Review Question - QID 204277

This patient likely has multiple myeloma with resultant hypercalcemia, an electrolyte disturbance that can cause severe constipation.

Multiple myeloma is a malignancy of plasma cells. Patients with multiple myeloma have plasma cells which produce large quantities of ineffective monoclonal antibodies leading to a variety of clinical manifestations. The most common mnemonic for the symptoms of multiple myeloma is CRAB (elevated Calcium, Renal failure, Anemia, Bone pain [often back pain]). The elevated calcium in multiple myeloma is typically a result of excess bone resorption by osteoclasts leading to lytic bone lesions. Clinical symptoms associated with hypercalcemia in general include fractures, nephrolithiasis, vomiting, constipation and altered mental status. These symptoms are typically summarized as "bones (fractures), stones (nephrolithiasis), groans (vomiting, constipation) and psychic overtones (altered mental status)."

George and Sadovsky discuss the recognition and management of multiple myeloma. Multiple myeloma cells produce monoclonal immunoglobulins that are often identifiable on serum and/or urine electrophoresis. While the most common clinical presentation of multiple myeloma is bone pain secondary to multiple lytic lesions, some patients are diagnosed incidentally. Standard treatment for multiple myeloma is melphalan-prednisone but only about 50 - 60 percent of patients respond to therapy.

Carroll and Schade discuss an approach to managing hypercalcemia. The most common causes of hypercalcemia are primary hyperparathyroidism and malignancy. In an outpatient setting, measuring parathyroid hormone levels and discontinuing medications that may cause elevated calcium are recommended first steps. While hypercalcemia may be an incidental finding in asymptomatic patients, possible clinical manifestations of hypercalcemia include neuromuscular, gastrointestinal, and renal symptoms. Patients with hypercalcemic crisis need to be treated with aggressive intravenous rehydration along with anti-resorptive agents (e.g. calcitonin, bisphosphonates).

Illustration A is a diagram documenting some of the findings in patients with multiple myeloma.

Incorrect Answers:
Answer 1: Hyperkalemia classically causes peaked T waves on EKGs, symptoms associated with hyperkalemia include nausea, vomiting, and muscle weakness.
Answer 2: Symptoms of hypermagnesemia include lethargy, weakness and paralysis, not constipation.
Answer 3: Hypophosphatemia typically causes diffuse muscle weakness and flaccid paralysis, not constipation.
Answer 5: Hypocalcemia can present with abdominal pain, and muscle cramps but doesn't typically present with constipation.