Acromegaly

From Anvita Health Wiki

Contents 1 Introduction 2 Etiology 3 Clinical-manifestations 4 Laboratory 5 Radiology 6 Complications 7 Management 8 More General Terms 9 Additional Terms 10 References

Introduction

• Hypersecretion of growth hormone after closure of epiphyses. Presumably, hypersecretion of somatomedin C would result in a similar disorder since growth hormone acts for most if not all of its activity via somatomedin C.

Etiology

• pituitary adenoma
• hyperplastic pituitary

Clinical-manifestations

• headache
• visual loss

• bitemporal hemianopsia
• blindness

• muscular weakness
• back pain
• pain in extremities
• sweating
• amenorrhea
• endocrine manifestations

• diabetes mellitus: polydypsia, polyuria
• diabetes insipidus
• hyperthyroidism: goiter, thyrotoxicosis
• hirsutism

• accentuated supraorbital ridges
• exophthalmos
• enlargement of:

• hands
• feet
• mandible with separation of teeth
• nose
• lips
• tongue

• cardiomegaly
• hepatomegaly
• hypertrichosis
• hypertension
• oily skin
• severe, premature osteoarthritis

Laboratory

• serum growth hormone (GH)

• random

• value < 1 ng/mL excludes diagnosis
• value > 50 ng/mL confirms diagnosis

• carbohydrate growth hormone (GH) suppression test

• elevated serum GH 1-2 hours after 100 g of glucose (failure to suppress to < 1 ng/mL) [2]
• elevated serum GH 30, 60 & 90 minutes after a glucose load (failure to suppress to < 5 ng/mL) [3]
• most specific test [3]

• serum somatomedin C ( IGF-1) is increased

• good sensitivity, poor specificity [3]

• serum growth hormone-releasing hormone
• serum chemistries

• elevated serum phosphate
• elevated serum alkaline phosphatase
• serum glucose: hyperglycemia may be present

• urinalysis

• increased urinary 17-ketosteroids
• glycosuria may be present

Radiology

• plain films

• overgrowth of cancellous bone
• enlarged sella tursica
• osteoporosis
• tufted phalangeal tips
• signs of osteoarthritis

• MRI of the sella tursica to determine tumor size

Complications

• increased incidence of tubular adenomas
• 2-3 fold increase in mortality when plasma growth hormone & IGF-1 levels are not normalized

Management

• surgical excision of tumor
• radiation therapy

• primary ablative therapy
• post-operatively perisistent disease
• cure rate of 70% in 10 years
• long latent period (months to years) before disease is activity controlled
• used in conjunction with pharmacologic therapy

• pharmacologic therapy

• bromocryptine 5-20 mg/day or higher
• octreotide 100-200 mg SC every 8 hours
• lanreotide
• pegvisomant

• periodic colonoscopy

More General Terms

• pituitary disease
• chronic endocrine disease

Additional Terms

• 17 ketosteroid
• pituitary adenoma/GH secreting (somatotrophinoma)
• somatotropin; growth hormone; somatropin (GH)

References

1. DeGowin & DeGowin's Diagnostic Examination, 6th edition, RL DeGowin (ed), McGraw Hill, NY 1994, pg 861
2. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 195-96
3. Medical Knowledge Self Assessment Program (MKSAP) 11, 15, American College of Physicians, Philadelphia 1998, 2009
4. AACE medical guidelines for clinical practive for the diagnosis and treatment of acromegaly. Endocr Pract 2004; 10(3):213 PMID: [1]
5. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) web page 'Acromegaly' [2]

acromegaly