E78

Disorders of lipoprotein metabolism and other lipidemias

Category E78 encompasses a diverse group of metabolic conditions characterized by abnormal levels of lipids (cholesterol and triglycerides) and lipoproteins in the blood. Lipoproteins are complex particles that transport hydrophobic lipids through the aqueous environment of the bloodstream. These disorders may manifest as elevation of plasma cholesterol (hypercholesterolemia), elevation of plasma triglycerides (hypertriglyceridemia), or both (mixed hyperlipidemia). Additionally, this category includes lipoprotein deficiencies and specific disorders of bile acid metabolism. Clinically, these disorders are of paramount importance because they are major, modifiable risk factors for the development of atherosclerotic cardiovascular disease (ASCVD), including coronary artery disease, cerebrovascular disease, and peripheral arterial disease. Severe elevations in triglycerides (often exceeding 1,000 mg/dL) also carry a significant risk for acute pancreatitis. These conditions can be primary (inherited genetic mutations such as Familial Hypercholesterolemia) or secondary to underlying factors like diet, obesity, diabetes mellitus, or certain medications.

Clinical Symptoms

  • Asymptomatic presentation (most common)
  • Xanthelasma (yellowish cholesterol deposits on or around eyelids)
  • Tendinous xanthomas (firm, subcutaneous nodules often found on the Achilles tendon or extensor tendons of the hands)
  • Eruptive xanthomas (small, yellowish-red papules appearing suddenly on the back, buttocks, or limbs in cases of severe hypertriglyceridemia)
  • Corneal arcus (a white, gray, or blue opaque ring in the corneal margin, especially significant if found in patients under age 45)
  • Palmar xanthomas (yellowish deposits in the creases of the palms, associated with Type III Dysbetalipoproteinemia)
  • Acute abdominal pain or pancreatitis (associated with severe hypertriglyceridemia)
  • Hepatosplenomegaly (enlargement of the liver and spleen, seen in specific chylomicronemia syndromes)
  • Lipemia retinalis (milky appearance of the retinal vessels)

Common Causes

  • Genetic mutations (e.g., mutations in LDLR, APOB, or PCSK9 genes causing Familial Hypercholesterolemia)
  • High-saturated fat and trans-fat dietary intake
  • Obesity and sedentary lifestyle
  • Type 2 diabetes mellitus (often resulting in diabetic dyslipidemia)
  • Chronic kidney disease and Nephrotic syndrome
  • Hypothyroidism (which reduces the clearance of LDL)
  • Alcohol consumption (particularly impacting triglyceride levels)
  • Medications (e.g., corticosteroids, thiazide diuretics, beta-blockers, and certain antipsychotics)
  • Pregnancy (which physiologically increases lipid levels but may unmask underlying disorders)

Documentation & Coding Tips

Distinguish between pure hypercholesterolemia and mixed hyperlipidemia.

Example: Assessment and Plan: Patient presents with persistent elevation of both LDL (190 mg/dL) and triglycerides (250 mg/dL), consistent with Mixed Hyperlipidemia (E78.2). This chronic condition is currently managed with Atorvastatin 40mg and lifestyle modifications. ASCVD 10-year risk is calculated at 15.5 percent, warranting aggressive lipid management to prevent coronary artery disease (I25.10).

Billing Focus: Identify specific lipid fractions (LDL vs. Triglycerides) to select E78.0x versus E78.2.

Document specific genetic variants such as Familial Hypercholesterolemia (FH).

Example: Diagnosis: Heterozygous Familial Hypercholesterolemia (E78.01). Patient has a confirmed LDLR mutation and a family history of premature MI in a first-degree relative. Current LDL is 210 mg/dL despite high-intensity statin therapy. Will initiate PCSK9 inhibitor (Evolocumab) and monitor closely for atherosclerotic progression.

Billing Focus: Use E78.01 for FH rather than E78.00 to indicate the genetic etiology.

Link hyperlipidemia to manifesting clinical signs like xanthomas.

Example: Physical Exam: Notable for bilateral Achilles tendon xanthomas and corneal arcus in a 35-year-old male. Assessment: Hyperchylomicronemia (E78.3) with secondary skin manifestations. Triglycerides exceed 1000 mg/dL, putting the patient at high risk for acute pancreatitis (K85.90).

Billing Focus: Documentation of physical manifestations (xanthomas) supports the specificity of Fredrickson Type codes.

Capture Lipoprotein(a) elevations as a distinct clinical entity.

Example: Assessment: Elevated Lipoprotein(a) (E78.41). While LDL is well-controlled at 70 mg/dL, Lp(a) is significantly elevated at 180 nmol/L. This independent risk factor for calcific aortic stenosis and myocardial infarction is noted in the context of the patient's existing essential hypertension (I10).

Billing Focus: Use the 2026-specific code E78.41 for Lp(a) rather than the generic other hyperlipidemia code.

Explicitly state when hyperlipidemia is secondary to other conditions like Diabetes or Hypothyroidism.

Example: Assessment: Secondary Mixed Hyperlipidemia (E78.2) due to poorly controlled Type 2 Diabetes Mellitus with hyperglycemia (E11.65). Triglyceride elevation is directly correlated with HbA1c of 9.2 percent. Management focused on insulin optimization and fibrate therapy to mitigate cardiovascular risk.

Billing Focus: Code the underlying condition (Diabetes) first if it is the primary cause of the lipid disorder.

Relevant CPT Codes

Related Diagnoses

Hierarchy