Acromegaly and Gigantism

Question 1

What is Acrogmegally/Gigantism ?

Answer 1

Excess release/production of growth hormone from the pituitary gland or from ectopic secretion, leads to release of insulin like growth factors causing an increased growth (of skeletal and organ systems).

Growth Hormone stimulates insulin like growth factor release causing bone and soft tissue growth

In children, this causes increased growth of all bones (long bones have not undergone endochondral ossification). Leads to increased height etc, gigantism.

In adults, this increased growth is associated with widening of flat bones, no endochondral ossification, and acromegaly

Question 2

What are the causes of Acrogmegally/Gigantism ?

Answer 2

Pituitary Adeonmoma (99% of cases)
Pituitary carcinoma
Ectopic GH release (lung cancer, cancer of the pancreas or ovarian cancer)
Hypothalamic Lesion

Question 3

What are the symptoms of Acrogmegally?

Answer 3

Symptoms: 
Sweating
Headache (independent of tumour size)
Tiredness and lethargy
Carpal Tunnel 
Effects of a mass in the pituitary fossa (visual field defects, hypopituitarism, headaches)
Typical Physical Features 
Joint problems 

Risk Factors:

Specific Questions To Ask:
Osteoarticular complications of acromegally: arthropathy, osteoarthritis
Cardiovascular complications of acromegally: : HTN, hypertrophic cardiomyopathy, arrhythmias, CHF
Metabolic complications of acromegally: : impaired glucose tolerance, diabetes mellitus
Increased risk of colon cancer so ask about features

Differentials:

Question 4

What are the signs of Acrogmegally?

Answer 4

End of the bed:
Deep voice
Skin darkening

Hands:
Carpal tunnel syndrome
Enlarged hands - Spade like
Hypertension

Neck:
Organomegally - Goitre
Acanthosis Nigracans - Back of neck

Face:
Characteristic facial appearance - wide nose, big supraorbital ridges, macroglossia (big tongue), wide teeth, large jaw
Lower Jaw sticking out - Prognathism
Forehead sticking out - frontal bossing

Chest:
Acanthosis Nigracans - Armpits

Abdomen:
Hepatosplenomegally

Legs:
Enlarged feet

Question 5

What investigations will you order in suspected Acrogmegally?

Answer 5

Bedside:
Urine Dipstick - looking for glucose

Bloods:
Serum insulin-like growth factor 1 (IGF-1) - Will be elevated and used as initial screen
Oral Glucose Tolerance test - GH is normally inhibited by glucose. If the glucose load fails to suppress the GH level below 1.0 mcg/L this confirms the diagnosis of acromegaly.
Bloods to check other pituitary functions - TSH/T4, Prolactin, FSH, LH, GH, IGF-1

Imaging:
MRI scan of pituitary and hypothalamus
CT Chest, Abdo, Pelvis only if no found cause – as this indicates it is ectopic secretion

Assessment of other pituitary hormones as clinically indicated: prolactin, adrenal, thyroid and gonadal hormones.

Question 6

What is the management of acromegally?

Answer 6

Lifestyle:
Yearly check ups with GH levels

Surgical:
1st line - Transphenoidal Surgery to remove tumour

Medical:
2nd Line - Radiotherapy can be used in place if surgery unsuitable or non curative
3rd Line - Somatostatin analogues only used if surgery not available/didn’t work or GH receptor blockers