Study Guides (238,606)
Canada (115,249)
Biochemistry (220)

Lecture 6- Lipid Tests.docx

5 Pages
Unlock Document

Western University
Biochemistry 3386B
L.Graham Smith

Lecture 6: Lipid Tests Why order them?  As a part of a general physical check up of an apparently healthy person  As part of a diagnostic investigation of an unwell patient (abnormality in the lipid profile) Assessment by a Physician:  Talks to the patient (history, documentation of symptoms etc.)  Observes patient while taking a history (type of obesity, presence of xanthomas) o Xanthoma: a white ring around the eye, indicative of a lipid abnormality, these are lipid deposits – not as big of a deal in older patients  Physical examination (weight, height, blood pressure, HR)  Orders the appropriate tests Indications of a Plasma Lipid Profile  Men ≥ 40 years old  Women  post-menopausal and/or ≥ 50 years old  Diabetes mellitus  includes lipid abnormalities  Hypertension (≥ 140/90 mmHg or taking hypertensive medications – may have forgotten to take their medications)  note systeole/diastole  Current or recent (within the previous year) cigarette smoking  Obesity  Family history of premature CAD (coronary artery disease) <60 years in first degree relatives (ie. Siblings or parents)  Inflammatory disease o Systemic lupus, erythematosis, rheumatoid arthritis, psoriasis)  Autoimmune – constant inflammation  Chronic kidney disease  Evidence of atherosclerosis (hardening of arteries – lesions)  HIV infection treated with highly active antiretroviral therapy  Manifestations of hyperlipidemia o Xanthelasma, xanthoma, premature corneal arcus  Erectile dysfunction (vascular problems)  Monogenic familial (genetic) lipid disorders (screen everyone in the family, including children) First Line Diagnostic Lipid Tests:  Total Cholesterol  Triglycerides  HDL-Cholesterol  LDL-Cholesterol Patient Preparation  Minimum 9-12 hour fast (usually overnight; water is permitted)  Habitual activity, diet  Stable weight over the past 4 weeks  No acute or recent illness, surgery or injury (esp. myocardial infarction, or coronary bypass surgery) o Dealing with stress o There will be a lipid suppression Reference Ranges  Total Cholesterol: ≤ 5.2 mmol/L  Triglyceride: ≤ 1.5 mmol/L  HDL Cholesterol: 1.30-1.55 mmol/L (doesn’t matter because it is good cholesterol) Approach to Diagnosis  Look at history and clinical evaluation  Evaluate the lipid test results (Tg, Chol, HDL-C)  Calculate a 10 year risk of CHD (coronary heart disease) based on: o Age o Lipid levels o Blood pressure o Smoking status o Diabetes  Consider primary – idiopathic (unknown cause) or genetic (family history) – causes  Evaluate a need for further tests (Apo E Phenotype, Lp(a))  Treat the primary cause if present Abnormal Results Hypercholesterolemia  Due to elevated LDL-C  a major risk factor in CHD  Due to elevated HDL-C  beneficial ≥ 1.55 mmol/L is actually protective against CHD o Benefit: remove cholesterol from tissues  reduce the deposition of cholesterol  Due to elevated LDL-C and HDL-C  the adverse effects of elevated LD will be offset by beneficial effects of elevated HDL-C (depending on the proportions of each)  If famililal genetic cause may be a defective LDL Receptor (impairs liver removal of LDL), apoB-100 or apo-E Hypocholesterolemia (misnomer)  In hyperthyroidism (look at TSH – manifestation)  Patient is being treated with drugs for hypercholesterolemia Examining the 10 year Risk of Total Cardiovascular Disease The Framingham Heart Study  Looking at the risk  Good = High HDL-C and BP<120  0 = neutral  points allotted based on criteria: o age o HDL-C o Total Cholesterol (problem around 4 pts) o SBP (systolic BP) o Smoker o Diabetic  Risk calculated is doubled if there is a first-degree relative with CV disease before the age of 60  There is differences in men and women o Women have an advantage to surviving a cardiovascular event  Low Risk = <10%  Medium Risk = 10-19%  High Risk = >19% Hypertriglyceridemia  An elevated triglyceride concentration is an independent risk factor for CHD  Inversely associated with a low HDL cholesterol concentration  Marked increases in triglyceride concentrations (ie. >10mmol/L) are associated with a significant risk of pancreatitis  can be life threatening o Want to keep it <5.6 mmol/L to reduce the risk of pancreatitis  If familial (genetic) it may be due to: o overproduction of VLDL triglycerides o over production VLDL triglycerides in combination with delayed catabolism of VLDL and chylomicrons (impaired clearance) o ApoC-II deficiency – which activates lipoprotein lipase o Lipoprotein lipase deficiency Combined Hypercholesterolemia and Hypertriglyceridemia  Occurs when VLDL, IDL and/or chylomicrons are elevated  If familial (genetic) may be due to: o Overproduction of VLDL apoB-100 o apoE deficiency  results in impaired hepatic clearance of chylomicron or remnant particles
More Less

Related notes for Biochemistry 3386B

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.