Which neuromuscular symptom can occur with hypocalcemia in CKD, and what electrolyte abnormality is typically responsible?

• A. Tetany or muscle cramps; due to hypocalcemia often with hyperphosphatemia
• B. Muscle weakness; due to hyperkalemia
• C. Paresthesias; due to hypomagnesemia
• D. Tremor; due to calcification

Answer: (D)

In CKD, hypocalcemia arises mainly because the failing kidneys can’t excrete phosphate effectively and can’t activate vitamin D well. The resulting hyperphosphatemia binds calcium and lowers circulating free calcium, while reduced active vitamin D lowers calcium absorption from the gut. The drop in calcium makes nerves and muscles more excitable, so the classic neuromuscular picture is tetany with muscle cramps (and sometimes tingling around the mouth or in the fingers). The key electrolyte driver here is hyperphosphatemia causing hypocalcemia.

Muscle weakness is more commonly linked to high potassium or uremic myopathy, not the immediate hypocalcemic excitability. Paresthesias can occur with other imbalances like low magnesium, but the primary CKD-related mechanism for neuromuscular symptoms tied to calcium is hypocalcemia from hyperphosphatemia. Tremor due to calcification isn’t the typical presentation driven by acute calcium derangements in CKD.