Elevated Alkaline Phosphatase in Acute Back Pain? Tumour Biomarker: Where Is the Source?

No conflicts of interest No funding obtained Background Back pain is a common symptom of spine pathologies. Although specific pathologies may be identified through their usual symptoms. Consideration of metabolic investigations may be required in more ambiguous yet serious cases. Methods A 58-year-old man presented with 8 weeks of acute lower back pain with no radicular pain attend in emergency department. Back pain was relieved by morphine. He was followed up by the primary care team for mechanical back pain. Further investigations demonstrated mild anaemia and an elevated serum alkaline phosphatase (ALP) of 272 IU/L. Results On physical examination, the patient had focal tenderness around L1-L2. Soft tissue tenderness of the sacral area. No saddle paraesthesia was detected with antalgic gait. Subsequently, the patient was referred to haematology clinic due to anaemia, raised ESR and Elevated ALP. Rheumatology and Haematology team revealed osteoblastic bone metastases on MRI. Further examinations confirmed the patient had prostate cancer that had caused spinal metastasis without any LUTS. Biopsy confirmed the source. After the diagnosis, oncology team determined his course of management. Conclusion This case suggests Acute Back pain with elevated ALP, and no history of liver disease may originate from bone. Imaging Studies by secondary team identified progressive bone disease. Lack of symptoms related to the prostate is also notable. Acute severe back pain and undifferentiated symptoms with raised ALP kinetics prompt clinicians to consider bone metastasis. This study also validated that ALP could be a tumour marker.