SPOTTERS MEDICINE
GIGANTISM
🔹 Definition:
Gigantism is a rare condition caused by excessive
secretion of growth hormone (GH) before epiphyseal closure (i.e., in
children and adolescents), leading to abnormally increased linear growth and
tall stature.
🔹 Cause:
- GH-secreting pituitary adenoma (most common)
- Hypothalamic GHRH-secreting
tumors (rare)
- Genetic conditions (e.g.,
McCune-Albright syndrome)
- MEN-1 syndrome (rarely
associated)
🔹 Pathophysiology:
- Excess growth hormone →
increased IGF-1 from liver
- IGF-1 stimulates epiphyseal
growth plates →
excessive height and size
- Affects long bones, soft
tissues, and visceral organs
🔹 Clinical Features:
🔸 General Features:
- Tall stature beyond genetic potential
- Large hands and feet
- Broad facial features
- Mandibular prognathism (enlarged jaw)
- Macroglossia (enlarged tongue)
🔸 Systemic Symptoms:
- Hyperhidrosis (excessive
sweating)
- Headache, visual field defects (due to pituitary tumor
compression)
- Delayed puberty or hypogonadism
- Joint pains and fatigue
- Insulin resistance / Diabetes
mellitus
- Hypertension and cardiomegaly
🔹 Diagnosis:
🔸 Hormonal Tests:
- Elevated serum IGF-1
- Oral glucose suppression test: GH fails to suppress
- Elevated GH levels (but may vary
due to pulsatile secretion)
🔸 Imaging:
- MRI brain – shows pituitary adenoma
- Bone X-rays – open epiphyseal plates,
increased bone length
🔹 Differential Diagnosis:
- Marfan’s syndrome (tall, thin
with hypermobility)
- Klinefelter’s syndrome (tall
males with hypogonadism)
- Constitutional tall stature
(familial)
🔹 Treatment:
🔸 Medical:
- Somatostatin analogs (e.g., Octreotide) – suppress
GH
- GH receptor antagonists (e.g., Pegvisomant)
- Dopamine agonists (e.g., Cabergoline – adjunct)
🔸 Surgical:
- Transsphenoidal removal of
pituitary tumor
– first-line in most cases
🔸 Radiotherapy:
- For residual or inoperable
tumors
🔹 Complications:
- Diabetes mellitus
- Cardiomyopathy and hypertension
- Pituitary apoplexy
- Psychological and social
difficulties due to extreme height
- Arthropathy (joint problems due
to weight and size)
🔹 Prognosis:
- Good with early treatment
- Untreated gigantism leads to severe
morbidity and reduced lifespan
- Requires long-term follow-up for
endocrine and growth monitoring
DR.C.GANESAN M.D.
PROFESSOR OF MEDICINE
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