Hyperlipidaemia in children

Special Considerations for Lipid-Lowering Therapy in Women Reflecting Recent Randomized Trials

PURPOSE OF REVIEW

Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of mortality in women across all racial and ethnic groups within the USA. Despite robust evidence from randomized controlled trials demonstrating that treatment of hypercholesterolemia in women reduces cardiovascular events, women who are eligible for lipid-lowering therapy are less likely than men to be prescribed guideline-recommended therapy or to have therapy prescribed at the appropriate intensity.

RECENT FINDINGS

Historically, women have been underrepresented in clinical trials. Recent randomized clinical trials have shown that women derive similar benefits as men when treated with lipid-lowering therapy, and recent studies demonstrate potential uses for lipid-lowering therapies that extend beyond their previously well-established indications. In this review, we will discuss lipid-lowering therapies in the context of recent clinical trials with a focus on special considerations in women.

Dyslipidemia in women: etiology and management

Dyslipidemia is highly prevalent among women. The management of dyslipidemia is a cornerstone in the prevention of both primary and secondary cardiovascular events, such as myocardial infarction, ischemic stroke, and coronary death. All major international guidelines on the treatment of dyslipidemia recommend similar approaches to the management of dyslipidemia in both men and women. Estrogen replacement therapy should not be considered as a therapeutic option for managing dyslipidemia in women. The reduction of atherogenic lipoprotein burden (reducing low-density lipoprotein cholesterol and non-high-density lipoprotein cholesterol based on risk-stratified thresholds and treatment targets) provided the framework for managing dyslipidemia in the US, Europe, Canada, and elsewhere in the world. Very recently, new guidelines in the US have changed this paradigm, whereby rather than focusing on treatment targets, risk now defines the intensity of treatment with statin therapy, with no specific goals for what level of low-density lipoprotein cholesterol should be attained. It is not clear if this will lead to changes in lipid guidelines in other parts of the world. In the meantime, region-specific guidelines should be followed. Lipid lowering with statin therapy does correlate with reductions in cardiovascular event rates in women. The clinical impact of treating dyslipidemias in women with nonstatin drugs (eg, fibrates, nicotinic acid, bile acid-binding resins, omega-3 fish oils) is as yet not determined.

Unmasking of childhood hypothyroidism by disseminated xanthomas

Secondary hyperlipidemia is a common laboratory finding in children with nephrotic syndrome, diabetes mellitus, and hypothyroidism. However, clinical signs of hyperlipidemia are extremely rare in childhood. We report on an 11-year-old girl who presented with a disseminated yellow papulomatous rash on the lower limbs and yellow skin creases on the palms of her hands. Blood tests yielded an opaque serum with a triglyceride concentration of 820 mg/dL and cholesterol of 1050 mg/dL. Skin biopsy of one of the papules confirmed the diagnosis of xanthomas. Additional examinations revealed clinical (weight gain, diminished growth rate) and biochemical primary hypothyroidism (free T4: 0.4 ng/L [normal 8-22 ng/L]; thyroid-stimulating hormone: >200 mU/L) as a consequence of Hashimoto thyroiditis (thyroid peroxidase and thyroglobulin: 4400 U/mL and >2000 U/mL, respectively; normal <60 U/mL). The patient was started on L-thyroxine, which led to a gradual decline of cholesterol and triglycerides to normal concentrations and a complete remission from the xanthomatous rash. For the first time, this case depicts disseminated xanthomas of the skin as the presenting complaint of severe hypothyroidism. hyperlipidemia, hypothyroidism, xanthoma.

Pharmacologic and surgical treatment of dyslipidemic children and adolescents

A wide variety of treatment modalities have been used in children with dyslipidemias to reduce the concentrations of atherogenic lipoprotein particles. Most of the published experience has focused upon children with familial hypercholesterolemia (FH). A variety of pharmacologic regimens have been utilized with variable degrees of success. The bile acid sequestrants colestipol and cholestyramine, lovastatin, pantethine, paraminosalicylic acid, and fenofibrate have all been successful in reducing total blood cholesterol concentrations by 18-24% in hypercholesterolemic children. Of these medications, only the bile acid sequestrants are not absorbed into the circulation. This theoretic advantage is paralled by long-term safety studies which indicate the absence of serious adverse effects with bile acid sequestrant therapy. Therefore, the bile acid sequestrants represent the drugs of choice in treating severely dyslipidemic children. In selected cases of profoundly dyslipidemic children, other therapeutic strategies have been utilized. Most of these efforts have been directed in the treatment of the child homozygous for FH. Despite the lipid lowering effects of partial ileal bypass surgery in hypercholesterolemic adults, homozygous familial hypercholesterolemic children are not adequately treated by this approach. Portacaval shunt has reduced the total cholesterol concentrations by 20-35% in homozygous FH children without having a negative impact on growth and development. These children have, however, gone on to develop atherosclerotic cardiovascular disease despite therapy. Liver transplantation has led to virtual normalization of the plasma lipoprotein concentrations in 3 children homozygous for familial hypercholesterolemia, and there is evidence for regression of vascular lesions in the coronary arteries in one of these children. However, considering the expense, the difficulty in posttransplantation management, and the irreversible nature of the therapy, liver transplantation should be reserved as the therapy of last resort for homozygous FH. The best therapy for FH homozygotes is the frequent removal of the atherogenic lipoproteins by one of the several apheresis procedures currently available. Total plasma exchange, immunoadsorption, membrane filtration, dextran sulfate adsorption, and heparin extracorporeal precipitation have all been used successfully in significantly reducing the concentrations of total and low-density lipoprotein cholesterol. Studies currently under way will more extensively evaluate the long-term safety as well as the efficacy of apheresis procedures.

Eruptive xanthomas in a child with the nephrotic syndrome

In a 4-year-old boy with steriod-resistant syndrome and extreme hyperlipidemia, an intense pruritic papular eruption developed on the trunk, buttocks, and extensor surface of the extremities. Findings from a skin biopsy specimen were consistent with an eruptive xanthoma. The patient was treated with gemfibrozil (Lopid), a low-fat diet, and antihistamines. Within 1 month pruritus diminished, the cutaneous lesions resolved, and serum lipid levels declined.

Lipoprotein measurements--a necessity for precise assessment of risk in children from high-risk families

Serum lipids and lipoproteins were measured in 67 high-risk children, aged between 2 and 17 years, who were the offspring of 33 fathers with hypercholesterolaemia. 18 of the 33 fathers had had a myocardial infarction (MI) before 44 years of age. In 15 of the fathers there was no history of accelerated coronary heart disease (CHD). No difference in the concentrations of the serum lipids and lipoproteins was found between the children whose fathers had a history of MI (n = 31) and the children with no family history of CHD (n = 36). Serum lipids and lipoproteins were also measured in a control group of 19 children, aged between 2 and 17, whose parents were normolipaemic and had no history of atherosclerosis. Serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDLc) concentrations were significantly higher—5·47 ± 1·36 mmol/l (211 ± 52 mg/100 ml) and 3·55 ± 1·16 mmol/l (137 ± 45 mg/100 ml) respectively—in the 67 `high-risk' children than in the control group—TC, 4·46 ± 0·64 mmol/l (172 ± 25 mg/100 ml); LDLc, 2·56 ± 0·64 mmol/l (99 ± 25 mg/100 ml). No statistically significant difference was found in serum triglyceride (TG) or high-density lipoprotein-cholesterol (HDLc) concentrations between these two groups. In 7 of the high-risk children, raised levels of serum TC >5·74 mmol/l (>221 mg/100 ml) were due to raised HDLc >1·95 mmol/l (>75 mg/100 ml) and normal LDLc <3·84 mmol/l (<148 mg/100 ml). In spite of their increased TC levels these children are probably at a lower risk for CHD as a result of the protective effect of HDL. In 3 children, raised concentrations of LDLc (>3·84 mmol/l) were accompanied by low levels of HDLc (<1·19 mmol/l) and normal concentrations of TC (<5·74 mmol/l). These children are probably at the highest risk for CHD. The correct diagnosis would have been missed in 10 (15%) of the children had only TC been measured. It is therefore imperative to measure lipoprotein levels in addition to TC in all children from `high-risk' families, regardless of their TC concentrations.

Screening for familial hyper-beta-lipoproteinaemia in children in hospital

1510 plasma cholesterol estimations were made in 1391 children admitted to hospital as part of a biochemical profile. Babies under 1 year and children known to have familial hyperlipoproteinaemia were excluded. The mean concentration was 4-28 mmol/l +/- 1-04 (1 SD) (165-3 mg/100 ml +/- 38-6), and levels exceeded 5-93 mmol/l (229 mg/100 ml) in 68 children. Repeat estimations on 55 of these children showed 34 still to have values greater than 5-93 mmol/l and family studies were performed in 19 of these. In 8 children hypercholesterolaemia was secondary and no familial lipoprotein disorder was present. Familial hyper-beta-lipoproteinaemia (FH) was diagnosed in 3 children and in 2 of the families there was a history of early ischaemic heart disease. In 2 children the diagnosis was in doubt. In the remaining 6 children FH and secondary hyperlipoproteinaemia were excluded so the hypercholesterolaemia was presumably environmentally induced, possibly in association with polygenic inheritance. In the present state of knowledge screening of the childhood population for FH by means of plasma cholesterol determinations cannot be recommended. Studies of lipoproteins should, however, be made in children from families known to have FH or early coronary heart disease.

Primary hyperlipoproteinemia in childhood and adolescence: identification and treatment of persons at risk for premature atherosclerosis

Determination of serum cholesterol values in three populations of children and adolescents, totalling 4013 subjects aged 1 month to 20 years, revealed 16 cases of primary hyperbetalipoproteinemia (overall frequency, 1:251) and led to the detection of the disorder in 12 asymptomatic siblings. The upper limit of normal for serum cholesterol concentration was approximately 200 mg/dl at all ages studied. Dietary treatment was instituted in patients whose serum cholesterol value exceeded this limit and in whom a primary lipid defect was confirmed; the serum cholesterol value decreased in all patients who adhered to the diet. However, since the potential hazards and long-term results of dietary treatment, with or without drug therapy, in growing children are not known, such treatment should be reserved for affected children with a family history of premature atherosclerosis, and follow-up is essential.