Introduction To Cushing’s Syndrome

Cushing syndromeDefinition: Cushing syndrome is a hormonal disorder and it describes the signs and symptoms associated with prolonged exposure to inappropriately high levels of the hormone cortisol. Cushing syndrome is also known as Hypercortisolism.

Causes:

1. Use Of Glucocorticosteroid Medicines: The most common cause of Cushing syndrome is the excessive use of  corticosteroid medicine. Prednisone, dexamethasone and Prednisolone are the examples of these medicines. The glucocorticosteroid given externally mimic the actions of the body,s normal hormone cortisol. These drugs are mainly used in the treatment of asthma, skin allergies, inflammatory diseases, etc.

2. Excess Production of the hormone Cortisol In The Body: The other cause is the excessive production of the hormone cortisol from the body. This hormone is normally produced from the adrenal glands in response to ACTH (adrenocorticotropic hormone) from the Pituitary gland. This hormone in turn is controlled by CRH (Corticotropic releasing hormone) from the hypothalamus. Some of the causes for excess production of cortisol in the body include:

  • A pituitary gland tumor that release too much ACTH leading to excess stimulation of adrenal glands to produce cortisol.
  • Tumors of the adrenal gland that produce excess cortisol.
  • Tumors elsewhere in the body that may produce ACTH or CRH.

Clearing Some Confusing Terminologies: 

1. Cushing Disease: refers to the pituitary dependent cause of cushing syndrome, that is when the syndrome is caused by the excess production of ACTH from the pituitary gland.

2. Cushing Triad: A condition unrelated to cushing syndrome that is caused by an increased intracranial pressure.

Clinical Features Of Cushing Syndrome:

A full blown case of Cushing syndrome presents with the following signs and symptoms:

  • Rounded moon like face
  • Weigh gain
  • A fat pad in the upper back.
  • Thin arms and legs.
  • Central obesity ( A lemon on tooth pick appearance).
  • Hirsutisim
  • Thinning of the skin with easy bruising and purple striae.
  • Backache
  • Bone tenderness and pain
  • Acne
  • Slow healing of the wounds
  • Fatigue
  • Proximal muscle weakness
  • High blood pressure
  • High blood sugar levels
  • Depression and anxiety
  • Osteoporosis
  • Pathological bone fractures
  • Irregular menstrual cycles
  • Sexual dysfunction
  • Headache

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Introduction to Loop Diuretics

Introdloop diureticsuction: A diuretic is a medicine that causes an increase in urine and the amout of water excreted from the kidneys. Loop diuretics are the drugs that act on the the ascending loop of Henle in the kidney to cause diuresis and are so named as loop diuretics.

Mode of Action:

Loop diuretics inhibit the Na+/K+/2Cl- co-transporter in the thick ascending loop of Henle, in the kidneys and stop the transport of sodium chloride out of the tubule into the interstitial tissue, causing a decrease in sodium and chloride re-absorption. They act on the chloride-binding site and have a direct inhibiting effect on the carrier.

Inhibition of this transporter leads to a significant increase in concentration of ions in the tubule and reduced hypertonicity in the surrounding interstitium, causing less water to be reabsorbed into the blood. This causes more urine to be produced and a decrease in blood volume.

Clinical Uses: Loop diuretics are basically used for following conditions;

  • Edema associated with heart failure
  • Fluid accumulation in renal impairment or nephrotic syndrome.
  • Edema with Hepatic cirrhosis
  • Hypertension
  • Sometimes as an adjuvant in cerebral or pulmonary edema where rapid diuresis is required.

Examples of Loop Diuretics: Common drugs in the group of loop diuretics include:

  • Bumetanide
  • Ethacrynic acid
  • Furosemide (Lasix)
  • Torsemide

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