Page 578 - Concise Pathology for Exam Preparation ( PDFDrive )

20 Endocrinology 563

Vascular system:
• Accelerated atherosclerosis (hallmark)
• Gangrene and myocardial infarction
• Hyaline arteriolosclerosis (amorphous hyaline thickening of the wall of the arterioles
causing narrowing of the lumen)
• Diabetic microangiopathy (diffuse thickening of the basement membrane, most evident
in the capillaries of the skin, skeletal muscle, retina, renal glomeruli, renal tubules, pe-
ripheral nerves and placenta)
Diabetic nephropathy:
• Microalbuminuria: Earliest manifestation of diabetes is the appearance of low amounts of
albumin in urine (.30 mg/day but ,300 mg/day).
• Glomerular lesions:
• Capillary basement membrane thickening
• Diffuse mesangial sclerosis
• Nodular glomerulosclerosis (Kimmelstiel–Wilson lesion; pathognomic of diabetes)
• Renal vascular lesions: Renal arteriosclerosis and atherosclerosis
• Pyelonephritis including papillary necrosis (necrotizing papillitis)
Diabetic ocular complications:
• Retinopathy
• Cataract
• Glaucoma
Diabetic neuropathy:
Central and peripheral nervous systems are both affected. It alters both motor and sensory
functions.
Defective immunity:
• Enhanced susceptibility to infections
• Defects in neutrophilic function

Q. Enumerate the criteria for diagnosis of DM. Enlist the investigations
advocated in a patient of DM.
Ans. Diagnostic criteria for diabetes mellitus are described in Table 20.2.

TABLE 20.2. Diagnostic criteria for diabetes mellitus

• HbA1C . 6.5%
• Symptoms of diabetes plus random plasma glucose . 200 mg/dL (symptoms of diabetes plus
random whole blood glucose . 175 mg/dL)
OR
• Fasting plasma glucose . 126 mg/dL; fasting is defined as no calorie intake for at least 8 h (fasting
whole blood glucose . 110 mg/dL)
OR
• Two-hour plasma glucose . 200 mg/dL during an oral 75 g glucose tolerance test (whole blood
. 175 mg/dL)
In the absence of unequivocal hyperglycaemia or presence of acute metabolic decompensation, these criteria
should be confirmed by repeat test.
Impaired fasting glucose (IFG)
• Fasting plasma glucose .110 mg/dL but ,125 mg/dL (whole blood glucose .100 mg/dL but
,110 mg/dL)
Impaired glucose tolerance (IGT)
• Plasma glucose between 140 mg/dL and 200 mg/dL, 2 h after oral glucose load (whole blood
glucose between 125 mg/dL, 2 h after oral glucose load)

Determination of Blood Glucose
• Glucose concentration is uniform in water phase of plasma and erythrocytes. Since,
plasma contains per unit volume 27% more water than erythrocytes, glucose levels are
higher in a given volume of plasma than in an identical volume occupied by erythrocytes.
For this reason, plasma glucose values are higher than whole blood glucose values.

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