sodium and its medical importance for medical students

sodium

Dr.M.Siva kumar Reddy MD,Department of Biochemistry

Sri Venkateswara Medical College

often touted as a nutrition villain

Sodium-chief cation of ECF

total body sodium

50% in bone

40% in ECF

10% in soft

tissues

Sodium distribution in the body

Acid base balance

Acid base balance

Muscle irritability and cell permeability

Sodium required for normal muscle irritability and cell permeability

Sodium necessary for initiating and maintaining heart beat.

Intestinal absorption of glucose & galactose

Maintenance of osmotic pressure and fluid balance

Dietary requirements

Normal individuals, the requirement of sodium is about 5-10 g/day

For persons with a family history of hypertension, the daily NaCl intake should be less than 5 g.

For patients of hypertension, around 1 g/day is recommended.

10 g of NaCl contains 4 g of sodium

Due to its flavour salt is taken more than the requirement

Sources of sodium

common salt (NaCl) is the major source of sodium.

The good sources of sodium include……

Bread

Whole grains

Leafy vegetables

Nuts

Eggs

Milk

very little of it (< 2%) is normally found in feces

In diarrhea, large quantities of sodium is lost in feces.

Absorption of sodium

Plasma sodium

Plasma

135-145mEq/L

Blood cell

35mEq/L

The mineralocorticoids, secreted by adrenal cortex, influence sodium metabolism. A decrease in plasma sodium and an increase in its urinary excretion are observed in adrenocortical insufficiency.

Excretion

Kidney is the major route of sodium excretion 800 g Na/day is filtered by the glomeruli. 99% of this is reabsorbed by the renal tubules by an active process. Controlled by aldosterone. Extreme sweating also causes considerable amount of sodium loss from the body

Diseased states due to sodium

Sodium diseased states

Hyponatremia< 135meq/L

Hypernatremia>145meq/L

Hyponatremia

Addison's diseaseAddison’s disease, also known as primary adrenal

insufficiency and hypocortisolism is a long-

term endocrine disorder in which the adrenal glands do

not produce enough steroid hormones.

Hormone replacement therapy is treatment of choice.

Oral corticosteroids or steroid injections are given

according to the need.

Addison's disease

primary secondary

autoimmune disease

Tuberculosis

Other infections of the adrenal glands

Spread of cancer to the adrenal glands

Bleeding into the adrenal glands, which may present as adrenal crisis without any preceding symptoms.

Pitutary abnormalities

Hypothalamic

abnormalities

Congenital ACTH deficiency

Hypernatremia

Hypernatremia

characterized by an elevation in the serum sodium level.

The symptoms include increase in blood volume and blood pressure.

May occur due to hyperactivity of adrenal cortex (Cushing's syndrome)

May occur due to prolonged administration of cortisone, ACTH and/or sex hormones.

Diabetes insipidus, pregnancy, steroid and placental hormones, administration of diuretic drugs .

In the patients of hypertension and congestive cardiac failure salt (Na+) restriction is advocated.

Cushing's syndromeAlso called hypercortisolism.

Cushing syndrome

Cushing syndrome• Treatments for Cushing syndrome are designed to lower the high level of

cortisol in your body. The best treatment for you depends on the cause of the

syndrome.

• Reducing corticosteroid use

• Surgery(for tumours)

• Radiation therapy

• Medications to control excessive production of cortisol at the adrenal gland

include ketoconazole (Nizoral), mitotane (Lysodren) and metyrapone

(Metopirone)

• If none of these treatment options are appropriate or effective, your doctor

may recommend surgical removal of your adrenal glands (bilateral

adrenalectomy)