NSG/501 Week 3: Pathophysiology Concept Map, sample paper

Concept Map With Narrative: How Estrogen Loss, Low Vitamin D and a Fall Combine Into a Fractured Wrist, and Where Each Treatment Acts

[Student Name]

University of Phoenix

NSG/501: Pathophysiology, Assessment Variables and Pharmacology I

Week 3 Assignment

[Instructor Name]

[Date]

The patient and the map are a composite written for a model paper.

Concept maps show relationships that a written explanation can hide. This map traces postmenopausal osteoporosis in Mrs. D., the 68-year-old woman from Week 2, from its causes to her wrist fracture, and marks where each treatment in the coming weeks will act. Each node is numbered, and each link names the relationship between two nodes.

Part 1: Causes

Node 1. Menopause at age 47: estrogen falls.

Node 2. Aging: osteoblast function declines, gut calcium absorption and skin vitamin D production fall.

Node 3. Low vitamin D (25-hydroxyvitamin D 18 ng/mL) and low dietary calcium.

Node 4. Long-term proton pump inhibitor use.

Node 5. Family history: mother's hip fracture, reflecting inherited peak bone mass and bone structure.

Links: Node 1 increases RANKL and lowers osteoprotegerin (to Node 6). Node 2 reduces bone formation (to Node 8) and adds to low calcium supply (to Node 3). Node 3 lowers blood calcium, which raises parathyroid hormone (to Node 7). Node 4 is associated with reduced calcium absorption (to Node 3). Node 5 means a lower starting bone mass (to Node 10).

Part 2: Cellular Mechanisms

Node 6. RANKL-to-osteoprotegerin ratio rises: more osteoclasts form and live longer.

Node 7. Secondary rise in parathyroid hormone.

Node 8. Osteoblasts cannot refill resorption cavities completely.

Node 9. Remodeling imbalance: each cycle removes more bone than it replaces, and more remodeling units open at once.

Links: Node 6 increases resorption (to Node 9). Node 7 increases resorption further (to Node 9). Node 8 leaves a deficit in each unit (to Node 9). Every cause on this map reaches the fracture through the same final step, an imbalance in bone remodeling, which is why treatments aimed at remodeling help regardless of cause.

Part 3: Tissue Changes

Node 10. Loss of bone mass.

Node 11. Trabecular bone thins, perforates and loses connections, first in the vertebrae and distal radius.

Node 12. Cortical bone thins and becomes porous.

Node 13. Bone strength falls more than density alone predicts.

Links: Node 9 causes Node 10. Node 10 is expressed as Node 11 and Node 12. Nodes 11 and 12 reduce strength (to Node 13).

Part 4: Signs and Diagnostic Findings

Node 14. No symptoms before fracture.

Node 15. Height loss of 4 cm and thoracic kyphosis: suggests silent vertebral compression fractures.

Node 16. DXA T-score minus 2.7 at the femoral neck.

Node 17. FRAX ten-year probability: major osteoporotic fracture about 25%, hip about 6%.

Links: Node 13 is silent (to Node 14) until it causes vertebral collapse (to Node 15). Node 10 is measured by Node 16. Nodes 16, 5 and the prior fracture are combined in Node 17 (Kanis et al., 2008).

Part 5: The Fracture

Node 18. Fall risk: Timed Up and Go 11 seconds with sway, home hazards, low vitamin D affecting muscle.

Node 19. Fall onto outstretched hand.

Node 20. Distal radius fracture from a force a healthy bone would withstand.

Node 21. High risk of the next fracture, spine or hip.

Links: Node 3 weakens muscle (to Node 18). Node 18 makes Node 19 more likely. Node 19 on bone weakened by Node 13 produces Node 20. Node 20 predicts Node 21.

Part 6: Where Treatments Act

T1. Vitamin D and calcium repletion: acts on Node 3 and Node 7, reducing parathyroid-driven resorption and supporting muscle.

T2. Bisphosphonates, such as alendronate or zoledronic acid: bind to bone mineral and inhibit osteoclasts, acting on Node 9. In a three-year trial, yearly zoledronic acid reduced new vertebral fractures by 70% and hip fractures by 41% compared with placebo (Black et al., 2007).

T3. Denosumab: a monoclonal antibody against RANKL, acting directly on Node 6 by blocking osteoclast formation.

T4. Anabolic agents, such as teriparatide: stimulate osteoblasts, acting on Node 8 to build new bone, reserved for very high fracture risk.

T5. Fall prevention: home changes and balance exercise act on Node 18.

T6. Medication review: reassessing the proton pump inhibitor acts on Node 4.

Narrative

The map shows that osteoporosis has several causes in Mrs. D. but one mechanism: remodeling that removes more bone than it replaces. Estrogen loss drives osteoclasts through the RANKL pathway, aging and low vitamin D add resorption through parathyroid hormone and weaken formation, and the result is thin, disconnected trabeculae and porous cortex. The disease is silent until bone fails, and in Mrs. D. it may already have failed quietly in her spine, as her height loss suggests.

The map also shows why the fracture happened when it did. Weak bone alone does not break; it breaks in a fall, and Mrs. D. had fall risk factors of her own. Treatment therefore has two targets, the remodeling imbalance and the fall, which is why her plan must include both drug therapy and fall prevention. Finally, placing the drugs on the map makes their differences clear: bisphosphonates and denosumab slow the removal of bone, while anabolic drugs build it, a distinction that will guide the drug evaluation in Week 4 (Compston et al., 2019).

What the Map Suggests for Nursing

A concept map is useful to a nurse only if it changes what the nurse notices and does. Three nursing implications follow from this one. First, because the disease is silent until a bone breaks, nurses in any setting should treat a fragility fracture, a height loss of 4 cm or new kyphosis as a trigger for bone health assessment rather than as incidental findings. Second, because low vitamin D sits on both chains, weak bone and falls, correcting it is a nursing priority that serves two purposes at once. Third, because the fracture requires both weak bone and a fall, nursing assessment after a fracture must include fall risk: gait, balance, vision, footwear, home hazards and medications that cause dizziness. A plan that treats bone without preventing falls, or prevents falls without treating bone, leaves one chain intact.

Limits of the Map

A concept map simplifies. This one shows the main pathways for Mrs. D. but leaves out others that matter in some patients, such as the effects of glucocorticoids, diabetes, thyroid excess or low body weight on bone, and it presents links as if each were equally strong. In reality, estrogen loss explains most of her bone loss, while the proton pump inhibitor may contribute only a little. A more detailed map could weight the links, for example with thicker arrows for stronger effects. For this course, the value of the map is in showing that many causes meet in one mechanism and that fractures require both weak bone and a fall, which is enough to guide the drug evaluation and the plan of care that follow.

Conclusion

Written as nodes and labeled links, the concept map shows many causes converging on a remodeling imbalance, the tissue changes that weaken bone, the silent signs that reveal it and the fall that turns weak bone into a fracture. It also locates each treatment on the chain, which prepares for the pharmacology analysis in Week 4.

References

Black, D. M., Delmas, P. D., Eastell, R., Reid, I. R., Boonen, S., Cauley, J. A., Cosman, F., Lakatos, P., Leung, P. C., Man, Z., Mautalen, C., Mesenbrink, P., Hu, H., Caminis, J., Tong, K., Rosario-Jansen, T., Krasnow, J., Hue, T. F., Sellmeyer, D., ... Cummings, S. R. (2007). Once-yearly zoledronic acid for treatment of postmenopausal osteoporosis. New England Journal of Medicine, 356(18), 1809-1822. https://doi.org/10.1056/NEJMoa067312

Compston, J. E., McClung, M. R., & Leslie, W. D. (2019). Osteoporosis. The Lancet, 393(10169), 364-376. https://doi.org/10.1016/S0140-6736(18)32112-3

Kanis, J. A., Johnell, O., Oden, A., Johansson, H., & McCloskey, E. (2008). FRAX and the assessment of fracture probability in men and women from the UK. Osteoporosis International, 19(4), 385-397. https://doi.org/10.1007/s00198-007-0543-5