A 49‐year‐old man with a history of schizophrenia, diabetes mellitus, and scleroderma presented with recurrent episodes of atypical chest pain and vomiting. Repeated physical examinations revealed intermittent peripheral cyanosis with decreased digital capillary refill. The cardiovascular exam was significant for a grade 3/6 systolic murmur at the lower left sternal border. The rest of the systemic examination was unremarkable. An echocardiogram revealed pulmonary hypertension with a pulmonary artery systolic pressure of 75 mm Hg. Upper GI series were consistent with lack of peristalsis and gastroesophageal reflux. During the hospitalization, the patient was found to have intermittently decreased capillary blood glucose (CBG) level, frequently less than 30 mg/dL as detected by the digital stick method. However there were no associated clinical systemic manifestations of hypoglycemia, including changes in mental status, shivering, tachycardia or sweating. The patient was initially treated for hypoglycemia based on her CBG levels with intravenous and oral glucose. Initially, simultaneous venous blood glucose levels were not drawn. The patient remained entirely asymptomatic even when the CBG was less than 20 md/dL. Later, repeated simultaneous venous glucose levels were found to be in the normal range, whereas CBG was persistently low (146 vs. 31). Interestingly, the digital stick method to assess glucose level revealed a normal glucose level when there was no associated peripheral cyanosis.
This case emphasizes the importance of assessing serum glucose level from venous samples rather than assessing CBG by finger stick in patients with Raynaud's phenomenon. The most likely explanation for the difference between these 2 readings in patients with active Raynaud's phenomenon is peripheral venous stasis due to vasoconstriction. This results in local utilization of glucose, when in fact the serum glucose levels are in normal range. Therefore, it is recommended that patients, especially diabetics with peripheral cyanosis secondary to shock, peripheral vascular disease or Raynaud's phenomenon, should have systemic glucose assessment rather peripheral (CBG) monitoring of their blood glucose to avoid unnecessary and potentially deleterious interventions.
The disparity between the finger stick and systemic measures of blood glucose is relatively unknown to clinicians. There are several reports of disparity between CBG and serum blood glucose values in hematologic disorders including leukemic leukocytosis and hyperviscosity syndromes. However, to the best of our knowledge, this is only the second reported case in which a patient with Raynaud's phenomenon exhibited an artifactual error in blood glucose measurement using the CBG approach.
K. Manzoor, none; W. Aftab, none; J. Nalamati, none.
To cite this abstract:Manzoor K, Aftab W, Nalamati J. Raynaud's Phenomenon with Profound Variations in Capillary Blood Glucose Levels: A Case of Pseudohypoglycemia. Abstract published at Hospital Medicine 2008, April 3-5, San Diego, Calif. Abstract 158. Journal of Hospital Medicine. 2008; 3 (suppl 1). https://www.shmabstracts.com/abstract/raynauds-phenomenon-with-profound-variations-in-capillary-blood-glucose-levels-a-case-of-pseudohypoglycemia/. Accessed April 1, 2020.