170 Pituitary Apoplexy
Key Points• Pituitary apoplexy is a rare but serious condition caused by hemorrhage or infarction of the pituitary gland.
• Patients are seen acutely with severe headache, meningismus, visual field deficits, cranial nerve palsies, loss of visual acuity, and altered mental status.
• Acute hypopituitarism may develop following pituitary apoplexy. Treatment of impending adrenal crisis is mandatory.
• Emergency consultation with a neurosurgeon who has expertise in pituitary surgery and management is required.
Epidemiology
Pituitary adenomas are common, with a prevalence of 3% to 27% in various autopsy series. They are rarely diagnosed in life, with a reported incidence of 4 per 100,000 in a Finnish population and a prevalence of 77 per 100,000 in a British one.1,2 Apoplexy occurs in a minority of such lesions and can occasionally be seen with normal glands. Because of the relative rarity of this condition, pituitary apoplexy may be confused with more common entities such as subarachnoid hemorrhage. Delay in diagnosis and treatment may lead to blindness, permanent cranial nerve palsies, or death.3,4
Pathophysiology
Tumors involved in apoplexy are typically nonfunctional and unsuspected macroadenomas. In patients undergoing an endocrine stimulation test for hypogonadism, hypothyroidism, or adrenal insufficiency, apoplexy may occasionally develop secondary to stimulation of a macroadenoma. Treatment of a pituitary tumor can also precipitate apoplexy, particularly in cases of surgery, irradiation, or bromocriptine administration. Other reported risk factors include pregnancy (Sheehan syndrome), head trauma, recent cardiac surgery, anticoagulation, hypertension, diabetic ketoacidosis, and ovarian stimulation medications.5
Presenting Signs and Symptoms
Classic
The findings in patients with pituitary apoplexy vary from mild headache to sudden collapse and coma. Most patients exhibit severe frontal or retroorbital headache, vomiting, impaired visual acuity, visual field defects, hypopituitarism, and subsequent adrenal crisis. A minority have ocular palsies, obtundation, meningismus, blindness, or long-tract signs. The visual field deficit is classically bitemporal upper quadrantopia or hemianopia. Associated cerebral infarction occasionally occurs secondary to vasospasm from subarachnoid hemorrhage or direct compression of the internal carotid artery by tumor. Table 170.1 lists the frequency of signs and symptoms reported in four case series.3,5–7
| SIGN OR SYMPTOM | FREQUENCY (% INCIDENCE) |
|---|---|
| Headache | 63-97 |
| Visual field deficit | 43-82 |
| Hypopituitarism | 81 |
| Adrenal crisis | 65 |
| Vomiting | 50 |
| Visual impairment | 60 |
| Complete blindness | 10 |
| Ocular palsies | 40-46 |
