Acromegaly: When Growth Hormone Goes Wrong

What Is Acromegaly?

Acromegaly is a rare hormonal disorder that occurs when the pituitary gland produces excess growth hormone (GH) over a prolonged period, usually due to a benign pituitary tumor (adenoma). The name comes from Greek: “acro” (extremities) + “megaly” (enlargement).

In children and adolescents (before growth plates close), excess GH causes gigantism — abnormally tall stature. In adults, since the bones can no longer grow longer, excess GH causes acromegaly — enlargement and thickening of bones, soft tissues, and organs.

Acromegaly affects approximately 3–4 per million people per year and is most commonly diagnosed between ages 40–60. However, symptoms often begin years before diagnosis — the average delay from symptom onset to diagnosis is 7–10 years.

What Causes Acromegaly?

Pituitary Adenoma (> 95% of Cases)

GH-secreting pituitary adenoma — a benign tumor of somatotroph cells
Macroadenomas (> 10 mm) in about 70% of cases at diagnosis
Microadenomas (< 10 mm) in about 30%

Rare Causes (< 5%)

Ectopic GH secretion — from non-pituitary tumors (extremely rare)
GHRH-secreting tumors — hypothalamic, bronchial, or pancreatic tumors producing growth hormone-releasing hormone
Familial syndromes — MEN1 (Multiple Endocrine Neoplasia type 1), McCune-Albright syndrome, Carney complex, familial isolated pituitary adenoma (FIPA)

Signs and Symptoms

Acromegaly develops gradually, making it one of the most commonly delayed diagnoses in endocrinology. Patients often don’t notice changes in their own appearance; it’s frequently a family member, friend, or doctor who first notices.

Classic Physical Changes

Enlarged hands — rings no longer fit, increasing shoe size
Enlarged feet — need progressively larger shoes
Coarsened facial features:
- Prominent brow ridge (frontal bossing)
- Enlarged nose
- Thickened lips
- Prominent jaw (prognathism)
- Widened spacing between teeth (diastema)
Enlarged tongue (macroglossia)
Deepened voice — due to laryngeal cartilage growth
Thickened skin — oily, with skin tags
Excessive sweating — a very common early symptom

Systemic Complications

Cardiovascular (leading cause of mortality):

Hypertension (40%)
Cardiomyopathy — thickened heart muscle
Heart failure
Arrhythmias
Increased cardiovascular mortality

Metabolic:

Diabetes mellitus (20–56%) — GH is a counter-regulatory hormone that raises blood sugar
Insulin resistance
Dyslipidemia

Musculoskeletal:

Arthropathy — joint pain and stiffness (especially knees, hips, spine)
Carpal tunnel syndrome (up to 60%)
Osteoarthritis

Respiratory:

Obstructive sleep apnea (60–80%) — due to soft tissue overgrowth in the airway
Snoring

Neurological:

Headaches (common)
Visual field defects — from tumor compression of the optic chiasm
Peripheral neuropathy

Other:

Goiter — thyroid enlargement
Colon polyps — increased risk of colorectal cancer
Organ enlargement (liver, spleen, kidneys)
Menstrual irregularity and decreased libido

Comparing Old Photographs

One of the most valuable diagnostic tools is comparing current photos with those from 10–20 years ago. The gradual changes become strikingly apparent in retrospect.

How Is Acromegaly Diagnosed?

Step 1: Clinical Suspicion

Think of acromegaly when you see:

Progressive change in facial appearance or hand/foot size
New-onset diabetes with other suggestive features
Carpal tunnel syndrome in a young person
Sleep apnea with characteristic features

Step 2: Biochemical Confirmation

Test	Purpose	Positive Result
Serum IGF-1	Screening test — reflects overall GH production	Elevated for age and sex
Oral Glucose Tolerance Test (OGTT) with GH	Gold standard confirmatory test — GH should suppress after glucose load	GH fails to suppress below 1 ng/mL (or 0.4 ng/mL with modern assays)
Random GH	Not reliable for diagnosis alone (GH is pulsatile)	But persistently elevated GH supports diagnosis

Step 3: Imaging

MRI Pituitary (with gadolinium contrast) — identifies and characterizes the pituitary adenoma
CT chest/abdomen — if ectopic GHRH source suspected (rare)

Step 4: Assess Complications

Echocardiography — cardiac involvement
Sleep study — sleep apnea assessment
Colonoscopy — screen for colon polyps (at diagnosis and every 3–5 years)
Glucose tolerance test — screen for diabetes
Visual field testing — if tumor near optic chiasm
Other pituitary hormones — check for hypopituitarism
Bone density — if hypogonadism present

Treatment of Acromegaly

The goals of treatment are:

Normalize GH and IGF-1 levels
Remove or control the tumor
Relieve mass effect symptoms
Preserve normal pituitary function
Reduce mortality to population norms

1. Surgery (First-Line in Most Cases)

Transsphenoidal surgery:

Minimally invasive approach through the nose
Cure rate:
- Microadenomas: 80–90%
- Macroadenomas: 40–60%
Performed by experienced pituitary neurosurgeons
Post-operative GH and IGF-1 levels checked at 3 months

2. Medical Therapy

Used when surgery is not curative, as adjuvant therapy, or when surgery is not feasible:

Somatostatin Receptor Ligands (SRLs) — First-Line Medical Therapy:

Octreotide LAR (monthly injection)
Lanreotide Autogel (monthly injection)
Normalize IGF-1 in 40–60% of patients
Shrink tumors in 20–50%
Pasireotide LAR — second-generation SRL for SRL-resistant cases (higher rate of hyperglycemia)

Dopamine Agonists:

Cabergoline — effective in mild cases, especially with co-secretion of prolactin
Oral medication, well-tolerated
Normalizes IGF-1 in ~30% of patients with mild elevation

GH Receptor Antagonist:

Pegvisomant — blocks GH action at the receptor level
Most effective medical therapy for normalizing IGF-1 (> 90%)
Does not shrink the tumor — requires ongoing MRI monitoring
Daily subcutaneous injection
Reserved for cases resistant to SRLs

3. Radiation Therapy

Used as adjunctive therapy after incomplete surgery
Stereotactic radiosurgery (Gamma Knife, CyberKnife) — focused, single-session
Conventional fractionated radiotherapy — over several weeks
Biochemical remission achieved in 50–60% over 5–10 years
Major risk: progressive hypopituitarism (50–80% over 10 years)

Combination Therapy

Many patients require combination therapy — surgery followed by medical therapy, with or without radiation. Treatment plans are individualized based on tumor characteristics, biochemistry, and patient factors.

Living with Acromegaly

What Improves After Treatment

Soft tissue swelling reduces (hands, feet, face become less swollen)
Sweating and headaches improve
Blood sugar control improves or diabetes resolves
Sleep apnea may improve
Cardiovascular risk decreases

What May Not Fully Reverse

Bony changes (jaw enlargement, brow prominence) are permanent
Joint damage (arthropathy) may persist
Some patients require lifelong medication

Long-Term Monitoring

IGF-1 levels — every 6–12 months
MRI pituitary — annually initially, then as needed
Pituitary function testing — annual screening for hypopituitarism
Colonoscopy — every 3–5 years
Echocardiography — periodic cardiac assessment
Diabetes screening — ongoing

The Bottom Line

Acromegaly is a rare but serious condition that often goes undiagnosed for years. Early recognition, accurate biochemical diagnosis, and a multidisciplinary approach (endocrinologist, neurosurgeon, radiation oncologist) are essential for optimal outcomes. With modern treatment, most patients can achieve disease control and significantly improved quality of life.

“If your rings don’t fit, your shoes keep getting bigger, or your face looks different from old photos — don’t ignore it. Acromegaly is rare but very treatable when caught early.”

If you notice progressive changes in your appearance or have been found to have a pituitary mass, consult an endocrinologist for comprehensive evaluation.