Acromegaly and Gigantism

Source:  Acromegaly and Gigantism    Tag:  gigantism treatment


Acromegaly (above picture) and gigantism (below picture) are chronic, progressive diseases marked by hormonal dysfunction and startling skeletal overgrowth. Acromegaly occurs after epiphyseal closure, causing bone thickening and transverse growth and visceromegaly. Gigantism begins before epiphyseal closure and causes proportional overgrowth of all body tissues. Acromegaly develops slowly, whereas gigantism develops abruptly. Although the prognosis depends on the on the causative factor, these disorders usually reduce life expectancy unless treated in a timely way.


Causes
  • Extrapyramidal pituitary lesions or other tumors that cause oversecretion of hGH
  • Oversecretion of human growth hormone (hGH) that produces changes throughout the entire body, resulting in acromegaly and, when oversecretion occurs before puberty, gigantism
  • Possible genetic cause
  • Somatotropic adennomas
Signs and Symptoms

Acromegaly
  • Arthropathy
  • Carpal tunnel syndrome
  • Proximal muscle weakness
  • Fatigue
  • Acanthosis nigricans (an eruption of velvet benign growths and hyperpigmentation occurring in the skin of the axillae, neck, anogenital area)
  • Skin tags
  • Oily skin
  • Cartilaginous and connective tissue overgrowth
  • Enlarged supraorbital ridge and thickened ears and nose
  • Marked projection of the jaw, which may interfere with chewing
  • Voice sounds deep and hollow
  • Thickened fingers
  • Coronary artery disease
  • Cardiomyopathy with arrhythmias, left ventricular hypertrophy, and decreased diastolic function
  • Hypertension
  • Upper airway obstruction with sleep apnea
  • Generalized visceromegaly, including cardiomegaly, macroglosia, and thyroid gland enlargement
  • Barrel chest and kyphosis
  • Signs of diabetes mellitus and glucose intolerance
Gigantism
  • Same skeletal abnormalities and signs of glucose intolerance seen in acromegaly
  • Pituitary tumor enlargement (causing loss of other trophic hormones, such as thyroid-stimulating hormone, lutenizing hormone, follicle-stimulating hormone, and corticotropin)
Diagnostic tests
  • Serum hGH levels measured by radio-immunoassay typically are elevated.
  • Glucose suppression test fails to suppress the hormone level to below the accepted normal value of 2 ng/ml.
  • Skull X-rays, a computed tomography scan, arteriography, and magnetic resonance imaging determine the presence and extent of the pituitary lesion.
  • Bone X-rays show a thickening of the cranium (especially of frontal, occipital, and parietal bones) and of the long bones as well as osteoarthritis in the spine.
Treatment
  • Cranial or transphenoidal hypophysectomy or pituitary radiation therapy is oredered to remove the underlying tumor.
  • Replacement of thyroid and gonadal hormones and cortisone are ordered, postoperatively.
  • Bromocriptine (Parlodel) and octreotide (Sandostatin) are used to inhibit hGH synthesis.
  • Provide the patient with emotional support to help him cope with an altered body image.
  • Assess the patient for skeletal changes and muscle weakness.
  • Perform or assist with range-of-motion exercises.
Do's & Dont's

Keep the patient's skin dry. Avoid using an oily lotion because the skin is already oily.

  • Monitor the patient's blood glucose level. Check for signs and symptoms of hyperglycemia, including fatigue, polyuria, and polydispsia.
  • Reassure the patient and his family that the disease causes mood changes, which can be managed with treatment.
  • Before surgery, reinforce what the surgeon has told the patient and try to allay the patient's fear.
  • After surgery
  1. Diligently monitor the patient's vital signs and neurologic status. Be alert for signs of increased intracranial pressure.
  2. Check blood glucose levels frequently. Remember, hGH levels usually fall rapidly after surgery, removing an insulin anatagonist effect in many patients and possibly precipitating hypoglycemia.
  3. Measure intake and output hourly and watch for large increases in urine output. Transient diabetes insipidus, which sometimes occurs after surgery for hyperpituitarism, can cause such increases in urine output.
  4. If the transphenoidal approach is used, the surgical site is packed with a piece of tissue usually taken from a midthigh donor site. Watch for cerebrospinal fluid leaks from the packed site. Look for increased external nasal drainage into the nasopharynx.
  5. Help the patient get out of bed and walk on the first or second day after surgery, per prescribed level of activity.
  • Make sure the patient and his family understand which hormones are to be taken and why, as well as the correct times and dosages.