General Pathology 601 for Dental Students

Endocrine Disorders and Diabetes
 Endocrine Disorders Continued

objectives | terms | pituitary & thyroid | parathyroid & adrenals | MEN & dental mgmt

3. Parathyroid

Parathyroid Hormone (PTH)
Important in serum calcium balance--increased PTH causes hypercalcemia and hypophosphatemia; decreased PTH causes hypocalcemia

hypercalcemia/hypophosphatemia--metabolic consequences

  • bone resorption with calcium and phosphorus released to blood

  • in kidney, increased calcium reabsorption, increased phosphate excretion, and activation of vitamin D

  • in intestine, increased calcium uptake by intestinal mucosa

General clinical presentations of parathyroid diseases
Hyperfunction/hyperparathyroidism--results in increased levels of PTH in the circulating blood

  • primary--due to parathyroid hyperplasia, or neoplasia

    • one of most common endocrine disorders

    • caused by:

      • solitary adenoma--solitary tumor affecting one of the parathyroid glands; causes excessive secretion of PTH producing signs and symptoms of hypercalcemia

      • primary hyperplasia of glands

      • parathyroid carcinomas--less than 1% of cases

    • treatment--surgical removal of hyperplastic glands or neoplasm

  • secondary-- most often due to chronic renal failure

    • secondary depressed serum calcium

    • parathyroid glands are hyperplastic

    • treatment--possible reduction in size of hyperplastic glands to normal following kidney transplantation

  • clinical features: emotional disorders; muscle atrophy; osteitis fibrosa/osteolytic lesions of the skeletal system including the jaws; peptic ulcer; pancreatitis; kidney stones; nephrocalcinosis

Hypofunction/hypoparathyroidism--results in decreased levels of PTH in the circulating blood

  • most commonly the result of surgical removal of the parathyroid glands

  • leads to hypocalcemia secondary to PTH deficiency

  • treatment--hormonal therapy with synthetic PTH

4. Adrenals

Adrenal Hormones
Adrenal Cortex--outer zone:

  • glucocorticoids for protein, fat and carbohydrate metabolism

  • mineralocorticoids for control of sodium and potassium balance

  • sex hormones for secondary role in sexual maturation

Adrenal Medulla--inner zone:

  • epinephrine for maintaining sympathetic tone

  • norepinephrine for maintaining sympathetic tone

Feedback Mechanisms
Corticotropic Releasing Factor (CRF)
Adrenocorticotropic Hormone (ACTH)

feedback mechanisms

General clinical presentations of adrenal diseases
Hyperfunction--results in excess adrenocortical hormones and resultant syndromes

  • Adrenal Cushing's syndrome--hypercortisolism--adrenal hyperplasia; tumor:
    • thinning of scalp hair
    • emotional instability
    • acne
    • moon face with increased facial hair
    • buffalo hump
    • osteoporosis
    • cardiac hypertrophy and hypertension
    • truncal obesity with striae of skin
    • easy bruising
    • muscle wasting and weakness with thin extremities
  • Conn's syndrome--hyperaldosteronism
  • Adrenogenital Syndromes

Hypofunction--adrenal atrophy and insufficiency--autoimmune; infection; tumor metastasis

  • Acute causes--can lead to acute adrenal cortical failure:
    • Waterhouse-Friderichsen syndrome--bilateral hemorrhagic necrosis of adrenals secondary to septicemia
    • sudden withdrawal of long-term steroid therapy--adrenal crisis
    • stress in patients with underlying adrenal insufficiency
  • Chronic causes:
    • Major
      • autoimmune adrenalitis
      • TB
      • metastatic disease
    • Minor
      • systemic amyloidosis
      • fungal infections
      • hemochromatosis
      • sarcoidosis
  • Symptoms of acute adrenal insufficiency (crises)--hypertension; weakness; nausea; vomiting; headache; fever
  • Addison's Disease--chronic adrenal cortical insufficiency most often due to autoimmune adrenalitis
    • pigmentations of the skin and mucous membranes
    • personality changes
    •  anorexia, nausea and vomiting
    • cardiac insufficiency
    • diarrhea and abdominal pain
    • muscle weakness

Diseases of Adrenal Medulla--2 neoplasms

  • Neuroblastoma (in children)
    • occurs in neonates and young children
    • fast growing highly malignant tumor
    • 90% cure rate with combined therapy
  • Pheochromocytoma (in adults)
    • most common tumor of adrenal glands in adults
    • benign 90% of the time
    • secretes epinephrine and norepinephrine
    • patients develop hypertension
    • treatment--surgical removal of tumor (excellent prognosis)

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Updated March 30, 2005