A 37-yrs-old man in DKA has yellowish papules scattered over his trunk and extremities. A tube of plasma that is collected from the patient develops a turbid supernate. This is consistent with which type of hyperlipoproteinemia?

The patient most likely has a type V hyperlipopro­teinemia, which is associated with eruptive xanthomas secondary to increased triacylglycerol. Type V hyperli­poproteinemia is a combination of type I, characterized by elevated chylomicrons, and type IV, characterized by increased very-low-density lipoproteins (VLDL). Diabetic ketoacidosis and alcoholism are two of the most common factors that promote type V hyperlipo­proteinemia. The absence of insulin characteristic of diabetic ketoacidosis decreases capillary lipoprotein li­pase activity, so neither chylomicrons nor VLDL are properly metabolized in the liver. The increased triac­ylglycerol concentration that results from the accumu­lation of chylomicrons and VLDL in the blood pro­duces a turbid specimen. Because chylomicrons have the lowest density, they form a turbid supranate in plasma left at 4°C overnight. The density of VLDL is slightly higher than that of chylomicrons, so it forms a turbid infranate. Presence of a supranate and in­franate, as in this case, indicates type V hyperlipopro­teinemia. A supranate without an infranate occurs in type I hyperlipoproteinemia, and an infranate without a supranate occurs in type IV hyperlipoproteinemia. Another feature of type V disease is hyperchylomicro­nemia. Clinical features include eruptive xanthomas caused by the deposition of triacylglycerol in the sub­cutaneous tissue. Once the triacylglycerol concentra­tion is reduced, the xanthomas disappear.