Case Presentation: This is a case report of a patient with severe peripheral arterial disease (PAD) who had several finger-stick capillary blood glucose readings demonstrating hypoglycemia refractory to treatment. The patient’s lack of symptoms prompted an investigation for pseudohypoglycemia which was confirmed with simultaneous point of care (POC) and peripheral venous glucose draws which demonstrated a large discrepancy. A 77 year-old male with end-stage renal disease on hemodialysis, insulin-dependent type II diabetes, and severe PAD complicated by left 1st through 3rd finger necrosis, left leg amputation, and right 1st through 3rd toe amputations presented for failure of arteriovenous fistula access during his regularly scheduled dialysis. On hospital day 1 the patient was made NPO for a fistulogram. Subsequently, the patient had a POC glucose reading of 19 mg/dL which prompted a Rapid Response Team activation. The patient was given an ampule of D50 to which his POC glucose reading responded and elevated to 96 mg/dL. Over the next hour his POC glucose dropped back to 39 mg/dL and was refractory to oral glucose loads. The POC blood glucose readings were capillary samples obtained via finger-stick. Despite multiple D50 ampules and a D5W drip he continued to demonstrate hypoglycemia on POC glucose readings. During these episodes, the patient remained asymptomatic with no mental status changes, lightheadedness, blurry vision, diaphoresis, or seizure-like activity. Notably, the patient had had not received any insulin since arrival to the hospital 12 hours before. The lack of symptoms raised suspicion for pseudohypoglycemia. A peripheral venous draw had been collected simultaneous to the initial POC glucose reading of 19 mg/dL. The glucose on the peripheral venous reading was 119 mg/dL. This confirmed the clinical suspicion that the POC glucose readings were falsely low and consistent with pseudohypoglycemia secondary to severe PAD. Subsequent POC glucose readings were obtained from the earlobe and consistently showed glucose levels >200 mg/dL.
Discussion: Pseudohypoglycemia is a well-established clinical phenomenon that has been linked with a wide variety of pathologies such as Raynaud’s disease, Eisenmenger syndrome, and leukemia. Surprisingly, there are very few published cases of pseudohypoglycemia caused by the very common disease PAD. The pathophysiology of this phenomenon is poorly understood. The leading hypothesis is that reduced blood velocity due to PAD allows proximal tissues to absorb the majority of the blood glucose, resulting in relatively lower concentrations in distal tissues such as fingertips1. This is a significant finding and should raise awareness that in patients with severe PAD and POC glucose readings can alternatively be obtained from the earlobe or from peripheral venous blood if there are concerns about accuracy.
Conclusions: Pseudohypoglycemia in PAD is an important phenomenon to recognize because severe hypoglycemia is a medical emergency that often requires intensive hospital resources to monitor and treat and avoiding unnecessary treatment or escalation of care is an important goal in hospital care.