Clues in the chemistry: Diagnosing Paget’s disease of bone

Vigneshvarprashanth Umapathy1, RM Subbaiah2

1Resident Internal Medicine, Kauvery Hospital, Tennur, Trichy, Tamil Nadu, India

2Consultant Haemato-oncologist, Kauvery Hospital, Tennur, Trichy, Tamil Nadu, India

Case Presentation

A 73-year-old elderly gentleman presented with complaints of low backache for 6 months, difficulty in walking for the past 2 months, loss of appetite, loss of weight and bilateral pedal edema. He was initially evaluated elsewhere and found to have bicytopenia, macrocytic blood picture and elevated alkaline phosphatase. He was then referred to us.

Upon examining, he had pallor but no lymphadenopathy or organomegaly. Laboratory investigations revealed bicytopenia with macrocytic blood picture, inappropriately low reticulocyte count, hyperuricemia, hyperphosphatemia, elevated alkaline phosphatase, elevated blood urea and serum creatinine. Serum calcium and lactate dehydrogenase (LDH) were normal. We suspected malignancy and metabolic diseases involving the bone such as Paget disease of bone.

Bone marrow biopsy (Figs. 1A and 1B) revealed marrow spaces encased by massive thickened bony trabeculae with occasional scalloping at places and clusters of osteoclasts, features consistent with Paget disease of bone. A diagnosis of Paget disease of bone was considered. Cytogenetics was normal. One dose of inj. Zoledronic acid 3 mg (renal dose adjusted) was given intravenously. He was subsequently discharged and advised to follow-up on an outpatient basis. His back pain had improved and was able to walk during the follow-up visit.

Fig. 1 (A, B): Bone marrow biopsy revealing marrow spaces encased by massive thickened bony trabeculae with occasional scalloping at places and clusters of osteoclasts, features consistent with Paget disease of bone.

Discussion

Paget’s disease of bone, first identified in 1877 by Sir James Paget, a British surgeon, was originally referred to as “Osteitis Deformans”.1 This chronic, progressive condition of the bone has an unclear cause and is characterized by an initial phase of increased bone resorption, followed by abnormal and excessive bone formation. This process leads to symptoms such as pain, fractures, and skeletal deformities. The disease can affect either a single bone (monostotic) or multiple bones (polyostotic).1,2

Paget’s disease is more prevalent in populations of Anglo-Saxon descent but is relatively uncommon in India. It is often asymptomatic and primarily affects older individuals. A significant rise in serum alkaline phosphatase levels is consistently observed, while calcium and phosphate levels generally remain within normal ranges. Treatment with bisphosphonates, a class of anti-resorptive medications, has proven effective in managing the condition, reducing both morbidity and mortality associated with it.1,2

In conclusion, basic laboratory investigations can provide valuable clues in diagnosing chronic diseases. In this case, tests such as alkaline phosphatase levels, blood counts, and bone mineral analysis, combined with the patient’s history, played a crucial role in narrowing down the diagnosis. Although Paget’s disease of bone is rare in India, it should be considered in elderly patients who present with symptoms such as bone pain, fractures, cytopenia, and elevated alkaline phosphatase levels, alongside other potential causes like multiple myeloma and metastasis.

References

  • Shankar YU, Misra SR, Vineet DA, Baskaran P. Paget disease of bone: a classic case report. Contemporary Clinical Dentistry. 2013 Apr 1;4(2):227-30.
  • Miao XY, Wang XL, Lyu ZH, Ba JM, Pei Y, Dou JT, Gu WJ, Du J, Guo QH, Chen K, Mu YM. Paget’s disease of bone: Report of 11 cases. World journal of clinical cases. 2021 May 16;9(14):3478.
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