anesthesia management for pituitary tumor
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Anesthesia management for Pituitary tumor
Dr. Abhijit Nair,
Axon Anesthesia Associates,
Consultant Anesthesiologist,
Care Hospital,
Hyderabad.
i
Pituitary adenomas are common, 1 in 1000
Benign
Slow growing, but can invade adjacent
structures ( cavernous sinus )
Carcinomas : RARE
Mechanism of tumor generation:
Malfunction of growth regulating genes
Abnormalities of tumor suppressor genes
Alteration in genes controlling programmed cell death
Risk factors for developing pituitary tumors:
MEN 1
Carney complex
Isolated familial
Acromegaly
Pituitary Gland:Master Endocrine Gland
Cont:
2 histological entities-
Large, vascular, pink anterior lobe
or adeno hypophysis
Small, grey-white posterior lobe
or neuro hypophysis
Stats :
6mm height,
13 mm width,
9mm AP.
Cont.Lies within pituitary fossa or sella turcica
Floor & anterior wall of sella – Roof of sphenoid sinus
Posterior wall – clivus
Lateral wall – cavernous sinus
Roof – Diaphragmatic sella
Type of Adenoma Secretion Pathology
Corticotrophic ACTH,POMC Cushing’s syndrome
Somatotrophic GH Acromegaly
Thyrotrophic ( Rare ) TSH Hyperthyroidism(asymptomatic)
Gonadotrophic LH,FSH Asymptomatic
Lactotrophic or Prolactinomas ( most common)
Prolactin Galactorrhoea,hypogonadism, amenorrhoea, impotence, infertility
Null cell adenomas No secretion
Classification: By nature:
1) Benign,
2) Invasive adenomas,
3) Carcinomas
By activity:
1) Non functioning,
2) functioning
By size:
1) Micro adenoma, < 1cm,
2) Macro adenoma, > 1cm
By site of origin :
Sellar ( tumors of anterior & posterior pituitary)
Suprasellar ( craniopharyngioma, suprasellar extension of pituitary lesion )
History:Pierre Marie, a French neurologist
in Paris was the first to describe
disease involving pituitary gland
In 1886, he studied patients
with clinical findings of what
he termed as acromegaly &
postulated that pituitary
gland was the culprit
Presentation:
Hormonal hyper secretion syndromes: Hyperprolactinaemia,acromegaly,Cushing’s disease
Mass effect: visual disturbance or raised ICP
Non specific: infertility, headache, epilepsy, pituitary hypofunction
Incidental: Detected during imaging for other conditionsPituitary apoplexy ( rarely )
Goals of pituitary surgery:
To remove as much as tumor
as possible to relieve compression
& to eliminate hormonally active tissue
Avoid additional neurological damage
To protect healthy pituitary tissue
Important factors:Experience of Surgeon
Size & location of tumor
Consistency of tumor
Other variables
( vascularity, presence of
venous sinuses )
Work up:
Basal prolactin concentration,
( 2.8-29.2 ng/ml in women,
2.1-17.7 ng/ml in males)
Growth hormone:
GH concentration:
short t1/2, misleading if done alone-
abnormal if > 10 mU/L )
Failure of GH suppression to < 2mU/L with 75 gm oral glucose,
Increased IGF-1 ( a somatomedin )
ACTH:
Primary screening procedures-
- Urinary concentration of free cortisol,
- Loss of diurnal cortisol control,
- Lack of response to ACTH suppression
Thyroid function tests,
High quality MRI,
CT scan – for bony invasions
Pre operative assessment:
:-Visual function
:-Signs and symptoms
of raised ICP
:-Endocrine studies,
effects of hormonal
hypersecretion
:-Co morbidities
- in acromegaly ,
Cushing’s syndrome
Anesthetic issues :Anatomical changes:
• Prognathism and macroglossia• thickening of the pharyngeal and laryngeal soft tissues and vocal cords• reduction in the size of laryngeal aperture• hypertrophy of periepiglottic folds • Recurrent laryngeal nerve palsy • enlarged thyroid: 25%
:- OSA
:- Hypertension
:- Glucose intolerance
AcromegalyIncreased skull size, enlarged lower jaw
Mal occlusion of teeth
Macroglossia, prognathism, thickened
pharyngeal & laryngeal tissues
Hypertension, Cardiomegaly
Impaired LV function
Impaired Glucose tolerance
Proximal myopathy, difficult cannulation
Enlarged thyroid
Cushing’s syndrome
Appearance
Impaired Glucose tolerance
Hypertension, ECG changes,
LVH, ASH
Hypernatremia, hypokalemia, alkalosis
OSA, GERD
Proximal myopathy
Cannulation
Surgical approach:
Trans sphenoidal approach
- Sublabial
- Endonasal
Trans ethmoidal approach
Trans cranial
- Subfrontal
- Pterional
Anesthetic management
Hemodynamic stability
Maintenance of cerebral
oxygenation
Facilitate surgical conditions
Prevent of intra operative
complications
Rapid emergence to facilitate
early neurological assessment
Cont:
Airway management:
4 grades described in acromegaly:-
Grade 1 – No significant involvement
Grade 2 – Nasal & pharyngeal mucosal hypertrophy with normal glottis
Grade 3 – Glottic stenosis or VC paresis
Grade 4 – Glottic & soft tissue abnormalities
South wick JP, Katz J. Unusual airway obstruction in acromegalic patients- indications for Tracheostomy. Anesthesiology 1979; 51: 72-3.
Cont:
Throat pack
Preparation of nasal mucosa
Lumbar drain ( in patients with significant suprasellar extension )
Position
Maintenance:“ Personal preference”
Any technique suitable for intracranial procedures
Extra cautious in presence of raised ICP
Short acting agents
Normocapnia
RAE tube south
Monitoring:
Standard
ABP
Filling pressures
( Cushing’s disease )
VEP ( Visual evoked potential )
PNS
Emergence from anesthesiaSmooth and rapid
Removal of pack, pharyngeal suction
Extubation in a semi seated position
Operative complications:False aneurysm ( Rx: endovascular / clipping )
Damage to pons ( minimised by frequent fluoroscopy )
In transcranial:
Frontal lobe ischemia- prolonged traction
Seizures ( subfrontal )
Anosmia ( olfactory tract damage )
Post op care:
Airway management
Analgesia
Hormone replacement
Post op hormone complications: Diabetes insipidus:
Develops within first 24 hrs
( when > 80% vasopressin
secreting neurons are destroyed
or become non functional )
Features :-
Increased Posm > 295 mosm/kg
Hypotonic urine ( < 300 mosm/kg )
Urine output > 2ml/kg/hr consistently
Treatment
DDAVP (desmopressin acetate ) nasal/ sc
s/c Vasopressin
Monitor plasma sodium, osmolality
IVF ( maintenance + 2/3rd urine output in previous hour )
Type of fluid ( on electrolyte picture)
Hyponatremia
Commonest cause: over enthusiastic DDAVP use
Rarely- SIADH
In SIADH : water retention,
Loss of sodium in urine
References:
Pituitary disease & Anesthesia. M Smith & N P Hirsch. BJA 85(1) : 3-14(2000)
Treatment of Pituitary tumors : a surgical perspective. Chandler, Barkan. Endocrinal Metab Clin A Am, 37(2008) 51-66
Barash’s Clinical Anesthesia
Miller’s Anesthesia
Harrison’s Principles of Internal Medicine
Google Web & Images
THANK YOU
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