Lab: Metabolic & Endocrine Pathology 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
What hormonal secretion helps decrease serum calcium levels by sequestering calcium in the mitochondria of the cells?
Calcitonin (from parathyroid)
What clinical term describes the blood results of a patient with a phosphate value of 10.3 mg/dl?
Hyperphosphatemia
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 proximal 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
Where does calcitriol come from?
How does it affect plasma calcium and PTH?
Calcitriol comes form the kidney
Calcium increases, PTH decreases
What is the function of calbindin?
Binds calcium in the gut, increases calcium absorption
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?
Oblique diaphyseal and transverse distal diaphyseal fractures: complete, noncomminuted, insufficiency (stress) pathological fractures
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
What disease pathogenesis (cellular events) would explain the bones in this radiograph?
Decreased cartilage formation, decreased osteoid mineralization, and increased organic to inorganic ratio leads to soft and weak bones increasing risk of fracture
rickets
What are the expected lab results for this patient?
ESR:
Vitamin D:
Calcium:
PTH:
Phosphate:
ESR: elevated (inflammation associated)
Vitamin D: deficient
Calcium: decreased (needs vitamin D)
PTH: increased (trying to increase calcium resorption in kidneys)
Phosphate: decreased (PTH decreases phosphate resorption)
What are the potential etiologies of this condition?
- Indadequate dietary intake of Vitamin D or sun (acquired)
- Vitamin D dependent rickets type I: defective hydroxylation of metabolites in liver or kidney (inherited)
- Vitamin D dependent rickets type II: end organ insensitivity to vitamin D (inherited)
rickets
What treatment would you recommend for a patient with an acquired deficiency and a radiograph similar to this?
Vitamin D supplementation
A 1 year-old female presents with bleeding gums and bilateral swelling in the thighs. The patient’s guardian reports constant crying, and her temperature is recorded at 98.6 F (37 C). The child also shows bruises in multiple stages of healing. The parents report no traumatic incidents to explain the bruises. Blood work and radiographs are ordered.
What are the relevant signs and symptoms in this case?
Bleeding gums and easy bruising (vessel fragility)
scurvy
A 1 year-old female presents with bleeding gums and bilateral swelling in the thighs. The patient’s guardian reports constant crying, and her temperature is recorded at 98.6 F (37 C). The child also shows bruises in multiple stages of healing. The parents report no traumatic incidents to explain the bruises. Blood work and radiographs are ordered.
What category of pathology (infection, fracture, collagen synthesis, etc.) matches the intial signs and symptoms we see for this patient?
Collagen synthesis and metabolic
scurvy
Is the radiopaque outline around the cortex in the radiograph osteolytic or osteoblastic activity?
What could create the outline around the cortex?
Osteoblastic activity created by subperiosteal bleeding/hemorrhage
scurvy
A 1 year-old female presents with bleeding gums and bilateral swelling in the thighs. The patient’s guardian reports constant crying, and her temperature is recorded at 98.6 F (37 C). The child also shows bruises in multiple stages of healing. The parents report no traumatic incidents to explain the bruises. Blood work and radiographs are ordered.
What diagnosis best fits this case?
Scurvy (hypovitaminosis C)
metabolic
The formation of which tissue type affecting bone is altered during this pathology? How?
Collagen synthesis; vitamin C is important for hydroxylation of prolyl and lysyl residues in collagen (hydroxyproline and hydroxylysine)
scurvy
What is causing the discoloration indicated by the blue arrows?
Is this obervation potentially reversible?
Repeated/chronic hemorrhage
Irreversible
scurvy
What does DEXA measure?
Bone density
What is the meaning of a DEXA T-score?
Comparison of bone density to that of a healthy young adult
What is the meaning of a DEXA Z-score?
Comparison of bone density to that of other patients the same age
What are the following DEXA scores according to World Health Organization?
Normal:
Osteopenia:
Osteoporosis:
Normal: +1 to -1
Osteopenia: -1 to -2.5
Osteoporosis: -2.5 or lower
A 53 year-old female patient of yours has asthma and has been using steroids to control her condition for decades. She was also prescribed a blood thinner following a recent heart attack and the placement of a stent in the right carotid artery. Based on her age and medications, her primary care provider suggested she receive a DEXA scan. On her next visit, she brings the results to show you.
What risk factors does this patient have that could impact bone density?
- Age
- Steroids
- Blood thinners
- Association with cardiovascular history
When does peak bone mass occur?
Ages 25-30
What are some factors that may negatively impact peak bone mass?
- Physical activity (lack thereof)
- Diseases
- Fractures
- Medications
- Hormones
What would you recommend for an osteopenic/osteoporotic patient?
- Weight bearing and strength training exercise
- Calcium and vitamin D supplementation
- Alterations to chiropractic treatment plan
Your 53 year-old patient (with osteoporosis) fell and caught herself on an outstretched hand. She presented to the emergency room with pain in the left wrist.
How would you describe this racture?
Osteoporotic/pathologic fracture; Colles fracture
What is the term for a common distal radius fracture, often acquired after falling on an outstretched hand?
Colles fracture
Which is more common in cases of rickets, genu varum or genu valgum?
Genu varum (bowlegged)
A 2 year-old child presents with hypotonia (decreased muscle tone) and delayed growth. The child is unable to stand and there is bowing in the legs (genu varum) and arms bilaterally. You also note that the patient presents with frontal bossing, rachitic rosary, and pectus carinatum. The patient’s blood work reveals serum calcium levels at the low end of normal. Blood work also indicated that the patient is hypophosphatemic but has high serum levels of Vitamin D.
What is the likely diagnosis for this patient?
Rickets
Vitamin D being stored trying to increase calcium
Besides genu varum, what are some other bony presentations found in children with rickets?
- Pectus carinatum (Pigeon breast)
- Frontal bossing
- Rachitic rosary
This enlargment of the costochondral joints of the ribs is seen in which pathology?
Rickets
In which pathology do we see pectus carinatum in children?
Rickets
In which pathology do we see pediatric frontal bossing that grows via intramembranous ossification?
Rickets
What produces genu varum in cases of rickets?
Lack of control over endplate growth
What are the expected PTH levels in the case of rickets?
Increased
A patient’s presentation indicates rickets, but their blood work revealed high Vitamin D levels in the blood
What could explain this?
Body is trying to retain/store vitamin D because of hypocalcemia
