| How is dx of chylomicronemia? | TG (>1000 if fasting, >2000 if not fasting)
Clinical signs (Lipidic drugs, acute pancreatitis (most severe), eruptive xanthomas (tender, small, yellow palpable skin lesions in elbowns, knees, ankles, when TG decreases size decreases), Lipidic retina (pink colored retina w/ no effect on vision), dyspnes, steatosis, neuro sequalae.) |
| How is Normal physiology of chylomicronemia? | TG increase (diet/ endogenous production in liver), chylomicron start appearing 1-3 hours after fatty meal, 12-14 hours of fasting no chylomicrons in plasma, LPL hydrolyses TGs/chylomicrons to chylomicron remnants |
| What are etiologies causing chylomicronemia? | Primary (genetic) moderate elevation in TGs (400-600) except familial chylomicronemia syndrome (FCS) LPL deficiency which increase alot in childhood.
Secondary |
| What are primary causes of chylomicronemias? | FCS (most common, LPL deficiency or ApoCII deficiency or LPL inhibitors, cause infancy HyperTG low tolerance to fat)
Familial combined hyperlipidemia (FCHL) (increased VLDL and TG and IDL and LDL and CT and decreased HDL)
Familial hypertriglyceridemia (FHTG) (increased VLDL and TG and decreased HDL, with normal LDL IDL and CT)
Dysbetalipoproteinemia (remnant removal disease, Type III hyperlipoproteinemia, defect ApoE, accumulation of remnant VLDL and chylomicrons (VLDL and TG high, LDL CT high , HDL low) |
| What are secondary causes of chylomicronemia? | Pregnancy (increase TG due to estrogen), steroids, OCP, DM (increase T6), hypothyroidism, Cushing's, Nephrotic syndrome. |
| What are goals of tx of hyperTG? | decrease TG <1000, low fat diet and exercise.
Drugs: Fibrates (gentibiozil/fenofibrate): activate LPL to decrease TG, tx of acute pancreatitis as well, no decrease of CVD for TG>400
Omega-3: Normal TG decrease, doesn't decrease CVD, purified decrease TG and CVD.
So if TG 300 give omega 3 (if no risk for pancreatitis as well)
Note: Statins decrease LDL and CVD risk. |
| What are genetic causes of low HDL? | ApoA1 complete deficiency (mutation), LCAT complete deficiency (partial fish eye disease), ABC-1 (tangier disease familial hypoalphalipoproteienemia), metabolic syndrome (FCH w/low HDL) |
| How is reverse cholesterol transport mechanism? | Activated PPARa will cause release of free cholesterol outside cells (efflux), which will lead to LCAT activation to convert pre-b-HDL into HDL, thus HDL will increase (rich in ApoAI and II), go to liver cells, and increase cholesterol catabolism and elimination (important mechanism for hypercholesterolism |
