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Diabetes Mellitus (DM), Impaired Glucose Tolerance (IGT): 140\ mg/dL …
Diabetes Mellitus (DM)
1. Definition of Diabetes Mellitus (DM)
Definition: According to the American Diabetes Association (ADA) 2025, DM is a metabolic disorder characterized by hyperglycemia (high blood sugar) in the absence of treatment.
Cause: It happens due to defects in insulin secretion, insulin action, or both.
2. Aetio-Pathology of Diabetes
The Main Issue: The core problem in all forms of diabetes is that pancreatic beta-cells (which make insulin) malfunction or are destroyed.
Aging Factor: These beta-cells are not replaced because the human pancreas loses its ability to renew them after the age of 30 years.
3. Types of DM
Type 1 Diabetes (T1D): Autoimmune destruction of beta-cells leading to an absolute lack of insulin. It is common in children, rare in old age, and must be treated with insulin.
Type 2 Diabetes (T2D): A progressive loss of beta-cell insulin secretion, usually caused by insulin resistance. It is the most common type among older adults and can go undiagnosed for years. Controlled by diet, exercise, oral drugs, or insulin.
Specific Types Due to Other Causes: Examples include exocrine pancreas diseases (like pancreatitis) or drug-induced diabetes (like from glucocorticoids/steroids).
Borderline DM (Previously Prediabetes): Diagnosed by:
Impaired Fasting Glucose (IFG):100 mg/dL to 125\ mg/dL.
{HbA1C}: 5.7% to 6.4%.
4. Risk Factors of DM Among Geriatric Patients
Non-Modifiable Risk Factors (Cannot be changed):
Age: Aging naturally causes T2D because it decreases beta-cell function (less insulin output), increases insulin resistance, reduces the number/function of insulin receptors, and shifts body fat to truncal obesity (belly fat).
Family History and Race.
Modifiable Risk Factors (Can be changed):
Sedentary lifestyle and obesity (high sugar/fat intake).
Borderline DM, smoking (increases insulin resistance), and illnesses like hypertension or hyperlipidemia.
Drug-induced: Medications that increase blood sugar.
Stress: Stress hormones reduce insulin's effect and raise cortisol, promoting insulin resistance.
Metabolic Syndrome: A cluster of conditions occurring together that increase the risk of heart disease, stroke, and T2D.
5. Clinical Manifestations of DM Among Geriatric Patients
Complications at Diagnosis: Older adults are often already suffering from complications by the time they are diagnosed. Diabetic Ketoacidosis (DKA) is rare in T2D unless caused by severe stress like an infection or specific drugs (corticosteroids, antipsychotics). Chronic signs include heart disease, stroke, kidney issues, vision loss, or diabetic foot.
Typical Signs & Symptoms (The 3 Ps) — May be missing in older adults:
Polyuria (excessive urination): Absent due to age-related decreases in bladder capacity.
Polydipsia (excessive thirst): Absent due to a naturally decreased thirst sensation.
Polyphagia (excessive hunger): Absent due to decreased stomach hunger contractions.
Atypical Signs & Symptoms (Common in older adults):
Fatigue, confusion, blurred vision, impotence, pruritus vulva (vaginal itching), weight loss, poor wound healing, and frequent infections (like UTIs in females).
6. Effect of Atypical S&S on Geriatric Patients
Because the symptoms are not typical, they cause:
Delayed diagnosis.
Faster development of complications.
Acceleration of the aging process.
7. Diagnosis of DM
HbA1C Test: Measures average blood glucose over the past 3 months. Needs no physical preparation (fasting). It is less reliable in conditions with high red blood cell turnover, hemodialysis, recent blood loss, or iron-deficiency anemia (plasma glucose tests must be used instead).
Oral Glucose Tolerance Test (OGTT): Requires fasting for 6–8 hours. The patient drinks 75g of glucose dissolved in 250–300 ml of water. Blood samples are drawn at 0, 0.5, 1, 1.5, and 2 hours.
Fasting Plasma Glucose (FPG): Requires no food intake for at least 8 hours.
Urine Analysis: Can be misleading because the renal threshold for glucose increases with age, meaning older adults can have high blood sugar without glucose showing up in their urine.
Confirming the Diagnosis
8. Complications of Diabetes in Geriatric Patients
Short-term (Acute):
Hypoglycemia (Low blood sugar): Highly dangerous in elderly because the brain depends entirely on glucose; severe drops can cause brain death.
Hyperglycemia (High blood sugar).
Long-term:
Hypertension (High blood pressure).
Microvascular (Small vessels): Diabetic Retinopathy (can cause blindness), Diabetic Nephropathy (kidney damage), and Diabetic Neuropathy (nerve damage).
Oral Health: Declining capillary blood flow to the mouth mucosa leads to dry mouth, inflammation, and cracked skin that serves as a portal for infections.
Increased risk of cancer
Impaired Glucose Tolerance (IGT): 140\
mg/dL
to 199\
mg/dL after an OGTT.
Confirmed if a patient has clear symptoms + random glucose > 200{ mg/dL}$.
Otherwise, requires two abnormal results from the same sample (e.g., A1C is 7.0% and repeat is 6.8%) or two different tests that are both above the cut-off. If tests contradict each other, repeat the one that was high.