Consecutive Multilevel Vertebral Paget’s Disease
of the Lumbar Spine: Differential Diagnosis
If spine pain becomes so severe that it disrupts daily life or is accompanied by swelling, tenderness, or redness, it’s important to seek medical attention.
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Learn about the common causes of spine pain and the treatment options available, including when surgery might be the best choice.
Overview
James Paget first described Paget’s disease of bone (PDB), also known as osteitis deformans, in 1877. This condition is characterized by abnormal remodeling of bones, resulting in polyostotic or monostotic lesions, due to excessive bone formation and resorption.
While Paget’s disease of bone (PDB) ranks as the second most prevalent metabolic bone disorder in European nations, it is a comparatively uncommon condition in eastern regions, particularly in China, Japan, and other Asian countries.
Paget’s disease of bone (PDB) is rare before the age of 50 and is a condition where localized areas of high bone turnover can cause problems like bone pain, deformities, and fractures.
Due to its gradual onset, diverse clinical symptoms, and radiographic results that resemble those of skeletal metastases, primary hyperparathyroidism, osteomyelitis, or osteosarcoma, diagnosing PDB can be delayed or misidentified. As a result, individuals with PDB often fail to receive timely and effective interventions during the initial phases.
The cause of this disease is not yet fully understood, but it is thought that genetic factors and paramyxovirus infection are the two most significant factors in its potential cause. PDB typically affects multiple bones in the body, with commonly involved sites including the pelvis, spine, skull, femur, and tibia.
It most commonly affects the pelvis and spine. When PDB affects the spine, the lumbar vertebrae are the most frequently involved, followed by the thoracic and cervical vertebrae.
When a single level or nonconsecutive multilevel vertebrae is affected and there is neurologic compromise, surgical treatment is usually necessary. However, in most cases, patients are referred to surgery due to a failure to diagnose and treat the condition in its early stages or due to neglect.
Paget’s disease of the spine is typically without symptoms, but common signs can include back pain, bone deformity, and difficulty with movement. Pathological fractures and neurological compression are responsible for numbness, tingling in the feet, motor disturbances in the legs, and bladder and bowel dysfunction.
Back pain is the most common symptom in Paget’s disease of bone (PDB) and is attributed to Pagetic osteoarthritis, blood engorgement of the vertebral body, hyperactive pagetic processes, and pathological fractures.
In the advanced stage of Paget’s disease of bone (PDB), radiographic imaging reveals a distinctive “picture frame” appearance of thickened cortical and encased vertebral margins. Magnetic resonance imaging (MRI) and computed tomography (CT) scans are useful in evaluating spinal stenosis and other neurological complications.
PDB is linked with heightened bone turnover, and this can be detected through increased radionuclide uptake in the affected bone with bone scintigraphy. This method is more sensitive than radiographs for diagnosis.
As a result, it is recommended to perform skeletal scintigraphy on patients suspected of having PDB to determine the extent of the disease distribution. While serum alkaline phosphatase (SAP) is not a definitive biomarker for Paget’s disease of bone (PDB), it is related to the heightened bone turnover that is present in 85% of untreated patients.
Furthermore, untreated patients show a significant correlation between the degree of increase in serum alkaline phosphatase (SAP) and the level of disease activity, as measured by scintigraphy. Ultimately, a definite diagnosis relies on pathology.
Histopathology
Abnormal remodeling results from initially increased bone resorption that triggers bone formation, as seen in the histopathological findings. During the process of bone formation triggered by initially increased bone resorption, collagen fibers are deposited in a disorganized manner and result in the formation of a “woven” bone pattern instead of the typical lamellar bone texture. The formation of structurally disorganized new bone leads to a decrease in overall bone quality and an increase in vulnerability to fractures.
Differential Diagnosis
It can be challenging to differentiate PDB from other diseases, particularly in regions with low incidence rates. PDB may be misdiagnosed as metastatic neoplasm, hemangioma, or other conditions such as renal osteodystrophy, fibrous dysplasia, primary hyperparathyroidism, or osteosarcoma. Misdiagnosis may occur due to a family history of cancer and neglecting crucial laboratory tests and bone biopsy.
In a case reported by literature, radiographs and MRI did not show any evidence of neoplastic tissue in the vertebral body and paravertebral soft tissue. There is a lack of positive tumor biomarkers. Given this evidence, it was justifiable to rule out the possibility of a metastatic neoplasm.
The absence of the “corduroy” appearance on X-ray film and the “polka dot” pattern on axial CT scan did not support the diagnosis of hemangioma. There was no indication of hemangioma as there was no “corduroy” appearance on X-ray film and “polka dot” pattern on axial CT scan.
The possibility of hyperparathyroidism was ruled out due to normal levels of serum calcium, urinary phosphate excretion, and parathyroid hormone. Furthermore, neither the Tc-bisphosphonate scintigraphic scan nor the ultrasonic examination provided evidence of ectopic parathyroid or hyperfunctional thyroid adenoma.
Chronic renal failure is the underlying cause of renal osteodystrophy. Rephrased: Bone mineralization deficiency is a defining feature of renal osteodystrophy and is caused by an underlying metabolic disorder of calcium and phosphorus, typically associated with chronic renal failure.
Mainly affecting adolescents, fibrous dysplasia is a condition characterized by the replacement of normal bone with fibrous tissue and immature woven bone. Fibrous dysplasia is frequently observed in the limbs and skull, and it is more prevalent in adolescents. The X-ray revealed oval lesions surrounded by a thick and distinct rim of sclerosis, along with expansion and osteolysis.
The pathological fracture and collapse of the vertebral body can result from bone fibrosis. Important indicators of osteosarcoma include increasing SAP levels and the presence of paraspinal soft tissue mass. While tumor biomarkers and MRI can be helpful in ruling out spinal tumors, a definitive diagnosis ultimately depends on pathology.
A percutaneous transpedicular vertebral biopsy is required to eliminate the possibility of osteoblastic metastases, osteosarcoma, or other diseases when the diagnosis is uncertain, especially when imaging tests, such as plain radiographs combined with CT scans (MRI), are inconclusive.
Final Diagnosis
Medical treatment for PDB primarily involves the use of bisphosphonates and calcitonin, which have been clinically proven to be effective, after confirming the diagnosis and evaluating the disease activity.
Surgery is recommended when medical therapy fails, there is neurological compression due to an unstable pathological fracture or dislocation, spinal deformity, severe arthritis, or sarcomatoid transformation.
Increased intraoperative risk due to blood loss may be a concern because pagetic bone is known to have a higher number of blood vessels compared to healthy bone. Hence, it is imperative to administer bisphosphonates therapy prior to surgery. Furthermore, administering bisphosphonates therapy before surgery can be crucial for enhancing bone strength and quality before the operation, resulting in better surgical results.
Spine surgeons need to be aware of Paget’s disease with multilevel vertebral involvement as it is a rare condition. This can help prevent delayed diagnosis, unnecessary invasive examinations, misdiagnosis, and inappropriate treatment.
Do you have more questions?
What exactly is Paget’s disease of bone (PDB)?
Paget’s disease of bone is a chronic disorder that results in the abnormal remodeling of bone. It can lead to enlarged and misshapen bones, and it usually affects older adults.
What causes Paget’s disease of bone?
The exact cause is unknown, but it is believed to involve both genetic factors and environmental factors, such as a possible viral infection.
What are the common symptoms of PDB?
Common symptoms include bone pain, bone deformities, fractures, and in some cases, neurological issues if the spine is affected.
How is Paget’s disease diagnosed?
Diagnosis typically involves a combination of medical history, physical examination, blood tests for serum alkaline phosphatase, imaging studies like X-rays, bone scans, and sometimes a bone biopsy.
What are the treatment options for Paget’s disease?
Treatments include medications like bisphosphonates and calcitonin to regulate bone turnover. In some cases, surgical intervention may be necessary to manage complications like fractures or severe arthritis.
How does PDB affect the spine specifically?
When PDB affects the spine, it can cause back pain, spinal deformities, and potentially neurological symptoms such as numbness or weakness if there is nerve compression.
What are bisphosphonates and how do they help?
Bisphosphonates are a class of drugs that slow down or prevent bone resorption. They help in reducing bone turnover and can relieve symptoms and prevent complications in PDB.
What are the potential complications of untreated PDB?
Untreated PDB can lead to significant complications such as severe bone deformities, pathological fractures, arthritis, and in some cases, hearing loss if the skull is involved.
Is Paget’s disease of bone hereditary?
There is a genetic component to PDB, and it can run in families. Individuals with a family history of the disease may be at higher risk.
Can Paget’s disease lead to cancer?
In rare cases, PDB can lead to osteosarcoma, a type of bone cancer. However, this is very uncommon.
What lifestyle changes can help manage PDB?
Maintaining a healthy diet with adequate calcium and vitamin D, regular exercise, and avoiding activities that stress affected bones can help manage PDB.
How often should I follow up with my doctor if I have PDB?
Regular follow-ups are important. Your doctor will determine the frequency based on the severity of your condition and response to treatment.
What role does physical therapy play in managing PDB?
Physical therapy can help maintain mobility, strengthen muscles, and reduce pain associated with PDB.
Can Paget’s disease be cured?
There is no cure for PDB, but treatments can help control the symptoms and prevent complications.
What should I do if I experience new or worsening symptoms?
Contact your healthcare provider if you experience new or worsening symptoms such as increased pain, changes in bone shape, or neurological issues.
Are there any specific dietary recommendations for people with PDB?
A diet rich in calcium and vitamin D is recommended to support bone health. Supplements may be necessary if dietary intake is insufficient.
Can Paget’s disease affect my daily activities?
Depending on the severity and the bones affected, PDB can impact daily activities. Pain management, physical therapy, and sometimes modifications in daily activities are necessary.
How does PDB affect bone quality?
PDB leads to the formation of structurally disorganized bone, which is weaker and more prone to fractures than normal bone.
What imaging studies are used to diagnose and monitor PDB?
X-rays, bone scans, MRI, and CT scans are commonly used to diagnose and monitor the extent of bone involvement in PDB.
How does Paget’s disease differ from other bone disorders?
PDB is characterized by localized areas of excessive bone turnover, leading to enlarged and deformed bones, whereas other bone disorders like osteoporosis involve a generalized decrease in bone density.
I am Vedant Vaksha, Fellowship trained Spine, Sports and Arthroscopic Surgeon at Complete Orthopedics. I take care of patients with ailments of the neck, back, shoulder, knee, elbow and ankle. I personally approve this content and have written most of it myself.
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