Pituitary apoplexy overview

# Overview
Pituitary apoplexy is caused by hemorrhage into the pituitary gland. The pituitary gland is a small gland joined to the hypothalamus at the base of brain. The pituitary produces many of the hormones that control essential body processes. Pituitary apoplexy is most commonly associated with pituitary adenoma. The common symptoms of pituitary apoplexy are severe headache with nausea and vomiting. Other symptoms depends upon the amount of hemorrhage and necrosis in the pituitary gland.  Hemorrhage into the pituitary gland may compress the surrounding structures and present with ophthlamoplegia, cranial nerve palsies, and signs of increased intracranial pressure. The initial diagnostic test is a CT scan without contrast which will show the hemorrhage as a hyperintense lesion. In the case of inconclusive CT, an MRI may be done to better visualize the lesion. Laboratory tests are done to identify specific hormone and electrolyte disturbances. The initial management of pituitary apoplexy includes rapid hemodynamic stabilization of the patient with replacement of hormones. Depending upon the patient's condition after initial management, neurological decompression may be done.

# Historical Perspective
Pituitary apoplexy was first discovered by Pearce Bailey in the year 1898. In 1905, Leopold Bleibtreu recorded the postmortem examination of a 21-year-old acromegalic patient, in whom he discovered that the pituitary gland had been replaced by an old hemorrhage. The term "pituitary apoplexy" was coined by Brougham, Heusner, and Adams in the year 1950.

# Pathophysiology
Pituitary apoplexy is an acute clinical syndrome caused by hemorrhage and necrosis in the pituitary gland. Most commonly, pituitary apoplexy is associated with pituitary adenoma. The pituitary adenoma predisposes the patient to an increased risk of bleeding within the pituitary gland. The pituitary adenoma has fenestrated endothelium surrounded by a variable number of smooth muscle cells, which are not found in the normal pituitary gland.Gene involved in the pathogenesis of pituitary apoplexy include a mutation in AIP gene, which is located on chromosome 11q13.2. On gross pathology, pituitary apoplexy presents with hemorrhage with or without necrosis. Electron microscopic shows evidence of abnormal fenestration of tumor vessels (pituitary adenoma) with fragmented basal membranes that may predispose the patient to hemorrhage.

# Differentiating Pituitary apoplexy From Other Diseases
Pituitary apoplexy must be differentiated from other diseases that cause severe headache such as subarachnoid hemorrhage, meningitis, intracranial mass, cerebral hemorrhage, cerebral infarction, intracranial venous thrombosis, migraine, head injury, lymphocytic hypophysitis, and radiation injury.

# Epidemiology and Demographics
The worldwide prevalence of pituitary apoplexy is 6.2 per 100,000 persons. The incidence of pituitary apoplexy is 0.7 per 100,000 persons.

# Risk Factors
Common risk factors in the development of pituitary apoplexy include bleeding disorders, diabetes, use of a breathing machine, radiation to the pituitary gland, angiography, head injury, surgery, pituitary stimulation, and pregnancy induced lactotroph hyperplasia.

# Screening
There are no screening guidelines for pituitary apoplexy.

# Natural History, Complications, and Prognosis
If left untreated, pituitary apoplexy is an acute life threatening condition. Pituitary apoplexy may lead to a sudden decline in pituitary hormone production. The most life threatening endocrinopathy is acute adrenal crisis. Complications of pituitary apoplexy include vision loss, optic neuritis, diplopia, ptosis, increased intracranial pressure, hypothyroidism, hypogonadism, and growth hormone deficiency. The prognosis of pituitary apoplexy depends upon presentation and initiation of therapy. Emergent application of medical and surgical treatment is associated with greater improvement in visual field defects, visual acuity, and diplopia. The outlook is good for people who are diagnosed early and treated. Patients require hormone(s) replacement therapy for life.

# Diagnosis

## History and Symptoms
Pituitary apoplexy usually has a short period of symptoms (acute). Symptoms usually include severe headache, paralysis of eye muscles, visual disturbances, nausea, and vomiting.

## Physical Examination
Patients with pituitary apoplexy appear ill and usually look tired. Physical examination of patients with pituitary apoplexy is usually remarkable for orthostatic hypotension, visual acuity and visual field defects, cranial nerve palsies, Horner syndrome, meningeal irritation, altered level of consciousness, severe mental status change, and other signs of hypopituitarism.

## Laboratory Findings
Laboratory findings consistent with the diagnosis of pituitary apoplexy include endocrinopathies from hypofunction of the pituitary gland. Blood tests will be done to check levels of ACTH, cholesterol, cortisol, growth hormone, LH, prolactin and somatomedin C (IGF-1).

## X-ray
X-ray is an inexpensive method for evaluating pituitary apoplexy. However, x-ray is neither the best initial test, nor the most accurate test in evaluating pituitary apoplexy.

## CT
CT scan without contrast is the initial test of choice in emergency department patients who present with sudden-onset severe headache, visual loss or ophthalmoplegia suggestive of pituitary apoplexy. A CT scan can also help to differentiate whether subarachnoid hemorrhage is arising from pituitary hemorrhage or an aneurysm.

## MRI
MRI is done if the CT scan is suspicious for pituitary apoplexy. MRI is more sensitive than CT scan. MRI is more accurate in distinguishing the soft tissues of the pituitary from the surrounding bony structures. MRI is also superior to CT scan for detecting ischemia and infarction in brain tissue.

## Ultrasound
There are no ultrasound findings associated with pituitary apoplexy.

## Other Imaging Findings
There are no other imaging findings associated with pituitary apoplexy.

## Other Diagnostic Studies
There are no other diagnostic studies associated with pituitary apoplexy.

# Treatment
The optimal therapy for pituitary apoplexy depends upon presentation of the patient. The emphasis is on early hemodynamic stabilization of the patient, with evaluation for signs of deficiency of pituitary hormones. Life threatening hypopituitarism must be treated with replacement of hormones.

## Surgery
Neurological decompression is done once the patient is hemodynamically stable. Surgery relieves pressure on the pituitary and improves visual field defects and ocular palsy. Early decompression has been associated with better visual and endocrine outcome.