Different apheresis methods in the treatment of hypercholesterolemia in primary biliary cirrhosis: a case report

The two different modes of low-density lipoprotein (LDL) apheresis, cascade filtration (CF) and dextran-sulfate cellulose (DSC) adsorption, were compared for efficiency of cholesterol removal in a patient with severe hypercholesterolemia due to primary biliary cirrhosis (PBC). Decrement in the total cholesterol level by the DSC method was less than that by the CF method. Apolipoprotein B was decreased to almost null by both modules whereas the decrease in albumin was much greater in the second filter of the CF method than in the DSC column. Lipoprotein X which constituted the major portion of serum cholesterol in PBC became negative by passing plasma through the second filter. The CF method was preferred to the DSC method for removal of lipoprotein X, but albumin substitution was mandatory to prevent the decrease of serum albumin in the CF method.

Secondary causes of hyperlipidemia

Secondary causes of hyperlipidemia are important to recognize. In fact, hyperlipidemia may be a clue to the presence of an underlying systemic disorder. It may greatly heighten the risk of atherosclerosis with a raised LDL-c, triglyceride-rich lipoprotein excess, and increased lipoprotein(a) as well as lowered HDL-c. The search for secondary causes may provide a clue as to why patients with primary lipid disorders suddenly develop worsening lipid profiles. The point is a crucial one because some acquired causes of hyperlipidemia, such as alcohol, estrogens, steroids, or pregnancy, when superimposed on a primary familial form of hypertriglyceridemia can result in a saturated removal system and a buildup of chylomicrons, which can lead to life-threatening pancreatitis. A convenient way to remember secondary causes is to think of the four D's of diet, drugs, disorders of metabolism, and diseases. Although diets rich in saturated fats and cholesterol are a common cause of the mild hypercholesterolemia seen in our society, alcohol excess and weight gain can explain much of the tendency toward hypertriglyceridemia. Interestingly anorexia nervosa has long been associated with severe but reversible hypercholesterolemia. Several classes of drugs need to be considered as common causes of altered lipid profiles. Glucocorticoids and estrogens elevate triglycerides and raise levels of HDL-c. Anabolic steroids taken orally markedly reduce levels of HDL-c in contrast to injectable testosterone, which does not adversely affect the LDL-to-HDL ratio. Oral contraceptives affect atherosclerotic risk depending on the kind and doses of progestin/estrogen. In those with an underlying primary hypertriglyceridemia and associated obesity, estrogenic medications can depress triglyceride removal mechanisms, leading to the chylomicronemia syndrome and pancreatitis. Antihypertensives have variable effects on lipids and lipoproteins. Although short-term thiazide usage raises cholesterol, triglycerides, and LDL-c, long-term usage is not necessarily associated with significant alterations in lipid levels. Alpha blockers may cause an increase in HDL-c, whereas beta blockers raise triglycerides and lower HDL-c. Sympatholytics, angiotensin converting enzyme inhibitors, and calcium channel blockers are essentially lipid neutral. Retinoids can be associated with increased LDL-to-HDL ratios and occasionally striking elevations in triglycerides. Cyclosporine raises LDL-c and lipoprotein(a). Classes of drugs that may raise HDL-c include cimetidine, antiepileptic drugs, and tamoxifen, but the effect may be seen primarily in women. Hypothyroidism is the most common secondary cause of hyperlipidemia after dietary causes are considered. A thyroxine and TSH level should be obtained on all new cases of clinically important hyperlipidemia.(ABSTRACT TRUNCATED AT 400 WORDS)