Updated: 1/18/2022

Rickets / Osteomalacia

0%
Topic
Review Topic
0
0
N/A
N/A
Questions
3
0
0
0%
0%
Evidence
2
0
0
Topic
Images
https://upload.medbullets.com/topic/120527/images/table.jpg
https://upload.medbullets.com/topic/120527/images/rickets1.jpg
  • Snapshot
    • A 6-year-old boy is brought to his pediatrician by his parents due to poor growth, weakness, and abnormal gait. On physical exam, there is bowing of the legs and tenderness upon palpation of the lower extremity. Laboratory testing is significant for a decreased serum calcium and phosphate levels and elevated parathyroid hormone and serum alkaline phosphatase levels. (Rickets secondary to vitamin D defiency)
  • Introduction
    • Clinical definition
      • osteomalacia
        • a condition due to defective mineralization of osteoid
      • rickets
        • a condition due to defective mineralization of cartilage in the epiphyseal growth plates
  • Epidemiology
    • Demographics
      • children can have both osteomalacia and rickets
      • adults can only have osteomalacia since their growth plates have been fused
    • Risk factors
      • vitamin D deficiency secondary to
        • poor dietary intake and sun exposure
        • malabsorption
          • e.g., inflammatory bowel disease and gastrointestinal bypass surgery
        • genetic causes that result in
          • vitamin D deficiency and vitamin D resistance
      • primary hypophosphatemia
        • e.g., X-linked hypophosphatemic rickets and autosomal dominant hypophosphatemic rickets
  • Etiology
    • Vitamin D deficiency
    • Hypophosphatemia
    • Chronic kidney disease
      • e.g., metabolic acidosis and decreased 1,25-dihydroxyvitamin D synthesis
    • Renal tubular acidosis
      • proximal (type II) renal tubular acidosis/Fanconi syndrome
        • secondary to phosphate wasting, metabolic acidosis which increases calcium loss, and secondary hyperparathyroidism
    • Inhibitors of bone mineralization
      • e.g., bisphosphonates, alimunum, and fluoride
    • Hypophosphatasia
      • a tissue non-specific alkaline phosphatase (TNSALP) gene mutation that leads to the accumulation of pyrophosphate
        • pyrophosphate inhibits bone mineralization
    • Pathogenesis
      • impaired mineralization of osteoid (osteomalacia) and/or cartilage at the epiphyseal plates (rickets)
  • Presentation
    • Symptoms
      • bone and joint pain
      • muscle weakness
      • difficulty with walking
      • fractures
    • Physical exam
      • pediatric
        • bowed legs
        • rachitic rosary line
          • costochondral thickenings
        • Harrison's groove
          • depression along line of diaphragmatic insertion into rib cage
        • kyphosis
          • as well as lordosis and scoliosis
        • poor growth
      • bone tenderness to palpation
  • Imaging
    • Radiography
      • indication
        • perform in patients with a clinical presentation concerning for osteomalacia or rickets
      • findings
        • osteomalacia
          • reduced bone mineral density
            • a non-specific finding
          • inability to radiologically distinguish vertebral body trabeculae
            • the film appears poor quality
          • Looser pseudofractures, fissues, or narrow radiolucent lines
            • characteristic radiologic findings
        • rickets
          • perform an anteriorposterior radiograph in skeletal areas that are rapidly growing (e.g., knee or wrist)
            • osteopenia
            • metaphysis may appear frayed and widened
            • distal physis may appear widened
            • bones of the arms and legs may have angular defomities
  • Studies
    • Labs
      • highly dependent on the cause
        • e.g., patients with vitamin D deficiency will have decreased 25-hydroxyvitamin D
    • Laboratory Abnormalities in Rickets/Osteomalacia
      Etiology
      Serum Phosphate
      Serum Calcium
      Serum Alkaline Phosphatase
      Parathydroid Hormone
      Vitamin D deficiency Decreased or normal
        Decreased or normal
          Elevated
            Elevated
              Urinary phosphate wasting Decreased
                Normal
                  Elevated or normal
                    Normal
                      Proximal (type II) renal tubular acidosis Decreased
                        Normal
                          Normal
                            Normal
                              Hypophosphatasia Normal
                                Normal
                                  Decreased
                                    Normal
                                  • Differential
                                    • Child abuse
                                    • Osteogenesis imperfecta
                                    • Osteoporosis
                                    • Paget disease of bone
                                    • Multiple myeloma
                                    • Vitamin D resistant rickets
                                      • normal vitamin D and normal PTH
                                    • Laboratory Abnormalities in Select Bone Disorders
                                      Etiology
                                      Serum Phosphate
                                      Serum Calcium
                                      Serum Alkaline Phosphatase
                                      Parathyroid Hormone
                                      Osteoporosis
                                      NormalNormal or decreasedNormalNormal
                                      Paget disease of the boneNormalNormalElevatedNormal
                                      Osteitis fibrosa cystica
                                      Primary
                                      hyperparathyroidism
                                      •decreased

                                      Secondary
                                      hyperparathyroidism
                                      •increased

                                        Primary
                                        hyperparathyroidism
                                        •increased

                                        Secondary
                                        hyperparathyroidism
                                        •decreased

                                          Primary and secondary hyperparathyroidism
                                          •increased

                                            Primary and secondary hyperparathyroidism
                                            •increased
                                              Hypervitaminosis DIncreasedIncreasedNormalDecreased
                                          • Treatment
                                            • Medical
                                              • treatment is directed against the underlying cause for example
                                                • vitamin D supplemention
                                                  • indication in patients with
                                                    • vitamin D deficiency
                                                    • hereditary hypophosphatemic rickets along with phosphate supplementation
                                                    • osteomalacia of renal tubular acidosis along with sodium or potassium citrate
                                          • Complications
                                            • Fractures
                                            • Growth abnormalities
                                          • Prognosis
                                            • Depends on the etiology
                                          Flashcards (0)
                                          Cards
                                          1 of 0
                                          Questions (3)
                                          Question locked
                                          Sorry, this question is for
                                          PEAK Premium Subscribers only
                                          Upgrade to PEAK

                                          (M2.OR.16.22) A 70-year-old woman presents to the office for a yearly physical. She states she has recently started experiencing pain in her legs and her back. Last year, she experienced a fracture of her left arm while trying to lift groceries. The patient states that she does not consume any dairy and does not go outside often because of the pain in her legs and back. Of note, she takes carbamazepine for seizures. On exam, her vitals are within normal limits. You suspect the patient might have osteomalacia. Testing for which of the following is the next best step to confirm your suspicion?

                                          QID: 104347

                                          7-dehydrocholesterol

                                          0%

                                          (0/10)

                                          25-hydroxyvitamin D

                                          40%

                                          (4/10)

                                          1,25-hydroxyvitamin D

                                          60%

                                          (6/10)

                                          Pre-vitamin D3

                                          0%

                                          (0/10)

                                          Dietary vitamin D2

                                          0%

                                          (0/10)

                                          M 6 E

                                          Select Answer to see Preferred Response

                                          (M2.OR.14.17) A 2-year-old boy presents to the pediatrician for a well-child visit. The child has been doing well and this is his first visit to a pediatrician after being adopted. His parents state that he is doing well and wanted him to generally be checked out. His temperature is 97.0°F (36.1°C), blood pressure is 100/65 mm Hg, pulse is 100/min, respirations are 17/min, and oxygen saturation is 98% on room air. Physical exam is notable for the finding in Figure A. Laboratory values are ordered as seen below.

                                          Serum:
                                          Ca2+: 9.1 mg/dL
                                          Phosphorus: 1.1 mg/dL
                                          Alkaline phosphatase: 462 U/L
                                          Parathyroid hormone: 23 pg/mL (N = 10-55)
                                          1,25-dihydroxyvitamin D: 22 pmol/L (N = 15-30)

                                          What is the most likely diagnosis?

                                          QID: 104464
                                          FIGURES:

                                          Pseudohypoparathyroidism

                                          50%

                                          (17/34)

                                          Renal osteodystrophy

                                          15%

                                          (5/34)

                                          Vitamin D deficiency rickets

                                          6%

                                          (2/34)

                                          Vitamin D resistant rickets

                                          24%

                                          (8/34)

                                          Type II vitamin D dependent rickets

                                          3%

                                          (1/34)

                                          M 6 E

                                          Select Answer to see Preferred Response

                                          Evidence (2)
                                          VIDEOS & PODCASTS (1)
                                          EXPERT COMMENTS (9)
                                          Private Note