Pituitary Disorders Flashcards
(106 cards)
1
Q
Pituitary gland location
A
Sella turcica within sphenoid bone
2
Q
Relationship of pituitary to hypothalamus
A
Inferior
3
Q
Pituitary in close proximity to
A
Close proximity to:
– Optic Chiasm
– Carotid Arteries
– C.N. III, IV, V, VI
4
Q
CRH
A
ACTH Cortisol
5
Q
TRH
A
TSH T3, T4
6
Q
GnRH
A
FSH,LH Sex Hormones
7
Q
GHRH
A
GH IGF
8
Q
PRF
A
Prolactin Lactation
9
Q
Dopamine
A
↓ Prolactin ↓ Lactation
10
Q
Somatostatin
A
↓ GH ↓ IGF
11
Q
2 types of pituitary tumors
A
Two Basic Types:
• Functional (hormone secreting “microadenoma”)
• Non-Functional (non-secreting “macroadenoma”)
12
Q
Hormone secreting is
A
Functional, “microadenoma”
13
Q
Non-secreting
A
Nonfunction, macroadenoma
14
Q
Functional (Micro-adenomas)
A
– Hypersecretion of usually one hormone
– Multiple hormones rare, most common
combination is GH & Prolactin
– Account for approximately 55% of pituitary tumors
15
Q
Non-Functional (Macro-adenomas)
– Signs/Symptoms due to___________
A
Compression
• pituitary gland itself or surrounding structures
• HA, visual disturbances, CN deficits, Hypopituitarism
– Account for approximately 45% of pituitary tumors
16
Q
Non-Functional Tumors Compression of:
A
Optic Chiasm Third Ventricle Cranial Nerves II – VI Carotid Arteries Hypophyseal Portal System & Infundibulum Pituitary gland itself
17
Q
Optic chiasm compression
A
Light from lateral (“temporal”) visual fields strikes medial
retina.
Medial axons cross at O.C.
Injury to O.C. results in loss of lateral visual fields.
18
Q
With transphenoidal surgery
A
may have deficit to trigeminal nerve
19
Q
Only _______cristcross, Lateral fibers_____
A
Medial fibers cristcross; does not
20
Q
Image on Lateral retinal axons travel straight back.
A
retina is flipped – Lateral light strikes medial retina.
21
Q
Medial retinal axons
A
carrying lateral image info cross over at O.C.
22
Q
Early enlargement compresses
A
inferior O.C. first, resulting in superiolateral visual loss
quadrantanopia
23
Q
in Optic chiasm compression Later,
A
all axons compressed – results in full loss of lateral visual
fields (BITEMPORAL hemianopia).
24
Q
Further Superior Extension of Tumor
A
- Compression/impingement of Third Ventricle
- Can cause obstruction of CSF flow
- Results in Obstructive Hydrocephalus leading to increased ICP.
25
Pre-operative Intracranial Hypertension may present with:
* N/V
* Altered Mental Status
* HA (bifrontal or bitemporal)
* Papilledema
26
Increased ICP Papilledema means
```
• Papilledema (optic disc swelling)*
– HA
– Enlarged blind spot
– Visual disturbances
– Vision loss
```
27
Papilledema is associated with
Blurred Disc Margins
28
Anesthesia Considerations in Increased ICP : Pre-Op sedation should be
carefully administered as these pt.s may be sensitive to
| sedative drugs.
29
Anesthesia Considerations in Increased ICP
| Drug induced hypoventilation can
exacerbate intracranial hypertension due to hypercapnia
| induced cerebral vasodilation.
30
Anesthesia Considerations in Increased ICP
| Anesthesia induction agents should be carefully
titrated to avoid hypotension.
31
Anesthesia Considerations in Increased ICP
| 2 meds that can increase ICP.
Ketamine and high-dose volatile anesthetics
32
Lateral Expansion of Tumor
* Invasion of cavernous sinus
* Compression of Cranial Nerves II – VI
* Compression of Carotid Artery
33
Cranial Nerve Compression Losses II
visual function (especially lateral fields)
34
Cranial Nerve Compression Losses III
pupillary constriction
35
Cranial Nerve Compression Losses III, IV, VI
extra-ocular movements
36
Cranial Nerve Compression Losses V
facial sensation (first & second branches)
37
Hypopituitarism Pituitary Failure, Caused by Tumor Compression of:
* Pitutary gland itself
* Infundibulum (stalk)
* Hypophyseal Portal System
38
Hypopituitary changes in hormones
Results in: ↓GH,ACTH,TSH,FSH/LH,ADH,OT, ↑PRL (because of dopamine) (prolactin inhibiting factor)
39
Hypophyseal Portal Compression Hypothalamic releasing factors cannot
reach target cells in the pituitary
40
PIF
Prolactin Inhibiting Factor (Dopamine)
41
Pituitary Failure can be Acute or Chronic
Acute Failure leads to
–________ failure
– __________have short half-lives
acute adrenal insufficiency
HPA axis
ACTH and Cortisol 10 mins. and 90 mins. respectively
42
Symptoms of Pituitary Failure:
Nausea, dilutional hyponatremia (from ↓aldosterone), profound hypotension or shock
43
Treatment of pituitary Failure with
corticosteroids can be life-saving
44
Chronic Failure initially and later
– ↓ GH initially
| – ↓ ACTH, ↓TSH later
45
Functional Tumors
| • ↑GH –
Acromegaly/Gigantism
46
• ↑ PRL
Hyperprolactinemia
47
• ↑ TSH
Pituitary Hyperthyroidism
48
↑ Gonadotropins similar to what kind of tumor (micro/macro)
similar to non-functional, usually asymptomatic
49
• MEN-1 (Multiple endocrine neoplasia type 1) a.k.a. “
Wermer’s syndrome”.
50
What happens in MEN-1
Pituitary tumor presents with neoplasms in PT and Pancreas – leads to hypercalcemia & hypoglycemia
51
↑ GH - Acromegaly/Gigantism Clinical Manifestations:
* ↑growth of hands and feet (ring, glove, shoe)
* Peripheral Neuropathies/Carpal Tunnel
* Thickening of facial bones/prognathism
* Thickening of skin and soft tissues
* Enlargement of all internal organs (except brain and nerves)
* Cardiac Hypertrophy
* HTN
* Peripheral Neuropathy
52
Anesthesia Considerations in Acromegaly/Gigantism
| • Mask ventilation
difficult due to enlarged mandible and facial bones.
53
Anesthesia Considerations in Acromegaly/Gigantism
| • Mandibular hypertrophy
increased distance from lips to vocal cords.
54
Anesthesia Considerations in Acromegaly/Gigantism
| Direct laryngoscopy difficult due to
enlarged
| tongue, epiglottis and glottic structures.
55
Anesthesia Considerations in Acromegaly/Gigantism Hoarseness/stridor may indicate
stretching of laryngeal nerve and impaired mobility of cricoarytenoid joints – smaller diameter tracheal tube
may be required.
56
Anesthesia Considerations in Acromegaly/Gigantism
| Larger than normal
tidal volumes from ventilator
| may be required (CAD common in these pts).
57
Anesthesia Considerations in Acromegaly/Gigantism
Avoid positioning extremities in a manner that may
exacerbate altered nerve function.– ie. Pt.’s elbows should remain extended to minimize
tension on ulnar nerve.
58
Anesthesia Considerations in Acromegaly/Gigantism Extension of Pt.’s hands should
be avoided to preclude stretching of ulnar and median nerves.
59
Anesthesia Considerations in Acromegaly/Gigantism
| ECG and arrhythmias
Arrhythmias and ECG changes are common – 12-lead
| ECG helpful to detect new-onset changes.
60
Anesthesia Considerations in Acromegaly/Gigantism
• High incidence of
• High incidence of_____
Peripheral Neuropathy –
| Obstructive sleep apnea – monitor for airway obstruction Alterations in BP/cardiac function post-operatively.
61
↑ PRL - Hyperprolactinemia
| Can Cause those symptoms
galactorrhea, amonorrhea, infertility,
decreased libido, osteopenia, impotence and
erectile dysfunction
62
PRL Normally controlled by
Hypothalamic Dopamine
63
↑ PRL - Hyperprolactinemia• Usually treated with
Dopamine agonist
64
↑ PRL - Hyperprolactinemia caused by
• ↑ PRL caused by functional prolactin secreting mass
or
• Non-functional tumor compressing and blocking
Hypothalamic Dopamine
65
Anesthesia Considerations in Hyperprolactinemia
| • Dopamine agonist side effects -
hallucinations, drowsiness, nausea, orthostatic hypotension
| • Can be exacerbated by General Anesthesia
66
↑ TSH – Pituitary Hyperthyroidism
| • Causes ↑T4,T3 =
palpitations, nervousness, heat intolerance, tremor and/or arrhythmias
67
↑TSH Pituitary Hyperthyroidism secreting tumors usually
large and invasive – can present with compression effects (HA, visual changes, C.N. palsies)
68
↑TSH Pituitary Hyperthyroidism tumors can also co-secrete 3 hormones? what is the significance of that
co-secrete GH, PRL & ACTH, therefore acromegaly, hyperprolactinemia or Cushing’s disase may coexist.
69
↑ TSH – Pituitary Hyperthyroidism
| • Treated with
somatostatin analogue (ex. Octreotide) – reduces TSH production
70
↑ TSH – Pituitary Hyperthyroidism used to control tachycardia
Beta-antagonist
71
↑ TSH – Pituitary Hyperthyroidism Some pt.s may have been initially treated for
primary hyperthyroidism/Grave’s disease (instead of pituitary hyperthyroidism) with removal of thyroid
– In this case, pt. may be clinically hypothyroid and
require thyroid hormone replacement
72
Anesthesia Considerations in Pituitary Hyperthyroidism
• Hypothyroid pt.s should continue to receive thyroid hormone in peri-operative period.
• Potential for intra-operative thyroid storm in
pituitary hyperthyroid possible, (but unlikely).
73
↑ Gonadotropins
Overproduction of FSH/LH
74
↑ Gonadotropins • Usually manifest as
disorders with sexual function and reproduction.
75
↑ Gonadotropins Largely present as
Macro-adenomas with symptoms related to mass effect.
76
Peri-operative anesthetic management↑ Gonadotropins
| similar to
non-secreting pituitary tumors.
77
Posterior Pituitary Disorders
| • ↑ ADH
SIADH (Syndrome of Inappropriate ADH)
78
Posterior Pituitary Disorders
| • ↓ ADH
DI (Diabetes Inspidus)
79
Posterior Pituitary Disorders
| ADH or “Vasopressin” binds to:
V1 receptors in blood vessels = vasoconstriction
V2 receptors in kidney = reabsorption of H2O
Increases blood pressure; decreases blood osmolarity
80
SIADH Causes
Hypo-osmolality and Hyponatremia
81
SIADH Symptoms:
– Nausea
– HA
– Lethargy
– Confusion
82
If Na+ level below 120 symptoms
– Stupor
– Seizures
– coma
83
SIADH
| • Acute hyponatremia treatment:
– Hypertonic saline (3%)
– In pt.s with mild neurologic symptoms, given at
0.5mEq/L/h
– In pt.s with severe neurologic symptoms, given at
1-2 mEq/L/h
84
• Infusion rate can be estimated using formula:
Vol. 3% NaCl/h = wgt (kg) x expected change in serum Na level.
Example: 70 ml NaCl/h = 70kg x 1 mEq/L/h
85
SIADH
| • Correcting serum sodium too rapidly
associated with central pontine myelinolysis
(osmotic demyelination syndrome)
Damage to CNS (Pons) as brain cells compensate
86
SIADH Tx In asymptomatic
```
pt.s, water restriction and/or
loop diuretics (ex. Furosemide)
```
87
SIADH treatment:
vasopressin receptor antagonists (ex. Conivaptan)
88
DI Causes
hypernatremia and hypovolemia
89
Two types of DI: =
Central DI and Nephrogenic DI
90
Central DI
failure of posterior pituitary
91
Nephrogenic DI
Lack of kidney response to ADH
92
DI Correction of hypernatremia is
with 0.9% saline. Plasma Na+ correction should not decrease by more than 1 mEq/L q 2 hrs.
Otherwise could cause cerebral edema
93
• Treatment of DI:
Desmopressin
94
Pituitary Surgrery: What is the most common approach?
Transnasal approach is most commonly used technique.
95
Pituitary Surgery
| Intra-operative complications:
– Bleeding because of close proximity to venous
CAVERNOUS SINUS and CAROTID
– HTN if a vasoconstrictor is added to submucosal
anesthetic
96
Large-bore intravenous access and availability of
blood products should be considered
97
Gastric accumulation of blood could
increase risk of post-op N/V
98
Pituitary Surgery and CSF what can occur?
* CSF leak could occur.
* Some surgeons may request placement of lumbar CSF drain catheter.
* (CSF can be drained or air can be injected to displace sellar contents, but will also cause transient change in ICP.)
99
Pituitary Surgery: examination post op
Post-op cranial nerve examination often performed to assess gross visual function
100
Most common symptom of pituitary surgery tumor and post CN issues? What causes it?
diplopia due to dysfunction of extra-ocular muscles
101
If air is injected via lumbar catheter, NO2
should not be used given its effect on volume
of gases in closed spaces. (NO2 passes easily
from blood into gas filled spaces causing
increased volume expansion).
102
What should be performed after pituitary surgery?
Gross neurological exam should be performed
103
With acromegaly, what is the exception as far as organ enlargement?
Nerves and Brain
104
Lateral movement muscles are
Lateral rectus (CN VI) (9am)
105
Superior Oblique is
CN IV
106
Inferior MEDIAL movement muscles are
Superior oblique CN IV (5pm)
