Pituitary Apoplexy

PITUITARY APOPLEXY

Definition and Importance

• Pituitary Apoplexy: An acute hemorrhage (often with infarction) within the pituitary gland, typically in the setting of an existing pituitary tumor (macroadenoma, cyst).
• Clinical Emergency: Prompt diagnosis and treatment are critical due to the risk of severe complications, including sudden vision loss and adrenal crisis.

Clinical Presentation

1. Sudden Severe Headache
   • Often described by patients as “the worst headache of my life.”
2. Visual Symptoms
   • Vision Loss: Hemorrhagic expansion typically extends superiorly, compressing the optic chiasm → bitemporal hemianopsia or other field cuts.
   • Ocular Nerve Palsies: Impingement of cranial nerves III, IV, VI in the cavernous sinuses → ptosis, diplopia, impaired eye movement.
3. Other Symptoms
   • Facial Pain, Nausea, Vomiting.
   • Signs of Meningeal Irritation: Neck stiffness, photophobia, confusion; may mimic meningitis or subarachnoid hemorrhage.
   • Altered Mental Status: Drowsiness, stupor from increased intracranial pressure.
   • Hypothalamic Dysfunction: Possible dysregulation of sympathetic autoregulation (cardiac dysrhythmia, abnormal breathing).
4. Differential Diagnosis
   • CSF Findings: RBCs and elevated protein in CSF may confuse with meningitis or subarachnoid hemorrhage.

Endocrine Consequences

1. Secondary Adrenal Insufficiency
   • Immediate loss of ACTH may precipitate hypotension and acute adrenal crisis (the most urgent hormonal deficiency).
2. Other Hormone Deficiencies
   • Complete failure of anterior pituitary function can occur, including deficiency of prolactin.
   • Posterior pituitary is typically spared (due to inferior hypophysial artery circulation), making diabetes insipidus rare.

Causes and Risk Factors

1. Preexisting Pituitary Macroadenoma or Cyst
   • Hemorrhage can be spontaneous or triggered by:
     • Head Trauma
     • Coagulation Disorders (e.g., idiopathic thrombocytopenic purpura)
     • Anticoagulant Therapy (heparin, warfarin)
     • Hypothalamic-Releasing Hormones (e.g., GnRH agonists)
     • Pharmacotherapy for Pituitary Tumors (e.g., bromocriptine for prolactinoma)
2. Initial Presentation of an Undiagnosed Tumor
   • In >50% of pituitary apoplexy cases, the event is the first clinical manifestation of a pituitary tumor.
3. Demographics
   • Risk is not significantly related to age or gender.

Diagnosis

1. Pituitary Imaging (MRI)
   • Reveals intrapituitary or intra-adenoma hemorrhage, fluid–fluid levels, compression of normal pituitary tissue.
2. Hormonal Evaluation
   • Often shows complete anterior pituitary failure, including low prolactin.
   • Posterior pituitary function usually intact (minimal diabetes insipidus).

Treatment and Management

1. Immediate Medical Stabilization
   • Stress-Dose Glucocorticoids to cover for potential adrenal insufficiency.
2. Neurosurgical Intervention
   • Surgical Decompression (often transsphenoidal approach) may be needed for:
     • Altered mental status from rising intracranial pressure.
     • Visual pathway compromise (to prevent irreversible optic nerve/chiasm damage).
   • Timing:
     • Operation within 1 week often improves recovery of visual acuity.
     • Ocular nerve palsies may recover even with delayed intervention, but early surgery is preferred for vision improvement.
3. Observation
   • In patients with stable condition, no vision defects, and no cranial nerve palsies, close observation can be considered.
4. Long-Term Follow-Up
   • Pituitary function may not recover; many require ongoing target gland hormone replacement (e.g., glucocorticoids, thyroid hormone, sex steroids, GH).