Category: Diabetes/Prediabetes/Hypoglycemia

EVAN'S SYNDROME: AN UNUSUAL CAUSE OF FALSE NEGATIVE HGBA1C

Monday, Apr 8
1:00 AM – 2:00 AM

Objective :

An 85 year old male presented to his primary care physician with complaints of unintentional weight loss, fatigue, and polyuria. Laboratory demonstrated random glucose of 298 mg/dL, and an elevated bilirubin (3.2 mg/dL). HgbA1c was noted to be 5.1%. The patient’s CBC was significant for anemia (Hgb 9.5 g/dL) and thrombocytopenia (Platelets 30 K/mm3) for which the patient was sent to Hematology. A peripheral blood smear demonstrated spherocytes; direct Coombs test was positive. A bone marrow biopsy was obtained and was negative for malignancy. The patient was diagnosed with Evan’s Syndrome and was started on Prednisone. Following initiation of Prednisone, the patient developed progressively worsened symptoms of weight loss, polyuria, and fatigue which prompted him to present to the emergency department for further evaluation. On admission, his glucose was 598 mg/dL, prompting formal diagnosis of diabetes mellitus with glucocorticoid-induced hyperglycemia; he was started on insulin with subsequent symptom improvement. 


Methods : n/a


Results :

n/a


Discussion :

Evan’s Syndrome (ES) is typically the combination of an autoimmune hemolytic anemia (AIHA) plus immune thrombocytopenia. AIHA, in the presence of warm agglutinins, is due to reaction of IgG antibodies and RBC surface protein antigens. The most common etiology is idiopathic; other causes include autoimmune/connective tissue diseases (SLE), viruses, malignancies, immunodeficiencies, drugs, and prior blood transfusion/stem cell transplant/solid organ transplant. In half of patients with ES, there tends to be another immune disorder present. Symptoms are nonspecific but can include pallor, jaundice, splenomegaly and cardiac decompensation. Laboratory measures include increased LDH, decreased haptoglobin, spherocytosis on peripheral blood smear, and a positive Coombs test. ES tends to have a higher mortality than AIHA on it’s own. ES, like other hemolytic conditions, can falsely lower HgbA1c in the setting of diabetes mellitus due to the shortened red blood cell survival.


Conclusion :

While HgbA1c is typically the most commonly used diagnostic tool for diabetes mellitus, it can be inaccurate in patients with hemolytic anemia. Any condition that shortens red blood cell survival can falsely lower HgbA1c and should not be used reliably. In such cases, such as Evan’s Syndrome, fasting blood glucose should be considered the gold standard for diagnosis. Additionally, random blood glucose greater than 200mg/dL with typical symptoms of diabetes mellitus meets criteria for diagnosis. Lastly, hemolytic processes should always be considered in a patient whose fasting/random blood glucose differ drastically from their HgbA1c.

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Timothy Reisner

Internal Medicine Resident
Mercy Medical Center Des Moines
Grimes, Iowa

Internal Medicine resident at Mercy Medical Center Des Moines.

Katelynn Splett

Internal Medicine Resident
Mercy Medical Center Des Moines

Internal Medicine resident at Mercy Medical Center Des Moines.

Austin Coder

Internal Medicine Resident
Mercy Medical Center Des Moines

Internal Medicine resident at Mercy Medical Center Des Moines.