Acromegaly and Gigantism Flashcards
gigantism
-before growth plate closure
-Skeletal growth velocity
-Stature increased
-Little bony deformity occurs
-Soft-tissue swelling occurs
-Peripheral nerves enlarged
-Delayed puberty or hypogonadotropic hypogonadism - frequently present
-Results in a eunuchoid habitus
acromegaly
-after fusion of growth plates
-stimulates tissues
-bones growth in width
-muscles
-Benign pituitary adenoma in >98% of cases
-Malignant GH-producing pituitary tumors - extremely rare
-Disfiguring and debilitating somatic growth disorder
-Characterized by bone and soft tissue overgrowth
-Excess secretion of growth hormone (GH)
-Subsequent elevation of insulin-like growth factor 1 (IGF-1) *
-GH hypersecretion
-MC affects middle-aged adults
-Insidious onset- not acute
-Earliest sx- Coarsening of facial features and Soft-tissue swelling of hands and feet
-Appearance changes
-Photographs
Acromegaly- Mortality and morbidity
-burden on metabolism, heart
-Lifespan may be reduced by 10-15 years
-Mortality 2-3 times that of the general population
-strain and stress on organ systems
-prone to malignancy
gigantism and acromegaly
-Syndromes of excessive secretion of growth hormone
-> 98% due to a pituitary adenoma
-Gigantism
-Acromegaly
-Diagnosis:
-Clinical & skull and hand x-rays- determine age of pt depending on carpal bones
-Measurement of GH levels
-Treatment surgical/irradiation of adenoma
acromegaly symptoms
-Excessive sweating and coarse, oily skin
-Increase in foot, hand, or head size
-Doughy moist handshake
-Naso-sinus abnormalities (causing increased snoring, sinusitis, and sleep apnea)
-Diplopia
-Arthralgias (75% of patients) & Arthropathy
-Temporomandibular arthritis
-Carpal tunnel syndrome
-Sensation of weakness in arms and legs
-Skin tags*
-prognathism- protruding jaw
signs due to increased insulin-like growth factor 1
-Coarse facial features
-Frontal bossing
-Increased spacing between lower teeth - gums growing
-Joint stiffness, especially the hands and knees
-Osteoarthritis
-Dorsal kyphosis; spinal stenosis
-Barrel chest
-Prognathism
-Voice changes, such as deepening and huskiness due to increased cartilage in larynx
-Macroglossia
signs due to increased GH production
-Hyperhidrosis of the face, head, hands, feet (enlargement of sweat and sebaceous glands)
-Spade-like hands and feet, sausage-shaped fingers
-Increase in soft tissue mass (hand, foot & tongue)
-Heel pad thickness >22mm
-Sleep apnea- due to enlarging of the neck area
-Sensorimotor polyneuropathy
-Myopathy
signs due to increased GH production
-Insulin resistance and glucose intolerance
-Hypertriglyceridemia
-Cardiovascular abnormalities
-Hypertension
-Pulmonary complications arising from soft tissue proliferation
-Colonic polyposis
-Hyperprolactenemia - Galactorrhea
-Decreased libido and impotence in >50% of men
signs
-Due to mechanical effect of tumor mass:
-Headache (often severe) - due to the tumor
-Visual symptoms, including visual field defects and decreased acuity
-Various impairments of pituitary function (e.g. hypopituitarism) due to compression of the tumor
non-pituitary tumor secretion of GH
-rare causes
-<2% of acromegaly caused by non-pituitary malignant tumors
-Pancreatic cancer
-Small cell lung cancer
-Tumors of the adrenal gland
-Carcinoid syndrome
-Carcinoma of the thyroid
-Hypothalamic tumors - extremely rare -> Hamartoma, glioma, or gangliocytoma
diagnostic work up
-Diagnosed by a combination of clinical features and biochemical tests
-Often first suspected by characteristic symptoms
-Once suspected — must be confirmed biochemically
-Serum IGF-1
-Best screening test
-High IGF-1 levels
-Useful for monitoring response to treatment
-Oral glucose tolerance test
-‘Gold standard’ test for the biochemical diagnosis of acromegaly
-Confirms diagnosis
-Definitive when serum GH levels fail to decrease to <1ng/mL by assay after ingestion of glucose
-give glucose- GH and IGF should decrease BUT with acromegaly it will not decrease
other investigation
-MRI - most used to determine the presence of pituitary adenoma*
-CT*
-Brain
-Whole body scan – for ectopic tumor
-If no tumor found
-Ectopic source of GH secretion should be investigated
-SPECT imaging
-Somatostatin receptor scintigraphy
treatment
-Directed at normalizing GH & IGF-1 levels -> with surgery and/or pharmacotherapy
-Treatment can reduce or even reverse many of the clinical manifestations
-Control may be achieved through surgery alone or in combination with medical treatment and/or radiotherapy
-Use of adjuvant medical therapy or radiotherapy before and after surgery optimizes cure rate
-Successful surgery will lead to a cure, often immediately following surgery
-Complications should be addressed and treated on an individual basis
surgery
-first line therapy
-resection of pituitary adenoma
-surgical cure rate:
-Microadenomas (<10mm diameter) - approx. 85%
-Macroadenomas (>10mm diameter) - 50% -> Comprise the majority of GH-secreting tumors
pharmoctherapy
-second line therapy
-somatostatin analogs- octreotide
-somatostatin analog pretreatment
-pre-op shrinkning of large or invasive tumors
-long acting preparations of octreotide AND/ OR
-dopamine agonists- cabergoline or bromocriptine
-GH- receptor antagonist- pegvisomant
