A rare case of severe hyperphosphatemia

Hyperphosphatemia is commonly associated with kidney failure. However, many other etiologies should be considered, and include increase tubular reabsorption of phosphate, endogenous or exogenous phosphate loads and transcellular shift. We present a case of a 71-year-old male with a medical history of anemia and constipation who presented to our hospital for abdominal pain. Initial Laboratory evaluation demonstrated a severely elevated serum phosphate level, calcium level within the normal limit, and a mild elevation of serum creatinine. He underwent a bone marrow biopsy confirming a diagnosis of IgG-kappa-type Multiple Myeloma (MM). There is an established association between electrolyte abnormalities in patients with hematological malignancies, however, MM is rarely associated with hyperphosphatemia. Spurious electrolyte abnormalities present a challenge for clinicians, pseudo-hyperphosphatemia in patients with MM has been associated with laboratory artifacts. Our patient did not have clinical characteristics of hyperphosphatemia, after the new diagnosis of multiple myeloma and ruling out other etiologies leading to hyperphosphatemia, the elevated phosphorous level was attributed to a spurious etiology.