Acromegaly & Gigantism

Introduction 

Acromegaly and gigantism are hormonal disorders caused by excessive growth hormone secretion usually due to a pituitary tumor 

-Acromegaly develops if excessive GH exposure occurs after closure of the long bone epiphyses (Adults = Acromegaly); where as gigantism develops if it occurs before closure of the epiphyses 

-Grown hormone hypersecretion leads to excessive generation of IGF-1, which acts as the mediator of most of the effects of GH 

-The average age at the time of diagnosis is 40 to 45 years 

Symptoms & Signs 

Facial Features: Frontal bossing, macroglossia, Jaw enlargement  (prognathism), widened teeth spacing 

Musculoskeletal features: Increased hat, shoe, glove and ring size; Enlargement of hands and feet with a doughy texture; arthropathy, carpal tunnel syndrome, kyphoscoliosis 

ENT: Large fleshy nose, deepening of the voice, snoring 

Skin: Doughy texture, cutis verticis gyrata, acanthosis nigricans, skin tags, thick heel pads, hyperhidrosis, hirsutism 

Eyes: Bitemporal hemianopsia (due to optic chiasm compression from the tumor) 

Associated conditions: Diabetes, hypertension, glucose intolerance, cardiomyopathy, left ventricular hypertrophy, diastolic dysfunction

Diagnosis 

Insulin-like growth factor – 1 : Elevated levels 

Growth hormone: Elevated levels in serial measurements; Failure to suppress Growth hormone levels by oral glucose-tolerance test 

Imaging: MRI of the pituitary may show macroadenoma 

Treatment 

Surgery: Removal of adenoma by transsphenoidal surgery 

Somatostatin analogues: Octreotide, lanreotide, pasireotide

Dopamine agonists: Bromocriptine, cabergoline 

GH receptor antagonist: Pegvisomant  

Radiation: Pituitary irradiation 

Q. What is the most important requirement for diagnosis of GH excess? Demonstration of unsuppressable GH secretion 

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