心臟病及保健 Heart Disease And Health http://心臟病.tw www.heartdisease.idv.tw
Andrew Ying-Siu Lee, MD,PhD.
Diabetes mellitus (DM) is due to deficiency of insulin secretion and/or resistance of body's cells to action of
insulin (= insulin resistance) leading to high blood sugar (=hyperglycemia) and disturbances of carbohydrate, fat and
protein metabolism in our body, resulting in diabetic symptoms and complications.
Symptoms of DM include: thirst, polydipsia, polyuria, weight loss,tiredness and malaise, constipation
(due to dehydration), recurrent or refractory infections, visual disturbance, paresthesia (due to peripheral
nerve damage), pruritus, cramp (due to diuresis) etc.
Acute complications of DM include:-
(1) Hypoglycemia: Predisposing factors are: excessive dose of insulin or oral hypoglycemic drugs,
inadequate or delayed food intake, sudden or prolonged exercise, renal and
hepatic failure, diabetic gastroparesis, age, pregnancy, drugs, alcohol, medical
conditions (heart failure, cardiogenic shock, starvation, sepsis, lactic acidosis,
adrenal insufficiency etc.). Autonomic symptoms include: palpitation, diaphoresis,
anxiety, hunger, irritability, pallor, nausea, angina. Neuroglycopenic symptoms
include: headache, weakness, fatigue, confusion, amnesia, blurred vision, focal
neurologic deficit, seizure, coma etc.
(2) Diabetic ketoacidosis (DKA) and hyperglycemic hyperosmolar syndrome (HHS) :
Predisposing factors are: coexistent medical illness (eg. infection, silent myocardial
infarction, stroke, pancreatitis, mesenteric ischemia), drugs (diuretics, sedative),
insulin omission and eating disorder. Symptoms include: nausea, vomiting, thirst,
polyuria, abdominal pain, signs of dehydration, acidotic respiration, ketones on breath,
hypothermia, deficits in electrolytes (Na, K, Mg, PO4), conscious disturbance.
Chronic complications of DM include:
Eye – retinopathy, maculopathy, cataract, squint
Ear – deafness
Kidney – nephropathy, renal failure, chronic pyelonephritis
Nerve – peripheral, autonomic neuropathy
Heart - coronary artery disease, heart failure
Leg – peripheral vascular disease
Brain – stroke
Feet – ulcer, infection, gangrene
Skin – dermopathy, necrobiosis lipoidica
American diabetes association diagnostic criteria for diabetes mellitus:-
nDiabetes mellitus (DM) –
- symptoms of DM + casual plasma glucose > 200 mg/dl
- repeated fasting plasma glucose > 126 mg/dl
- repeated plasma glucose > 200 mg/dl at 2 hours after 75 gm oral glucose challenge (not recommended
for routine use)
nImpaired fasting glucose –
fasting plasma glucose 110-126 mg/dl
nNormal fasting glucose –
fasting plasma glucose < 110 mg/dl
American diabetes association classification of diabetes mellitus:-
nType 1 DM (5-10%) : caused by pancreatic beta cell destruction, often immune mediated à loss of insulin
secretion (absolute insulin deficiency). Common in children and adolescent,
characterized by abrupt onset of severe symptoms, need insulin to substain life,
prone to ketosis.
nType 2 DM (90-95%): caused by genetic and nongenetic factors (eg. age, high calorie intake, overweight,
central obesity, sedentary lifestyle etc) --> insulin resistance and relative (not absolute)
nOther specific types of DM (1-2%) : causes include genetic defects affecting beta cell function or insulin
action, endocrinopathies, drugs, infection etc.
nGestational DM(3-5%): caused by insulin resistance and relative insulin deficiency associated with
Type 1 DM need insulin therapy. If inadequate, oral hypoglycemic drugs such as metformin,
glitazones oracarbose can be added. Types 2 DM need oral hypoglycemic drugs including : insulin
secretagogues (sulfonyluras, meglitinides,phenylalanine derivatives), metformin, peroxisome
proliferator-activated receptor (PPAR_ modulators (thiazolidinediones), glinides (starlix, novonorm).
If inadequate, single injection of intermediate-acting insulin at bedtime can be added.
Aside from drug therapy, the mainstays of DM control = weight loss, diet control, exercise, stop
smoking, abstain alcohol and change of lifestyles. Ideal DM control can prevent (1) ketoacidosis and
hyperosmolar coma, (2) diabetic symptoms and (3) diabetic complications.
Age-adjusted goals of treatment of DM:-
preprandial postprandial HbA1c urinary glucose
blood sugar blood sugar and ketones
prescholars 150-160 < 250 7.5-8.5% glycosuria but rare ketonuria
adults 140-150 < 160 6.5-7.4% intermittent glycosuria, rare ketonuria
elderly with 150-160 < 250 7.5-8.5% ,,
HbA1c = glycosylated glucose attached to hemoglobin indicating
glycemic load during 120 day lifespan of red blood cell