Patient presents with hypernatremia, confirmed by a serum sodium level of [Sodium level] mEq/L.  Clinical manifestations include [List symptoms e.g., thirst, lethargy, irritability, muscle weakness, seizures, coma].  Differential diagnosis considered dehydration, diabetes insipidus, osmotic diuresis, excessive sodium intake, and renal dysfunction.  Assessment includes a detailed history focusing on fluid intake, output, medications, and comorbidities such as diabetes mellitus, kidney disease, and endocrine disorders.  Physical examination reveals [Document findings e.g., dry mucous membranes, tachycardia, orthostatic hypotension, altered mental status].  Laboratory evaluation includes serum electrolytes, blood urea nitrogen (BUN), creatinine, urine osmolality, and urine sodium.  Treatment plan focuses on correcting the underlying cause and gradually lowering serum sodium concentration with appropriate fluid management.  Intravenous hypotonic fluids such as 0.45% saline or 5% dextrose in water (D5W) may be initiated.  Close monitoring of serum sodium, fluid balance, and neurological status is crucial.  Patient education emphasizes the importance of adequate fluid intake and recognizing signs of dehydration.  ICD-10 code E87.0 (Hypernatremia) and relevant CPT codes for laboratory tests and intravenous fluid administration will be documented for billing and coding purposes. The prognosis depends on the severity and underlying etiology of the hypernatremia.  Follow-up care is scheduled to monitor sodium levels and adjust treatment as needed.