This endocrine case report from Brady Pregerson, KMD, features a woman in her mid-30s with a history of cerebral astrocytoma status post radiation therapy presenting with generalized weakness, a gradual onset generalized headache, and excessive thirst. Can you determine the correct diagnosis?
History of Present Illness:
A patient in their mid-30s with history of cerebral astrocytoma status post radiation therapy presents to the hospital with generalized weakness, a gradual onset generalized headache and excessive thirst. She denies any recent fevers or any nausea/vomiting/diarrhea, black or bloody stool or other complaints. There have been not seizures, falls or injuries.
Vital Signs & Physical Exam:
Vital signs are normal except for mild blood pressure elevation. The physical exam is essentially normal and the oropharynx does not look dry.
Initial Diagnostic Testing:
Chem-7: The sodium is very high at 163 with elevated chlorine as well. Other values are essentially normal.
Imaging: Brain CT showed no significant change from baseline.
What is the most likely diagnosis?