Acromegaly & gigantism

1. ACROMEGALY & G IGANTISM BY : RITWAN BIN TAPENG

2. ACROMEGALY DEFINITION Chronic metabolic disorder in which there is too much growth hormone and the body tissue gradually enlarge

3. PATHOPHYSIOLOGY Acromegaly is characterized by hypersecretion of growth hormone (GH), which is caused by the existence of a secreting pituitary tumor in more than 95% of acromegaly cases. Pituitary tumors are benign adenomas and can be classified according to size ( microadenomas being less than 10 mm in diameter and macroadenomas being greater than 10 mm in diameter).3,4 In rare instances, elevated GH levels are caused by extra pituitary disorders. In either situation, hypersecretion of GH in turn causes subsequent hepatic stimulation of insulin-like growth factor-1 (IGF-1).1

4. SYMPTOMS Body odor Carpal tunnel syndrome Decrease muscle strength ( weakness ) Easy fatique Enlarge feet Enlarge hands Enlarge glands in the skin ( sebaceous glands ) Enlarge jaw and tongue Excessive height Excessive sweating

5. SYMPTOMS ( cont … ) Headdache Hoarseness Joint pain Limited joint movement Sleep apnea Swelling of bony areas around a joint Thickening of skin, skin tags Widely spaced teeth Excess hair growth in females Weight gain

6. DIFFERENTIAL DIAGNOSIS Pseudoacromegaly Presence of similar acromegaloid features in the absence of elevated GH or IGF-I levels Physiologic growth spurt during puberty Familial tall stature or large hands and feet Myxedema

7. INVESTIGATION Visual field tests Assessment of other pituitary hormones: prolactin, adrenal, thyroid, and gonadal hormones MRI scan of pituitary and hypothalamus: more sensitive than CT scan CT scan: for lung, pancreatic, adrenal or ovarian tumours that may secrete ectopic growth hormone or GHRH Total body scintigraphy with radio-labelled OctreoScan ® ( somatostatin ) to aid localisation of the tumour Cardiac assessment: electrocardiogram, echocardiogram

8. PROGNOSIS Pituitary surgery is successful in most patient, depending on the size of the tumor and the experience of the surgeon Without treatment the symptoms will get worse,a nd the risk of cardiovascular disease increase

9. COMPLICATIONS Arthritis Cardiovacular disease Carpal tunnel syndrome Colonic polyps Glucose intolerance or diabetes High blood pressure Sleep apnea Spinal cord compression Uterine fibroids Vision abnormalities

10. REFERENCES http:// onlinelibrary.wiley.co http:// www.harrisonspractice.com/practice/ub/view/Harrisons%20Practice/141312/2.0/acromegaly http:// www.patient.co.uk/doctor/Acromegaly.htm http:// www.acromegalyinfo.com/health-care-professional/epidemiology-pathophysiology.jsp

11. GIGANTISM DEFINITION Abnormally large growth due to an excess of growth hormone during childhood, before the bone growth plates have closed.

12. CAUSES The most common cause of too much growth hormone release is a noncancerous (benign) tumor of the pituitary gland. Other causes include: Carney complex McCune-Albright syndrome (MAS) Multiple endocrine neoplasia type 1 (MEN-1) Neurofibromatosis If excess growth hormone occurs after normal bone growth has stopped, the condition is known as acromegaly .

13. SYMPTOMS Delayed puberty Double vision or difficulty with side (peripheral) vision Frontal bossing and a prominent jaw Headache Increased sweating Irregular periods (menstruation) Large hands and feet with thick fingers and toes Release of breast milk Thickening of the facial features Weakness

14. EXAMS & TESTS CT or MRI scan of the head showing pituitary tumor Failure to suppress serum growth hormone (GH) levels after an oral glucose challenge (maximum 75g) High prolactin levels Increased insulin growth factor-I (IGF-I) levels Damage to the pituitary may lead to low levels of other hormones, including: Cortisol Estradiol (girls) Testosterone (boys) Thyroid hormone

15. TREATMENT Medical treatments of gigantism Medications may be used to reduce GH release, block the effects of GH, or prevent growth in stature. They include: Dopamine agonists, such as bromocriptine mesylate ( Cycloset , Parlodel ) and cabergoline ( Dostinex ), which reduce GH release GH antagonist, pegvisomant ( Somavert ), which blocks the effects of GH Sex hormone therapy, such as estrogen and testosterone, which may inhibit the growth of long bones Somatostatin analogs, such as octreotide ( Sandostatin ) and long-acting lanreotide ( Somatuline Depot), which reduce GH release

16. TREATMENT ( cont … ) Other treatments of gigantism Radiation of the pituitary gland to regulate GH. This is generally considered the least desirable treatment option because of its limited effectiveness and side effects that can include obesity , emotional impairment, and learning disabilities Surgery to remove a pituitary tumor, which is the treatment of choice for well-defined pituitary tumors

17. PROGNOSIS Pituitary surgery is usually successful in limiting growth hormone production.

18. COMPLICATIONS Delayed puberty Difficulty functioning in everyday life due to large size and unusual features Diminished vision or total vision loss Embarrassment, isolation, difficulties with relationships, and other social problems Hypothyroidism Severe chronic headaches Sleep apnea

19. REFERENCES http:// health.nytimes.com/health/guides/disease/gigantism/overview.html http:// www.localhealth.com/article/gigantism/treatments http:// emedicine.medscape.com/article/925446-overview http:// www.scientificamerican.com/article.cfm?id=what-causes-gigantism-sandy-allen http:// www.yourhormones.info/endocrine_conditions/gigantism.aspx