Disorders Related to the Endocrine SystemJeff ButtramBio 120 - Medical Terminology

This presentation will focus on the following two disorders:

 hypercalcemia

 glycosuria

hypercalcemiaexcessive amounts of calcium in the blood.

Normal levels of calcium in the body (blood) assist with:

bone maintenance.

muscle contraction.

hormone release.

brain and nerve function.

 * too much or too little calcium can interfere with the above functions.

Endocrine system glands that regulate healthy calcium levels:

parathyroid - produces more parathyroid hormone (PTH) when calcium levels fall or less when levels are too high.

thyroid - produces calcitonin which slows the release of calcium from the body.

* Image of parathyroid and thyroid gland placement in the cervical (neck) area.

 

Causes of hypercalcemia

overactive parathyroid (main cause).

cancer.

certain medications.

certain diseases.

excessive use of calcium or vitamin D supplements.

Overactive parathyroid will increase parathyroid hormone ( PTH) release, therefore:

the bones will release excess calcium into blood.

the digestive system will absorb excess calcium.

the kidneys will excrete less calcium and activate vitamin D (calcitriol). Vitamin D is crucial to proper calcium absorption.

* diagram of normal PTH interaction with the body systems.

Types of cancer associated with hypercalcemia:

lung.

breast.

multiple myeloma (cancer of plasma cells in bone marrow).

tumors can cause paraneoplastic sydrome, where a protein that acts like PTH is released, initiating calcium release.

Medications associated with hypercalcemia

Lithium - used to treat bipolar disorder. Increases release of PTH.

Thiazide diuretics - used to treat hypertension and edema - decreases amount of calcium urinated.

Diseases associated with hypercalcemia:

tuberculososis (TB) - infectious inflammatory disease most commonly affecting the respiratory system.

sarcoidosis - inflammatory autoimmune disease of the lymph system.

* both of the above are considered granulomatous disease because they are related to granuloma, or areas of inflamed tissue, that cause excess release of vitamin D (calcitriol).

familial hypocalciuric hypercalcemia - a rare genetic defect results in  faulty calcium receptors.

Hypercalcemia complications

osteoporosis - bones release too much calcium.

kidney stones - crystals form from excess calcium.

kidney failure - excess calcium affects kidneys ability to cleanse blood.

nervous system - confusion, dementia, confusion.

heart arrythmias - too much calcium can affect normal electrical impulses in the heart.

Hypercalcemia symptoms

nausea/vomiting.

loss of appetite.

excess thirst.

frequent urination.

constipation.

abdominal pain.

muscle weakness.

muscle/joint aches.

confusion.

fatigue.

Diagnostic tests for hypercalcemia:

Blood tests - look for high calcium levels in blood or for excess PTH levels.

Mammogram.

Chest x-ray.

MRI (magnetic resonance imaging).

CT (computerized tomography) scan.

 * above 4 tests test for lung or breast cancer, or granulomatous diseases.

glycosuria

presence of excess sugar in the urine

Two main categories of causes for glycosuria

hyperglycemia - blood glucose levels are so high that the renal tubules cannot absorb all of the gluscose (can't keep up).

renal glycosuria - renal tubules cannot absorb glucose even when blood glucose levels are at normal to low levels (due to a defect in nephron ).

* Detail of renal tubules

 

Conditions associated with glycosuria

diabetes mellitus (most common) -insulin shortage  results in inefficient breakdown of glucose.

hyperthyroidism - leads to poor absorption of glucose from body's waste fluids.

liver problems - conditions such as cirrhosis impair liver's ability to process carbohydrates.

kidney disease - infections or disease impair glucose filtration.

pregnancy - sugar "leaks" from kidney to urine common in pregnancy.

* Diagram detailing physiology of diabetes mellitus (type II)

Glycosuria diagnostics

a urine sample is collected.

a color sensitive "dipstick" changes color and is used to determine amount of glucose in urine.