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'The worst headache I have ever had'
An elderly gentleman presented to the emergency department with sudden onset of “the worst headache I have ever had” that had lasted unremittingly for several hours. He felt weak and mentioned that his vision was a little blurred.
His vital signs were OK, visual fields were intact, and there was no neurologic deficit. Labs were drawn and an MRI obtained. The MRI revealed a 2-cm pituitary adenoma but no evidence of bleeding into the pituitary or other intracranial bleedings. The sodium was 120, potassium 3.5, hemoglobin 10.8, and he was admitted with a diagnosis of pituitary tumor and hyponatremia.
The absence of bleeding blurred the diagnosis of pituitary apoplexy, and I am not even sure that such a diagnosis can be made without bleeding. I was certain, however, that there was a very strong likelihood that the patient had acute pituitary insufficiency as indicated by the clinical presentation, the MRI findings and the hyponatremia. This was confirmed by an almost undetectable level of adrenocorticotropic hormone and a very low serum cortisol.
With this presentation, there is no need to worry about the time of day for these measurements — they should be drawn stat and replacement therapy started even before the lab results are available. (In a patient being evaluated for excess cortisol production, diurnal variation is important as is the timing of the specimen collections. When evaluating a patient for cortisol deficiency, this is not an issue — draw the blood and begin replacement!) The impact of the lab findings is to make sure that pituitary surgery is performed as soon as possible and that the patient receives stress doses of steroids preoperatively. The steroids corrected the electrolytes, and successful surgery was completed within 24 hours.
What about other pituitary hormones? How much do you need to know about them preoperatively? Not very much if surgery is going to be done in a very timely manner since the values will change following surgery. In this patient’s case thyroid-stimulating hormone and free thyroxine were measured and were both low. It may seem paradoxical, but it is inappropriate to begin thyroid hormone therapy before surgery unless and until you are satisfied that the patient has adequate steroid on board. Measurement of gonadal steroids and growth hormone can be delayed until the patient has fully recovered from surgery. That is not an indication to ignore them completely.
Immediate postoperative care can be difficult as you attempt to determine whether the surgery has resulted in diabetes insipidus (DI), either transient or permanent. Polyuria is common post-pituitary surgery, particularly when a large tumor has been removed as large volumes of intravenous fluid may be ordered. Painstaking and boring as it might be, it is essential to monitor fluid intake and output and consider (and treat) DI if there is any evidence of a fluid deficit. The DI may be transient and over-dosing with vasopressin (Pitressin, Parke Davis) must be avoided if possible. By the time of discharge, one should have a reasonable idea about the presence or absence of DI and manage appropriately. Nonetheless, the patient should be advised to let you know if thirst and polyuria do develop during recovery at home.
Full recovery from this acute event is anticipated but lifelong HT is indicated. Once recovery is complete and replacement therapy stabilized, it would be worthwhile to learn how long the patient might have had symptoms suggestive of panhypopituitarism prior to his acute event. After all, the onset of symptoms was acute, but the 2-cm pituitary tumor did not happen overnight. Symptoms of pituitary insufficiency often develop slowly to a point that the patient almost forgets when he/she was last fully well. Taking the time to jog this patient’s memory will enhance your skills at seeking clinical manifestations of pituitary hormone deficiency in other patients who present with seemingly vague and inconsequential symptoms.
