Frequent serum GH measurements in normal subjects (left panel) demonstrate that GH can fluctuate between undetectable levels most of the time interspersed with peaks of up to 30 μg/L (90 mIU/L); in acromegaly (right panel) GH hypersecretion is continuous with no undetectable levels. If acromegaly is suspected, medical laboratory investigations followed by medical imaging if the lab tests are positive confirms or rules out the presence of this condition. IGF1 provides the most sensitive lab test for the diagnosis of acromegaly, and a GH suppression test following an oral glucose load, which is a very specific lab test, will confirm the diagnosis following a positive screening test for IGF1. A single value of the GH is not useful in view of its pulsatility (levels in the blood vary greatly even in healthy individuals).Magnetic resonance image of a pituitary macroadenoma that caused acromegaly with compression of the optic chiasm GH levels taken 2 hours after a 75- or 100-gram glucose tolerance test are helpful in the diagnosis: GH levels are suppressed below 1 μg/L in normal people, and levels higher than this cutoff are confirmatory of acromegaly. Other pituitary hormones must be assessed to address the secretory effects of the tumor, as well as the mass effect of the tumor on the normal pituitary gland. They include thyroid stimulating hormone (TSH), gonadotropic hormones (FSH, LH), adrenocorticotropic hormone, and prolactin. An MRI of the brain focusing on the sella turcica after gadolinium administration allows for clear delineation of the pituitary and the hypothalamus and the location of the tumor. A number of other overgrowth syndromes can result in similar problems. Differential diagnosis Pseudoacromegaly is a condition with the usual acromegaloid features, but without an increase in growth hormone and IGF-1. It is frequently associated with insulin resistance. Cases have been reported due to minoxidil at an unusually high dose. It can also be caused by a selective post receptor defect of insulin signalling, leading to the impairment of metabolic, but preservation of mitogenic, signalling.
symptom of Congenital generalized lipodystrophy
symptom of Laron syndrome
symptoms of Rotor syndrome
symptom of Prader–Willi syndrome
picture of Congenital hypothyroidism
symptom of Scheuermann's disease
symptom of Maroteaux–Lamy syndrome
symptom of Rotor syndrome