A 70-year-old white woman is brought to the emergency department due to acute right hip pain after a fall. She was walking in her house when she tripped on a floor rug and fell, landing on her hip. The patient has been unable to bear weight on the right leg since the fall and had to call for emergency transport to the hospital. She has no significant medical history and does not use tobacco, alcohol, or illicit drugs. The patient's only medication is an over-the-counter multivitamin. Family history is notable for a hip fracture in her mother. Blood pressure is 150/90 mm Hg and pulse is 112/min. The patient is in moderate pain and her right leg appears shortened and externally rotated. There is tenderness and swelling of the right hip. Radiographs reveal a right femoral neck fracture. Which of the following changes in bone structure is most likely responsible for this patient's condition?

Question

A 70-year-old white woman is brought to the emergency department due to acute right hip pain after a fall.  She was walking in her house when she tripped on a floor rug and fell, landing on her hip.  The patient has been unable to bear weight on the right leg since the fall and had to call for emergency transport to the hospital.  She has no significant medical history and does not use tobacco, alcohol, or illicit drugs.  The patient's only medication is an over-the-counter multivitamin.  Family history is notable for a hip fracture in her mother.  Blood pressure is 150/90 mm Hg and pulse is 112/min.  The patient is in moderate pain and her right leg appears shortened and externally rotated.  There is tenderness and swelling of the right hip.  Radiographs reveal a right femoral neck fracture.  Which of the following changes in bone structure is most likely responsible for this patient's condition?

Quizplus · Accepted Answer

11ec160b_3a62_132e_9249_0dd17ef9524a_MD0001_00 This patient has a fragility fracture (ie, due to low-intensity trauma that would not cause a fracture in normal bone). In light of her white ethnicity and post-menopausal age, this is likely due to osteoporosis. After menopause, declining estrogen levels accelerate the loss of bone mass with a decrease in osteoblastic and an increase in osteoclastic activity. Other common risk factors include low body weight, smoking, heavy alcohol intake, and sedentary lifestyle. The 2 major types of bone are trabecular (also called cancellous or spongy bone) and cortical. Trabecular bone composes only 15% of the skeleton by weight but is metabolically more active due to its large surface area. Initially following menopause, bone loss predominantly affects trabecular bone, especially in the dorsolumbar vertebral bodies. Morphologic characteristics include trabecular thinning and perforation with loss of interconnecting bridges. With continued aging, cortical bone, which composes most of the appendicular skeleton, also becomes involved. The neck of the femur has components of both trabecular and cortical bone, and is a common site of osteoporotic fracture. (Choice A) Paget disease of bone is caused by defective osteoid formation and increased bone remodeling. Collagen is laid down in a haphazard manner, resulting in a mosaic pattern of bone with irregular sections of lamellar bone linked by prominent cement lines. Paget disease typically presents with bone pain and deformity with osteolytic or mixed lytic/sclerotic lesions on x-ray. (Choice B) Osteomalacia is commonly due to vitamin D deficiency, and is characterized by unmineralized osteoid deposits on trabecular surfaces. The bone is weak and prone to fracture, but symptomatic patients typically have bone pain, muscle weakness, and impaired ambulation. (Choice C) Osteopetrosis is a group of disorders characterized by impaired osteoclast function. This leads to persistence of the primary spongiosa in the medullary cavity. These rare disorders typically present early in life with fractures, deformities, and hematologic cytopenias (due to obliteration of the marrow space). (Choice D) Bone disease in hyperparathyroidism is characterized by increased bone resorption in cortical bone with subperiosteal thinning and cystic degeneration (osteitis fibrosa cystica). However, this is typically seen in advanced cases along with diffuse bone pain and manifestations of hypercalcemia (eg, constipation, neuropsychiatric symptoms). Educational objective: Initially in osteoporosis, bone loss predominantly affects trabecular bone, leading to trabecular thinning and perforation with loss of interconnecting bridges. Over time, cortical bone, which composes most of the appendicular skeleton, also becomes involved.

A 70-Year-Old White Woman Is Brought to the Emergency Department