Differentiating Osteoporosis from other diseases

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Eiman Ghaffarpasand, M.D. [2], Cafer Zorkun, M.D., Ph.D. [3], Raviteja Guddeti, M.B.B.S.[4]

Overview

Osteoporosis must be differentiated from other diseases that cause a decrease in the bone mineral density (BMD), such as idiopathic transient osteoporosis of hip, osteomalacia, scurvy, osteogenesis imperfecta, multiple myeloma, homocystinuria, and hypermetabolic resorptive osteoporosis.

Differentiating Osteoporosis from other Diseases

Osteoporosis must be differentiated from other diseases that cause a decrease in the bone mineral density (BMD), such as idiopathic transient osteoporosis of hip, osteomalacia, scurvy, osteogenesis imperfecta, multiple myeloma, homocystinuria, and hypermetabolic resorptive osteoporosis. The major similarities and differences among the diseases are discussed in the following table:

Diseases	History and Physical Examination					Imaging findings			Laboratory Findings				Other Findings
	Bone pain	Fatigue	Short stature	Scoliosis	Bone tenderness	BMD	Sub-chondral cortical loss	Bone fracture	Vitamin C	Ca	Vitamin D	ALKph
Osteoporosis	+	-	+	-	+	↓↓↓	-	+	↓	-	-	-
Idiopathic transient osteoporosis of hip	+	-	-	-	-	↓↓	+	-	-	-	-	↑	Mostly pregnant women Self-limiting
Osteomalacia	-	-	-	-	-	↓	-	+	-	↓	↓	-
Scurvy	+	+	-	-	-	-	-	+	-	-	-	-	Mucosal bleeding Bleeding gums
Osteogenesis imperfecta	-	-	+	+	-	↓	-	+	-	-	-	-	Tooth defect Hearing problems Blue sclera
Multiple myeloma	+	+	-	-	+	↓	-	+	-	-	-	↑	Bone lytic lesions
Homocystinuria	+	-	-	-	-	↓	-	+	-	-	-	-	Visual impairment Homocysteine in urine

Idiopathic transient osteoporosis of hip

• It was initially thought to be seen in women during the third trimester of pregnancy but it is seen also in middle-aged men.
• Acute hip pain is the main feature of the disease, usually self-limited and resolves after 6-8 months.
• Sometimes it may be explained as early or benign avascular necrosis (AVN).
• Subchondral cortical loss and diffuse osteopenia of the femoral head and neck are the pathognomonic features.
• Treatment includes joint protection, limited weight bearing, and NSAIDs.

Osteomalacia

• Osteomalacia is the inability to mineralize the newly formed bone matrix, caused by the deficiency of vitamin D in adults.

• It is due to low turn-over of bone in which osteoblasts are deficient.
• Diffuse bone pain, fatigue, and fractures are the most common symptoms.
• It can also progress to osteoporosis.

Scurvy

• Vitamin C deficiency causes defective collagen synthesis, leading to dysfunction of every collagen containing organ such as bones.
• New bone formation is disturbed and the old bone becomes brittle due to lack and poor quality of collagen.
• Treatment is vitamin C replacement.

Osteogenesis imperfecta

• Osteogenesis imperfecta is mainly induced by defect in the synthesis of collagen type I along with improper osteoblasts functioning.
• Short stature, scoliosis, tooth defects, hearing defects, blue sclera, and propensity for fractures are the main clinical features of the disease.

Multiple myeloma

• Multiple myeloma is a malignant proliferation of the plasma cells, mostly in bone marrow.
• It accounts for 40% of all bone tumors.
• Diffuse bone pain and tenderness are common.
• Radiologically, osteolytic lesions could be found in the bones.
• The prognosis is poor.
• Chemotherapy is the mainstay of treatment.

Homocystinuria

• Homocystinuria is an autosomal recessive disorder that affects the metabolism of the amino acid methionine.
• Clinical features include failure to thrive, visual and musculoskeletal problems.

References

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