Endocrine disorders 1

Endocrine Disorders

• Endocrine disorders stem from impaired control/feedback mechanisms, resulting in hormone levels that are too high or too low.
• Two main categories of disorders are excessive hormone amounts and deficient hormone amounts.

Most Common Causes of Endocrine Disorders

• Excess hormone levels:
  • Benign tumors (adenomas)
  • Impaired excretion by the liver and kidneys
  • Congenital defects
• Deficit of hormone level or reduced effects:
  • Destructive tumors producing too little hormone
  • Target cells resistant or insensitive to the hormone
  • Abnormal immune reactions
  • Atrophy or surgical removal of the gland
  • Increased production of antagonistic hormones
  • Congenital defects

Diagnostic Tests

• Blood tests: Measure hormone levels using radioimmunoassay (RIA) or immunochemical methods.
  • Blood glucose or calcium levels can reflect hormone activity.
• Urine tests: Assess daily hormone levels or metabolites over 24 hours.
• Stimulation or suppression tests: Evaluate gland function by stimulating or suppressing hormone release.
• Scans, ultrasound, and MRI: Diagnose the location and type of lesions.
• Biopsy: Rule out malignancy.

Insulin and Diabetes Mellitus

• Diabetes mellitus results from decreased insulin secretion or insulin resistance.
• Insulin is an anabolic hormone important for carbohydrate, protein, and fat metabolism.
• Impaired glucose and amino acid transport into cells, and synthesis of protein and glycogen, happen.
• Many tissues and organs are affected, although some are not directly influenced by insulin deficiency.

Insulin and Diabetes Mellitus: Specific Tissues

• Brain: Glucose transport does not require insulin for uptake.
• Digestive tract: Glucose uptake does not require insulin.
• Skeletal Muscle: Exercise can increase glucose uptake in skeletal muscle, even without proportional insulin levels.
• Kidney and myocardium: Insulin facilitates glucose and other substance uptake.

Types of Diabetes Mellitus

• Type 1 (IDDM): Autoimmune destruction of pancreatic beta cells, leading to an absolute insulin deficiency.

  • Requires insulin replacement therapy.
  • Associated with acute complications, such as hypoglycemia or ketoacidosis
  • Predisposition to strokes, heart attacks, peripheral vascular disease, kidney failure, and blindness.

• Type 2 (NIDDM): Decreased effectiveness of insulin or a relative insulin deficiency.

  • Caused by decreased pancreatic beta-cell production, insulin resistance, or increased liver glucose production.
  • Controlled by lifestyle modifications (diet and exercise) or medications targeting insulin resistance or stimulating insulin secretion.

Type 2 Diabetes (Milder Form)

• Often develops gradually in older adults, and frequently in overweight individuals.
• Metabolic syndrome, which is a complex of pathophysiological conditions, can occur in younger or adolescents, and is often marked by obesity, cardiovascular problems, and insulin resistance due to increased adipose tissue.
• Prevalence increases with age, with almost half of the cases found in individuals older than age 55.

Pathophysiology of Insulin Deficiency

• Initial Stage: Decreased glucose uptake, increased glucose in the blood (hyperglycemia), glucose spills into urine (glucosuria), increased urination (polyuria), excessive thirst (polydipsia), and increased appetite (polyphagia).
• Progressive Stage: Catabolism of fats and proteins leads to excessive ketone/keto acid production in the blood (ketoacidosis). Ketoacids combine with bicarbonate buffer to decrease blood pH. Ketoacids excreted in urine (ketonuria), dehydration develops, and there is metabolic acidosis.

Diabetic Ketoacidosis (DKA)

• Occurs frequently in untreated type 1 diabetes.
• Excessive buildup of ketoacids due to the lack of glucose in cells resulting in fat breakdown.

Signs and Symptoms of Diabetes

• Type 2: often characterized by weight gain or abdominal girth, but can also include polyuria, polydipsia, polyphagia, and increased appetite.
• Type 1: often characterized by weight loss.

Diagnostic Tests for Diabetes

• Fasting blood glucose: A fasting blood sugar equal to or above 126 mg/dL taken on more than one occasion confirms diagnosis.
• Oral glucose tolerance test: Tests how efficiently the bodies cells can use glucose.
• Glycosylated hemoglobin (HbA1c): Monitors blood glucose levels over several months, with an acceptable level of 6% or lower.

Diagnostic Tests (Additional tests used to diagnose diabetes)

• Blood tests: Capillary blood glucose levels monitored with portable devices.
• Urine tests: Screen for ketones.
• Arterial blood gas analysis: Necessary if ketoacidosis develops.
• Serum electrolytes: Checked to evaluate imbalances.

Treatment of Diabetes

• Level 1: Diet and Exercise: balanced meal with exercise and maintaining optimum weight.
• Level 2: Oral medications: reduce insulin resistance stimulate B cells to make more insulin like Metformin, Sulfonylureas, Meglitinides, Thiazolidinediones, DPP-4 inhibitors, GLP-1 receptor agonists, and SGLT2 inhibitors.
• Level 3: Insulin replacement therapy: subcutaneous injection, blood glucose monitoring frequently, use of biosynthetic insulin.

Complications of Diabetes Mellitus

• Acute complications: Hypoglycemia (insulin shock), Diabetic ketoacidosis, and Hyperosmolar hyperglycemic nonketotic coma.
• Chronic complications: Vascular problems, Neuropathy, Infections, Cataracts, Complications during pregnancy.

Parathyroid Hormone and Calcium

• Parathyroid hormone (PTH) and Calcitonin regulate blood calcium levels.
  • PTH increases blood calcium by stimulating bone demineralization, increasing absorption of calcium from intestines, and increasing calcium reabsorption from kidneys.
  • Calcitonin decreases blood calcium by decreasing calcium reabsorption in the kidneys and increasing its release into bones.
• Hypoparathyroidism results in low calcium levels (hypocalcemia).
• Hyperparathyroidism results in high calcium levels (hypercalcemia).

Complications of Hypoparathyroidism

• Weak cardiac contractions
• Increased neuronal excitability(spasms and muscle twitching).

Complications of Hyperparathyroidism

• Forceful cardiac contractions
• Osteoporosis (weakening of bones, prone to fractures)
• Increase in kidney stones

Hypoglycemia Treatment

• Immediate administration of a concentrated carbohydrate such as juice or candy.
• For unconscious patients, glucose or glucagon can be given intravenously.

Treatment of Diabetic Ketoacidosis (DKA)

• Insulin administration and fluid and electrolyte replacement.
• Bicarbonate administration is usually required to correct acidosis.

Hyperosmolar Hyperglycemic Nonketotic Coma (HHNC)

• Occurs with type 2 diabetes, often in elderly individuals with infections.
• Characterized by hyperglycemia, dehydration, and the absence of significant ketoacidosis.

Chronic Complications (Diabetes Mellitus)

• Vascular Problems: Increased risk of atherosclerosis (hardening of arteries), heart attacks , strokes, peripheral vascular disease.
• Microangiopathy: Thickening of capillary basement membranes can cause retinopathy (blindness), diabetic nephropathy, and chronic renal failure.
• Peripheral Neuropathy: Nerve damage due to ischemia, reduced sensation (tingling, numbness), and muscle weakness.
• Autonomic Neuropathies: Can cause problems with bladder control, digestion, heartbeat and vision control.
• Infections: Recurrent infections are common.
• Cataracts: Lens clouding.
• Complications of pregnancy: Increased risk of spontaneous abortion, birth defects.

Control of Type 2 Diabetes

• Diet: Increase fiber, reduce simple sugars, and reduce lipids.
• Exercise: Regular exercise to lower blood glucose.
• Body Mass Index (BMI): reduce insulin resistance by maintaining normal BMI
• Monitor blood glucose: Regularly monitor blood glucose levels
• Medications: Drugs that stimulate B-cells to secrete more insulin, including Metformin and other oral medications or insulin administration.
• Routine follow-up and blood tests: Regular check-ups and blood tests to monitor disease progression.

Additional Information (Questions)

• Etiology of Diabetes Mellitus: Genetic predisposition, obesity, lifestyle, infections, and some other factors may contribute to diabetes development.
• Predisposing Factors for Diabetes Mellitus: Genetic family history, obesity, inactivity, use of some prescription medication, and infections