Symptoms usually appear gradually. August 20, 2. With severe magnesium depletion, cardiovascular manifestations can include widening of the PR interval, diminution of T-waves, and atrial and ventricular arrhythmias. Orofacial Facial numbness left jaw neck in cancer part II: Perineural invasion of the infraorbital nerve visualized by immunohistochemical staining for Cytokeratin 5.