Endocrinology

Question 1

Diabetes

Answer 1

• Hyperglycemia d/t inability to produce insulin, insulin resistance or BOTH
• Complications of DM
  
  • Neuropathy
    
    • Decreased proprioception “stocking glove” pattern
  • Retinopathy
    
    • Painless deterioration of small retinal vessels
  • Nephropathy
    
    • Progressive kidney deterioration leading to microalbuminuria (1^st sign of diabetic nephropathy)
    • DM is the MCC of ESRD (HTN 2^nd MC)
  • Hypoglycemia
    
    • Usually d/t too much insulin use, too little food or excess exercise
• Management and goals of DM
  
  • Diet, exercise & lifestyle changes: should be tried first in type II DM - oral antihyperglycemic agents
    
    • Diet = Carbs 50-60%, protein 15-20%, 10% unsaturated fats
  • Glucose control goals
    
    • Hgb A1C <7.0% (check q3 months if not controlled; check twice a year if controlled)
  • Lipid control
    
    • LDL <100; HDL ≥40, TG <150
  • Neuropathy: Gabapentin
  • Nephropathy: ACEI if microalbuminuria
  • 1^st line PO meds = METFORMIN
    
    • SE = lactic acidosis
  • Sulfonylureas (Glipizide, Glyburide, Glimepiride) = stimulate pancreatic insulin release from beta cells
    
    • SE = hypoglycemia!!; disulfram rxn, weight gain

Question 2

Thyroid Cancer

Answer 2

• Most pts w/ thyroid cancer are euthyroid
• Papillary
  
  • MC type (80%); in young females; MC after radiation exposure
  • Least aggressive
  • Local (cervical) METS common; distant METS uncommon
  • Excellent cure rate
  • Management
    
    • Total thyroidectomy
    • Subtotal thyroidectomy
• Follicular
  
  • More aggressive than papillary but also slow growing
  • Distant METS common d/t characteristic vascular invasion
  • Excellent prognosis
  • Management
    
    • Total thyroidectomy
    • Subtotal thyroidectomy
• Medullary
  
  • MC associated w/ MEN 2
  • More aggressive; arises from parafollicular (C) cells that secrete calcitonin
  • Local cervical lymph node occurs early in dz
  • Distant METS occurs late
  • Poorer prognosis (These tumors don’t take up iodine)
  • Management
    
    • Total thyroidectomy
    • Monitor calcitonin levels
• Anaplastic
  
  • MC in males >65y
  • MOST AGGRESSIVE; RAPID GROWTH
  • May invade trachea; local and distant METS
  • Poor prognosis (most don’t live 1 year after dx)
  • Management
    
    • Most are not amenable to surgical resection
    • External beam radiation
    • Chemotherapy
    • Palliative tracheostomy to maintain airway

Question 3

Osteoporosis

Answer 3

• Loss of bone density over time d/t increased absorption of bone or decreased formation of new bone
• Loss of both bone mineral & matrix
• 2 types
  
  • Primary
    
    • Postmenopausal
    • Senile
  • Secondary
    
    • D/t chronic dz or meds
      
      • Prolonged high dose steroid use
• Clinical manifestations
  
  • Usually asymptomatic
  • Pathologic fx = MC vertebral, hip, & distal radius w/ or w/o trauma
  • Spine compression = MC upper lumbar & thoracic
    
    • Loss of vertebral height
• Diagnosis
  
  • Labs à serum calcium, phosphate, PTH & ALP usually normal
  • DEXA scan à best test to show extent of demineralization
    
    • Osteoporosis: bone density T score ≤-2.5
    • Osteopenia: T score ≤-1.0 to -2.5
• Management
  
  • Adequate vitamin D, & exercise
  • Bisphosphonates = 1^st line tx
  • Vitamin D – ergocalciferol associated w/ decreased progression
  • Selective estrogen receptor modulator (SERM): Raloxifene
  • Estrogen

Question 4

Hypercalcemia

Answer 4

• 90% of cases of hypercalcemia are d/t Primary hyperparathyroidism or malignancy
• PTH – mediated
  
  • Primary hyperparathyroidism; MC cause overall
    
    • Triad: Increased Ca++, increased intact PTH + decreased phosphate
• PTH – independent
  
  • Malignancy (secretes increased PTH-related protein), decreased intact PTH
  • Vitamin D excess
  • Vitamin A excess, thiazides, lithium
• Clinical manifestations
  
  • Most are asymptomatic
  • Stones: kidney stones
  • Nephrogenic DI: polyuria
  • Bones: painful bones, fractures
  • Abdominal groans: ileus, constipation
  • Psychic moans – decreased DTRs
• Lab findings
  
  • Increased ionized Ca++
• EKG findings
  
  • Shortened QT interval, prolonged PR interval, QRS widening
• Management
  
  • Severe symptomatic
    
    • IV saline à Furosemide 1^st line
      
      • AVOID HCTZ
    • Calcitonin, Bisphosphonates in severe cases
  • Mild
    
    • No tx needed; tx underlying cause

Question 5

Dislipidemia

Answer 5

• Hyperlipidemia
  
  • Clinical manifestations
    
    • Most patients are asymptomatic
    • May develop Xanthomas (ex: Achilles tendon) or Xanthelasma (lipid plaques on the eyelids)
  • Goals
    
    • Weight reduction, increased exercise
    • Restric cholesterol & carbs, decrease trans fatty acids
    • Lipid-lowering agents
  • Screening
    
    • AHA à adults 20-79 free of CVD = assess risk factors q4-6 years to calculate their 10-year CVD risk
  • Lipid guidelines for initiation of statin therapy
    
    • Determined by a 10-year and lifetime risk calculator instead of strict numbers only
    • Tx of following patients –
      
      • Pts w/ Type 1 or 2 DM b/w 40-75 years
      • Patients w/o CVD ages 40-75 yrs & >7.5% risk for having a heart attack or stroke within 10 yrs
      • People >21 years of age w/ LDL >190
      • Any pt w/ any form of clinical atherosclerotic CVD
  • Benefit of lipid lowering meds
    
    • Statins = best meds to lower elevated LDL
      
      • SE = Myositis/myalgias/rhabdo
    • Fibrates = best meds to lower elevated triglycerides
    • Niacin = Best meds to increase HDL

Question 6

Hypoglycemia clinical manifestations

Answer 6

• Clinical manifestations
  
  • Autonomic: sweating, tremors, palpitations, nervousness, tachycardia
  • CNS: HA, lightheadedness, confusion, slurred speech dizziness
• Diagnosis
  
  • Random blood sugar 50-60 mg/dL
• Management
  
  • Mild <60: 10-15g fast acting carbohydrate, fruit juice, hard candies
    
    • Recheck in 15 mins
  • Severe/unconscious <40 mg/dL: IV bolus D50 or inject glucagon SQ

Question 7

Type I DM management

Answer 7

• Most need 0.5-1.0 units/kg of insulin per day
• Rapid acting
  
  • Humalog, Novolog
    
    • Onset = 5-15mins; duration 3-4h
    • Given at the same time of meal
• Short-acting
  
  • Regular (humulin-R)
    
    • Given 30-60 mins prior to meal
• Long acting
  
  • Detemir, Glargine
    
    • Onset = 6-8hrs; duration 20-30hours
    • Covers insulin for 1 full day (basal insulin)
• Long acting should not be mixed w/ other types insulin in the same syringe