What are the laboratory findings in pituitary apoplexy?

From the Guidelines

Laboratory findings in pituitary apoplexy typically include abnormal hormone levels reflecting pituitary dysfunction, with the most critical finding being low cortisol, which requires immediate corticosteroid replacement to prevent life-threatening adrenal crisis. Patients often show decreased levels of anterior pituitary hormones including ACTH, TSH, LH, FSH, and growth hormone, leading to corresponding decreases in target hormone levels such as cortisol, thyroid hormones, testosterone/estrogen, and IGF-1 1. Hyponatremia may be present due to SIADH or adrenal insufficiency. Elevated inflammatory markers like white blood cell count, ESR, and CRP can occur. Cerebrospinal fluid analysis may reveal xanthochromia or elevated protein levels if a lumbar puncture is performed. Blood glucose levels might be low due to adrenal insufficiency. Serum prolactin can be either elevated from stalk compression or decreased from lactotroph damage.

Key Laboratory Findings

• Decreased anterior pituitary hormones (ACTH, TSH, LH, FSH, growth hormone)
• Decreased target hormone levels (cortisol, thyroid hormones, testosterone/estrogen, IGF-1)
• Hyponatremia (due to SIADH or adrenal insufficiency)
• Elevated inflammatory markers (white blood cell count, ESR, CRP)
• Low blood glucose (due to adrenal insufficiency)
• Abnormal serum prolactin levels (elevated or decreased) These laboratory abnormalities reflect the sudden hemorrhage or infarction within a pituitary tumor that characterizes pituitary apoplexy. The most critical laboratory finding is low cortisol, which requires immediate corticosteroid replacement (typically hydrocortisone 100mg IV initially, followed by 50-100mg every 6-8 hours) to prevent life-threatening adrenal crisis, as supported by the latest guidelines and studies 1. Thyroid function tests and electrolytes should be closely monitored, as hypothyroidism and diabetes insipidus may develop and require specific treatment.

From the Research

Laboratory Findings in Pituitary Apoplexy

• The diagnosis of pituitary apoplexy should be considered in all patients with acute severe headache with or without neuro-ophthalmic signs 2
• Patients with suspected pituitary apoplexy should have urgent blood samples drawn to test: + Electrolytes + Renal function + Liver function + Coagulation screen + Complete blood count + Basal levels of pituitary and peripheral hormones + To rule out adrenocorticotropic hormone (ACTH) deficiency 2
• Most patients have hormonal and/or electrolyte disturbances at the time of presentation, which needs to be quickly corrected 3
• Corticotropic deficiency (secondary adrenal failure) may be life-threatening if untreated 4
• Pituitary function is impaired in most patients before apoplexy, and ACTH deficiency is common, which makes glucocorticoid replacement needed in most cases 5
• Patients often require emergent intravenous fluids, blood transfusions, and high-dose corticosteroids 6

Imaging Studies

• Magnetic resonance imaging (MRI) is the imaging test of choice to confirm diagnosis 2, 3, 6
• Computed tomography (CT) or MRI can confirm the diagnosis by revealing a pituitary tumour with haemorrhagic and/or necrotic components 4
• MRI is useful for identifying blood components in the subacute setting (4 days to 1 month) 4

Treatment and Management

• Indications for empirical urgent corticosteroid therapy in patients with PA include hemodynamic instability, impaired consciousness, reduced visual acuity, and severe visual field defects 2
• Surgery should be considered in patients with severe neuro-ophthalmic signs, and preferably performed within seven days of the onset of symptoms 2, 3, 5, 6
• Patients with mild and stable signs may be managed conservatively with careful monitoring 2, 3