Post on 17-Dec-2015
Diabetes MellitusDiabetes Mellitus Pathology and complicationsPathology and complications
ByByDr. Abdelaty ShawkyDr. Abdelaty Shawky
Assistant professor of pathology Assistant professor of pathology
Diabetes Mellitus Metabolic disease affecting CHO, protein and
fat metabolism due to insulin deficiency or
inefficiency.
Two types:
1.Type I (insulin dependent).
2.Type II (insulin independent).
TYPE I Type II
1. Age Under 25 years. Above 40 years.
2. B. Cell mass. Reduced Not reduced.
3. Insulin
secretion
Reduced Not reduced
4. Etiology 1. Hereditary.
2. Autoimmune destruction of
the B.cells.
1. Decreased insulin
specific surface receptors
on most of the body cells.
2. Premature aging of body
cells including B.cells.
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* Pathological lesions:
1. Pancreas:
- In type I: the pancreas is atrophic. M/P:
degranulated and destroyed B.cells, lymphocytic
infiltration and fibrosis.
- In type II: the pancreas is normal. M/P: normal in
early stage, later on shows hyalinosis.
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2. Disturbance of metabolism:
A. Carbohydrate metabolism: Hyperglycemia due to
either decreased glucose utilization or due to
glycogenolysis, leads to:1. Glucose retention in the tissue (increase the liability to infection).2. Glycogen deposition in the tissues (heart, muscle, kidney and pancreas).3. Glucosuria: leads to osmotic diuresis and dehydration.
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B. Fat metabolism: Lipolysis: Leads to:1. Hperlipidaemia (atheroma formation and fatty infiltration in the parenchymatous organs).2. Formation of ketone bodies in the liver with keto-acidosis and coma.
C. Protein metabolism: Loss of weight.
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3. Vascular changes:1. Diabetic macroangiopathy: accelerated atherosclerosis in aorta, large and medium sized arteries. 2. Hyaline arterioloscelrosis: hyaline thickening of the arterioles due to deposition of hyaline material.3. Diabetic microangiopathy: diffuse thickening of the basement membranes due to deposition of hyaline material. Involves predominantly the capillaries of, retina, renal glomeruli, and peripheral nerves. Leads to diabetic nephropathy, retinopathy and neuropathy.
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* Complications of diabetes mellitus:
I. Acute complications:
1. Diabetic ketoacidosis2. Hypoglycemic coma
II. Chronic complications:a. Microvascular
Retinopathy Nephropathy Neuropathyb. MacrovascularI. Cerbrovascular.II. Cardiovascular.III. Peripheral vascular disease.
Diabetic ketoacidosis (DKA)
• May be the 1st presentation of type 1 DM.
• Result from absolute insulin deficiency or increase requirement.
• Mortality rate around 5%.
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* Predisposing factors for DKA• Infection • Trauma• Myocardial Infarction• Stroke• Surgery• Emotional stress
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* Clinical presentation of DKA:• Polyurea and polydepsia.• Nausea and vomiting.• Anorexia and abdominal pain.• Tachycardia.• Signs of dehydration.• Hypotonia.• Coma.
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* Diagnosis of DKA:
• Hyperglycemia• Ketonuria and ketonemia• Acidosis (PH< 7.3 )
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* Treatment of DKA:
• Fluid replacement. • Insulin therapy for hyperglycemia.• Electrolyte correction.• Acidosis correction.• Treatment of precipitating cause.
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* Complications of DKA:
• Cerebral edema• Vascular thrombosis• Infection• M I• Respiratory distress syndrome
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Hypoglycemic coma
• Hypoglycemia is the most frequent acute complication in type 1 diabetes.
• Hypoglycemia is the level of blood glucose at which autonomic and neurological dysfunction begins
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* Clinical manifestations of hypoglycemia:• Autonomic dysfunctions: 1. Hunger 2. Tremor 3. Palpitation 4. Anxiety 5. Pallor 6. Sweating
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• Neurologic dysfunctions: 1. Impaired thinking 2. Change of mood 3. Irritability 4. Headache 5. Convulsion 6. Coma
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* Predisposing factors:
• Missed meal• Change in physical activity• Alterations or errors in insulin dosage• Alcohol ingestion
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* Treatment of hypoglycemia
• In mild cases oral rapidly absorbed carbohydrate.
• In sever cases (comatose patient) I.V hypertonic glucose 25% or 50% concentration & glucagon injection.
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Chronic Complications of DM
A. Macrovascular Complications.
B. Microvascular Complications.
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A. Macro-vascular Complications:
• Accelerated atherosclerosis involving the aorta and
large- and medium-sized arteries.
• Myocardial infarction, caused by atherosclerosis of
the coronary arteries, is the most common cause of
death in diabetics.
• Gangrene of the lower extremities.• Hypertension due to Hyaline arteriolosclerosis.
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• Microvascular complications are specific to diabetes
and related to longstanding hyperglycaemia.
• In diabetes, the microvasculature shows both
functional and structural abnormalities.
• The structural hallmark of diabetic microangiopathy is
thickening of the capillary basement membrane.
B. Microvascular Complications
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• Many chemical changes in basement
membrane composition have been identified
in diabetes, including increased type IV
collagen and its glycosylation (i.e. binding of
glucose to wall of blood vessels).
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• The main functional abnormalities include increased
capillary permeability and disturbed platelet
function.
• Increased capillary permeability is manifested in the
retina by exudation and in the kidney by increased
urinary losses of albumin.
• Platelets from diabetic patients show an exaggerated
tendency to aggregate, perhaps mediated by altered
prostaglandin metabolism.24
Diabetic retinopathy
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* Pathological lesions:
•Thickening of the capillary basement membrane.
•Capillary dilatations (microaneurysms) which may give
rise to; haemorrhage or exudate (red dots and blots).
•Vascular occlusion leads to large ischaemic areas
(cotton-wool spots).
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Normal Retina
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Diabetic Retinopathy
Cotton wool spots
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Other Eye Complications
- Cataracts.- Glaucoma-Vitreous Bleeding.
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Vitreous Bleeding
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Diabetic Nephropathy (DN)
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- Diabetic nephropathy is defined by persistent
albuminuria (>300 mg/day), decrease glomerular
filtration rate and rising blood pressure.
- About 20 – 30% of patients with diabetes develop
diabetic nephropathy .
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Diabetic Neuropathy
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1. Sensorimotor neuropathy.2. Autonomic neuropathy.
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Sensorimotor Neuropathy
• Numbness, paresthesias.
• Feet are mostly affected, hands are seldom affected.
• Complicated by ulceration (painless), charcot
arthropathy, Callosities
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Complications of Sensorimotor neuropathy
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Autonomic Neuropathy
Postural hypotension.
Diabetic diarrhea.
Erectile dysfunction.
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The end
Mon 29 0ct 201339