Este documento describe la acromegalia, un trastorno causado por un exceso de hormona de crecimiento. Explica que la mayoría de los casos son causados por un adenoma hipofisiario que secreta hormona de crecimiento. Detalla los síntomas y efectos sistémicos de la acromegalia, así como los métodos de diagnóstico y tratamiento, incluida la cirugía, medicamentos análogos de la somatostatina y antagonistas del receptor de hormona de crecimiento. El seguimiento del tratamiento implica monitorear los niveles
5. PATOGENESIS
• 95% de los casos adenoma hipofisiario.
• Adenonas puros de células GH: 60% de los tumores
que causasn acromegalia
• Citoplasma densamente granulado (crecimiento lento)
Citoplasma escasamente granulado
(crecimiento rápido)
The New England Journal of Medicine, S. Melmed,2008
6. PATOGENESIS
• Adenomas mixtos PRL-GH
• Mitocondrias gigantes
• Rápido crecimiento e invasivos
• Puede predominar la hiperprolactinemia
• Adenomas monomorfos
• GH-PRL
• Tumores plurihormonales
• Monomorfos o plurimorfos
• Expresan GH, con cualquier combinación de PRL,
TSH, ACTH o subunidades α
The New England Journal of Medicine, S. Melmed,2008
7. PATOGENESIS
• Carcinoma productor de GH
• Raros
• Raramente metastatizan
• Hiperplasia de células productoras de GH
• Estimuación GHRH extrahipofisiaria
The New England Journal of Medicine, S. Melmed,2008
8. ACROMEGALIA EXTRAHIPOFISIARIA
DIAGNOSTICO DIFERENCIAL
• Síndrome Mcune
Albright
• Displasia fibrosa
poliostótica
• Pigmentación cutánea
• Precocidad sexual,
hipertiroidismo
• Hipercortisolismo
• Hiperprolactinemia
The New England Journal of Medicine, S. Melmed,2008
• NEM 1
• Tumor pancreático
• Tumor paratiroides
• Acromegalia
• Gigantismo
• Niños con talla > 3 DE
sobre la altura normal
para la edad
• Talla > 2 DE sobre la talla
ajustada media ajustada
a la de los padres.
9. CAUSAS DE GIGANTISMO
• Genetico
• Familiar, redundancia de cromosoma sexuales
• Síndrome de Marfan
• Homocistinuria, Neurofibromatosis
• Endocrino-metabólicos
• Adenoma productor de GH
• Hiperinsulinismo, diabetes lipoatrofica,
hipertiroidismo
• Exceso de esteroides sexuales prepuberales
• Inclasificables
• Gigantismo cerebral
The New England Journal of Medicine, S. Melmed,2008
10. CARACTERISTICAS CLÍNICAS
Efectos tumorales locales
• Agrandamiento
hipofisiario
• Defectos de los
campos visuales
• Paralisis de nervios
craneales
• Cefalea
The New England Journal of Medicine, S. Melmed,2008
• Somáticas
• Agrandamiento acrial
• Engrosamiento de tejidos
blandos de manos y pies
• Musculoesqueléticas
Prognatismo
Maloclusión
Artralgia
Síndrme del tunel del
carpo
• Acroparestesis
• Miopatía proximal
• Hipertrofia del hueso
frontal
•
•
•
•
11. CARACTERISTICAS CLÍNICAS
• Piel
• Hiperhidrosis
• Grasosa, manchas
• Colon
• Polipos
• Cardiovascular
• HVI
• Hipertrofia septal
asimétrica
• HTA
• ICC
The New England Journal of Medicine, S. Melmed,2008
• Alteraciones del sueño
• Apnea del sueño
• Narcolepsia
• Visceromegalia
•
•
•
•
•
Lengua
Tiroides
Glandulas salivales
Bazo
Riñón
12. CARACTERISTICAS CLÍNICAS
ENDOCRINAS METABÓLICAS
• Reproductivas
• Anormalidades
menstruales
• Galactorrea
• ↓ libido
• Disfunción erectil
• NEM I
• Hiperparatiroidismo
• Tumor de los islotes
pancreáticos
• Tiroides
• ↓ TG
The New England Journal of Medicine, S. Melmed,2008
• Carbohidratos
• Intolerancia a la glucosa
• Resistencia a la insulina e
hiperinsulinemia
• Diabetes mellitus
• Lipidos
• Hipertrigliceridemia
• Mineral
• Hipercalciuria, 1,25(OH)2
vitamina D3
• Electrolitos
• ↓ renina, ↑ aldosterona
16. DIAGNOSTICO
Niños y adultos
jóvenes
masculino
femenino
1-2 años
30-122 ng/ml
56-144 ng/ml
3-4 años
54-178
74-202
5-6 años
60-228
82-262
6-7años
113-261
112-276
8-9años
123-275
140-308
10-11años
139-395
132-376
13-14 años
152-540
192-640
15-16 años
257-601
217-589
17-18 años
236-524
176-452
10-20 años
281-510
217-475
Endocrinology Expected Values and S. I. Conversion Tables
18. TRATAMIENTO: OBJETIVOS
• Suprimir la hipersecreción autónoma de GH.
• Remover o reducir la masa tumoral
hipofisiaria.
• Corregir los defectos en los cambos
visuales.
• Peservar la función trópica hipofisiaria.
• Tratar las complicaciones.
• Prevenir secuelas sistemicas de
hipersomamotropismo.
• Prevenir recrrencia bioquímica y local.
The New England Journal of Medicine, S. Melmed,2008
19. TRATAMIENTO MEDICO
Analogos de la somatostatina:
•Octeotride (Sandostatin®). Se administra en inyecciones subcutáneas 20 mg
cada 4 semanas.
•Lanreótida (Somatulina®). Se administra como inyección intramuscular cada 7,
10 o 14 días, La dosis promedio es de 30 mg cada 10
días.
Acromegaly Follow-up, Hasnain M Khandwala, MD, FRCPC; 2012, MEDSCAPE
20. EFECTOS ADVERSOS DEL
TRATAMIENTO
análogos de la somatostatina:
pérdida del apetito
náuseas, vómitos
molestias o dolor intestinales,
diarreas
heces grasas
caída del pelo
retardo de la movilidad del tubo digestivo y de la
vesícula biliar.
Acromegaly Follow-up, Hasnain M Khandwala, MD, FRCPC; 2012, MEDSCAPE
21. TRATAMIENTO MEDICO
Antagonista de los receptores de GH
•Pegvisomant
bloquea los sitios donde la Hormona de Crecimiento
se acopla para ejercer sus funciones. Cuando se
administra a dosis de 20 mg subcutáneos al día, IgF1
se normaliza en el 90% de los pacientes.
The New England Journal of Medicine, S. Melmed,2008
22. EFECTOS ADVERSOS DEL
TRATAMIENTO
Antagonistas de los receptores de GH
Reacciones anfilacticas.
Malestar general (catarro)
Alteracion de las transaminasas
•fiebre, escalofríos, dolor del cuerpo, síntomas de la
gripe;
•náusea leve, diarrea;
•cambios en la forma o la ubicación donde se
acumula la grasa del cuerpo
Acromegaly Follow-up, Hasnain M Khandwala, MD, FRCPC; 2012, MEDSCAPE
23. RADIOCIRUGIA
Radiocirugía estereotácica.•Los resultados son más precoces que con la
radioterapia convencional, con menos efectos
indeseables y más tardíos que con la cirugía. En
general, se han publicado normalización hormonal
un año después del tratamiento en un 58% de los
casos.
•Está indicada en los pacientes operados que no se
controlan con la medicación o en los casos de
nódulo tumorales residuales situados en el seno
cavernoso.
Acromegaly Follow-up, Hasnain M Khandwala, MD, FRCPC; 2012, MEDSCAPE
FIG. 2. Regulation of GH synthesis and secretion. The hypothalamic hormones GHRH and somatostatin elicit an increase and decrease in circulating GH levels, respectively. Circulating GH binds to the GHR on peripheral tissue such as muscle, liver, and bone to induce the secretion of IGF-I. IGF-I itself then has growth-promoting effects on target tissues. IGF-I can also decrease circulating GH levels via feedback inhibition at either the hypothalamic or pituitary level. [Adapted from J. J. Kopchick and J. M. Andry: Mol Genet Metab 71:293–314, 2000 (267).]
GH receptor antagonists
Pegvisomant is a novel, genetically engineered GH receptor antagonist that, in contrast with dopamine agonists and somatostatin analogues, inhibits GH action rather than secretion. It exerts its biological actions by preventing functional dimerisation of the GH receptor.77 Clinical studies have shown that pegvisomant is remarkably effective, improving clinical symptoms and signs and resulting in IGF1 normalisation in over 90% of patients.78–80 The drug
seems to be safe and well tolerated. Because pegvisomant works by blocking the actions of GH, efficacy is independent of tumour characteristics, such as the density of somatostatin receptors. Despite normalised IGF1 levels, GH levels remain raised in these patients, albeit with minimal or neutralised
bioactivity because of receptor block. Concerns of the raised GH concentrations being reflected in tumour growth need to be clarified by additional long term monitoring studies.
GH receptor antagonists
Pegvisomant is a novel, genetically engineered GH receptor antagonist that, in contrast with dopamine agonists and somatostatin analogues, inhibits GH action rather than secretion. It exerts its biological actions by preventing functional dimerisation of the GH receptor.77 Clinical studies have shown that pegvisomant is remarkably effective, improving clinical symptoms and signs and resulting in IGF1 normalisation in over 90% of patients.78–80 The drug
seems to be safe and well tolerated. Because pegvisomant works by blocking the actions of GH, efficacy is independent of tumour characteristics, such as the density of somatostatin receptors. Despite normalised IGF1 levels, GH levels remain raised in these patients, albeit with minimal or neutralised
bioactivity because of receptor block. Concerns of the raised GH concentrations being reflected in tumour growth need to be clarified by additional long term monitoring studies.
GH receptor antagonists
Pegvisomant is a novel, genetically engineered GH receptor antagonist that, in contrast with dopamine agonists and somatostatin analogues, inhibits GH action rather than secretion. It exerts its biological actions by preventing functional dimerisation of the GH receptor.77 Clinical studies have shown that pegvisomant is remarkably effective, improving clinical symptoms and signs and resulting in IGF1 normalisation in over 90% of patients.78–80 The drug
seems to be safe and well tolerated. Because pegvisomant works by blocking the actions of GH, efficacy is independent of tumour characteristics, such as the density of somatostatin receptors. Despite normalised IGF1 levels, GH levels remain raised in these patients, albeit with minimal or neutralised
bioactivity because of receptor block. Concerns of the raised GH concentrations being reflected in tumour growth need to be clarified by additional long term monitoring studies.
GH receptor antagonists
Pegvisomant is a novel, genetically engineered GH receptor antagonist that, in contrast with dopamine agonists and somatostatin analogues, inhibits GH action rather than secretion. It exerts its biological actions by preventing functional dimerisation of the GH receptor.77 Clinical studies have shown that pegvisomant is remarkably effective, improving clinical symptoms and signs and resulting in IGF1 normalisation in over 90% of patients.78–80 The drug
seems to be safe and well tolerated. Because pegvisomant works by blocking the actions of GH, efficacy is independent of tumour characteristics, such as the density of somatostatin receptors. Despite normalised IGF1 levels, GH levels remain raised in these patients, albeit with minimal or neutralised
bioactivity because of receptor block. Concerns of the raised GH concentrations being reflected in tumour growth need to be clarified by additional long term monitoring studies.