Endocrine Flashcards
The endocrine system
- Functions as a negative feedback system
- if a hormone is low, then the body works harder to compensate and produce more of this hormone
- if a hormone is high, the body works to stop its production
Thyroid Function
- Normal Lab Values:
- TSH: 0.5 - 4.5
- T4: 0.8 - 1.8
- T3: 80 - 220
- The BEST screening test for thyroid disease (hypothyroidism and hyperthyroidism)
- Thyroid Stimulating Hormone (TSH)
- IF TSH is HIGH, add a free T4 to help determine the degree of hypothyroidism
- IF TSH is low, add a free T4 and T3 to determine the degree of hyperthyroidism
- Thyroid Stimulating Hormone (TSH)
HYPERthyroidism
LOW TSH, HIGH T4 and T3
Presentation:
- Tremor, palpitations, tachycardia, weight loss, heat intolerance
- Graves Disease: most common cause for hyperthyroidism.
- Classic patient with Grave’s:
- Ophthalmopathy (Upper eyelid retraction, lid lag, swelling, conjunctivitis, and bulging eyes), enlarged non-modular, with correlating labs.
Treatment:
- Anti-thyroid medications (thionamides), radioactive iodine and surgery
Thyroid Storm:
- Rare, life-threatening condition that can occur from untreated hyperthyroidism, thyroid surgery, trauma or infection
Presentation:
- Tachycardia, high fevers, GI symptoms (nausea, vomiting), dysfunction of the CNS as made evidence by agitation, psychosis and even coma.
REMEMBER: think HYPERthyroidism = STORM
HYPOthyroidism
HIGH TSH, LOW T4 and T3
Presentation:
- Fatigue, bradycardia, cold intolerance, weight gain, constipation, irregular menstrual cycles
- Hashimoto’s Disease: Most common cause in the USA
- In areas of the Western Pacific, South East Asia and Africa, Iodine deficiency is most common cause.
Treatment:
- Levothyroxine (synthetic T4)
- Begin patients with cardiac history and > 60 years of age on low dose (25 to 50mcg/day)
- Re-check in 4 to 6 weeks and titrate dose if needed slowly.
Myxedema Coma: Occurs from severe hypothyroidism and can cause a decrease in function in a variety of organs
Presentation:
- Decreased LOC, hypothermia, hypotension, bradycardia, hypoventilation and hypoglycemia
REMEMBER: Hashimoto go SLOW/HYPO
Diabetes
Type 1: Insulin deficient
- Typically presents earlier in life however can present in adulthood
Type 2: Insulin resistant
- Approximately 90% of patients with diabetes have type 2.
Risk factors:
- Obesity, genetic susceptibility, lifestyle choices such as alcohol and smoking tobacco, a sedentary lifestyle style, history of gestational diabetes, PCOS and metabolic syndrome.
Presentation:
- Classic symptoms of a patient with hyperglycemia includes polyuria, polydipsia, weight loss and blurred vision.
REMEMBER: D comes before R ( Deficiency is Type 1, Resistant is type 2)
Lab Findings (Diabetes)
Normal Labs
- Fasting Plasma glucose: < 100
- A1C: < 5.7%
Pre-Diabetes:
- Fasting Plasma glucose: 100 to 125
- A1C: 5.7-6.4%
- Oral glucose tolerance test: 140 to 199
Diagnosis (DMT2)
- Symptomatic
- Symptoms of hyperglycemia PLUS a random blood glucose of 200 or greater
- Asymptomatic
- If a patient is asymptomatic, they need 2 positive lab test OR the abnormal test must be repeated the following day.
- Fasting plasma glucose of 126 or greater
- 2 hour plasma glucose of 200 or greater during an oral glucose tolerance test
- A1C value of 6.5% or greater
- If a patient is asymptomatic, they need 2 positive lab test OR the abnormal test must be repeated the following day.
A1C Target
Pregnant Women
- < 6%
Most Adults
- < 7 %
Elderly, significant commorbidities, history of hypoglycemia
- < 8%
Type 2 Diabetes treatment
Lifestyle modifications
- Nutrition, physical exercise, comprehensive diabetes education and preventing complications
Pharmacological treatment:
- Metformin: Decreases hepatic glucose by inhibiting gluconeogensis
- Benefits: Cam decrease A1C by 1-2%, not known to cause hypoglycemia, has shown to decrease food intake and body weight and may help reduce likelihood of cardiac events
- Side effects: Diarrhea most reported side effect
- Stop and wait for diarrhea to resolve before attempting Metformin again at a lower dose and slowly titrate to desired dose
- Contraindications: (risk factors for lactic acidosis)
- Impaired kidney function (eGFR <30)
- Active liver disease
- Metabolic Acidosis
- Dehydration
- Sepsis
- History of lactic acidosis
Type 2 Diabetes Treatment (continued)
- generally, if a patient has been implementing life style changes and using metformin for 3 months without reaching A1C goal, a second agent should be added
Second Agents
- Insulin
- Glucagon-like peptide receptor agonist (GLP1)
- Semaglutide, Dulaglutide, Iraglutide
- Preferred for patients with established cardiac disease
- Sodium-glucose co-transporter-2 (SGLT2 inhibitors)
- Canagliflozin, Dapagliflozin, Empagliflozin
- Good alternative to GLP1 for cardiac patients
- Dipeptidyl Peptidase IV inhibitors (DPP4 Inhibitors)
- Sitagliptin, Saxagliptin, Linagliptin, Alogliptin
- Avoid with heart failure patients
- Thiazolidinediones
- Rosiglitazone, Pioglitazone
- Avoid with heart failure patients
- Sulfonylureas
- Glimepiride, glyburide, glipizide
- Cheapest, however highest risk for hypoglycemia
When is Insulin indicated?
- A1C > 9%
- Symptomatic, hyperglycemia and ketonuria present
How to initiate Insulin:
- Start with an intermediate acting insulin at bedtime or a long-acting insulin in the morning or at bedtime
- It is appropriate to start with 10 units or 0.2 units/per kg
- Check fasting glucose daily and increase dose by 2 units every 3 days until in target range of 80 to 130 FPG
- Increase by 4 units if FPG > 180
- IF FPG < 80, reduce by 4 units or by 10% (whichever is greater)
Somogyi Effect
- High blood sugar in the morning caused by a rebound effect
- More common in type 1 diabetes
- Things to consider:
- Taking too much insulin?
- Skipping evening meal?
- Things to consider:
REMEMBER: Somogyi has a Y in it like YO-YO and YOYOs rebound back to you
Somogyi = rebound hypoglycemia
Dawn Phenomenon
- Normal hormonal surge, that causes fasting blood glucose to rise between 4 and 8 am
Addison’s Disease (Adrenal Insufficiency)
- The adrenals secrete cortisol, aldosterone, adrenaline (epinephrine), noradrenaline (norepinephrine), catecholamines and steroid hormones
Causes:
- Up to 90% is a result of an autoimmune disease
- Other causes include infection, malignancy, drug use, adrenal hemorrhage or adrenal infarction
Treatment:
- Hydrocortisone, prednisone or methylprednisolone to replace the cortisol insufficiency and fludrocortisone acetate to replace the aldosterone
Adrenal Crisis: Acute Adrenal Insufficiency
- Symptoms:
- Shock, hypotension, abdominal, flank, back or lower chest pain, nausea, vomiting, fatigue, unexplained fever, unexplained hypoglycemia, hyperpigmentation or vitiligo (loss of skin color), confusion, coma
Cushing’s Disease
Causes:
- Taking high doses of oral or injectable corticosteroids over time, or from over production of cortisol, either caused by a pituitary tumor, an ACTH secreting tumor or primary adrenal gland disease.
Symptoms:
- Hump between the shoulders (buffalo hump), a round face (moon face), striae on the skin, hirsutism, irregular or absent periods, decreased fertility or erectile dysfunction in men.
Diagnosis:
- 24 hour urinary cortisol excretion test, or a late-night salivary cortisol measurement test
Treatment:
- Slowly tapering off of corticosteroids (if applicable)
- Meds used to manage over production of cortisol: Ketoconazole, Mitotane (Lysodren), and metyrapone (Metopirone)
REMEMBER: Cushing causes cortisol to climb
