ACROMEGALY

By Isra

Acromegaly Definition and

State of excess GH secretion

Causes

• Pituitary adenoma (macroadenoma $>10mm$ ) either solitary tumor or part of MEN type one syndrome
• Ectopic secretion of hormone by extra pituitary tissues (small cell cancer of the bronchus and carcinoid tumor)
• Hypothalamic secretion of GHRH (very rare)

Clinical features of the disease

GH will stimulate secretion of IGF1 from the liver to do it is action

• Headache
• Frontal bossing, deepening of supraorbital ridges
• Enlarged nose
• Lower lip enlargement
• Lowe jaw overbite (prognathism)
• Teeth spacing
• Goiter (usually they are in euthyroid state)
• Acanthosis nigricans
• Cardiomegaly
• Gynecomastia
• Hepatosplenomegaly
• Colorectal cancer
• Spinal canal stenosis
• Osteoarthritis, pseudogout.
• Lower limb edema due to heart failure

Signs of disease activity

• Excessive sweating
• Skin tags
• Increase size of the ring and shoes
• Presence of signs and symptoms (HTN, Headache, DM, Increase bitemporal visual loss)

Complications of Acromegaly

• DM, HTN, visual loss
• HF
• Carpel tunnel syndrome
• Proximal myopathy
• Osteoarthritis and pseudogout
• Neurological deficit
• Colorectal cancer
• Obstructive sleep apnea
• Pituitary hormones deficiency
• Pituitary apoplexy

Investigations

• Investigations to prove excess GH
  • A. GH level after 75 mg of glucose, normally it should be suppressed to less than 1 mg. if the no suppression occur it means there is high level of GH
  • B. IGF-1 high
• Investigations for the cause
  • A. Serum calcium to exclude or include MEN 1
  • B. MRI pituitary, CT chest and abdomen
• Investigations for complications
  • A. HBA1c, BP
  • B. Perimetry+ fundoscopy (papilledema, optic atrophy, angiod retinal streak and hypertensive changes in the retina)
  • C. ECHO (HF, cardiomegaly)
  • D. NCS (Carpel tunnel syndrome)
  • E. X-ray knee (narrowing of joint space in OA, chondrocalcinosis in pseudogout)
  • F. MRI spine (spinal canal stenosis)
  • G. Colonoscopy (repeat every five years)
  • H. ABG, Sleep studies
  • I. Other hormones measurements
• Causes of death
  • Cardiovascular complications
  • Colorectal cancers

Treatment

• Surgical: transsphenoidal tumor resection
  • If tumor is large trans frontal tumor resection
  • Complications includes: panhypopituitarism and encephalitis
• Medical treatment
  • Suppress GH secretion by
    1. Somatostatin analogue e.g., octreotide. AE: gall stone formation
    2. Dopamine receptors agonist e.g., Bromocriptine. AE: valvopathy and retroperitoneal fibrosis
    3. GH receptors blockers: Pegvisomant (with this medication GH level will still be high)
• Radiation therapy Only after failure of other methods of treatment
  • Side effects includes (cognitive decline, cranial nerve palsies and panhypopituitarism)