Metabolic & Endocrine Pathology Lab Flashcards
What is the normal serum calcium level range?
8.6-10.6 mg/dl
What is the normal serum phosphate level range?
1.5-4.5 mg/dl
What does DEXA measure?
Bone density
What is the DEXA T-score for osteopenia?
-1.0 to -2.5
What is the DEXA T-score for osteoporosis?
Below -2.5
In short, what is rickets?
Impaired bone mineralization
What are the expected lab findings for rickets?
Calcium:
Phosphate:
PTH:
Alkaline phosphatase:
Calcium: decreased
Phosphate: decreased
PTH: increased
Alkaline phosphatase: increased
Osteomalacia is an adult ___ deficiency
Vitamin D
What is the typical cause of hypervitaminosis D?
Over supplementation
What are the lab findings for Vitamin D toxicity (hypervitaminosis D)?
Calcium:
PTH:
Calcium: increased (in blood and urine)
PTH: decreased
A patient has a serum calcium level of 7/4 mg/dl.
Would PTH production be elevated or decreased?
What term describes this serum calcium value?
PTH would be elevated (hyperparathyroidism) due to hypocalcemia
Which Vitamin D metabolite is necessary to facilitate calcium absorption in the gut?
Calbindin
Which Vitamin D metabolite interacts with PTH on bone to increase serum calcium levels?
Calcitriol
Calcitriol, a Vitamin D metabolite, works with ___ to ___ serum calcium levels
works with PTH to increase serum calcium levels
In response to increased PTH levels, what functions does the kidney perform to increase serum calcium levels?
- Increase calcitriol
- Conserve calcium
- Excrete phosphate
This bone was sectioned with a butter knife
What metabolic pathology is present?
Osteomalacia
What do the white areas in this bone indicate?
Increased osteoid (organic, unmineralized tissue)
osteomalacia
There is reduction in normal ___ bone in this specimen
trabecular
osteomalacia
How does the organic vs inorganic bone composition of this femur compare with a normal adult specimen?
Increased organic to inorganic ratio
osteomalacia
stress strain
How does the replacement of trabecular bone with osteoid alter the biomechanical properties of bone?
Bones soften and weaken making them more likely to bend and break
This is the proximal metaphysis and diaphysis of the humerus
What is the dense white substance that has accumulated in the marrow cavity at the purple arrow?
Osteoid
osteomalacia
This is the procimal metaphysis and diaphysis of the humerus
Would the bending of this specimen’s diaphysis generally be reversible without surgical intervention?
No
osteomalacia
Which metabolic pathology created these changes in bone?
Rickets
At what age did these changes occur?
Young age
rickets
What are the expected lab results for this patient?
Calcium:
Phosphate:
Calcium: decreased
Phosphate: decreased
rickets
How would serum levels of phosphate and calcium contribute to this bowing?
Less calcium and phosphate means the bone is more organic, thus more elastic and more plastic, leading to deformity
rickets
What is the presentation of this knee?
Normal skeletally immature knee
What is unusual about the metaphyses seen here?
Paintbrush metaphyses; widened
rickets
What sort of fracture has occurred in the right fibula?
Transverse, diaphyseal, complete, noncomminuted, insufficiency (stress) pathological fracture
rickets
How are these joints affected by their pathology?
Not dislocated, but subluxated/misaligned
rickets
How has the composition of this individual’s bones changed in response to stress?
More bone laid down according to weight bearing (Wolff’s law)
rickets
Based on this radiograph, what is your suspected diagnosis?
Rickets
