomit, and a few days later, he showed lower than normal platelet and red blood cell counts, as well as an increase in inflammation markers. Bone tests showed elevated calcium levels (hypercalcemia).
Additional blood tests revealed red blood cell fragments, suggesting a microangiopathic hemolytic anemia, a subgroup of hemolytic anemia caused by blood flow disruptions that lead to the fragmentation and destruction of red blood cells.
No clotting issues were found, however, and the man started medicine to treat hypercalcemia. Further imaging tests revealed nodules in both lungs, lymph node swelling in the chest, and an enlarged spleen.
Immunodeficiency, autoimmune disorders, and infections were excluded. While it’s well known that cancer can trigger both TMA and sarcoidosis-like reactions, no signs of cancer were detected on imaging or biopsies.
More blood tests showed higher than normal levels of angiotensin-converting enzyme, which plays a key role in regulating blood pressure and is usually present at high levels in sarcoidosis-associated granulomas.
A kidney biopsy showed severe acute TMA, but no granulomas. Blood tests revealed high levels of creatinine, a marker of kidney damage.
Sarcoidosis as ‘primary underlying’ disease
The doctors suspected atypical hemolytic uremic syndrome (aHUS), a type of TMA that particularly affects the kidneys. However, his kidney function began improving a few days later without any additional intervention and genetic testing showed no genetic changes known to cause aHUS.
Although two cases of sarcoidosis and aHUS have been previously reported, the man’s case was “unique” both in the severity of symptoms and the absence of granulomas in kidneys, the researchers wrote, noting this “would indicate co-presentation rather than a causal link.”
Biopsies from the lymph nodes found granulomas characteristic of sarcoidosis.
“Given the widespread features of acute sarcoidosis and the sequence of events, a plausible explanation is that sarcoidosis represents the primary underlying [disease] of this patient’s multi-organ dysfunction,” the researchers wrote. “Sarcoidosis-driven hypercalcemia resulted in acute pancreatitis … which in turn led to TMA.”
The man was started on an oral prednisolone, an anti-inflammatory steroid, for sarcoidosis. At follow-up visits, he showed improvement, having achieved normal levels of calcium, platelets, and hemoglobin (the protein in red blood cells responsible for carrying oxygen), as well as a normal kidney function. Chest scans showed improvements and lung function tests found no serious changes.
This new, rare case “highlights the need to consider sarcoidosis as part of the differential diagnosis for unusual multi-organ presentations and for early multidisciplinary involvement in such cases to permit optimal treatment,” the researchers said.
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