Diabetes mellitus

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Diabetes

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Definition
• A chronic multisystem disease characterized by
hyperglycemia related to
• Absent or insufficient insulin production
• Impaired insulin utilization
• cells stop responding to insulin
• Or both
• Prevalence is increasing worldwide

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•Normal blood suger is
•70-120mg/dl
•3.9-6.66nmol/L
•Insulin production
•40-50 U daily
•0.6U/kg of body weight
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Etiology and Pathophysiology
•Theories link cause to single/ combination
of these factors:
•Genetic
•Autoimmune
•Viral
•Environmental (e.g. stress)

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Diabetes Mellitus
Insulin
•Produced by the  cells of Islets of Langerhans
•Released continuously into bloodstream in small
increments with larger amounts released after food
intake.

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Normal Insulin Secretion
Fig. 49-1

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Functions of Insulin
• Transports and metabolizes glucose for energy
• Stimulates storage of glucose in the liver and muscle as glycogen
• Inhibits gluconeogenesis : Production of new glucose from amino
acids and other substrates by liver
• Enhances fat deposition
• Enhances the storage of dietary fat in adipose tissue
• Accelerates transport of amino acids into cells

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•Counter-regulatory hormones
•Opposite effects of insulin
•Increase blood glucose levels
•Help maintain normal blood glucose levels
•Examples
•Glucagon, epinephrine, growth hormone,
cortisol

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Diabetes Mellitus
Glucagon:
• secreted by the alpha cells of islets of Langerhans.
• released when blood glucose levels decrease and stimulates the
liver to release stored glucose.
• Glycogenolysis: breakdown of glycogen in liver to produces
glucose
• Gluconeogenesis : breakdown of noncarbohydrate substances to
produce glucose, including amino acids

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Risk Factors
•family history of diabetes
•Obesity BMI ≥27 kg/m2)
•age greater than 45 years
•Hypertension ≥ 140/90,
•HDL cholesterol ≤ 35 and/or triglycerides ≥ 250,
• history of gestational diabetes ‫الحمل‬ ‫سكري‬

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Classifications of Diabetes
1. Type 1 diabetes
2. Type 2 diabetes
3. Gestational diabetes
4. secondary diabetes mellitus: associated with
other conditions or syndromes

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Diabetes Mellitus- Signs & Symptoms
• Without enough insulin activity, the glucose stays in
your blood leading to hyperglycemia = elevated
blood glucose level.
• Polyuria = increase urine production
• Polydipsia = increased thirst
• Polyphagia = increased hunger and eating

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Diabetic Ketoacidosis (DKA)

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Diabetic Ketoacidosis DKA
• Caused by profound insulin deficiency
• results in disorders in the metabolism of carbohydrate,
protein, and fat.
• Most likely occurs in type 1
• 3 main clinical features of DKA
• Hyperglycemia
• Dehydration and electrolyte loss
• Ketosis
• Acidosis

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Pathophysiology
• Effects of hyperglycemia.
• Kidneys excrete the glucose along with water and
electrolytes (eg, sodium, potassium).
• Excessive urination (polyuria), leads to dehydration and
marked electrolyte loss.
• Without insulin, glucose cannot enter cells to make
energy.
• Cells start to break down fats for energy.
• Breaking of fats produces ketones, an acid end product.
• Free fatty acids converted into ketone bodies by the liver.
• Excessive production of ketone bodies(metabolic
acidosis).

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Acute Complications (Cont’d)
• Precipitating factors ???
• Illness
• Infection
• Inadequate insulin dosage
• Undiagnosed type 1
• Poor self-management
• Errors in insulin dosage
• missed dose of insulin
• Neglect

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Clinical Manifestations
• polyuria
• polydipsia
• blurred vision, weakness, and headache
• hypotension
• Weak and rapid pulse.
• GI symptoms: anorexia, nausea, vomiting, and abdominal
pain.
• acetone breath (fruity odor)
• Hyperventilation with very deep respirations: body's
attempt to decrease the acidosis
• mental status changes (alert, lethargic, or comatose)

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Diagnostic Findings
• Blood glucose levels vary between 300 and 800 mg/dL.
• others have values of 1000 mg/dL or higher ( depending
on the degree of dehydration).
• Some patients have severe acidosis with modestly
elevated blood glucose levels, whereas others have no
evidence of DKA despite blood glucose levels of 400 to
500 mg/dL
• Kussmaul breathing is a deep and
labored breathing pattern often associated with severe
metabolic acidosis,

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Diabetes Mellitus- Complications
Over time, having too much glucose in your blood can
cause serious problems= long-term complications:
• Cardiovascular disease = atherosclerosis,
coronary artery disease, myocardial infarction,
heart failure, aortic aneurysm, stroke and even
gangrene of the toes or feet leading to the need to
remove a limb = amputation.
• Damage to the eyes = retinopathy, cataracts,
glaucoma, blindness.
• Damage to the kidneys = nephropathy,
glomerulosclerosis, renal failure
• Damage to the nerves = neuropathy
• Increased susceptibility to infections

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