Hyperlipoproteinemia is a disorder of lipid metabolism that results in higher levels of circulating lipoproteins in the plasma.
Hyperlipoproteinemia is usually asymptomatic and is more commonly seen in people who have a personal/family history of atherosclerosis and coronary artery disease or in patients who are obese, smokers, hypertensive, or diabetic [1] [2].
Triglyceride levels greater than 1000-2000 mg/dL may trigger the onset of abdominal symptoms such as epigastric pain due to acute pancreatitis. The pain may also originate in the chest or back. Chylomicronemia syndrome is characterized by recurrent episodes of abdominal pain accompanied by nausea, vomiting, and breathlessness [3]. Some patients have also reported episodes of memory loss and depression. This syndrome may be easily confused with an acute cardiac event or a biliary colic. Individuals with hyperlipoproteinemia may suffer from recurrent bouts of acute pancreatitis when triglyceride levels rise above 5000 mg/dL [4].
An accumulation of lipid-laden macrophages under the skin may result in lesions known as xanthomas. Eruptive xanthomas, seen in the chylomicronemia syndrome, are small, yellow papules occurring most commonly on the trunk, thighs, and buttocks. Xanthomas occurring in the tendons are seen mostly in familial hypercholesterolemia whilst palmar xanthomas could be seen in dysbetalipoproteinemia. Nodular and painless lesions called tuberous xanthomas are frequently seen on the knees and elbows.
Ocular lesions are uncommon yet distinctive findings of hyperlipoproteinemia. Amongst the most common ophthalmological findings is arcus senilis which is a grayish-white opacification of the corneal periphery [5]. Lipid deposits in and around the eyelid lead to the formation of yellow, raised lesions called xanthelasmas. Retinal lesions such as lipemia retinalis may be observed in some patients.
Hyperlipoproteinemia is suspected in patients presenting with the clinical features associated with dyslipidemia, those with a positive family history of premature coronary artery disease, patients suffering from certain conditions such as diabetes mellitus and hypertension, those with an elevated body mass index, and in individuals with significant tobacco smoke exposure. The diagnosis of hyperlipoproteinemia is clinched by a full lipid profile measuring the total cholesterol (TC), triglycerides (TG), high-density lipoproteins (HDL), low-density lipoproteins (LDL), and very-low-density lipoproteins (VLDL).
The TC and TG values measure the amount of cholesterol and triglycerides present in all the lipoproteins in the plasma. TC and TG values can show a day-to-day variation of 10% and up to 25%, respectively, in normal individuals and are measured directly, as is HDL cholesterol. Direct measurements of LDL cholesterol are usually not required. LDL values reflect the amount of non-VLDL, non-HDL cholesterol circulating in the plasma. VLDL values are derived from the TG levels.
For accurate measurements, the serum lipid profile needs to be done in a fasting state of 12 hours [6]. Testing should be delayed in the presence of an active focus of infection or an acute cardiac event.
Other tests that may be done in patients with hyperlipoproteinemia include lipoprotein (a), apoprotein B-100 (apo B), and C-reactive protein (CRP) [7] [8].