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Table of contents :
)),
pallor, depression,
and many other manifestations may occur. When cachexia is a prominent feature,
it is called hypophysial or pituitary cachexia.
or surgery
> LH
> FSH
> TSH
> ACTH
> PRL),
or excessive (PRL).
Sometimes there is downward herniation of the optic chiasm, which leads
to defects in the visual field.
=> hemorrhagic
shock
during delivery, and leading to variable patterns of hypopituitarism-producing)
(60-90% of circulating growth hormone is in the form of tetramers and dimers
(normal, 14-39% in plasma) and the patients' GH polymers are abnormally
resistant to conversion into monomers by urea)
due to increased LDL-Ch and decreased HDL-Ch => premature atherosclerosis
=> bone fracturs (RR = 3)]plasma
after challenge < 3 ng/mL]plasma
: a single low value is useless; lack of nocturnal peak]plasma
and [IGFBP3]plasma
reduced or normal (depending on sex and age)]plasma
(i.v. injection 1 mg/kg) + L-Arg
(30 g (adults) or 0.5 g/kg (babies)) => sampling at 0, 15', 30', 45', 60',
120' => normal if [GH]plasma
> 20 ng/mL
(i.v. injection of 0.05-0.15 IU/ kg) => sampling at -30', 0, 30', 60',
120' (insulin-tolerance test (ITT)) => glycemia < 40 mg/dL, [GH]plasma
> 3 ng/mL (or > 140 pmol/l) (> 10 ng/ml or > 465 pmol/l in babies) (sensitivity
= 85-100%)
(i.v. injection 1 mg/kg) => sampling at 0, 15',
30', 45', 60', 120' => normal if [GH]plasma
> 3 ng/mL]plasma
> 3 ng/mL (> 10 ng/ml in babies)
(4 ng/kg) => sampling at 60-120' => normal if [GH]plasma
> 3 ng/mL (sensitivity = 80%)
(p.o. 500 mg (adults) or 10 mg/kg (babies)) => sampling at 0, 30', 60',
120' => normal if [GH]plasma
> 3 ng/mL (sensitivity = 56-81%)-
and FSH-producing),
lack of sexual hairs)
=> [LH]plasma
increased by 10 IU/L and [FSH]plasma
increased by 2 IU/L
agonists
-producing)
=> [TSH]plasma
increased by 5 mU/L if thyroid hormones are not increased
(0.075-0.15 mg/die)
-producing)
(i.v. injection ovine at 8 a.m.) => sampling at 0, 15', 30', 60', 90',
and 120' => normal if [ACTH]plasma
increased by 2-4-folds, peak at 20-100 pg/mL]plasma
> 21 mg/dL; [aldosterone]plasma
4 ng/dL above normal level
every 8 hrs => [cortisol]plasma
> 21 mg/dL
tolerance test (ITT) (i.v. injection of 0.05-0.15 IU / kg) => glycemia
< 40 mg/dL => sampling at -30', 0, 30', 60, and 90' => normal if [cortisol]plasma
increase by 7 mg/dL or > 20 mg/dL
(inhibitor of conversion of 11-DOC into cortisol => removal of negative
feedbak on ACTH incretion) (30 mg/kg at 12 p.m.) => normal if at
8 a.m. [cortisol]plasma
< 4 mg/dL, [11-deoxycortisol (11-DOC)]plasma
> 7.5 mg/dL or > 0.22 mmol/L,
[ACTH]plasma
> 75 pg/mL-producing)]plasma
: as its value increases with stress (also venipuncture), basal values
are taken 15 minutes after cannulation
(bolus injection to prevent peripheral proteolysis before crossing the
BBB) => [PRL]plasma,
basal > 2 mg/dL with increase by 200%
(side effects : skin rash and incontinence)
(200 mg i.v.) => [PRL]plasma,
basal < ?,
1 mg/kg CRH,
100 mg GnRH
/ LHRH,
and 200 mg TRH)
or receptor agonist therapy
and one or more of the glycoprotein types
and GH
and is presumed to be a stem cell for both lactotrophs and somatotrophs.
and PRL-producing)-increting
tumors
incretion (< 1%)-increting
tumors (98%)ref1,
ref2,
ref3,
ref4
and breast cancerrefrefref.
It is a severe autosomal recessive dwarfism characterized by complete GH
insensitivity. Genetic and mutation analyses have attested to the high
molecular heterogeneity of this syndrome, and, to date, more than 30 different
GHR mutations including deletion, frameshift, nonsense, missense and splicing
defects have been described. However, among them, missense mutations are
of particular interest in potentially providing critical information on
the structure-function relationship of the GHR and related molecules. The
study of the recently described forms of atypical LS is now very promising.
These patients display detectable plasma GH binding activity associated
with complete or partial GH insensitivity. Molecular analysis of such a
phenotype with positive GHBP and complete GH insensitivity has revealed
the existence of a missense mutation abolishing receptor homodimerization,
thereby providing in vivo evidence for the critical role of the dimerization
process in the growth-promoting action of GH. Similarly, mutations in the
cytoplasmic region, which are expected to be associated with normal GH
binding activity, should contribute to the identification of other functionally
important domains. Partial GH insensitivity syndromes may theorically encompass
a wide range of distinct phenotypes with variable degrees of GH resistance.
Missense GHR mutations and a quantitative GHR mRNA defect have been identified
in some cases belonging to this heterogeneous group. Interestingly, exclusion
of linkage between the Laron phenotype and the GHR locus was demonstrated
in one affected family. This latter situation may indicate the existence
of other genes controlling GHR expression or required at different steps
of the signal transduction pathway. In this regard, the availability of
a possible animal model for LS should offer new prospects in the identification
of GH-inducible genesref.
Associated anormalities include spinal stenosis, os odontoideum, degenerative
changes of the atlanto-odontoid joint, and small oropharynxref.,
snoring, obstructive
sleep apnea syndrome (OSAS)
and thyroid stimulation by GH
and IGF-1)
(40%)
(acromegalic heart disease) => tachyarrhythmias
=> toothprint on tongue
(due to increased PRL and decreased DA)]plasma
(4.6%)]plasma
basal (3-4 dosages separated by 20-30' : doubtful result if 5 < x <
10 ng/mL) and circadian rhythm]night
urine]plasma
(more important than GH in follow-up)]plasma
:,
MRI
to look for SST2
and SST5
expression
agonists, SST2
agonists, SST3
agonists, SST4
agonists, SST5
agonists, D2
agonists, GH-R
antagonists. Even cases negative at 111In-DTPA-octreotide
scintigraphy
may respond, so a trial may be attempted for 5-8 months]plasma
basal > 2 ng/ml, the patient can be considered cured if after 2 hrs from
OGTT [GH]plasma
< 1 ng/ml)-producing)]plasma
> 200 ng/mL (directly relates with diameter)
(30% of patiens and 80% of patients in hemodialysis)
excess : hypothyroidismand
oligomenorrhea-hypomenorrhea-mild menorrhage (50%) => primary or secondary
amenorrhoea,
none after menopause ; hypoestrogenism (hot flushes, colpoxerosis, mastodynia,
decreased libido and depression)
test
agonists (bromocriptine, dihydroergocristine, lisuride, metergoline,
cabergoline) : only 33% of patients are cured-producing)
cells : hypertrophied thyrotrophs found in the adenohypophysis after
thyroidectomy and in severe thyroid hormone deficiency
-
and FSH-producing)-producing)
for Cushing's syndrome; it is
characterized by aggressive growth of the tumor and diffuse
hyperpigmentation of the skin
(10-20 mg at morning, 10 mg at evening)
(25 mg at morning, 12.5 mg at evening)
(5 mg at morning; 2.5 mg at evening)
appearance :
and nasal obstruction due to stirring of dura mater over diaphragma sellae
(rarely hydrocephalus)
(better assessment of posterior fossa and skull base). Improvements in
diagnostic imaging techniques over the last several years have led to an
increasing recognition of asymptomatic lesions in the pituitaryref1,
ref2.
The management of such pituitary incidentalomas is controversialref1,
ref2,
ref3,
ref4,
ref5,
ref6,
ref7,
ref8.
Some lesions may increase in size, owing to impaired pituitary hormone
production or compressed optic chiasm, whereas others will remain unchanged
in size and will never produce tumoral or hormonal symptoms. The type of
initial endocrinological assessment and the required frequency and length
of follow-up for pituitary incidentaloma need to be carefully determined,
taking cost effectiveness into account. In this setting, it is crucial
to obtain precise information about the natural history of each type of
pituitary lesion. Besides pituitary masses, physiological enlargement of
the pituitary gland is a frequent cause of incidentaloma and of referrals
to endocrinologists for hormonal evaluation and therapeutic advice. Sex-
and age-dependent variations in size and shape of the pituitary have been
reported. In neuroradiological series, 25–50% of healthy women, 18–35 yr
old, had a convex superior pituitary contour, but pituitary height exceeds
9 mm in less than 0.5% of casesref1,
ref2,
ref3,
ref4.
No thorough clinical and hormonal data or long-term endocrinological and
imaging follow-up data are available on these subjects. The present study
was thus designed to obtain more information, at the time of initial referral
and during follow-up, on the clinical, hormonal, and neuroradiological
characteristics of young women with incidentally diagnosed pituitary gland
enlargement (height 9 mm) and a suspected pituitary tumor, with the
aim of proposing practical guidelines. 7 eugonadal nulliparous women, 15-27
yr old, referred between 1989 and 1998 with incidentally diagnosed pituitary
gland enlargement (height > 9 mm) and a suspected pituitary tumor, were
studied. At presentation and at yearly intervals, PRL plasma levels and
corticotropic, somatotropic, and thyrotropic pituitary function were measured;
and pituitary dimensions and signal on magnetic resonance imaging (MRI),
before and after iv gadolinium-diethylene-triamine-pentaacetic acid injection,
were assessed. PRL plasma levels were normal; and corticotropic, somatotropic,
and thyrotropic pituitary function was considered normal in all cases.
In all the women, the upper boundary of the pituitary was convex, on MRI,
and touched the optic chiasm in 4 cases. The width and anteroposterior
diameter of the gland were normal. The pituitary itself seemed normal,
with a homogeneous signal, on plain and dynamic studies with iv contrast
injection. Despite normal initial hormone values, two women underwent surgery,
by the transsphenoidal approach, in another center. During surgery, the
pituitary seemed normal in both cases, with no evidence of tumoral or inflammatory
processes. Biopsy specimens showed the morphologic characteristics of a
normal, nonhyperplastic pituitary gland. All seven women were seen at yearly
intervals for 2-8 yr (median, 4 yr). Clinical and hormonal status remained
stable, as did the structure and size of pituitary, on serial MRI. No tumor
formation occurred, supporting the diagnosis of physiologic hypertrophy
of the pituitary gland. In conclusion, these observations suggest that
careful examination of MRI results may help to distinguish physiologic
pituitary hypertrophy from pituitary tumors and infiltrating lesions. The
former diagnosis is confirmed by normal baseline pituitary function in
extensive hormonal tests. Correct identification of such patients is important
to avoid unnecessary pituitary surgery and costly MRI surveillanceref.
,
L-T4,
and cortisol acetate
))-producing
cells : central or pituitary
diabetes insipidus (CDI)
,
desmopressin
i.n. 5-20 mg b.i.d. or p.o. 300-600
mg/die-producing
cells
(closed and penetrating)
=> nausea and vomiting,
confusion, mild headache,
seizures, coma
=> hypouricemia)),
60% at age 70. 14-40% of infant nodules are malignant (expecially when
male, single nodule, exposure to ionizing radiations, dysphonia, rapid
growth, adhesion to contigue tissues, cervical adenopathies)
or pink-yellow colour of FNAB) : they are more commonly degeneration of
solid nodules rather than epithelial cysts, so that 0.5-3% can degenerate
into carcinomas. They should be excised when larger than 4 cm, containing
bloody fluid, or undergo constant refilling after drainage.
detects cysts > 2 mm and solid nodules > 3-4 mm,
calcified amyloid in MTC), signs of extrathyroid extension
for cold or undeterminated nodules : sensitivity = 65-98%; specificity
= 72-100%; accuracy = 95%; false positives = 2.9%; false negatives = 0.5%;
useful also for cervical lymph nodes, associated with [thyroglobulin]washing
fluid in the needle. In general, FNAB results are classified as:)
: poor sensitivity and specificity, useless in babies unless thyrotoxicosis,
uncertain cytology (differential diagnosis with functional adenoma), thyroid
agenesis, neonatal hypothyroidism, ectopic thyroid tissue, follow-up of
differentiated carcinoma
for babies (evaluation of extension and accurate presurgical topographical
planning)
due to increased [TSH]plasma
or thyroid-stimulating immunoglobulin (TSI)
,
which inhibits iodide oxidation and incorporation into thyroglobulin (Wolff-Chaikoff
effect).