Search This Site

Monday, December 15, 2008

In which type of hypertriglyceridemia are chylomicron & VLDL remnants increased

Question 26
In which type of hypertriglyceridemia are chylomicron & VLDL remnants increased .
a.       I
b.      IIa
c.       III
d.      IV
Answer :
C) Type III
Reference :
Harper 27th Edition Page 239
Discussion
Lipoproteins have been classified on the basis of their densities into five major classes:(1) chylomicrons, (2) very low density lipoproteins (VLDL), (3) intermediate-density lipoproteins (IDL), (4) LDL, and (5) high-density lipoproteins (HDL).
Explanation
Name
Defect
Remarks
Familial Type III Hyperlipoproteinemia (Broad beta disease, remnant removal disease, familial dysbetalipoproteinemia)
Deficiency in remnant clearance by the liver due to abnormality in apo E. Patients lakc Isoforms E3 and E4 and have only E2 which does not react with E receptor
Comments
This answer is based on Harper. There are few differences between the table given in Harper (Table 26.127th Edition Page 239) and Table 344-4 in Harrison (15th Edition). If the question had asked about Chylomicrons alone or VLDL alone, then the answer would have to be based on Harrison
Characteristics of Common Hyperlipidemias (From Harrison)
Lipopoteins
Lipid Phenotype
Plasma Lipid Levels,
mmol/L (mg/dL)
Elevated
Phenotype
Clinical Signs
ISOLATED HYPERCHOLESTEROLEMIA
Familial hypercholesterolemia
Heterozygotes: total chol = 7-13 (275-500)
LDL
IIa
Usually develop xanthomas in adulthood and vascular disease at 30-50 years
Homozygotes: total chol > 13 (>500)
LDL
IIa
Usually develop xanthomas and vascular disease in childhood
Familial defective apo B100
Heterozygotes: total chol = 7-13 (275-500)
LDL
IIa
Polygenic hypercholesterolemia
Total chol = 6.5-9.0 (250-350)
LDL
IIa
Usually asymptomatic until vascular disease develops; no xanthomas
ISOLATED HYPERTRIGLYCERIDEMIA
Familial hypertriglyceridemia
TG = 2.8-8.5 (250-750) (plasma may be cloudy)
VLDL
IV
Asymptomatic; may be associated with increased risk of vascular disease
Familial lipoprotein lipase deficiency
TG > 8.5 (>750) (plasma may be milky)
Chylomicrons
I, V
May be asymptomatic; may be associated with pancreatitis, abdominal pain, hepatosplenomegaly
Familial apo CII deficiency
TG > 8.5 (>750) (plasma may be milky)
Chylomicrons
I, V
As above
HYPERTRIGLYCERIDEMIA AND HYPERCHOLESTEROLEMIA
Combined hyperlipidemia
TG = 2.8-8.5 (250-750)
Total chol = 6.5-13.0 (250-500)
VLDL, LDL
IIb
Usually asymptomatic until vascular disease develops; familial form may also present as isolated high TG or an isolated high LDL cholesterol
Dysbetalipoproteinemia
TG = 2.8-5.6 (250-500)
Total chol = 6.5-13.0 (250-500)
VLDL, IDL; LDL normal
III
Usually asymptomatic until vascular disease develops; may have palmar or tuboeruptive xanthomas
NOTE: total chol, the sum of free and esterified cholesterol; LDL, low-density lipoprotein; TG, triglycerides; VLDL, very low density lipoproteins; IDL, intermediate-density lipoprotein.
Tips
There is an association between patients possessing the apo E4 allele and the incidence of Alzheimer’s disease. Apparently apo E4 binds more avidly to beta amyloid found in neuritic plaques

No comments:

Post a Comment

If you cannot locate what you want to find, please search using the box given below