Endocrine System Quiz

Endocrine System Overview

• Composed of numerous glands producing hormones
• Hormones travel through the bloodstream to target organs, affecting their function
• The endocrine system is responsible for:
  • Fetal development of reproductive system and CNS
  • Growth and development in childhood/adolescence
  • Coordinating reproductive systems
  • Maintaining internal environment
  • Responding to emergency situations

Primary Function

• Secretion of hormones

Glands

• Pituitary
• Thyroid
• Parathyroid
• Adrenal
• Pancreas
• Pineal
• Thymus
• Ovaries/Testes

Endocrine Dysfunction

• Dysfunction causes alterations in the body's systems because the endocrine system regulates growth and development

Results from

• Hyperfunction or hypofunction

Neuroendocrine Response to Stress

• Immune and endocrine systems are intimately related
• Stress increases sympathetic nervous system activity
• Adrenal glands release catecholamines
  • Pituitary gland releases:
    • ADH (antidiuretic hormone)
    • Prolactin
    • GH (growth hormone)
    • ACTH (adrenocorticotropic hormone)

Neuroendocrine Response to Stress (Catecholamines)

• Epinephrine
  • Increases heart rate and strength
  • Causes peripheral vasoconstriction
  • Elevates blood pressure
  • Elevates blood glucose
  • Stimulates fat breakdown
• Norepinephrine
• Dopamine

Neuroendocrine Response to Stress (Cortisol)

• Released from adrenal cortex
• Regulates proteins, carbohydrates, and lipids to increase blood glucose
• Inhibits fibroblast proliferation (poor wound healing, increased infection risk)
• Helps with fight-or-flight response
• Reduces inflammation

Pituitary Gland

• Master gland
• Anterior Lobe (Adenohypophysis)
  • Secretes ACTH, TSH, LH, FSH, HGH, Prolactin
• Posterior Lobe (Neurohypophysis)
  • Stores ADH (antidiuretic hormone), Oxytocin

Pituitary Tumors (Adenomas)

• Signs/symptoms:
  • Headaches
  • Increased intracranial pressure (ICP)
  • Decreased drainage from 3rd ventricle
  • Visual disturbances (optic chiasm, bilateral temporal hemianopsia)
  • Endocrine abnormalities

Anterior Pituitary Gland Disorders

• Over secretion of at least one hormone (hyperpituitarism):
  • HGH (Human Growth Hormone) → acromegaly in adults (usually benign tumor)
    • Excessive growth (overgrowth of long bones, hypertrophy of soft tissues, widened joint spaces)
    • Children can grow to >7ft (often up to 9 ft).
    • Adults (30-50yrs)-Increased size of jaw bones, hands/feet
  • ACTH → Cushing's disease (often due to an adenoma or exposure to glucocorticoids)
    • Muscle wasting, osteopenia, moon face, easy bruising, abdominal striae, acne, obesity, glucose intolerance, 5:1 women to men ratio, typically seen in childbearing years.
• Prolactin diseases (over-secretion) - Amenorrhea, Gynecomastia, Lactation, Decreased libido, impotence.

HYPERpituitarism Medical/Surgical Treatment

• Benign tumors → surgery and/or radiation
• Medications to decrease or stunt hormone production

HYPERpituitarism Physical Therapy Implications

• Ambulation/exercise encouraged 24 hours post-op
• Watch for changes in consciousness, vision, pulse, and blood pressure (may signal increased ICP); report these changes
• Monitor for meningitis symptoms (headache, irritability, neck rigidity)

HYPOPituitarism

• Diminished secretion by anterior lobe (>70%)
• Congenital and acquired etiologies:
  • Tumours
  • Postpartum hemorrhage
  • Anorexia
  • Anemia
  • GI dysfunction
• Gradual onset of symptoms and signs
• HGH → decreased growth, delayed puberty (affects cartilage, skeletal muscle, connective tissue, skin; enhances fatty acid production)
• LH/FSH → sexual/reproductive disorders

HYPOPituitarism - Signs and Symptoms

• Fatigue
• Muscle weakness
• Weight loss
• Poor appetite
• Joint stiffness
• Low blood pressure
• Headaches
• Erectile dysfunction
• Irregular menstruation
• Delayed growth/poor growth in children

Congenital HGH Deficiency

• Normal birth length
• Drop off height curve by 1-2 years of age
• Normal intelligence
• Obesity
• Delayed skeletal maturation
• Delayed puberty
• Short
• HGH replacement therapy (daily shot or during growth periods)

Acquired HGH Deficiency

• Tumor or treatment for tumor
• Increased cardiac disease
• Central adiposity
• Insulin resistance
• Poor lipid profile

HYPOPituitary Disease - Gonadotropin deficiency

• Amenorrhea
• Breast atrophy
• Testicular atrophy
• Diminished libido
• Minimal pubic and axillary hair
• Hypothermia
• Hypotension
• Hypoglycemia

HYPOPituitary Disorders: Tests & Measures

• Blood work: Cortisol, prolactin, thyroxine, TSH, testosterone, estrogen, LH, FSH, HGH
• MRI of hypothalamus/pituitary
• Radiographs of hands in children to determine growth

HYPOPituitary Disease Medical Treatment

• Removal of causative factor (e.g., surgical tumor removal)
• Hormone replacement therapy (lifelong):
  • Steroids to replace adrenal hormones
  • Synthroid to correct loss of TSH
  • Sex hormones
  • Growth hormones

HYPOPituitarism - Implications for Physical Therapy

• May observe weakness, fatigue, lethargy, apathy, orthostatic hypotension
• Prevent infections
• Impaired vision may occur (bilateral hemianopia)

Posterior Pituitary Lobe Disorders

• Diabetes Insipidus:
  • Rare; caused by damage to hypothalamus or posterior pituitary
  • ADH (antidiuretic hormone) deficiency
    • Kidneys don't reabsorb enough water
    • Copious, diluted urine
    • Dehydration, dizziness,fatigue, polydipsia
  • Treatment: ADH replacement with medication
• Syndrome of Inappropriate ADH Secretion (SIADH)
  • Increased ADH secretion
  • Caused by infections, trauma, tumors, medications
  • Increased water retention, hyponatremia (low sodium in blood)
    • Lethargy, weakness, coma
  • Treatment: Correct sodium balance (surgery, chemotherapy, radiation if tumor, fluid restriction, diuretics)

Thyroid Gland

• Located inferior to larynx
• Secretes:
  • Thyroxine (T4)
  • Triiodothyronine (T3)
  • Calcitonin
• Actions:
  • Regulates basal metabolism
  • Promotes growth and development
  • Mobilizes fat
  • Exchanges electrolytes and proteins

Thyroid Disorders

• More common in women (4:1) and those with family history
• Affects many body systems:
  • Hair
  • Nails
  • Eyes
  • GI tract
  • Lungs
  • Heart
  • Nervous tissue
  • Bones
  • Muscles

Hyperthyroidism

• Graves Disease: An autoimmune disease causing thyroid enlargement and increased hormone secretion (sympathetic nervous system activity increase)
  • Accounts for 85% of hyperthyroidism cases
  • Typically occurs between 20-40 years of age; predominantly seen in women (4:1)
  • Can occur during pregnancy
• Symptoms:
  • Increased size of thyroid (goiter)
  • Heat intolerance
  • Weight loss
  • Sweating
  • Tremor
  • Tachycardia
  • Irritability
  • Poor concentration
  • Diarrhea
  • Mood swings
  • Exophthalmos (eye protrusion)
• Diagnosis: Decreased or normal TSH, elevated T3 & T4, increased radioactive iodine uptake
• Treatment: Medication to inhibit synthesis (30% remission without treatment), radioactive iodine (RAI), followed by thyroid medication (RAI causes hypothyroidism), surgery
• Physical Therapy Implications: Exercise intolerance and reduced exercise capacity, proximal muscle weakness and myopathy, thyrotoxicosis can aggravate pre-existing heart disease, lead to atrial fibrillation, congestive heart failure, and worsen angina pectoris, increased risk for myocardial infarction.

Hypothyroidism

• Decreased thyroid hormones, slowing metabolism
• Causes:
  • Autoimmune (Hashimoto's Thyroiditis)
  • Surgery affecting thyroid
  • Overmedication for hyperthyroidism
  • Diet
  • Congenital
• More prevalent in women (30-60 years old)
• Type I: Hormone deficient (loss of thyroid tissue).
• Type II: Hormone resistant (pituitary failure to synthesize adequate TSH)
• Pathology: Thyroid tissue destruction → decreased thyroid hormone secretion → increased TSH secretion from the anterior pituitary
• Symptoms:
  • Slowed metabolism (decreased GI tract mobility, weight gain)
  • Bradycardia
  • Slowed neurologic function (slow speech, decreased short-term memory, increased sleep, headache, cerebellar ataxia, mood changes)
  • Increased cholesterol and triglycerides
  • Anemia
  • Musculoskeletal effects (proximal hip weakness, myalgia, stiffness in small joints, paresthesia, joint edema, increased bone density, carpal tunnel)
• Diagnosis: Elevated TSH, normal or decreased T3 & T4, elevated CPK-MB
• Treatment: Synthetic thyroid hormones (Synthroid)
• Prognosis: Untreated can cause severe CAD (increased triglycerides and cholesterol)
• Physical Therapy Implications: Correlation between hypothyroidism and fibromyalgia syndrome (FMS) continues to be investigated. Increased activity and exercise help clients with constipation from slowed metabolism and decreased peristalsis.

Thyroid Cancer

• Rare, usually slow-growing
• More prevalent in women (20-60 years old)
• Risk factors: Low iodine, radiation exposure
• Types:
  • Papillary carcinoma: Develops in one lobe and spreads to lymph nodes
  • Follicular carcinoma: Spreads to lungs and bones
• Treatment: Surgery, radioactive iodine, chemotherapy, radiation

Parathyroid Gland

• Two glands on each lobe of the thyroid.
• Secretes parathyroid hormone (PTH).
• Manages calcium levels: If calcium levels are low, PTH releases calcium from bones and absorbs it from the GI tract.
• Hyperparathyroidism: too much PTH production.
  • Primary: Tumor in one or both glands. Symptoms may include thirst, frequent urination, high blood pressure, heartburn, confusion, kidney stones, and joint pain.
  • Secondary: Low calcium levels in the blood. Common causes are low vitamin D and kidney diseases which affect phosphate
• HYPOparathyroidism: decreased PTH secretion, leads to hypocalcemia (low calcium levels), increased phosphate, and tetany (muscle spasms)
  • Causes: Iatrogenic (accidental removal during thyroidectomy), hypovolemia and infarction of parathyroid, scar tissue, tumors, Low vitamin D Deficiency.
  • Symptoms: Irritable, anxiety, agitation, increased osteoclast activity, spasms of respiratory muscles.
  • Diagnosis: PTH levels, electrolytes, X-rays,
  • Treatment: IV calcium if tetanic, vitamin D supplements, medications.

Adrenal Gland

• Located in each kidney, outer cortex and inner medulla
• Adrenal Cortex: Secretes mineralocorticoids (aldosterone- regulates blood pressure, sodium and potassium balance), glucocorticoids (cortisol-affects metabolism, response to stress, inflammation), androgens (testosterone, estrogen, progesterone)
• Adrenal Medulla: Secretes epinephrine, increasing heart rate, contractility, blood pressure, blood glucose

Adrenal Insufficiency (Addison's Disease)

• Cause is a drop in the secretion of cortisol (glucocorticoid) and aldosterone (mineralocorticoid)
• Possible etiologies: TB complications, autoimmune diseases, radiation, neoplasm, infections.
• Risk factors: Surgery, pregnancy, trauma, infection
• Pathogenesis: Hypoglycemia, weakness, hypotension, nausea, emotional lability, paranoia, increased skin pigmentation
• Diagnosis: Cortisol levels
• Treatment: Corticosteroids
• Prognosis: Untreated cases are usually fatal
• Physical Therapy Implications: Aquatic therapy may be contraindicated, because heat/humidity of the pool environment requires more cortisol, adrenal gland cannot regulate body temperature sufficiently

Secondary Adrenal Insufficiency

• Causes: Tumors in hypothalamus or pituitary, rapid taper of corticosteroids
• Symptoms: Arthralgia, myalgia, tendon calcification
• Treatment: ACTH replacement, managing fluid/electrolyte balances

Cushing Syndrome

• Increased cortisol levels, resulting from adrenal gland tumors or high-dose steroid treatments
• Symptoms: Muscle loss (amino acids), stretch marks, decreased wound healing, thin skin, muscle weakness, osteoporosis, fractures, Cushingoid face, increased weight, hair growth, buffalo hump
• Physical Therapy Implications: Adverse effects of corticosteroid treatment such as changes in sleep/mood, GI irritation, hyperglycemia, and fluid retention.