Anesthesia Pharmacology: Diabetes
Late Complications of Diabetes
Atherosclerosis: more extensive and occurs earlier (accelerated course)
Lesions initiated by oxidized LDL
Increased platelet adhesiveness
Increase secretion of endothelin-1
Endothelin-1: powerful vasoconstrictor; vascular smooth muscle mitogen
Decreased nitric oxide production:
Nitric oxide: vasodilator; anti-mitogenic in vascular smooth muscle
Diabetes: procoagulant state
Increased levels of tissue factor
Deficiency of tissue factor pathway inhibitor type 1
Factor VIII elevated
Impaired fibrolysis: (probably as a result of increased tPA inhibitor, type 1)
Symptoms:
Intermittent claudication, gangrene, impotence (vascular)
Coronary artery disease; stroke:common
Silent myocardial infarction
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Diabetic retinopathy: leading cause of blindness in the U.S.
Retinopathic lesions
Simple (background)
Proliferative
Progression
Increased capillary permeability
Retinal capillary occlusion (saccular and fusiform aneurysms)
Vascular lesions associated with:
Proliferation of lining endothelial cells
Pericyte loss around vessels
Proliferative retinopathy is associated with new vessel formation and scarring.
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Renal disease: leading cause of death and disability due to diabetes.
50% of end-stage renal disease in United States: diabetic nephropathy
Complication rates:
35% of IDDM patients
15 to 60% of NIDDM patients (ethnic background dependent; highest -- Pima Indians;lowest- Europeans)
Two pathologic patterns
Diffuse (more common)
Widening of glomerular basement membrane
Menangial thickening
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Nodular
Periodic acid-Schiff-positive material: deposited at glomerular tuft periphery
Hyalinization of afferent and efferent arterioles
deposition of albumin and other proteins in tubules and glomeruli
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Major cause of morbidity
Peripheral polyneuropathy presents most commonly.
Bilateral, characterized by:
Numbness
Paresthesias
Severe hyperesthesias
Pain (deep-seeded, severe)
Mononeuropathy is associated with:
Wrist drop
Foot drop
Paralysis of third, fourth or sixth cranial nerve
Radiculopathy
Sensory syndrome: pain distribution of one or more spinal nerves, usually in chest wall or abdomen
Autonomic neuropathy
Significant target: gastrointestinal tract -- symptoms include:
Esophageal dysfunction
Delayed gastric emptying
Constipation or diarrhea
Orthostatic hypotension
Syncope
Cardiopulmonary arrest; sudden death
Bladder dysfunction (may require chronic catheter drainage)
Impotence/retrograde ejaculation
Pain:
Although opioids may be used (e.g. tramadol (Ultram) side effects make these agents problematic for long-term therapy.
Other options include:
Gabapentin, prgabalin and carbamazepine (from the anti-seizure medication class)
Amitriptyline, imipramine, desipramine and nortriptyline from the tricycylic antidepressant class.
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Secondary to diabetic neuropathy is abnormal pressure distribution
Vascular disease (decreased perfusion): augments ulcer development
Infection: common (multiple organisms)
Initial antibiotic treatment (until culture results are available):
ampicillin-sulbactam plus gentamycin or aztreonam
Autonomic Dysfunction and Diabetes Mellitus
Initial finding: often asymptomatic abnormal vagal function (reduced heart rate variation with deep breathing)
Loss of myelinated and non-myelinated small nerve fibers in splanchnic distribution, carotid sinus, and vagus nerve
Disturbances and gut motility.
Nausea/vomiting.
Achlorhydria.
Bowel incontinence.
Impotence
Urinary incontinence.
Pupillary abnormalities.
Postural hypotension.
Symptoms of hypoglycemia -- blunted or detectable because damage to sympathetic adrenal gland innervation prevents epinephrine release.
Autonomic dysfunction may lengthen Q-T interval, an effect which may be associated with sudden cardiac death.
Karam, J. H., Pancreatic Hormones and Antidiabetic Drugs, in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, pp 684-703
Foster, D. W., Diabetes Mellitus, In Harrison's Principles of Internal Medicine 14th edition, (Isselbacher, K.J., Braunwald, E., Wilson, J.D., Martin, J.B., Fauci, A.S. and Kasper, D.L., eds) McGraw-Hill, Inc (Health Professions Division), 1998, pp 2060-2080
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