A Case of Pseudohypoglycemia in Connective Tissue Disease

Presentation Number: MON 294
Date of Presentation: April 3rd, 2017

Pooja Rao*1, Zachary Benson2 and Francesco S. Celi3
1Virginia Commonwealth Univeristy, Richmond, VA, 2Virginia Commonwealth University Health Systems, Richmond, VA, 3Virginia Commonwealth University, Richmond, VA

Abstract

Background:Point of care glucometers are commonly used to guide the treatment of hyper- and hypoglycemia in the hospital setting. Here we report a case of pseudohypoglycemia due to Connective tissue disease.

Clinical Case: A 62 year old African-American woman affected by mixed connective tissue disease with Raynaud phenomenon, Sjogren syndrome, extensive systemic scleroderma and rheumatoid arthritis was admitted to the hospital with seizures. On admission the capillary blood glucose was 18 mg/dL (n 65-100 mg/dL) and the patient was treated with 50 mL of IV dextrose 50% solution; the repeat capillary blood glucose was 25 mg/dL while venous blood glucose was 140 mg/dL. During the hospital course multiple capillary blood glucose measurements were low in the absence of symptoms attributable to the Whipple’s Triad. Her Hemoglobin A1c was 5.1%. In retrospect, she reported being diagnosed with hypoglycemia and having home glucometer readings consistently below 60 mg/dL in the absence of hypoglycemic symptoms.

Due to the discrepancy between patient’s bedside glucometer and venous blood samples readings, simultaneous testing was requested to ensure there was a true discrepancy. We were able to obtain point of care capillary sample, point of care glucose determination with a venous sample and a serum sample with the following readings: 42 mg/dL, 146 mg/dL, 142 mg/dL respectively. Concomitant venous glucose measurements were consistently 2-3.5 times higher than capillary testing via glucometer. Due to these findings her capillary testing was discontinued and the primary team was advised to perform glucose monitoring exclusively by venous blood sampling. Throughout her hospitalization she had no further seizure activity and did not have a documented hypoglycemic episode.

Conclusion: This patient had capillary glucose levels consistently lower than concurrent venous glucose levels in the setting of vasoconstrictive disease emphasizing the need for venous glucose measurements to confirm the diagnosis of true hypoglycemia. The seizure episode (secondary to intracranial hemorrhage) was a complicating feature of this particular case. Review of the literature reported three similar case reports, two associated with Raynaud phenomenon and one with peripheral vascular disease, in which the term “pseudo-hypoglycemia” was used to describe the discrepancy between capillary and venous blood sugar (2). The pathogenesis of pseudohypoglycemia in this case is due to increased glucose extraction by the tissues because of low capillary flow and increased glucose transit time (1). As shown in this case, capillary glucose measurements are not reliable in cases of diminished peripheral circulation such as Raynaud's phenomenon and therefore alternative diagnostic testing with venous glucose measurements should be employed for accurate testing.

 

Nothing to Disclose: PR, ZB, FSC