- Published on
KembaraXtra-Medicine- Acromegaly
Acromegaly is a chronic, progressive disorder caused by excess secretion of growth hormone (GH), which in turn stimulates increased production of insulin-like growth factor 1 (IGF-1). The disease develops insidiously, often over many years, and may lead to significant morbidity and mortality if left untreated, particularly from cardiovascular and respiratory complications.
The ICD-10-CM code for acromegaly and pituitary gigantism is E22.0. The incidence is approximately 3 to 4 new cases per 1 million people annually, with a prevalence of 50 to 60 cases per 1 million, and some estimates as high as 90 per 1 million. Acromegaly occurs slightly more often in women. The typical age at diagnosis is around 40 years in men and 45 years in women.
Clinically, patients develop coarse facial features due to progressive soft tissue overgrowth. Common findings include coarse, oily skin, excessive sweating, and macrocephaly. Enlargement of the hands and feet produces broad, spade-like, fleshy extremities, often accompanied by a history of increasing ring, glove, hat, or shoe size. Facial changes such as enlargement of the nose, brow, and jaw, along with prognathism, may result in an underbite.
Musculoskeletal symptoms are common and include muscle weakness, decreased exercise tolerance, arthralgias, severe osteoarthritis, and vertebral fractures. Neurologic and compressive symptoms from the pituitary tumor may include headaches and visual field defects. Carpal tunnel syndrome is frequently seen due to soft tissue swelling.
Acromegaly is also associated with multiple systemic complications. These include diabetes mellitus, hypertension, mild to moderate obesity, and severe obstructive sleep apnea, often related to macroglossia and upper airway soft tissue enlargement. Cardiac involvement is a major contributor to morbidity and mortality and may manifest as cardiomyopathy, left ventricular hypertrophy, valvular heart disease, diastolic dysfunction, and arrhythmias. Patients may also develop benign tumors such as skin tags, uterine fibroids, prostate hypertrophy, and colon polyps, and women may experience menstrual dysfunction.
In most cases, acromegaly results from a pituitary adenoma arising from the anterior pituitary gland. Rarely, it is caused by ectopic secretion of GH or growth hormone–releasing hormone (GHRH) from nonpituitary tumors. Conditions that may mimic or be associated with acromegaly include neuroendocrine tumors, McCune-Albright syndrome, and pachydermoperiostosis.
Diagnosis begins with biochemical testing followed by imaging to localize the source of hormone excess. The initial screening test is a serum IGF-1 level; a normal IGF-1 level makes acromegaly unlikely. If IGF-1 is elevated or equivocal, an oral glucose tolerance test is performed. Failure of GH to suppress to below 1 ng/mL after a glucose load confirms the diagnosis. Random GH measurements are not recommended because of the hormone’s pulsatile secretion.
Once biochemical confirmation is obtained, imaging is used to identify the tumor. MRI of the pituitary and hypothalamus is the preferred modality, while CT scanning is reserved for patients who cannot undergo MRI.
The treatment of choice is transsphenoidal microsurgical removal of the pituitary adenoma. Surgical success depends on tumor size, with failure rates of approximately 10% to 20% for microadenomas and 25% to 50% for macroadenomas confined to the sella. When surgery is contraindicated, incomplete, or when rapid control is needed before surgery (such as in patients with severe sleep apnea or heart failure), medical therapy is indicated.
Medical treatment options include somatostatin receptor ligands (octreotide, lanreotide, pasireotide), which suppress GH secretion and are commonly used preoperatively or postoperatively in patients with residual disease. Pegvisomant, a GH receptor antagonist, is particularly effective for moderate to severe persistent disease or in patients intolerant of somatostatin analogs. Combination therapy with somatostatin analogs and pegvisomant can achieve very high biochemical control rates. Cabergoline, a dopamine agonist, may be used in patients with mild residual disease or as adjunct therapy.
Radiotherapy, including stereotactic radiosurgery (gamma knife), is reserved for patients with persistent or recurrent disease after surgery who do not respond adequately to medical therapy. A major long-term complication of radiotherapy is hypopituitarism, which can occur in up to 50% of patients, necessitating lifelong endocrine follow-up.
If left untreated, acromegaly is associated with an increased mortality rate, mainly due to cardiovascular and respiratory complications. Achieving biochemical control significantly reduces the risk of diabetes and cardiovascular disease. While treatment can reverse many soft tissue and metabolic changes, bone and joint abnormalities are generally irreversible, highlighting the importance of early diagnosis and management.
A key clinical pearl is that GH excess occurring before epiphyseal closure in children and adolescents results in pituitary gigantism, rather than acromegaly. The safety and efficacy of somatostatin receptor ligands and pegvisomant during pregnancy remain uncertain.
0 Comments
