growth/bone probs

• Acromegaly results from overproduction of growth hormone in adults, causing enlargement of bones and soft tissue in the face, hands, feet, and other parts of the body.
• Acromegaly


  Secretes too much growth hormone, in adulthood from an adenoma on pituitary
• Acromegaly signs/symptoms


  • Bony/soft, insidious/progressive/slow onset, excessive growth of hands, feet, jaw and internal organs
• Gigantism


  Secretes too much growth hormone, before growth plates are fused/closure of epiphyses
• Gigantism signs/symptoms


  • Tall af, 3 SD above mean height
• Acromegaly and gigantism lab findings


  • Elevated GH, IGF-1>5x normal, oral glucose suppression test; HTN, cardiomegaly, CHF, acanthosis nigricans, doughy texture, MRI in pituitary
• Pituitary dwarfism


  Pituitary gland fails to release GH
• Pituitary dwarfism signs/symptoms


  • Infant hypoglycemia/micropenis, delayed puberty, adults have dec bone density/muscle mass, long bone growth is slowed, causes poorly developed sexual organs, impaired sexual maturation, skeletal deformities/kyphosis, sleep apnea, spinal stenosis, motor delays, hearing infections/loss
• Pituitary dwarfism diagnosis


  2.5 deviations below normal mean
• Pituitary dwarfism lab findings

  • Low GH, low IGF1, bone age is two yrs behind, CT/MRI of brain
• Dwarfism


  Autosomal dominant, variant in GFRG3, 80% new mutations, 20% inherited, if both parents have achondroplasia, 25% lethal risk
• Dwarfism clinical features


  • Short/disproportionate, long bones short, macrocephaly, delayed motor development, cognitive development is normal, Rhizomelic shortening, bradydactyly, kyphosis, lordosis, saddle nose deformity, knee deformities, cervicomedullary compression
• Dwarfism complications


  • OM, obs sleep apnea, obesity, leg bowing, spinal stenosis, cervical medullary compression
• Osteoblasts


  Bone builders
• Osteoclasts

  Bone cutters
• RANKL


  Helps osteoclasts survive
• Parathyroid hormone and calcitriol

  Regulators of bone formation and resorption
• Osteoporosis

  • EPI= postmenopausal
  • ETI= meds, endocrine disorders, GI/nutritional disorders
  • PATHO= bone resorption>bone formation
• Osteoporosis risk factors


  • Smoking
  • Old age
  • Previous fracture
  • Long term glucocorticoid use
  • Parental history of fracture
  • Race (high risk in White than Black, Hispanic, or Asian Americans)
  • Excessive alcohol use
  • Physical inactivity
  • Poor nutrition
  • Low body weight
• Osteoporosis labs


  • CMP
  • Phosphorus
  • 25-hydroxyvitamin D
  • Fracture risk assessment tool
• DXA scans


  Measure bone mineral density at hip, wrist, lumbar spine
• Hip measurements


  Most useful in predicting risk of osteoporotic fracture
• Spine readings


  Good at measuring response to therapy
• Arthritic changes


  Can interfere with readings in the spine
• T-score

  Number of SD away from the normal bone mineral density of a young, healthy adult
• Z score

  Compares a patient's BMD to an age-matched population
• 1. Z-scores of -2 or lower are below expected range of normal and should prompt evaluation of patient for risk modifiable risk factors
• Mechanism of action of bisphosphonates

  Bisphosphonate is taken up by osteoclasts which causes the osteoclast to lose resorptive function and they undergo apoptosis
• Adverse effects of bisphosphonates

  • Osteonecrosis of the jaw
  • GI issues
  • Flu-like symptoms after IV administration
  • Musculoskeletal pain
  • Atypical femur fractures
• Calcium supplementation


  1200-1500 mg/d
• Vitamin D supplementation


  800-1000 IU/d