The endocrine glands and the hormones they secrete are capable of carrying chemical instructions through the circulatory system (and body fluids) to certain target organs (or cells) of the body. The target organ (or cell) will then be obliged to respond to the instructions. A soldier medic will encounter metabolic and endocrine disorders during peacekeeping. They will also encounter civilians, during peacekeeping or wartime, with such disorders. The soldier medic must recognize signs and symptoms of emergency situations and provide appropriate care as the emergency develops. Adult onset diabetes may first appear in times of stress, illness, or injury. Stress and injury are readily found on the battlefield. The first indication of a severe diabetic problem may be identified during combat conditions.
Anatomy and Physiology, General Characteristics of the Endocrine System
(1) Description of Endocrine System - a system of glands which function in the coordination of metabolic processes through chemical messengers
(a) Control the rate of chemical reactions
(b) Aids in the transport of substances through membranes
(c) Regulates fluid and electrolyte balance
(d) Reproductive processes and developmental growth
(2) Definitions
(a) Endocrine gland - secretes its products directly into the blood. (Ductless)
(b) Exocrine gland - secretes its products into ducts that lead to the lumen of an organ, body surface or body cavity
(c) Hormone - an organic substance secreted by a cell that has an effect on another cell. Chemical messenger.
(d) Target cells - specific cells that possess receptors for the hormones
(e) Action - the response(s) or effect(s) of a hormone on its target cells
(f) Hypersecretion - the release of a hormone from a gland in greater than normal amounts
(g) Hyposecretion - the release of a hormone from a gland in less than normal amounts
(h) Prostaglandin -
(i) Respiration, blood pressure, GI secretions
(ii) Reproductive system
(iii) Cellular metabolism
(iv) Intensifies pain and fever
NOTE: ASA and Tylenol work by inhibiting the synthesis of prostaglandins.
(1) Hormones are classified into two major types
(a) Steroids - hormones derived from cholesterol. Soluble in lipids and can enter cells easily by diffusion. Steroid-protein complex binds to DNA and activates cell. This influences target cell directly.
NOTE: Examples are aldosterone, cortisol and androgen, secreted by the adrenal cortex; testosterone, secreted by the testes; estrogen and progesterone, secreted by the ovaries. Steroid hormones are produced in both mitochondria and smooth endoplasmic reticulum.
(b) Nonsteroids - Proteins, amines, and peptides. They combine with specific receptor molecule binding sites in the target cell membrane to cause the desired intracellular changes.
(2) Responses to hormones include changes in:
(a) Membrane permeability
(b) Enzyme activity
(c) Protein synthesis
(d) Metabolic pathway changes
(e) Secretion of other substances
(3) Normally, the amount of hormone released by a gland is proportional to the body's need for that hormone at any given time
(4) Cells have receptors for specific hormones making them target cells for those hormones, but not all cells respond to a particular hormone
(5) After hormones have accomplished their tasks, they are degraded and removed from the system
(1) Negative feedback - effects regarding the level of hormone secreted or its effects are fed back to the secreting gland to stop its production. Most hormones are controlled by negative feedback.
Example: Elevated blood sugar level stimulates the pancreas to secrete insulin to lower the blood sugar levels. When this level reaches normal (or slightly below normal), a signal is sent back to stop its insulin production.
(2) Positive feedback - mechanisms that amplify change rather than reverse them
Example: Oxytocin is released at the onset of labor to help expel the baby during childbirth. Stronger contractions lead to more oxytocin being released and this continues until the fetus is expelled.
(3) Nerve control - nerve cells in the hypothalamus produce releasing or inhibiting hormones to control the pituitary gland
(1) Pituitary gland (Hypophysis) - sometimes called the master gland of the body because it exerts its control on other glands. It is attached at the base of the brain to the hypothalamus. The brain controls most activities of the pituitary.
(a) Anterior lobe - (sometimes called the Adenohypophysis) Secretes several major hormones and makes up about 75% of total weight of the gland
(i) Growth Hormone (GH)
* Stimulates body cells to increase in size and undergo rapid cell division
* Enhances movement of amino acids through cell membrane
* Increases the rate at which cells use carbohydrates and fats
(ii) Prolactin (PRL) - stimulates and sustains milk production and breast development (during pregnancy)
(b) Posterior lobe - (sometimes called Neurohypophysis), composed of nerve fibers and neuroglial cells that originate in hypothalamus. It releases 2 hormones:
(i) Antidiuretic Hormone (ADH)
* Secreted when blood volume is low
* Causes the body to hold onto water and constricts blood vessels
(ii) Oxytocin - secreted by the hypothalamus and stored in the posterior pituitary
* Stimulates smooth muscle contraction of the pregnant uterus; initiates and maintains labor
* Stimulates milk ejection from breast during suckling
(2) Thyroid gland - vascular structure that has two large lobes on either side of the larynx, this gland secretes:
(a) Thyroxine
(i) Increases rate of metabolism (affects all body cells)
(ii) Regulates metabolism of carbohydrates, lipids, and proteins
(iii) Enhances protein synthesis
(iv) Needed for growth and development
(v) Important for the maturation of the nervous system
(vi) Dietary iodine (iodized salt in diet) is required for production of this hormone
(b) Calcitonin - produced by parafollicular cells of the thyroid gland and lowers blood calcium and phosphate concentration.
(3) Parathyroid gland - 4 structures located on the posterior surface of the thyroid gland, normally two on each lobe
(a) The main hormone secreted is parathyroid hormone (PTH) which causes an increase in blood calcium and a decrease in blood phosphate concentrations by acting on the kidneys, small intestines, and bone.
(i) Stimulates bone tissue resorption and inhibits bone growth
(ii) Causes kidney to conserve calcium and excrete phosphate
(iii) Indirectly stimulates the absorption of calcium from small intestines
(b) Regulated by negative feedback
(4) Adrenal gland - located on superior aspect of both kidneys and classified structurally and functionally into Adrenal Cortex and Adrenal Medulla
(a) Adrenal medulla - inner portion composed of irregularly shaped cells in groups around blood vessels that secrete epinephrine and norepinephrine. These hormones cause:
(i) Increase heart rate, blood pressure, and strength of contraction
(ii) Increase the rate of respiration, dilates respiratory passages
(iii) Decrease rate of digestion
(iv) Increase blood sugar level
(v) Stimulates cellular metabolism
(b) Adrenal cortex - composed of three layers that synthesize steroids
(i) Mineralocorticoids (MC) - the main mineralocorticoid is aldosterone which has the following effects:
* Causes kidneys to reabsorb sodium and water
* Increase excretion of potassium in urine
* Increase blood volume and, therefore, blood pressure
(ii) Cortisol (Glucocorticoid) - it influences metabolism of glucose, protein, and fat in most body cells
* Production is changed to meet the demands of differing conditions and can be triggered by stress due to surgery, hemorrhage, infections severe burns, and intense emotions
(5) Pancreas - located inferior and posterior to the stomach behind the parietal peritoneum. Extends from the duodenum to the spleen. Both an endocrine and exocrine gland. The endocrine portion consists of clusters of cells called Islets of Langerhans. The 2 major cell types are Alpha and Beta cells.
(a) Glucagon - produced by alpha cells
(i) Acts primarily on the liver
(ii) Increases blood glucose levels by causing glycogen to be removed from storage in the liver and be converted into glucose and return to the blood (glycogenolysis- glycogen back to glucose); other nutrients such as amino acids, glycerol, and lactic acid are also converted to glucose
(iii) Is regulated by negative feedback in which low concentrations of blood sugar stimulates glycogen release
(b) Insulin - the hormone produced by beta cells. Insulin brings about a decrease in blood glucose levels.
(i) Causes most body cells to increase the uptake of glucose into the cells
(ii) It also causes the liver to store glucose as glycogen and inhibits glucogenolysis
(iii) Promotes storage of sugars and fats in body tissues and promotes building of body proteins
(iv) Is regulated by negative feedback mechanism which is determined by the level of glucose in the blood
(6) Gonads/Sex Glands (Ovaries and Testes) - male and female gamete producing glands and located in the pelvic region
NOTE: Diabetes is a serious disease resulting from the imbalance between insulin and sugar levels in the blood. Most diabetics can control this disease, but sometimes the sugar/insulin imbalance is too much for the body to compensate for and an emergency occurs.
Acidosis –
Excessive acidity of body fluids due to accumulation of acids or loss of bases
Diabetes mellitus –
Metabolic disorder that affects the body's ability to metabolize glucose due to inadequate amounts of insulin or defective insulin. Results in elevation in the circulating blood sugar.
Diabetic ketoacidosis (DKA) –
Occurs when there is not enough insulin in the blood to transport glucose into the cells. Without insulin to metabolize glucose, fats are burned for energy, which results in ketosis and acidosis
Hyperglycemia –
Abnormally high blood sugar levels
Hypoglycemia –
Abnormally low blood sugar levels
Insulin –
Hormone produced by the pancreas in the Islets of Langerhans that allows blood sugar to enter cells for use as energy
Insulin shock –
Severe hypoglycemia that results in a depleted glucose supply to the brain, a decreased level of consciousness and, if untreated seizures and unconsciousness. The heart and brain use glucose for energy.
Oral glucose –
A simple sugar that is quickly absorbed by the body and is the chief nutrient of the brain
Oral hypoglycemic agent –
An oral medication that causes a decrease in blood sugar and stimulates the pancreas to produce and release insulin
Polydipsia –
Excessive drinking. Excessive thirst resulting in increased fluid intake.
Polyphagia - excessive hunger
Polyuria - excessive urination
Type I diabetes –
An insulin dependent diabetes mellitus (DDM) that usually has a juvenile onset
Type II diabetes –
A non-insulin dependent diabetes mellitus (NIDDM) with an adult onset. The onset is often during or following a stressful period. It is also associated with obesity and aging.
a. All body cells use glucose as an energy source
b. The brain requires a constant supply of glucose
c. The blood stream delivers glucose to the cells for use as energy
d. Insulin must be present for glucose to enter the cells
e. Glucose and insulin balance are necessary for effective metabolism and use of glucose as an energy source
f. Without insulin
(1) Glucose cannot enter the cell from the bloodstream
(2) Acids are formed when fat is used for energy needs and can lead to diabetic ketoacidosis
g. The three Ps of weight loss occur when glucose is not adequately metabolized. Frequently seen in undiagnosed diabetics.
(1) Polyuria – The excess amount of glucose in the blood forces water into the bloodstream. The extra water is secreted as excess urine.
(2) Polydipsia – increased thirst that results in increased water drinking. Secondary to increased volume of urine.
(3) Polyphagia – The cells and tissues cannot utilize the sugar in the blood; therefore, the cells begin to starve. This starvation causes hunger and excessive eating.
(4) Weight loss – The cells cannot use the sugar, so they break down fat and protein for energy causing weight loss
WARNING: Hypoglycemia is a true medical emergency!
Hypoglycemia
(1) Generally defined as a serum glucose level of less than 50 mg/dl
(2) Signs and symptoms (tachycardia, cool, moist or clammy skin, dizziness, complaints of hunger) are consistent with the diagnosis
(3) Signs and symptoms are resolved following glucose administration.
Causes of hypoglycemia
(1) In an insulin-dependent diabetic is often the result of too much insulin, too little food, or both
(2) A diabetic who has not eaten does not have enough dietary intake of glucose to use for a circulating level of insulin
(3) Excessive exercise or exertion uses up the glucose energy stores
(4) Vomiting or diarrhea depletes the body of fluids, electrolytes, and potential sources of glucose
Signs and symptoms of hypoglycemia
(1) Rapid onset - over a period of minutes
(2) Intense hunger
(3) Cold, pale, moist, or clammy skin
(4) Full, rapid pulse
(5) May appear intoxicated
(6) Dizziness and headache
(7) Copious saliva (drooling)
(8) Normal blood pressure
(9) Altered mental status and seizures are symptoms of severe hypoglycemia (blood glucose < 30 mg/dl)
Treatment and transport considerations for hypoglycemia
(1) Conscious patient
(a) Perform the initial assessment. Check for a medical alert identification
(b) Perform a focused history and physical exam and SAMPLE history
(c) Perform a D (dextrose) stick or Accucheck as per local protocol
(d) Administer oral glucose IAW local protocol if all three of the following are present:
(i) The patient has a history of diabetes
(ii) The patient's mental status is altered
(iii) The patient is awake enough to swallow
(iv) Dose - one glucose tube
(e) Adult - Place glucose on the tongue depressor between the cheek and the gum or self administer it between the cheek and the gum
(f) If oral glucose is not available, give granular sugar, honey, hard candy, or orange juice
(g) If a patient becomes unconscious, remove the tongue depressor and assure and open the airway
(h) Monitor and maintain airway
(2) Unconscious patient and/or inability to swallow
WARNING: DO NOT GIVE UNCONSCIOUS PATIENTS ANYTHING BY MOUTH!
(a) Initiate and maintain IV of normal saline (promotes excretion of keynote bodies)
(b) Administer pharmacological interventions
(i) 50% Dextrose
(ii) Therapeutic effects: Rapidly restores blood sugar levels to normal in states of hypoglycemia
(iii) Indications: To treat suspected hypoglycemia or a coma of unknown cause
(iv) Contraindications: Intracranial hemorrhage, known stroke (CVA)
(v) Side effects: Will cause tissue necrosis if it infiltrates
(vi) How supplied: Prefilled syringes containing 50 cc of 50% dextrose (25 Grams)
(vii) Administration and dosage: Give through patent IV line. If possible obtain serum glucose prior to administration dosage is 50ml of 50% solution
(c) Treat patient like any other with an altered mental status
(d) Continue to monitor and maintain airway
(e) Administer oxygen, if available
(f) Start artificial ventilations if necessary
(g) Transport - Continue ongoing assessment en route.
(3) Position patient - If the patient does not require artificial ventilations, place him in a lateral recumbent position in case s/he vomits
When cause is known, treat as though hypoglycemia; give sugar
(1) A patient in diabetic ketoacidosis will not be harmed by having sugar
(2) A patient in severe hypoglycemia will respond rapidly
CAUTION: When a patient appears intoxicated, treat the patient as a diabetic emergency. Always check for underlying conditions. Never assume the patient is "only drunk."
Hyperglycemia
(1) Generally defined as a random blood glucose > 200 mg/dl or a fasting blood glucose > 140 mg/dl
Causes of hyperglycemia
(1) Undiagnosed/untreated diabetic condition
(2) Insulin not taken
(3) Overeating
(4) Infection that disrupts glucose/insulin balance
(5) Myocardial infarction (heart attack)
Signs and symptoms (Blood glucose 200-400 mg/dl)
(1) Patients are often asymptomatic. Increased blood glucose is found on incidental laboratory examination or a random self glucose test.
(2) Slow onset - occurs over a period of days or weeks
(3) Dry mouth
(4) Intense thirst
(5) Frequent urination
(6) Blurred vision
(7) Frequent infections
Signs and symptoms (Blood glucose > 400 mg/dl)
(1) Usually more dramatic presentation
(2) Intense thirst
(3) Abdominal pain
(4) Vomiting
(5) Progressive restlessness/confusion
(6) Respiration may be very deep and rapid (Kussmaul respirations)
(7) Weak, rapid pulse
(8) Warm, red, dry skin
(9) Sunken eyes
(10) Acetone breath (fruity odor)
(11) May appear intoxicated
(12) Normal to slightly low blood pressure
Treatment and transport considerations
(1) Maintain an open airway
(2) Administer a high concentration of O2, if available
(3) Perform D (dextrose) stick or Accucheck per local protocol
(4) Initiate and maintain an IV of Normal Saline
(5) Transport immediately
(6) Continuously monitor vital signs
WARNING: If untreated, hyperglycemia will eventually lead to diabetic ketoacidosis. The metabolism of substances other than sugar creates high levels of acid in the blood. THIS PROCESS CAN LEAD TO DEATH.
(1) Hyperthyroidism – presence of excess thyroid hormones in the blood
(2) Thyrotoxicosis – a condition that reflects prolonged exposure of body organs to excess thyroid hormones, with resultant changes in structure and function. Thyrotoxicosis is generally caused by Grave’s Disease
(3) Thyrotoxic Crisis – "Thyrotoxic Storm" life threatening emergency characterized by hyperthermia, nervous symptoms, and rapid metabolism
(4) Hyperthyroidism – presence of inadequate thyroid hormones in the blood
(5) Myxedema – condition that reflects long-term inadequate levels of thyroid hormones with resultant change in function and structure
(6) Myxedema Coma – uncommon complication of myxedema that can be fatal if respiratory depression occurs. Usually triggered by acute infection, trauma, cold infection, exposure to CNS depressants such as alcohol and drugs.
(1) Less serious than Thyroid Storm
(2) Important causes of palpitations
(3) Commonly caused by undiagnosed or untreated Graves’ disease, infectious process or surgery
Thyroid storm (more serious form of Thyrotoxicosis)
(1) Medical emergency
(a) Elevated temperature (T>38.7o C, but may be as high as 41 o C)
(b) CNS dysfunction (anxiety, emotional lability, delirium)
(c) Cardiovascular dysfunction
(d) Gastrointestinal dysfunction (nausea, vomiting, hyperdefecation or diarrhea, crampy abdominal pain)
(e) May mimic or complicate sepsis, sympathomimetic intoxication, or a drug withdrawal
(1) Sinus tachycardia (heart rate > 100 bpm) is almost always present
(2) Heart rate may be fast and irregular
(3) Enlarged thyroid may be palpable
(4) Proptosis and other eye findings indicative of Graves’ disease
(5) Brisk reflexes
(6) Anxiety
(7) Tremor
(8) Weakness
(9) Heat intolerance
(10) Weight loss
(11) Hyperdefecation
(12) Sweating
(13) Angina and congestive heart failure (CHF) may be present
NOTE: In most cases mild thyrotoxicosis is referred for outpatient evaluation and treatment. If patient is symptomatic but not acutely ill, beta–adrenergic blockade with propranolol (slow 1 mg IV bolus may be administered in accordance with physicians’ orders).
(1) Emergency care for Thyroid storm
(a) Provide supportive care including cooling measures (ice packs, cooling blankets)
(b) Contact MD/PA immediately for specific guidance
(c) Initiate and maintain IV access and fluids
(d) Administer oxygen
(2) Provide on-going management for Thyroid storm
(a) Monitor patient’s response to treatment
(b) Monitor airway if unconscious
(c) Place patient in quiet, reassuring environment, if possible
(d) Maintain IV fluids as directed
(e) Evacuate for further treatment as required
(3) It is imperative to consider other processes as precipitants of thyroid storm or as a primary cause of symptoms
(a) Infection
(b) Surgery
(c) Trauma
(d) Emotional stress
A condition of decreased activity of the thyroid gland
(1) Body’s normal rate of functioning slows causing mental and physical sluggishness
(2) Most severe form is called myxedema, which is a medical emergency
(1) Over 50 years old
(2) Female
(3) Obesity
(4) Thyroid surgery
(h) X-ray or radiation treatments to the neck
(1) Physical Examination and X-Ray
(a) Enlarged thyroid on physical exam
(b) Delayed reflexes
(c) Slow heart rate
(d) Low blood pressure
(e) Low temperature
(f) Chest x-ray indicates an enlarged heart
(2) Early symptoms:
(a) Weakness
(b) Fatigue
(c) Cold Intolerance
(d) Constipation
(e) Weight gain
(f) Depression
(g) Joint or muscle
(h) Thin, brittle fingernails
(i) Coarse thick hair
(j) Pale color
(3) Late symptoms:
(a) Slow speech
(b) Dry flaky skin
(c) Thickening of the skin
(d) Puffy face, hands and feet
(e) Decreased taste and smell
(f) Thinning of eyebrows
(g) Hoarseness
(h) Menstrual disorders
Untreated severe hypothyroidism
(1) Thickness of connective tissue in the skin and other tissues including the heart
(2) Most commonly seen in middle aged or elderly
(3) Myxedema Coma is a medical emergency and is manifested by profound hypothermia, bradycardia, and respiratory depression
(4) Treatment is supportive – maintain and monitor airway
(5) Transport/evacuate to definitive care facility immediately
(6) May be fatal if left untreated
SUMMARY
Given a standard fully stocked M5 Bag or Combat Medic Vest System, IV administration equipment and fluids, oxygen, suction and ventilation equipment (if available) and glucometer. You encounter a casualty who has a metabolic and endocrine systems problem.