History

Fact Explanation
Changes in appearance: Prominent jaw (prognathism), spade like hands and feet with increasing ring/ gloves/ shoe size. [1][2] Only 13% of patients present with these changes even though 98% of patients with acromegaly have these changes. [1]
Joint pain, swelling, reduced joint movements [1] Occurs due to large joint arthropathy due to thickening of cartilages and periarticular fibrous tissue. [1][3]
Abnormal posture: Kyphoscoliosis [1][5] Axial skeleton is already affected in 60% of patients at presentation. This may result in kyphoscoliosis which can cause hypoventilation.[1] This occur due to disk space widening, vertebral enlargement, and osteophyte formation [3]
Thickening of skin, mainly noticed in face, hands, and feet [1] Glycosaminoglycans accumulation causes thickening of skin. [1]
Oily, sweaty skin [1] Due to hypertrophy of sebaceous and sweat glands resulting in hyper-secretion of sebum and sweat respectively. [1]
Pigmented skin tags/ coarse hair [1][3] Skin tags are common in patients with acromegaly. [3]
Upper airways obstruction resulting in sleep apnea/ excessive snoring [1] Maybe due to macroglossia, prognathism, thick lips, and hypertrophy of laryngeal mucosa and cartilage. [1][5]
Features of congestive heart failure: ankle edema, shortness of breath, reduced exercise tolerence. Less than 1% to 10% of patients with acromegaly have obvious features of congestive heart failure. This is due to biventricular cardiac hypertrophy caused by excess GH.[1]
Hypertension [1] It is observed that both systolic and diastolic blood pressure is high with loss of circadian variability in patients with acromegaly. But whether this occurs higher than that in normal population is not clear. [1]
Peripheral neuropathy with symmetrical sensory and motor involvement/ proximal myopathy/ muscle cramps [1] These have been described in patients with acromegaly. Unpleasant paraesthetic symptoms with compelling urge to move the limbs while sleeping (restless leg syndrome) may even result in insomnia, leading to daytime sleepiness and consequently affecting the quality of life.[5]
Carpal tunnel syndrome: poor gripping strength, tingling sensation of thumb, middle, index and radial half of index fingers. [1][4] Wrist joint synovial edema and hypertrophy of ligaments and tendons results in medial nerve compression. [1]
Exophthalmos/ open-angle glaucoma [1] Due to hypertrophy of extraoccular tissues and tissues around Schlemm’s canal. [1]
Hyperprolactinemia with or without galactorrhea: Amennorhea, impotence, abnormal milk secretion Occurs in around 30% of patients with acromegaly. Maybe due to pituitary stalk compression resulting in reduced dopamine secretion which inhibits prolactin secretion or maybe due to a mixed tumor secreting both GH and PRL(prolactin). [1]
Features of hypopituitarism: amenorrhea, impotence, loss of libido/ weight gain, cold intolerence/ weight loss, collapse on fight or flight situations. This result in compression of the normal pitutary tissue leading to involvement of other hormonal axes, resulting in secondary thyroid/ adrenal/ gonadal failure can be evident [1]
Goiter/ hyperthyroidism: weight loss, heat intolerance. [1] Direct stimulation of thyroid gland with IGF-1(insulin like growth factor 1) which increases in response to high GH levels will result in growth of gland, thus leading to goitre and hyperthyroidism, also a pituitary adenoma secreting multiple hormones including GH and TSH (Thyroid stimulating hormone) may also cause this. [1]
Cushing’s disease A pituitary tumor co-secreting both GH and corticotropin or as part of the McCune-Albright syndrome [1]
Insulin resistance/ diabetes mellitus [1] Due to direct anti-insulin effects of GH [1]
Osteoporosis [1] May occur due to secondary gonadal failure (as part of hypopituitarism), it is shown that occurence of vertebral fractures correlates with disease activity.
Headache [1] Due to pituitary tumor.
Visual defects.[1] Visual field defects may occur due to compression of optic chiasma by the pituitary tumor.
References
  1. BEN-SHLOMO Anat, MELMED Shlomo, Acromegaly [online] Endocrinology and Metabolic Clinic of North America. Mar 2008; Volume 37, Issue 1, Page 101–viii. [Viewed on 30/04/2014] Available from: doi: 10.1016/j.ecl.2007.10.002 (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697616/#R51)
  2. D'URZO AD. Case report: acromegaly. [online] Canadian Family Physician. Jun 1997; Volume 43, Pages 1121–1122. [Viewed on 30/04/2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2255260/
  3. KANAKAPURA Giriraja, CHANDRASHEKAR Pavitra, PRABHU Vishnudas. Acromegaly: A Case Report [online] International Journal of Oral & Maxillofacial Pathology. 2012;3(1):38-43 Available from: http://journalgateway.com/ijomp/article/view/246/544
  4. AROORI Somaiah, SPENCE AJ Roy. Carpal tunnel syndrome. [online] Ulster Medical Journal. Jan 2008; 77(1): 6–17. [Viewed on 03/05/2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2397020/
  5. LUGO Gloria, PENA Lara, CORDIDO Fernando. Clinical Manifestations and Diagnosis of Acromegaly [online] International Journal of Endocrinology. 2012; 2012: 540398. [Viewed on 05/05/2014] Available from: doi: 10.1155/2012/540398 (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3296170/)
  6. MELMED Shlomo. Acromegaly [online] New England Journal Medicine 2006; 355:2558-2573 December 14, 2006. [Viewed on: 02/05/2014] Available from: DOI: 10.1056/NEJMra062453 http://www.nejm.org/doi/full/10.1056/nejmra062453

Examination

Fact Explanation
Facial features: Prognathism, jaw malocclusion, frontal bossing, wide nasal bridge, large lips, macroglossia [1][2] Comparison with older pictures would help the clinician to differentiate the facial changes.[6]
Spade like hands and feet. Due to increased soft tissue [1]
Excessive sweat/ sebum Due to hypertrophy of sebaceous and sweat glands resulting in hyper-secretion of sebum and sweat respectively. [1]
Carpel tunnel syndrome: Positive Tinel's sign, Phalen's sign and tourniquet test. Hypalgesia in the thumb, middle, index and radial half of index fingers (median nerve distribution) Poor grip with poor abduction, opposition and flexion of thumb. [4] Wrist joint synovial edema and hypertrophy of ligaments and tendons results in medial nerve compression. [3] Tinel's sign is when tapped on distal wrist crease over median nerve, a tingling sensation or discomfort develops. Phalen's sign reproduce the symptoms when the wrist is flexed. Tourniquet test is when a blood pressure cuff is inflated above systolic pressure paresthesia in distribution of the median nerve occurs. The motor symptoms are due to affected abductor pollicis brevis, opponens pollicis and flexor pollicis brevis which are supplied by median nerve. [4]
Goitre/ Hepatosplenomegaly [2] As a part of generalized visceromegaly due to high GH. Enlarged bones and salivary glands also occur. [2]
Visual field defect [1] suprasellar extension resulting in impingement of optic chiasma, thus earliest visual-field defect occur in superior temporal quadrant. Bitemporal hemianopsia, unilateral temporal hemianopsia may result.[7]
Headache [1] Due to pituitary enlargement. [1]
Joint swelling, joint stiffening, deformities, increased or decreased joint mobility [2][3] Occurs due to large joint arthropathy due to thickening of cartilages and periarticular fibrous tissue. [2][3]
Kyphoscoliosis This occur due to disk space widening, vertebral enlargement, and osteophyte formation [2][3]
Coarse body hair Due to deposition of glycosaminoglycan and increased connective tissue collagen production [2]
Nasal polyps [1] Maybe examined with nasal speculum.
Pigmented skin tags [3] Skin tags are thought to be markers for the presence of adenomatous colonic polyps.[2]
Features of congestive heart failure: ankle edema, pulmonary fine basal crepitations. Biventricular cardiac hypertrophy caused by excess GH as it is seen independent to hypertension. [3][5]
High blood pressure [1] Hypertension is commonly associated.
References
  1. MELMED Shlomo. Acromegaly [online] New England Journal Medicine 2006; 355:2558-2573 December 14, 2006. [Viewed on: 02/05/2014] Available from: DOI: 10.1056/NEJMra062453 http://www.nejm.org/doi/full/10.1056/nejmra062453
  2. KANAKAPURA Giriraja, CHANDRASHEKAR Pavitra, PRABHU Vishnudas. Acromegaly: A Case Report [online] International Journal of Oral & Maxillofacial Pathology. 2012;3(1):38-43 Available from: http://journalgateway.com/ijomp/article/view/246/544
  3. BEN-SHLOMO Anat, MELMED Shlomo, Acromegaly [online] Endocrinology and Metabolic Clinic of North America. Mar 2008; Volume 37, Issue 1, Page 101–viii. [Viewed on 30/04/2014] Available from: doi: 10.1016/j.ecl.2007.10.002 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697616/#R51
  4. NEMERGUT C Edward, DUMONT S Aaron, BARRY T Usha, LAWS R Edward. Perioperative Management of Patients Undergoing Transsphenoidal Pituitary Surgery [online] Anesthesia and Analgesia 2005;101:1170 –81 [Viewed on 30/04/2014] Available from: http://anesthesiology.unm.edu/_Docs/neuro/TransPituitary.pdf
  5. DUNCAN E, WASS JAH. Investigation protocol: Acromegaly and its investigation [online] Clinical Endocrinology 1999 50: 285–293. [Viewed on 02/05/2014] Available from: doi: 10.1046/j.1365-2265.1999.00615.x http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2265.1999.00615.x/full
  6. KAPOOR Shailendra, Correspondence to Acromegaly [online] New England Journal of Medicine 2007; 356:1274-1276 March 22, 2007 [Viewed on 02/05/2014] Available from: DOI: 10.1056/NEJMc070019 http://www.nejm.org/doi/full/10.1056/NEJMc070019

Differential Diagnoses

Fact Explanation
Pituitary GH-secreting adenomas [1] ~98% of acromegaly; generally benign GH alone or co secretion with prolactin (PRL), or plurihormonal adenomas secreting PRL, thyrotropin, corticotropin, gonadotropins [follicle-stimulating hormone (FSH) and luteinizing hormone (LH)], and α subunit are present. [1]
Metastatic pituitary carcinoma secreting GH [1] These are extremely rare
Multiple endocrine neoplasia type 1 [1][2] This is due to germ cell inactivation of the MENIN tumor suppressor gene resulting in pituitary, parathyroid, and pancreatic tumors. [1]
McCune-Albright syndrome [1][2] This occurs due to Gsα mutation, patient may have typical clinical appearance due to polyostotic fibrous dysplasia and cutaneous pigmentation along with pituitary hypersecretion. [1]
Carney complex [1] This is due to PRKAR1A gene mutations, patient have typical clinical appearance of skin pigmentation, mucocutaneous mixomatosis, they will also have cardiac myxoma, thyroid and breast involvement and GH-secreting pituitary adenoma.[1]
Isolated familial acromegaly [1] Due to loss of heterozygosity in chromosome 11q13. [1]
Hypothalamic hamartoma, choristoma, ganglioneuroma [1][2] May result in GHRH oversecretion
Peripheral neuroendocrine tumors of lungs or pancreas. [1][2] May result in GHRH oversecretion
Exogenous administration of GH to patients who are not GH-deficient [1] Exogenous GH has is sometimes used in athletic performance enhancer or anti-aging treatment, where it may cause acromegaly. [1]
Laron's syndrome [1] Abnormality is in the GH receptor gene resulting in GH resistance. There will be high GH levels owing to low IGF-1, due to low IGF 1 patient present with growth failure.[1]
References
  1. BEN-SHLOMO Anat, MELMEDV Shlomo, Acromegaly [online] Endocrinology and Metabolic Clinic of North America. Mar 2008; Volume 37, Issue 1, Page 101–viii. [Viewed on 30/04/2014] Available from: doi: 10.1016/j.ecl.2007.10.002 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697616/
  2. DUNCAN E, WASS JAH. Investigation protocol: Acromegaly and its investigation [online] Clinical Endocrinology 1999 50: 285–293. [Viewed on 02/05/2014] Available from: doi: 10.1046/j.1365-2265.1999.00615.x http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2265.1999.00615.x/full

Investigations - for Diagnosis

Fact Explanation
GH serum levels 2 hours following 75-g oral glucose tolerance test (OGTT) [1] Nadir levels <1 μg/L of growth hormone per liter rule out the diagnosis but in ultrasensitive growth hormone assays it should preferably be <0.3 μg/L. GH secretion has a circadian periodicity and is secreted in pulses and affected by exercise, starvation, and blood glucose levels. Thus post OGTT 2 hour value is measured standardly.[1]
IGF-I levels GH may not be suppressed by glucose in patients with liver/ renal disease, uncontrolled diabetes, malnutrition, pregnancy, on estrogen therapy, in late adolescence. Thus, IGF-I levels are measured as they mark the GH activity. [2]
Magnetic resonance imaging (MRI) of the pituitary gland contrast Adenomas that are more than 2 mm in diameter can be visualized; tumor dimensions, invasive nature, and optic tract impingement can also be described. More than 75% of patients with acromegaly have macroadenoma (Tumor diameter>10 mm) [1][2]
Abdominal and chest computed tomography/ MRI When MRI of pituitary gland is normal and nonpituitary cause of excess Gh or GH–releasing hormone is suspected abdominal and chest CT/ MRI is done to find the source of ectopic secretion.[1][2]
References
  1. BEN-SHLOMO Anat, MELMEDV Shlomo, Acromegaly [online] Endocrinology and Metabolic Clinic of North America. Mar 2008; Volume 37, Issue 1, Page 101–viii. [Viewed on 30/04/2014] Available from: doi: 10.1016/j.ecl.2007.10.002 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697616/#R51
  2. MELMED Shlomo. Acromegaly [online] New England Journal Medicine 2006; 355:2558-2573 December 14, 2006. [Viewed on: 02/05/2014] Available from: DOI: 10.1056/NEJMra062453 http://www.nejm.org/doi/full/10.1056/nejmra062453

Investigations - Fitness for Management

Fact Explanation
Fasting blood sugar [2] Hyperglycaemia is often associated with acromegaly and should be controlled prior to surgery.
2D echocardiogram [1] Not routinely recommended, but should be done if symptoms of heart failure is suspected. [4]
ECG [1] Supraventricular and ventricular ectopy, bundle branch blocks, ST segment depression, T-wave abnormalities, and conduction defects are commonly seen in patients with acromegaly. [1]
Preoperative airway assessment [1] This should be done by experiencded anesthetist as intubation maybe very difficult. [1]
Thyroid function test/ Adrenal function test Thyroid and adrenal axis may also be affected in acromegaly and it should be tested and treated if necessary before surgery. [4]
Full blood count, chest x-ray, renal function tests, blood gases, lung function [3] Full blood count is done as a basic investigation pre operatively and others should be done according to patient's symptoms and according to the ASA (American society of anesthesiologists) category patient falls in. [3]
Visual field assessment Can be done to detect any visual problems if there is optic chiasma involement as seen in MRI or if patient complains of visual defects.[4]
References
  1. NEMERGUT C Edward, DUMONT S Aaron, BARRY T Usha, LAWS R Edward. Perioperative Management of Patients Undergoing Transsphenoidal Pituitary Surgery [online] Anesthesia and Analgesia 2005;101:1170 –81 [Viewed on 30/04/2014] Available from: http://anesthesiology.unm.edu/_Docs/neuro/TransPituitary.pdf
  2. BEN-SHLOMO Anat, MELMEDV Shlomo, Acromegaly [online] Endocrinology and Metabolic Clinic of North America. Mar 2008; Volume 37, Issue 1, Page 101–viii. [Viewed on 30/04/2014] Available from: doi: 10.1016/j.ecl.2007.10.002 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697616/#R51
  3. Preoperative Tests: The Use of Routine Preoperative Tests for Elective Surgery. NICE Clinical Guidelines, No. 3. [online] London: National Collaborating Centre for Acute Care (UK); 2003 Jun [Viewed on 30/04/2014] Available from: http://www.ncbi.nlm.nih.gov/books/NBK48482/
  4. KATZNELSON Laurence, ATKINSON John LD, COOK David M et al. American Association of Clinical Endocrinologists Medical Guidelines for Clinical Practice for the diagnosis and treatment of acromegaly. [online] Endocr Pract. 2011;17(Suppl 4) [Viewed on 05/05/2014] Available from: https://www.aace.com/files/acromegaly-guidelines.pdf

Investigations - Followup

Fact Explanation
Post OGTT GH levels(2 hour value)/ IGF 1 levels [1] For symptomatic patients these investigations should be done quarterly until the disease is inactive, after which annual follow up is necessary to detect recurrence regardless of the treatment method used.[1][2] Note that if patient has undergone radiotherapy IGF-I levels attenuate very slowly and maximal control of GH may take upto 15 years or even more.[1] Even if IGF 1 is normal if there is persistent subtle elevations of GH level recurrence could be suspected. [1]
Pituitary MRI [1] Should be done annually and the tumor mass should be monitored continuously. [1] If on Pegvisomant (GH receptor antagonist) this should be done 6 monthly to detect tumor growth, if present. [1]
Gallbladder ultrasonogram Should be done while on somatostatin receptor ligands (SRL), if signs and symptoms pointing towards cholelithiasis or cholecystitis occur, since SRL are known to cause gallbladder sludge and gallstones. [1][2]
Liver function tests (LFT) [1] LFT should be done if patient is on Pegvisomant (GH receptor antagonist), monthly for the first 6 months, followed by every 6 months thereafter, since elevated hepatic aminotransferase levels have been reported.[1]
Where necessary, 2D echocardiogram/ ECG/ fasting blood sugar/ X ray skull/ pulmonary function should be monitored. [1][2] To monitor disease complications, these investigations should be done if patient is symptomatic and should be followed up according to the initial findings. Heart failure, reduced pulmonary functions are life threatening conditions associated with acromegaly. Stroke volume, cardiac output, ventricular mass can be monitored with 2D echocardiogram; diastolic dysfunction is often seen while systolic function is generally preserved in acromegaly. [3]
References
  1. MELMED Shlomo. Acromegaly [online] New England Journal Medicine 2006; 355:2558-2573 December 14, 2006. [Viewed on: 02/05/2014] Available from: DOI: 10.1056/NEJMra062453 http://www.nejm.org/doi/full/10.1056/nejmra062453
  2. BEN-SHLOMO Anat, MELMEDV Shlomo, Acromegaly [online] Endocrinology and Metabolic Clinic of North America. Mar 2008; Volume 37, Issue 1, Page 101–viii. [Viewed on 30/04/2014] Available from: doi: 10.1016/j.ecl.2007.10.002 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697616/#R51
  3. NEMERGUT C Edward, DUMONT S Aaron, BARRY T Usha, LAWS R Edward. Perioperative Management of Patients Undergoing Transsphenoidal Pituitary Surgery [online] Anesthesia and Analgesia 2005;101:1170 –81 [Viewed on 30/04/2014] Available from: http://anesthesiology.unm.edu/_Docs/neuro/TransPituitary.pdf

Investigations - Screening/Staging

Fact Explanation
Colonoscopy [1] Total colonoscopy is required rather than sigmoidoscopy. Patients with adenoma at first screening colonoscopy and those with increased serum IGF-1 level should undergo colonoscopy every three years. The frequency maybe increased depending on colonoscopic findings. Patients with negative first colonoscopy or if only a hyperplastic polyp is present colonoscopy at five year intervals should be done. Regular colonoscopic screening should be provided to all patients with inactive disease as general population. [1]
Screening for breast/ prostate cancer: Mammography/ measurement of prostate-specific antigen(PSA) In patients with inactive disease these tests should be performed according to guidelines for the general population [2]
Computed tomography to screen presence of coronary artery calcifications. [3] The Framingham score of acromegaly patients are calculated (according to their risk factores) and if at risk this investigation is carried out. Along with diabetes, hypertenstion, increased media thickness is also thought to play a role in increasing cardiovascular risk in these patients. They also have elevated triglyceride levels. [3][4]
References
  1. JENKINS PJ, FAIRCLOUGH PD. Screening guidelines for colorectal cancer and polyps in patients with acromegaly. [online] Gut 2002; Volume 51: Issue 5 [Viewed on 30/04/2014] Available from: doi:10.1136/gut.51.suppl_5.v13 http://gut.bmj.com/content/51/suppl_5/v13.full
  2. BEN-SHLOMO Anat, MELMEDV Shlomo, Acromegaly [online] Endocrinology and Metabolic Clinic of North America. Mar 2008; Volume 37, Issue 1, Page 101–viii. [Viewed on 30/04/2014] Available from: doi: 10.1016/j.ecl.2007.10.002 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697616/#R51
  3. LUGO Gloria, PENA Lara, CORDIDO Fernando. Clinical Manifestations and Diagnosis of Acromegaly [online] International Journal of Endocrinology. 2012; 2012: 540398. [Viewed on 05/05/2014] Available from: doi: 10.1155/2012/540398 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3296170/
  4. NEMERGUT C Edward, DUMONT S Aaron, BARRY T Usha, LAWS R Edward. Perioperative Management of Patients Undergoing Transsphenoidal Pituitary Surgery [online] Anesthesia and Analgesia 2005;101:1170 –81 [Viewed on 30/04/2014] Available from: http://anesthesiology.unm.edu/_Docs/neuro/TransPituitary.pdf

Management - General Measures

Fact Explanation
Medical management of heart failure, hypertension, hyperglycaemia should be undertaken if present. Overt heart failure has poor prognosis and medical mangement of it is of utmost priority since it may cause death. [1]
Patient counselling Regarding disease, facial changes and fertility should be addressed. Educational materials would help patient to understand the disease and make decisions regarding the treatment. Help of a support group with a professional facilitator would be ideal. [2]
Cosmetic or functional maxillofacial surgery [2] Maybe necessary in severe sleep apnoea or if patient demands.
References
  1. DUTTA P, DAS S, BHANSALI et al. Congestive heart failure in acromegaly: A review of 6 cases [online] Indian J Endocrinol Metab. 2012 Nov-Dec; 16(6): 987–990. [Viewed on: 05/05/2014] Available from: doi: 10.4103/2230-8210.103007 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3510973/#!po=43.7500
  2. MELMED Shlomo. Acromegaly [online] New England Journal Medicine 2006; 355:2558-2573 December 14, 2006. [Viewed on: 02/05/2014] Available from: DOI: 10.1056/NEJMra062453 http://www.nejm.org/doi/full/10.1056/nejmra062453

Management - Specific Treatments

Fact Explanation
Surgery Indicated in growth hormone–secreting microadenomas and for adenoma with mass effects.[1] Endoscopic transsphenoidal and transnasal pituitary surgery are available. Small tumors (less than 10 mm in diameter) and growth hormone level <40 μg/L will benefit with transsphenoidal surgery. Intraoperative MRI and endoscopic approaches improves the surgical outcome. [1][2] ~10% of tumors recur, mainly due to persistent growth of nonresectable residual tumor. Tumors with cavernous sinus invasion cannot be completely resected thus GH will be persistently elevated. [1] Presurgical hypopituitarism improved in 30%, did not change in 50%, and worsened in 2% of patients after transsphenoidal adenomectomy. [2]
Radiotherapy: Conventional external-beam radiotherapy Indicated in persistant and recurring tumors after surgery and in patients with resistance to or intolerant to medical treatment. This has to be administered over a period of several week.[1] IGF-I levels decreases very slowly and maximal control of the secretion of GH require >15 years. Within 10 years after therapy, ~50% of patients develop hypopituitarism involving one or more axis.[1]
Radiotherapy: Stereotactic radiosurgery with the use of gamma knife Precise delineation of tumor mass is done by advanced computarized imaging, thus minimizing radiation effect on surrounding tissues.[1] Serum IGF-1 levels normalized within 54 months and hypopituitarism develops only when irradiated by ≥15 Gy [2]
Somatostatin receptor ligands(SRL): octreotide/ lanreotide Indicated after failed surgery and after radiotherapy while GH levels are still elevated. Primary medical treatment is effective and safe thus, can be offered to patients with large extrasellar tumors without compressive effects, and to patients who can't/ do not want to undergo surgery.[1] They bind to somatostatin( growth hormone-inhibiting hormone (GHIH)) receptors and suppress GH secretion, proliferation of somatotroph cells and block the synthesis of IGF-I in liver [1] Octreotide oral(50–400 μg every 8 hours) and long acting intramuscular preparations(10–40 mg IM every 4 weeks) are available where as lanreotide slow releasing intramuscular preparations (30 or 60 mg IM every 10 or 14 or 21 days) lanreotide gel for subcutaneous injections (60, 90, or 120 mg deep SC every 4 weeks) can be used. [1][2] Tumor shrinkage occurs in ~ 50% of patients but reverses when drug is discontinued[1]
Pasireotide (SOM230) This drug is currently under clinical trials. It selectively activate somatostatin receptors resulting in additive suppression of GH thus it suppresses GH levels in patients who are resistant to octreotide.[1]
Pegvisomant: a Growth Hormone–Receptor Antagonist Indicated in patients with resistance to or intolerant to somatostatin analogues. Daily injection of 40 mg is given. [1] Combined treatment with SRL and a growth hormone–receptor antagonist is effective as this reduces IGF 1 levels and improves glucose tolence. (SRL alone causes abnormality of glucose metabolism.)[1][2] GH will increase because of loss of negative feedback by lower IGF-I levels. Thus, IGF-I levels rather than GH levels should be used in monitoring treatment response. [1][2]
Dopamine receptor agonists: cabergoline Poor efficacy when compared with other drugs. Combination with SRL is used where patient shows resistance to maximal doses of SRL. Cabergoline is also effective where tumors co-secretes prolactin.[1][2]
References
  1. MELMED Shlomo. Acromegaly [online] New England Journal Medicine 2006; 355:2558-2573 December 14, 2006. [Viewed on: 02/05/2014] Available from: DOI: 10.1056/NEJMra062453 http://www.nejm.org/doi/full/10.1056/nejmra062453
  2. BEN-SHLOMO Anat, MELMEDV Shlomo, Acromegaly [online] Endocrinology and Metabolic Clinic of North America. Mar 2008; Volume 37, Issue 1, Page 101–viii. [Viewed on 30/04/2014] Available from: doi: 10.1016/j.ecl.2007.10.002 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697616/#R51