Neurosurgery notes/Tumours/Sellar tumours/Pituitary adenoma/Pituitary neuroendocrine tumour/Pituitary apoplexy

Pituitary apoplexy

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Pituitary adenoma/Pituitary neuroendocrine tumour

Definition

  • A clinical diagnosis, radiological one does not count
  • Neurologic and/or endocrinology deterioration due to sudden expansion of a mass within the sella turcica.

Mech

  • HTN (26%)
  • Major surgery (coronary artery bypass) → fluctuating BP + use of anticoagulants
  • Dynamic testing of pituitary hormones using (GnRH, TRH, CRH, Insulin tolerance test)
    • 83% occur in 2 hrs
  • Normal pituitary gland or Rathke’s cleft cyst haemorrhage
  • Anticoagulation therapy & Coagulopathies
  • Oestrogen therapy
  • Initiation or withdrawal of dopamine receptor agonist
  • Radiation therapy
  • Head trauma
  • Pregnancy → stop taking carbergoline (teratogenic) → pituitary tumour grow → intrasellar pressure inc. → dec. Blood to gland → pituitary tumour and adjacent pituitary gland (haemorrhage → necrosis → infarction)

Numbers

  • 3% macroadenomas
  • 2% clinical but 25% radiological (subclinical haemorrhage)
  • 80% of patients apoplexy is the first sign of pituitary tumour

Clinical features

Abrupt onset of
  • H/A (100%)
    • Retroorbital or bifrontal or diffuse
  • Visual disturbance (75%)
    • Upward enlargement of intrasellar contents → chiasmal compression
  • Loss of consciousness
Neurologic deficit
  • Visual disturbances: most common finding
    • Ophthalmoplegia (unilateral or bilateral):
      • Opposite the situation with a pituitary tumour
        • Ophthalmoplegia occurs (78%) > visual pathway deficits (52–64%)
      • One of the typical field cuts seen in pituitary tumours
  • Reduced mental status:
    • ↑ ICP
      • SAH → ob(x) HCP
    • Hypothalamic compression
    • Adrenal insufficiency leading to arterial hypotension and hypoglycemia
  • Cavernous sinus compression → venous stasis and/or pressure on any of the structures within the cavernous sinus
    • Trigeminal nerve symptoms
    • Proptosis
    • Ophthalmoplegia (III palsy > VI)
      • Most: CN3 (50% of CN palsy)
    • Ptosis may be an early symptom
    • Pressure on carotid artery
    • Compression of sympathetic within the cavernous sinus → third order (incomplete) Horner syndrome with unilateral ptosis & miosis, but anhidrosis may be absent or limited to the central forehead
    • Carotid artery compression may cause stroke or vasospasm
  • If haemorrhage breaks through the tumour capsule + the arachnoid membrane → chiasmatic cistern, signs and symptoms of SAH
    • N/V
    • Meningismus
    • Photophobia
  • Increased ICP may produce lethargy, stupor, or coma
  • Hypothalamic involvement may produce
    • Hypotension
    • Thermal dysautoregulation
    • Cardiac dysrhythmias
    • Respiratory pattern disturbances
    • Diabetes insipidus
    • Altered mental status: lethargy, stupor, or coma
  • Suprasellar expansion can produce
    • Acute hydrocephalus
    • Visual field defects
 

Investigation

  • Endocrine assessment
    • Corticotroph deficiency 70%
    • Thyrotrophin deficiency 50%
    • Gonadotrophin deficiencies 75%
    • Hyponatremia 40% due to
      • SIADH
      • Hypercortisolism
  • Radiological
    • CT
      • Diagnostic for 30%, but can see enlarged pituitary in 80%
    • MRI
      • Diagnostic in 90%
      • Gold standard
    • MRA/CTA for differentiating apoplexy and aneurysmal SAH
  • Pituitary apoplexy score (not used clinically to stratify patients yet but might be used in the future)
      • Variable
      Points
      Variable
      Points
      Level of Consciousness
      ㅤ
      Visual field defects
      ㅤ
      Glasgow coma scale 15
      0
      Normal
      0
      Glasgow coma scale <8–14
      2
      Unilateral defect
      1
      Glasgow coma scale <8
      4
      Bilateral defect
      2
      Visual acuity
      ㅤ
      Ocular paresis
      ㅤ
      Normal* 6/6
      0
      Absent
      0
      Reduced – unilateral
      1
      Present – Unilateral
      1
      Bilateral
      2
      Bilateral
      2

Management

  • HDU
  • Rapid administration of corticosteroids
    • Hydrocortisone
      • IV 100–200 mg bolus →
        • 2–4 mg/hr by continuous intravenous infusion or
        • IM 50–100 mg 6 hrly by intramuscular injection.
          • Given the saturation kinetics of cortisol binding globulin, intermittent intravenous injections of hydrocortisone are less favoured; much of the administered steroid will be filtered into the urine and not pharmacologically available
    • Post acute episode → taper dose to 20-30mg/day
    • Review ACTH reserves in 3 months
    • Dexamethasone is not favoured
      • Only used for reducing oedema for treatment of pituitary apoplexy
  • Absence of visual deficits, prolactinomas may be treated with bromocriptine.
  • Medical treatment vs surgical treatment: still debated. Any study one is better than the other has selection bias. Apoplexy is rare so RTC is hard. No long term differences in endocrine outcome between the two.
    • Surgical
      • Indication
        • Sudden constriction of visual fields, (not including ocular paresis)
        • Severe and/or rapid deterioration of acuity
        • Neurologic deterioration due to hydrocephalus
      • Should be done within 7 days
        • Surgery ≤ 7 days of pituitary apoplexy resulted in better improvement in ophthalmoplegia (100%), visual acuity (88%), and field cuts (95%) than surgery after 7 days, based on a retrospective study of 37 patients
      • Done by surgeon that does >5 trans-sphenoidal cases/yr
    • Medical
      • Indication:
        • Haemodynamically unstable patients needs to be stabilised first
        • Without neurological, acuity or field deterioration
      • Monitor I/O → blds (if deteriorate)
      • Monitor acuity and fields → MRI (if deteriorate)
      • Check 9AM Cortisol, leave PM HC dose → if ABNORMAL keep on HC and recheck 4 wks
        • Long term replacement corticosteroids in 60–80%
      • Check T4 free and TSH → if NORMAL → recheck in 4 wks
        • Long term replacement thyroid hormone in 50–60%,
      • GH deficiency is almost present in all patients is rarely replaced
      • Long term desmopressin in 10–25% of patients
      • Long term testosterone in 60–80% of men.
  • Long term check
    • Annual biochemical check of pituitary function
      • T4 free, TSH
      • LH, FSH, Oestradiol (female), testosterone (male)
      • Prolactin
      • IGF1
      • Cortisol
      • GH
    • MRI at 3 months, 6 months, 1 yr then annually for 5 yrs
    • Annual clinical review in joint neurosurgery and endocrine clinic
  • Pregnancy:
    • Do the same as above
    • Balance health of baby and surgery to decompress
    • If not decompress the apoplexy can be reabsorbed

Outcomes

  • Endocrine outcomes
    • Same regardless of surgery or not
    • Partial or complete recovery of pituitary function in up to 50% of patients.
    • Nearly 80% of the patients will need some form of hormone replacement
      • Corticosteroids in 60–80%
      • Thyroid hormone in 50–60%
      • Desmopressin in 10–25% of patients
      • Testosterone in 60–80% of men
  • Visual outcome (acuity, field, ophthalmoplegia)
    • Improved after surgery
    • Poor outcome if having monocular or binocular blindness
    • Visual recovery is less likely in patients presenting with monocular or binocular blindness