Essential hypercholesterolemia

The laboratory must be informed when the therapeutic regimens include drugs specifically administered to change the blood level of a biochemical constituent. Cholestyramine resin, a nonabsorbable anion exchange resin administered orally to patients with hyperlipoproteinemia produced a 24% decline in serum cholesterol levels in 14 patients with essential hypercholesterolemia. In these patients the mean cholesterol fell from 414 98 mg/100 ml to 176 21 mg/100 ml (FI). Pectin added to the diet caused a 5% decrease in serum cholesterol values (K4), as did an oral hydrophobic colloid (G4). Levels fell in one case from 220 mg/ 100 ml to 160 mg/100 ml (G4). Nicotinic acid, neomycin, and p-chloro-phenoxyisobutyrate have all been used to reduce serum cholesterol (G7). 

Figures in parentheses indicate the number of subjects in each group. In essential hypercholesterolemia (type II), familial history is unclear, tendon xanthomata are absent, and serum cholesterol is usually only moderately increased. 

Another group of hypercholesterolemic (type II) patients, indicated in Table II by the term essential hypercholesterolemia, was also studied. These patients differed from familial hypercholesterolemia patients in that the family history was less clear, serum cholesterol was less elevated, and xanthomata were not present. Hypercholesterolemia may be primarily caused by environmental, primarily dietary, factors. Bile acid production in this group is less significantly reduced than in the familial group, and the relative catabolism of cholesterol by way of bile acids is within normal limits. Sodhi (151) observed in this type of hypercholesterolemia a markedly low fecal bile acid excretion. 

Hood, B., and G. Angervall Studies in essential hypercholesterolemia and xanthomatosis. Belationship between age, sex, cholesterol concentrations in plasma fractions, and rise of tendinous deposits. Amer. J. Med. 26, 35 (1959). 

Fredrickson and Lees (1965) have described as their type III hyperlipoproteinemia, individuals who, in addition to clinical and laboratory evidence of essential hypercholesterolemia, show elevation of VLDLP (pre-j8-lipoproteins) and are markedly susceptible to carbohydrate induction. In common with other endogenous hyperlipidemics, they manifest carbohydrate intolerance. 

It is likely that cases who have been described in the past as essential hyperlipemia on the basis of lipemic plasma and who exhibited tendon xanthomas belong in this group. Cases of essential hypercholesterolemia with and without plasma turbidity, whose plasma triglycerides exceed the levels expected from increased /3-lipoproteins, would qualify for membership. Such cases can be found in reports by Lever et al. (1954), Adlersberg (1955), Furman et al. (1961), Kuo and Basset (1963) and others. 

Xanthomata plana (xanthelasmas) are not considered characteristic of hyperlipemia their occurrence however has been described by Malmros and coworkers (1954), Adlersberg (1955), Schettler (1955), Matras (1956), Schirren (1957) and Haensch (1958). The presence of xanthelasmas in EHL seem either to indicate that one is dealing with a combination with essential hypercholesterolemia or that they are unrelated to the disease since they do occur in a significant percentage of normolipemic subjects. 

Hyperglyceridemia has been reported to correlate better with CHD than hypercholesterolemia (Albrink and Man 1959), and subjects with CHD exhibit marked and prolonged postprandial lipemia (Brown et al. 1961). However, while there is wide agreement on a strong correlation between essential hypercholesterolemia and the premature occurrence of CHD, evidence for an increased incidence of atherosclerotic complications in essential hyperlipemias is controversial. 

In pure carbohydrate-induced hyperlipemia, restriction of carbohydrate compatible with acceptability of the diet and prevention of ketosis is recommended. Thus 50—70% of calories may be given as fat with a carbohydrate content below 25%. If a significant amount of the fat comes from unsaturated sources, it may be cleared from plasma faster than saturated fats (Engelberg 1964) and hypercholesterolemia may be further reduced. Such a regimen should also be optimal in the combination of essential hypercholesterolemia and hyperhpemia. 

Although dietary manipulation in EHL will produce most striking results if it is adhered to (as opposed to the state of affairs in essential hypercholesterolemia, where dietary treatment is frequently ineffective), in many cases such a dietary regimen fails to achieve complete control of hyperlipemia. Also patient cooperation may be poor if a quite restricted diet is prescribed for an indefinite period. 

Essential hyperlipemia which at one time seemed to be a well defined entity has now been recognized to consist of a number of subgroups, whose pathogeneses appear to be quite different, and whose classification is by no means definite. Similar problems exist for essential hypercholesterolemia . 

B. Lewis and N. B. Myant, Studies in the metabolism of cholesterol in subjects with normal plasma cholesterol levels and in patients with essential hypercholesterolemia. Clin Sci (Oxf) 32 201 (1967). 

---