Patient presents with symptoms suggestive of hypermagnesemia, including lethargy, muscle weakness, and nausea.  Onset of symptoms was reported as gradual over the past [timeframe].  Relevant past medical history includes [list relevant PMH, e.g., chronic kidney disease, diabetes, use of magnesium-containing medications such as antacids or laxatives].  Physical examination revealed diminished deep tendon reflexes and hypotension.  Serum magnesium level was elevated at [numeric value] mgdL, confirming the diagnosis of hypermagnesemia.  Differential diagnosis considered included hypocalcemia and hyperkalemia.  Electrocardiogram (ECG) showed [ECG findings, e.g., prolonged PR interval, widened QRS complex].  Treatment plan includes discontinuation of magnesium-containing medications and administration of intravenous fluids such as normal saline.  For severe hypermagnesemia, calcium gluconate will be administered intravenously to antagonize the effects of magnesium.  Patient education provided on magnesium restriction and the importance of monitoring renal function.  Follow-up serum magnesium levels will be monitored to assess response to treatment.  ICD-10 code E83.4 is documented for hypermagnesemia.  CPT codes for relevant laboratory tests and procedures will be billed accordingly.  Prognosis is generally good with prompt diagnosis and appropriate management of hypermagnesemia.  This documentation supports medical necessity for the services rendered and the prescribed treatment plan.