ENDOCRINE SYSTEM Easy Overview for NCLEX-RN 2024

As a nurse, you must know about the basics of the endocrine system. Have you know about role of the glucocorticoids, mineralocorticoids, vasopressin, oxytocin, role of thyroid hormone, calcitonin, parathyroid hormones, and so on.

1. Release hormones directly into the bloodstream (ENDOCRINE SYSTEM)
2. Pituitary Gland: Also called MASTER gland, HYPOPHYSIS.
   • ANTERIOR PITUITARY: responsible for the synthesis and releases of the pituitary hormones.
   • ACTH: Adrenocorticotrophic hormone.
     • Stimulates adrenal cortex to release aldosterone and cortisol.
     • Stress is the stimulus for release.
   • FSH: Follicle-stimulating hormone.
     • Men: sperm production
     • Women: Ovarian follicles for eggs.
     • GnRH is the stimulus for release.
     • Gonadotropin-releasing hormone.
   • LH: Luteinizing hormone
     • Men: Testicular
     • Women: Ovulation(release of the egg)
     • GnRH is the stimulus again.
   • GH: Growth hormone
     • Increased during anabolic metabolism, cartilage growth and catabolism of fat. Blood glucose and insulin effects.
     • Stimulus is the normal growth and development.
   • PRL: Prolactin
     • Stimulates production of milk in the breast.
     • Stimulus are estrogen, pregnancy and nursing.
   • TSH: Thyroid-stimulating hormones
     • Stimulates thyroid to release T3 and T4
     • Stimulus is the thyroid needs.
   • POSTERIOR PITUITARY:
   • ADH: Antidiuretic hormone
     • Memory trick is the ADH i.e., Add Da H2O
     • Add water back into the body by telling the kidneys to reabsorb water.
     • Stimulus for release is decreased B.P., pain, high osmolality of the blood.
   • Oxytocin:
     • Maternity: Stimulates uterine contractions and lactation of breast milk.
     • Labor and delivery of newborn or infant breast feeding (stimulus for release)
3. THYROID:
   • T4 –> T3 (active thyroid hormone)
   • TSH: Thyroid stimulating hormones
   • PATHOPHYSIOLOGY:
     • HYPOTHALAMUS –>releasing –> TRH (Thyrotropin- releasing hormone) which tells the ANTERIOR PITUITARY –> to release –> TSH (Thyroid stimulating hormone), at last TSH –> stimulates –> THYROID.
     • 3 KEY PLAYERS: T4 (thyroid hormone), T3 (active thyroid hormone), CALCITONIN (puts a “TON of Ca IN bone
     • hypO- thyroid lOw T3 and T4
     • HYPER- thyroid HIGH T3 and T4
     • Iodine deficiency is the major cause of hypothyroidism.
     • CAUSES of HYPER-thyroid (high T3&T4): Graves (Gains High); Iodine excess; Levothyroxine excess
     • CAUSES of HypO- thyroid (low T3&T4): HashomOtOS; Low dietary iodine; Pituitary Tumor; Thyroidectomy.

NCLEX TIP: Focus on T3 and T4 level first. TSH always opposite of T3 and T4.

Signs and symptoms of hypo and hyper thyroid are super simple. In HYPER: everything is HIGH and HYPO: everything is LOW.

4. Parathyroid Glands: PTH Parathyroid Hormones: Memory tricks: PTH: Puts The Calcium High inside the blood.

Parathyroid gland are almost responsible for regulation of the blood calcium. Memory trick : PC means Parathyroid and Calcium (9.5-10.5 mg/dl normal value of calcium). MAIN POINT is If Parathyroid hormone high–> Calcium is high, and If parathyroid hormone is LOW–> Calcium is Low.

HYPERPARATHYROID means HYPERCALCEMIA.

HYPOPARATHYROID means HYPOCALCEMIA

PTH (parathyroid hormone) Puts The calcium High

NEGATIVE FEEDBACK LOOP:
Calcium high --> PTH SHUTS OFF
Calcium Low --> PTH TURNS ON

Calcium is increased in the blood by 3 ways: 

Remember the acronym: RIB

R: Renal Reabsorb (calcium from the urine)
I: Intestinal (GI) Absorption {help of Vit D activation} {absorbing calcium from FOOD}
B: BONES into the blood. {hard bones are made up of calcium and when your body needs more calcium it usually drains the bones to get it, so with too much PTH in hyperparathyroidism, there is too much calcium in the blood. 

Hyper Ca+ = STONES, MOANS, GROANS. Stone means Kidney stones, Moans means Fractured bones, Groans means Constipation.

PTH makes bones weak by taking calcium from their storages. This makes them BRITTLE meaning big risk for fractures.
  
Kidneys (the washer machines of the blood) have to filter out all that excess calcium from the body and into the body, but they get overloaded, and we get kidney stones AKA renal calculiform all that overload of calcium and lastly the GI, intestinal tract gets overloaded with calcium causing rock hard bowels (a common sign and symptom of hypercalcemia too much calcium). 

Calcium and Magnesium love Vitamin D and they all work together. (You most often see calcium, magnesium and Vit D all in the same multivitamin.

ADRENAL GLAND: Present on the top of the kidney.

ADRENAL CORTEX: the outer part of the adrenal gland. 3 parts: 1. Zona glomerulosa, 2. Zona fasciculata, 3. Zona reticularis.

ADRENAL MEDULLA: the inner part of the adrenal gland. It makes fight and flight Catecholamines. Epinephrine (adrenaline) and norepinephrine (noradrenaline)

MACC HORMONES

M: (MINERAL-CORTICOIDS STEROIDS) ALDOSTERONE A: Adds sodium and water IN L: Lets Potassium K+ OUT

A: ANDROGEN STEROIDS (SEX HORMONES)

C: Cortisol Steroid (GLUCOCORTICOID)”Stress hormones”

C: Catecholamines: Epinephrine and Norepinephrine (Adrenaline) Fight and Flight hormones which increase heart rate and blood pressure.

Mineralocorticoids ALDOSTERONE = high {A= Adds Sodium and Water = high} which leads to HYPERNATREMIA over 145mEq/L and HYPERTENSION over 140/90. {L=Loss of potassium} The loss of potassium is greater so HYPOKALEMIA 3.5mEq/L or less. K+ & H+ ions (alkalotic)= high pH level as the body loses more hydrogen ions in the urine. This is called Metabolic alkalosis. 

MC inc. = HYPERTENSION
MC dec. = HYPOTENSION

Sodium retains with water.
Sodium is the ENEMY of the Potassium.

GLUCOCORTICOIDS maintain the level of the glucose in the body. 

POTASSIUM 3.5-5.1mEq/L MOST ABUNDANT INTRACELLULAR CATION 
HYPERKALEMIA: 
More than 5.1 mEq/L
Life threatening condition
Because it can cause some life-threating dysrrhymias.

CAUSES: a. Increased potassium intake, b. injection KCL, c. Addison's disease (in this disease, aldosterone level decreased, {aldosterone helpful in maintaining sodium and fluid}, because of the deficiency of the aldosterone, sodium deficiency occur, {SODIUM AND POTASSIUM are ENEMY}, When there is deficiency of the sodium, body starts to retain the POTASSIUM in the body, hence, HYPERKALEMIA occurs., d. KIDNEY  DISEASE {Because of the water intoxication, there is deficiency in SODIUM, hence POTASSIUM increase,  e. TISSUE INJURY {when there is damage in tissue, POTASSIUM release in the body}, f. DIURETICS {POTASSIUM-RETAINING DIURETICS}, Example: SPIRONOLACTONE, g. HYPERCATABOLISM {when the metabolic reactions fast in the body, more catabolic reaction occur, in that case, cell could be damage, that damage cell, will release the potassium, because potassium is the most abundant intracellular cation.
  
SIGN AND SYMPTOMS: a. Cardiovascular system {weak and thready pulse, low B.P., dysrhythmias}, b. Respiratory system {weak, shallow respiration}, c. Neuromuscular system {in Early sign, muscles overexcited, twitches, paresthesia, tetany; Late sign, muscle weak slowly, flaccid ascending paralysis occur in legs and arm}, d. GI tract {increased motility of intestines, peristaltic movement more, diarrhea occur}, e. in BLOOD, potassium level is more than 5.1mEq/L, f. ECG changes {Tall, peaked T wave, widened QRS complexes, depressed ST segment, wide, flat P wave. 

NURSING INTERVENTION:
a. Assess Cardiovascular status {critical} cardiac arrest chances
b. Respiratory status {chances of respiratory failure}
c. Neuromuscular system {LOC, muscle condition,}
d. GI system

ALERT:
1. STOP KCL immediately
2. STOP oral potassium supplement
3. STOP POTASSIUM SPARING DIURETICS 
4. Antidote is Sodium Polystyrenes sulphonate (Kayexalate) {Cation exchanging resin which help in sodium absorption and Potassium excretion}
5. Doctor may prescribe: CALCIUM GLUCONATE {Help muscle contraction, stabilize cardiac dysrhythmias} 
6. Dialysis may be done in case of severity.
7. FRESH BLOOD TRANSFUSION: {NEVER TRANSFUSE OLD BLOOD} [In old blood, more hemolyzed RBC's, more potassium in it].

TREATMENT MODALITY:
1. DEXTROSE 25% in INSULIN [ In addition to take Glucose, the INSULIN takes POTASSIUM inside the cells, hence, in blood, the level of the potassium will be less]
2. Restrict Potassium Diet. 

IMPORTANT POINT:
While administering KCL injection to the patient, kindly check the URINE OUTPUT i.e., must be more than 30ml/hr, if the level of urine output is less than 30ml/hr, hyperkalemia occurs.

POTASSIUM Principal role: Myocardial functioning, maintain proper rhythm

HYPOKALEMIA
Less than 3.5 mEq/L

CAUSES:
a. DIURETICS 
b. Excessive Production of Aldosterone {CUSHING SYNDROME}
c. Wound Irrigation e.g., Colostomy
d. Continuous Nasogastric suction.
e. Hyperinsulinism {movement of potassium for extra to intracellular fluid}
f. Water intoxication
g. Alkalosis

SIGN AND SYMPTOMS:
a. Weak, irregular pulse, dysrhythmias, weak peripheral pulses
b. Shallow respiration
c. Deep tendon hyporeflexia, paresthesia, loss of tactile discrimination, leg cramps, 
d. Paralytic ileus decreased motility.
e. ST depression, shallow flat, or inverted T wave, prominent U wave.

NURSING MANAGEMENT:
a. Assess cardiovascular, respiratory, neuromuscular, gastrointestinal system.
b. Administer Oral Potassium supplement. {never empty stomach, chances of nausea and vomiting}
c. In case Liquid potassium chloride, given with juice or other liquid {unpleasant taste}
d. IV KCL administered using an infusion device. Always diluted.
Never give IV push. KCL mix with Normal Saline (shake properly), Allowable concentration is 1mEq per 10mL NS. 
Usually, flow rate 5 - 10 mEq/hr
Never exceed 20mEq/hr 
Review order with physician in case more than 20mEq/hr flow rate of potassium.
e. Urine output assess always more than 30ml.

2 Registered nurses responsible for administering the KCL.

How to Become a Registered Nurse in Canada (Guide for International Nurses) Easy process 2024 – brandednurses

Standards & Guidelines (cno.org)