Acromegaly and the Heart

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• Elevated somatomedin C blood levels

• Inability to suppress growth hormone to < 2 ng/mL during glucose tolerance test

• Pituitary adenoma found on MRI

• Biventricular hypertrophy with systolic and diastolic dysfunction

• Hypertension, diabetes, and premature coronary artery disease

GENERAL CONSIDERATIONS

• Acromegaly is caused by excessive growth hormone secretion from a pituitary adenoma

• It is characterized by excess bone growth, organ enlargement, and premature death due to cardiorespiratory complications

• Rarely other endocrine tumors can secrete growth hormone

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Headache, bitemporal hemianopsia from tumor growth

• Impotence, galactorrhea or amenorrhea

• Diaphoresis, hoarseness, polyuria, polydipsia

• Carpal tunnel syndrome

• Symptoms of:

  • – Heart failure, such as dyspnea

  • – Coronary artery disease, such as chest pain

PHYSICAL EXAM FINDINGS

• Systemic hypertension

• Thick lips, macroglossia, bulbous nose, protrusive lower jaw, frontal bossing, prominent cheek bones, and hollow temporal fossae

• Joint swelling, kyphosis, barrel chest, spade-like hands with sausage-like digits

• Left ventricular lift

• Signs of congestive heart failure, such as pulmonary rales

DIFFERENTIAL DIAGNOSIS

• Other causes of cardiomyopathy and heart failure

• Other causes of hypertension

• Other causes of premature coronary artery disease

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• Growth hormone, somatomedin C, and insulin-like growth factor-1 levels

• Growth hormone during a glucose tolerance test

• Hyperglycemia, hypertriglyceridemia

• Hyperphosphatemia

ELECTROCARDIOGRAPHY

• Left ventricular hypertrophy

• Atrial and ventricular tachyarrhythmias

• Nonspecific ST-T changes and intraventricular conduction defects

IMAGING STUDIES

• Chest x-ray: cardiomegaly

• Echocardiography: eccentric left ventricular hypertrophy or asymmetric hypertrophy and left ventricular systolic dysfunction

• Doppler echocardiography: diastolic dysfunction

DIAGNOSTIC PROCEDURES

• Stress cardiac imaging or cardiac catheterization may be indicated to diagnose coronary artery disease

TREATMENT

CARDIOLOGY REFERRAL

• Suspected cardiac disease

• Difficult to control hypertension

HOSPITALIZATION CRITERIA

• Heart failure

• Acute coronary syndromes

• Planned surgery

MEDICATIONS

• Pharmacologic therapy with somatostatin analogs, eg, octreotide 200–500 μg/day SC, or Sandostatin LAR (octreotide) Depot 10–40 mg IM every 4 weeks, or lanreotide 60–120 mg SC every 4 weeks, or dopamine agonists, eg, bromocriptine 5–30 mg/day PO (start at 2.5 mg/day)

• Heart disease treated conventionally

THERAPEUTIC PROCEDURES

• Cardiac catheterization and angioplasty may be required

SURGERY

• Surgical removal of the pituitary tumor with postoperative radiation therapy

MONITORING

• ECG monitoring in hospital as appropriate

DIET AND ACTIVITY