Endocrine Flashcards
Thyroid Gland
Free and total thyroid
T4/T3
Primary effects:
Metabolism
Temperature management
Growth & Development
Hypothyroidism – Signs and Symptoms
Increased weight gain
Cold intolerance
Hair loss
Hypothyroidism treatment
Supplementation
-T4 (Levothyroxine) Synthroid ®
-T3 (Liothyronine) Cytomel®
-T4/T3 Combination - Armour Thyroid®
Long half-life of T4 (7-10 Days)
Onset of action:
-initial 3-5 days
-peak 4-6 weeks
Hashimoto’s Disease
Most prevalent
Inherited with unknown gene expression
Women>Men
40-60 years of age
Immune cells target and destroy thyroid tissue
Myxedema Coma
Severe form of hypothyroidism
No edema/no coma
Deteriorating mentation
Myxedema Coma treatment
Supportive care
IV levothyroxine
Reverse underlying cause if known
Hyperthyroidism – Signs and Symptoms
Atrial Fibrillation, Muscle Weakness, Heat Intolerance, neck swelling (Goiter)
Hyperthyroidism treatment
Propylthiouracil (PTU) - Blocks synthesis of new thyroid hormone, prevents conversion of T4 to T3
Methimazole - Block synthesis of new thyroid hormone
Graves Disease
Autoimmune disorder
-Hyperthyroidism
Rapid/irregular heart rate
Osteoporosis
Muscle weakness
Vision changes
Weight loss
Thyrotoxicosis – Umbrella Term
1% prevalence, Most common cause is Graves Disease (Autoimmune disease)
Of that population – 1% will experience thyrotoxicosis crisis “Thyroid Storm”
Extremely elevated T4 and T3
20% mortality rate
Thyrotoxicosis - Treatment
For Symptomatic Relief, beta blockers (propranolol, slows everything down and only used for symptom relief in this case)
Antithyroid agents (PTU or methimazole)
Other therapies
-Radioactive iodine
-Thyroidectomy (hypothyroidism is a concern after this)
Iodide
Blocks new hormone synthesis & release
Tachyphylaxis ~2 weeks
Parathyroid
Parathyroid Hormone (PTH)
Maintains calcium homeostasis
Hypoparathyroidism
Poor PTH secretion
Reduced bone resorption – hypocalcemia
Supplement
-Calcium & Vitamin D
Hyperparathyroidism
Excessive PTH secretion
-Tumors
-Hypercalcemia
Resection
Vitamin D
Supports bone mineralization
Calcitriol stimulates calcium absorption from the GI tract
Decreases PTH, promoting bone mineralization by decreasing catabolic effects of PTH
Calcitonin
Secreted by thyroid
Stimulated bone formation -> increases incorporation of calcium into skeletal storage
Bisphosphonates
often first line in therapy for bone mineralization homeostasis, inhibits osteoclastic activity
Side effects: GI upset, abdominal pain, nausea, flu-like symptoms
Rare side effects: Atypical fractures, osteonecrosis of the jaw (ONJ), bone/muscle/joint pain
Atypical Fractures
Subtrochanteric & diaphyseal femur fractures
Can be bilateral
Higher risk patients: long term therapy, Asian race, steroid use >1yr, femoral bowing
Prodrome of pain in weeks or months prior
Osteonecrosis of the Jaw (ONJ)
Destruction and death of bone that affects the mandible
Most cases reported are with patients on bisphosphonates
Higher risk patients: Cancer, longer duration of therapy, concurrent steroid use
Calcium
Supplements calcium to maintain adequate levels for bone formation
*Dietary is preferred source
*Target RDA based on patient specific factors
*Hypercalcemia is harmful
Vitamin D analogs
Enhance bone formation by increased absorption of calcium
*Fat soluble vitamin = toxicity risk
*Weekly or daily dosing
Adrenocorticosteroids
Cholesterol backbone
Glucocorticoids
-Cortisol (glucose metabolism)
-Inflammation
-Immune system
Glucocorticoids
Receptor binding
Extra & Intra-cellular
-DNA expression
-Protein synthesis
Increase in glucose
-Liver
-Increased storage (glycogen)
Muscle/Adipose Tissue
-Increased breakdown
-Decreased storage
Immune system suppression
Adverse Effects of steroids
Adrenocortical Suppression
Connective Tissue Breakdown
-Muscles & tendons
-Hyperglycemia
-Skin break down
Mineralocorticoids
Aldosterone
Maintains fluid/electrolyte balance via sodium and water regulation in the kidneys
Example: fludrocortisone
Sex Hormones
Androgen/testosterones- increase muscle mass
Androgen abuse- for athletic gains
Risk include
-Liver damage
-Cardiomyopathy, arrhythmias, ischemic heart disease
-Decrease HDL
-HTN, stroke, heart attack
Diabetes Complications
Blindness, kidney failure, heart disease, stroke, neuropathy
Hyperglycemia symptoms
extreme thirst, headache, frequent urination, hunger, abdominal pain, blurry vision, warm, flushed skin, irritability.
Symptoms of very high blood sugar include rapid shallow breathing, vomiting, and fruity breath
Diabetes treatment
Non-pharmacologic 1st line
Diet & Exercise
T1DM: insulin
Pre-diabetes: Non-pharmacologic interventions
T2DM: diabetes meds (oral or injectable) +/- insulin
Targeting glycemic control and A1C goal
Metformin MOA
Decrease glucose production from liver; increase insulin sensitivity
Metformin side effects
Diarrhea - common, transient (significant, but gets better
Nausea and vomiting - transient
stomach cramping
lactic acidosis - rare; serious
Sulfonylureas MOA (Glipizide, Glimepiride, Glyburide)
Increase insulin secretion from pancreas
Sulfonylureas side effects
HYPOGYLCEMIA
Weight gain
Need to take this with a meal
GLP-1 Receptor Agonist side effects (Exenatide (Byetta), Liraglutide (Victoza), Semaglutide (Ozempic))
Tachycardia (resting HR), weight loss, GI upset
DPP-4 Inhibitor side effects (Sitagliptin (Januvia), Linagliptin (Tradjenta) )
well tolerated, weight neutral, pancreatitis (postmarketing, rare)
SGLT-2 Inhibitors side effects (Empagliflozin (Jardiance), Dapagliflozin (Farxiga), Canagliflozin (Invokana))
UTI/Genital yeast infection / increased urine output
Weight loss
Pioglitazone (Actos) MOA
increase insulin sensitivity
Pioglitazone (Actos) side effects
Heart failure
Edema (LE extremity)
Weight gain
Bone fracture (?)
Increased LFTs
NovoLog
Rapid acting insulin
onset 15 minutes, peak effects 35-50 mins, duration 3-5 hours
HumaLog
Rapid acting insulin
onset: >30 minutes, peak effects 30 mins to hour and a half, duration 2-5 hours
Lantus
Long-acting insulin,
onset: 2-5 hours
peak: 5-24 hours
duration: 18-24 hours
Levemir
Long acting insulin,
Onset: 3-4 hours
Peak: 3-14 hours
Duration: 6-24 hours
Hypoglycemia symptoms
sweating, hunger, headache, blurred vision, extreme tiredness and paleness, dizziness, trembling, mood change
Night time symptoms include night sweats, tiredness, irritability upon waking, morning headache
Glucose monitoring
Rule of 15:
15 g carbs, check glucose in 15 minutes, repeat if <70 mg/dL
Anything less than 70 will present with symptoms
Exercise induced hypoglycemia
Depends on intensity, type and duration of exercise
May require dose adjustment of short acting insulin prior to workout
Do not inject short acting insulin until at least 1 hour post workout
Inject insulin in stomach instead of arms or thighs to help slow absorption
