Scenario: A 55-year-old male presents to the office with complaint of worsening low back pain over the last 2 months. He describes the pain as “bone pain” consisting of a deep, dull, constant ache in the region of his lumbar spine. He also has noticed over the last week, short episodes of numbness in his left lower extremity (LE) when he stands for long periods of time. It is relieved with lying supine or sitting. A 14-point review of systems was otherwise negative. Past medical history is unremarkable. His temperature is 98 degrees F, BP is 124/74, HR is 70 bpm, RR is 16 breaths/min, and O2 sat is 100%. On exam, there is tenderness to palpation over transverse processes of L4 and L5 as well as increased warmth to the skin in the same region. Lumbar spine ROM is limited in flexion and extension secondary to increased pain. Strength is 5/5 in his LE bilaterally, as well as 2+ reflexes at L4 and S1. Overall, lumbar lordosis is decreased. The patient is referred to the physician. Serum alkaline phosphatase (ALP) is mildly elevated, with normal calcium and phosphate. X-ray shows the L4 and L5 vertebrae to be enlarged and an ivory appearance to them. 

Question: What are the three phases of Paget Disease in order of development, and which one is this patient presenting in based on their clinical presentation?  

Potential answers: 

a.      Sclerotic, Osteolytic, Mixed; This patient is presenting in the Mixed phase.  

b.    Osteolytic, Sclerotic, Mixed; This patient may be presenting with all three phases at once.  

c.   Osteolytic, Mixed, Sclerotic; This patient may be presenting with all three phases at once. 

d.    Osteolytic, Sclerotic, Mixed; This patient is presenting in the Sclerotic phase.  

Answer with rationale: Osteolytic, Sclerotic, Mixed; This patient may be presenting with all three phases at once.¹ 

The Osteolytic phase is the first phase of Paget Disease. This phase involves prominent bone resorption and hyper vascularization. Degenerative arthritis is common during this stage.^1,3 

The Sclerotic phase is the second phase, involving decreased cellular activity and vascularity.  Bone structure alterations and deformities occur in this stage.^1,3 

The Mixed phase is the third and final phase, involving both active bone resorption and bone formation as well as a weakening of the bones.  Bone reformation has stopped during this phase.^1,3 

While Paget Disease is classified in phases, a patient may be presenting with a multitude of phases at different places throughout the body at any given time, so the patient may present with all three phases at the same time.¹ 

For more information See Chapter 248 Paget Disease in the Color Atlas of Physical Therapy.

A 48-year-old woman with Paget disease of the skull. (Left) Lateral radiograph showing areas of both bone resorption and sclerosis. (Right) ^99mTc HDP bone scan with anterior, posterior, and lateral views of the skull showing diffuse isotope uptake by the frontal, parietal, occipital, and petrous bones. (From Longo DL, Fauci A, Kasper D, Hauser S, Jameson J, Loscalzo J eds. Harrison’s Principles of Internal Medicine. 18th ed. New York, NY: McGraw-Hill, 2012.)