Acromegaly is a rare medical condition with a prevalence of only 50 to 70 individuals per million people. Acromegaly awareness is crucial because patients often suffer for years and develop complications if untreated.
This endocrine disorder is caused by an excess of growth hormone (GH), and it is most often associated with a GH-secreting adenoma in the pituitary gland. These pituitary tumours are usually not malignant, but they cause widespread hormonal manifestations as well as pressure effects on the brain and cranial nerves.
GH excess can cause either gigantism or acromegaly. In children, before their epiphyses have fused, GH oversecretion can cause gigantism — an increase in linear growth and unusual height. Once the epiphyses have fused, the hormone causes acromegaly. The two conditions often overlap; most people with gigantism have features of acromegaly, and many people with acromegaly are tall.
Causes of Acromegaly
The most common cause of gigantism and acromegaly is an isolated pituitary adenoma. Other etiologies are tumours in the lungs, pancreas, or another brain site. Hypothalamic hamartomas, ganglioneuromas, and choristoma can cause excessive production of growth hormone-releasing hormone (GHRH), leading to acromegaly. Some genetic conditions are associated with acromegaly.
Most manifestations of acromegaly are caused by high levels of GH and insulin-like growth factor-1 (IGF-1). Tumours also cause symptoms by putting pressure on surrounding structures, such as visual disturbances due to pressure on the optic nerve. The presence of more than one of these manifestations should lead to suspicion:
- Excessive sweating
- Joint pain
- Muscle weakness
- Increasing shoe, ring, or hat size
- Reduced libido, infertility, amenorrhoea
- Growth and distortion of the jaw and face
- Difficulty concentrating
- Dysarthria because of tongue overgrowth
- Visual disturbances (double vision, blurred vision, loss of sight)
- Diabetes mellitus
Acromegaly is associated with several significant conditions:
- Left ventricular hypertrophy
- Cardiac arrhythmias
- Diabetes mellitus
- Intestinal polyps and malignancy
- Cranial nerves disorders
Acromegaly awareness plays a crucial role in preventing complications and mortality.
The diagnosis of acromegaly is usually delayed by 8 years because the disease is rare, most physicians are unfamiliar with it, and early symptoms are vague and non-specific. Men and women are diagnosed on average around ages 40 and 45, respectively. Children around puberty have a natural growth spurt, and the signs of acromegaly may be missed. Pediatric GH excess is often associated with various syndromic diseases, including neurofibromatosis, McCune Albright syndrome, and Carney complex.
If you suspect acromegaly, it can be helpful to ask your patient to provide photos from 5-10 years ago. Compare for changes in appearance, most notably in size of facial features.
Once acromegaly is suspected, measuring blood levels of GH and IGF-1 can confirm the diagnosis. Combining a GH assay with an oral glucose tolerance test is helpful; blood levels of GH fall in normal people, but GH excess persists in people with acromegaly. A magnetic resonance imaging (MRI) scan often shows a pituitary adenoma. A pituitary mass is sometimes detected on a scan performed for another indication; investigating people with such incidentalomas may lead to a diagnosis of acromegaly.
Treatment of Acromegaly
Transsphenoidal adenectomy is performed through the nose and is the most frequently chosen treatment for this endocrine disorder. Larger tumours may need a craniotomy, though this is very rare. Removal of the GH-secreting adenoma reduces GH levels and is frequently curative. Surgery is preferred because it also relieves the mass effect-associated symptoms of the adenoma.
Medical therapy can be used to normalize insulin-like growth factor 1 (IGF-1) levels and prevent the emergence of disease-related comorbidities. Common therapeutics include somatostatin analogues (SSAs), dopamine agonists, and GHR antagonists.
The mortality of people with acromegaly is 1.2 to 3.3 times that of the general population. Treatment is necessarily long-term and needs careful monitoring of GH and IGF-1 levels. Heightened acromegaly awareness and swifter diagnosis will improve patient outcomes.
Radiation can be considered when surgery or drug therapy are not effective. This may be given either in one dose, or in a series of doses over a period of 4-6 weeks.
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