A patient with profound hypomagnesemia is at risk for which immediate complication?

Hypomagnesemia is a critical electrolyte disturbance characterized by serum magnesium levels < 1.3 mEq/L, leading to neuromuscular irritability and impaired cardiac repolarization. Magnesium acts as a physiological calcium channel blocker; its absence causes an influx of calcium into neurons and myocytes, resulting in hyperexcitability, tetany, and potentially lethal ventricular tachyarrhythmias. Rationale: A. This condition involves fluid accumulation within the alveolar spaces. Pulmonary edema is typically a consequence of left-sided heart failure or volume overload, whereas magnesium deficiency primarily impacts electrical conductivity and neuromuscular stability rather than the acute hydrostatic shifts associated with congestive heart failure. B. This involves the loss of skin integrity due to pressure or friction. Skin breakdown is a chronic complication of immobility, malnutrition, or poor perfusion; it does not constitute an immediate complication of electrolyte imbalances, which present with more acute neurological and cardiovascular manifestations. C. Low magnesium lowers the seizure threshold and disrupts cardiac electrical stability. This instability frequently manifests as torsades de pointes or generalized tonic-clonic activity due to neuronal hypersensitivity, requiring emergent intravenous magnesium sulfate to stabilize the myocardial membrane and prevent sudden cardiac death. D. These conditions relate to elevated vascular resistance and cerebral ischemia. While magnesium deficiency can cause mild vasoconstriction, hypertension is not the primary acute risk; magnesium is actually used to treat severe hypertension in preeclampsia, while its deficit is most specifically linked to neuromuscular hyperactivity.