Acromegaly
Definition: It is a Hormonal Disorder that develops due to hypersecretion of GH in adulthood, after the epiphyseal closure of bones, which cause an increase in size (girth) of bones, including that of face, hands and feet
Incidence:
- Annual incidence= 3-4cases/million population
- Prevalence= 60-70 cases/million population
- Male=female
- Mean age of presentation Males-42yrs, Females-44yrs
Pathogenesis: There are several reasons for overproduction of GH. The most common reason is the presence of a Pituitary Adenoma (In more than 95% of people with acromegaly), which is a benign tumor of the pituitary gland. These tumors produce excess GH. When there is too much growth hormone in the body, these tissues grow larger than normal. This excessive growth can cause serious disease and even premature death. The other causes are not by pituitary tumors but by tumors of the pancreas, lungs, and other parts of the brain, which they are rare. These tumors also lead to excess GH, either because they produce GH themselves or, more frequently, because they produce GHRH, the hormone that stimulates the pituitary to make GH. When these non-pituitary tumors are surgically removed, GH levels fall and the symptoms of acromegaly improve.
Clinical Features: Mnemonic: ICONIC-J
- Increased sweating: sweat glands enlarge
- Colonic polyps, including increased risk of colon cancer
- Obstructive sleep apnea
- Nerve entrapment such as carpal tunnel from surrounding tissue pressing on the nerves
- Anti-insulin effects: Hyperglycemia, hyperlipidemia
- Cardiomyopathy
- Joint pain: bones and joints grow out of alignment
Investigations:
1. Biochemical-
- GH Levels- basal GH levels done at 0900hrs in fasting 24hr mean GH levels
- OGTT- GH levels Atleast 1 sample in normal population has levels suppression of 2.0 (<0.5U/L) Active disease… suppression/ undetectable level/ paradoxical rise
- IGF-1 Levels: investigation of choice- increased IGFBP-3 Levels- diagnostic as well as prognostic
- GHRH Levels
- Urinary GH levels
- Thyrotrophin Releasing Hormone
- GnRH levels
- Dopaminergic test Dopamine infusion 4microg/ml/min for 3hrs or bromocriptine 2.5mg oral
- Normal: increase GH levels paradoxical fall in GH levels
- Somatostatin Analogues Somatostatin or octreotide- fall of GH in somatotroph adenoma
2.Others
- MRI BRAIN: Pituitary glan, hypothalamus, cavernous sinus, optic chiasma
- Visual acuity
- Pituitary function- anterior and posterior
- ACTH- Adrenal axis
- TSH-Thyroid axis
- ECG
- CXR
- KFT
- SERUM.electrolyte If kft n electrolyte altered- look.for hypercalcaemia to rule out MEN-1
- Pulmonary Function Test
- ECHO L. Colonoscopy(in case of symptoms)
Treatment:
- Surgery.- Patients with small tumors (less than 10 mm in diameter) and growth hormone levels of less than 40 μg per liter should do well with transsphenoidal surgery, provided the neurosurgeon is experienced 6.7
- Radiotherapy.- is generally reserved for tumors that have recurred or persisted after surgery in patients with resistance to or intolerance of medical treatment
- Receptor Targets for Medical Therapy: – Somatostatin Receptor Ligands – Growth Hormone–Receptor Antagonist – Dopamine Receptor Agonists
