Acromegaly resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Tayyaba Ali, M.D.[2]

Synonyms and keywords:Somatotroph adenoma; Growth hormone excess; Growth hormone secreting pituitary adenoma

Overview

This section provides a short and straight to the point overview of the disease or symptom. The first sentence of the overview must contain the name of the disease.

Causes

Life Threatening Causes

Life-threatening causes include conditions that may result in death or permanent disability within 24 hours if left untreated. There is no life-threatening cause of acromegaly. However, if left untreated, 30% of patients with acromegaly may progress to develop cardiovascular manifestations, pulmonary dysfunction, and cerebral complications. These comorbidities will increase the mortality rate.

Common Causes

• Primary Growth hormone (GH) excess
  • GH-cell adenoma
  • Mixed GH-cell and PRL-cell adenoma
  • Mammosomatotroph-cell adenoma
  • Plurihormonal adenoma
  • GH-cell carcinoma
• Familial syndromes
  • Multiple endocrine neoplasia type 1 (GH-cell adenoma)
  • Familial acromegaly
  • McCune-Albright syndrome (rarely adenoma)
  • Carney's syndrome
• GH excess (ectopic or iatrogenic)
  • Pancreatic islet-cell tumor
  • Lymphoma
  • Iatrogenic
• GHRH excess
  • Central ectopic (<1 percent)
    • Hypothalamic hamartoma, choristoma, ganglioneuroma
  • Peripheral ectopic (1 percent)
    • Bronchial carcinoid, pancreatic islet-cell tumor, small cell lung cancer, adrenal adenoma, medullary thyroid carcinoma, pheochromocytoma

Diagnosis

The approach to diagnosis of Acromegaly is based on a step-wise testing strategy. Below is an algorithm summarising the identification and laboratory diagnosis of Acromegaly.

Characterize the symptoms: ❑ Headaches ❑ Enlargement of the hands (change in ring or glove size) and feet (change in shoe size) ❑ Lethargy ❑ Hyperhidrosis (excessive sweating) ❑ Paraesthesia ❑ Fatigue ❑ Jaw pain ❑ Body odor ❑ Blood in the stool ❑ Sleep apnea ❑ Weight gain ❑ In males: ❑ Sexual dysfunction ❑ Loss of libido ❑ Gynecomastia ❑ In females: ❑ Amenorrhea ❑ Galactorrhea

Examine the patient: ❑ HEENT Changes in facial appearance (large bones of the face, large jaw and tongue, widely spaced teeth) Visual disturbance Hoarseness of voice Enlargement of thyroid gland ❑ Musculoskeletal exam: Joint pain Limited joint movement Swelling of the bony areas around a joint Carpal tunnel syndrome ❑ Neurological exam: Decreased muscle strength and power (Muscle weakness) Kyphoscoliosis Cranial nerves palsy ❑ Cardiovascular exam: High blood pressure ❑ Skin exam: Thickening of the skin Skin tags Acne Acanthosis nigricans Hyperhidrosis

Measure Insulin like growth factor-1 (IGF-1) levels

Normal

Equivocal

Elevated

Active acromegaly ruled out

Oral glucose tolerance test (OGTT) with growth hormone (GH) levels

Acromegaly confirmed in a patient with typical clinical manifestations

Growth hormone (GH) suppressed

Inadequate suppression

Active acromegaly ruled out

Order pituitary MRI

Normal

Mass or empty sella

Chest and abdominal CT, Growth hormone-releasing hormone (GHRH) measurement

GH-secreting pituitary adenoma

Extra-pituitary acromegaly

This algorithm developed and modified according to Endocrine Society (ES): Clinical practice guideline on acromegaly.

Treatment

Shown below is an algorithm summarizing the treatment of Acromegaly according the the Endocrine Society (ES): Clinical practice guideline on acromegaly.

Acromegaly

Transphenoidal surgery ❑ Complete resection ❑ Tumors that are unresectable, a surgical debulking procedure may be performed followed by medical therapy

Yes

Patient is not a surgical candidate ❑ Patient preference ❑ High risk due to medical comorbidities ❑ Unresectable tumors

Are the following criteria met postoperatively? ❑ Morning serum GH the day after surgery <1ng/ml ❑ 12 weeks postoperative: Normal serum IGF-1 (for age and gender) No evidence of residual tumor on pituitary MRI

Yes

No

Remission ❑ Monitor with annual IGF-1

Is there residual tumor that appears resectable and readily accessible (eg, not invading the cavernous sinus)?

Perform MRI for clinical or biochemical evidence of recurrence

Medical therapy ❑ Somatostatin analogs: Preferred regimen (1): Octreotide 50 mcg q8hr subcutaneous as initial dose and 100 mcg q8hr as effective dose. Preferred regimen (2): Lanreotide 90 mg q4week for 3 months every 4 weeks subcutaneous. Preferred regimen (3): Pasireotide 40 mg q4wk intramuscular. ❑ Dopamine agonists: Preferred regimen (1): Cabergoline 0.25 mg 2x/week orally. Preferred regimen (2): Bromocriptine 1.25-2.5 mg qDay orally. ❑ GH receptor antagonist: Preferred regimen (1): Pegvisomant 10 mg qDay subcutaneous.

Failure of medical therapy

Radiation therapy ❑ Stereotactic radiotherapy is most common method

This algorithm developed and modified according to Endocrine Society (ES): Clinical practice guideline on acromegaly.

Do's

• The content in this section is in bullet points.

Don'ts

• The content in this section is in bullet points.

References

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