Thursday, April 9, 2009

Essentials of Endocrinology -part 1

Muscle weakness in the absence of neurological diseases, is a feature of severe metabolic disorders like cushing syndrome,thyrotoxicosis,and vitamin D deficiency. Almost all cases of metabolic myopathies can have proximal muscle weakness especially the shoulder and hip girdle musculature. Symptomatically it is presented as difficulty in climbing stairs or rising from sitting posture. Out of all these conditions, vitamin D deficiency ,osteomalacia and hypothyroidism are painful myopathies.

Hyperhydrosis (increased sweating) may present as a constitutional abnormality. More recent increase in sweat secretion may be an early indication of thyroid overactivity. One must also consider Pheochromocytoma, a rare cause of hyperhydrosis.In autonomic dysfunction,there is an intermittent sweating pattern after meals(gustatory hyperhydrosis).Growth hormone excess(Acromegaly) can also have increase sweating.A case of hyperhydrosis has to be differentiated from flushing which is a common feature in menopausal age group.Flushing may be a presenting symptom in Seratonin secreting carcinoid tumors of gut .

Tremor:In Anxiety, the pattern of tremor is coarse and irregular with cold peripherals whereas in thyrotoxicosis, it is fine rapid resting tremor (with warm skin). Tremor in neurological diseases may present at rest with greater amplitude and slower rate.It may either present at rest(parkinson’s diseases) or in motion(cerebellar intention tremor)

Dizziness or postural unsteadiness on standing: Postural hypotension (a fall of diastolic blood volume on standing occurs with reduced blood volume.) may be the reason for majority of cases.But, in the absence of bleeding or gastrointestinal fluid loss adrenal insufficiency may be the common possibility. In long standing diabetis mellitus, postural hypotension may occur due to autonomic neuropathy.Moreover, it can also occur as a common complication of any hypertensive drug for essential hypertension.

Weight loss is the single most differentiating feature of insulin dependent diabetis from non insulin dependent diabetis.Thyroid over activity is always associated with a combination of increased appetite and weight loss in which the appetite may be stimulated more. Another common cause of weight loss in young little girls is anorexia nervosa where there is a peculiar history of low body weight in the absence of other features of illhealth.

Weight gain occurs as a result of reduced metabolic rate. So, it is a common feature of primary hypothyroidism.In Cushing syndrome,the pattern is truncal obesity and paradoxical thinning of the limbs.Occasionaly increased body weight can be a feature of hypothalamic lesions

Cold intolerance: A feature of hypothyroidism which has to differentiated from Raynauds diseases which is due to localized vasomotor symptoms(Vasospasm)

Source and links: Hutchison's clinical method,endocrineweb

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