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Date posted: November 27, 2011

Dr.Sheeba
The adrenal glands are two small flattened bodies of a yellowish color, situated at the back part of the abdomen, behind the peritoneum, and immediately above and in front of the upper end of each kidney. The right one is somewhat triangular in shape, bearing a resemblance to a cocked hat; the left is more semilunar, usually larger, and placed at a higher level than the right. Their usual size is from 3 – 5 cm. in length, rather less in width, and from 4 – 6 mm. in thickness. Their average weight is from 1.5 to 2.5 gm. each.

Development : Each suprarenal gland consists of a cortical portion derived from the celomic epithelium and a medullary portion originally composed of sympatho-chromaffin tissue.

Relations : The relations of the suprarenal glands differ on the two sides of the body.

The right suprarenal is situated behind the inferior vena cava and right lobe of the liver, and in front of the diaphragm and upper end of the right kidney. The left suprarenal, slightly larger than the right, is crescentic in shape, its concavity being adapted to the medial border of the upper part of the left kidney. Small accessory suprarenals (glandulæ suprarenales accessoriæ) are often to be found in the connective tissue around the suprarenals.

Structure : The gland has two portions -  an external or cortical and an internal or medullary. The former constitutes the chief part of the organ, and is of a deep yellow color; the medullary substance is soft, pulpy, and of a dark red or brown color.

The cortical portion (substantia corticalis) consists of a fine connective-tissue net-work, in which is imbedded the glandular epithelium. Three distinct zones can be made out:

(1) The zona glomerulosa, situated beneath the capsule, consists of cells arranged in rounded groups, with here and there indications of an alveolar structure; the cells of this zone are very granular, and stain deeply.  These secrete Aldosterone.

(2) The zona fasciculata, continuous with the zona glomerulosa, is composed of columns of cells arranged in a radial manner; these cells contain finer granules and in many instances globules of lipoid material. These secrete cortisol.

(3) The zona reticularis, in contact with the medulla, consists of cylindrical masses of cells irregularly arranged; these cells often contain pigment granules which give this zone a darker appearance than the rest of the cortex. These secrete androgens.

The medullary portion is extremely vascular, and consists of large chromaphil cells arranged in a network

Arterial supply : There are numerous arteries derived from the aorta, the inferior phrenic, and the renal.

Venous return : The suprarenal vein returns the blood from the medullary venous plexus and receives several branches from the cortical substance; on the right side opens into the IVC, on the left into the renal vein.

The lymphatics end in the lumbar glands.

The nerves are exceedingly numerous, and are derived from the celiac and renal plexuses.

Adrenal cortex
Adrenal cortex secretes an entirely different group of hormones called CORTICOSTEROIDS. They are synthesized from steroid cholesterol and have similar chemical formulae.

Chemistry of adrenocortical secretion

  • glucocorticoids (cortisol, corticosterone),
  • mineralocorticoids (aldosterone, deoxycorticosterone), and
  • sex steroids (mainly androgens).

Chemistry of adrenocortical hormones

  • All of them are steroid compounds.Formed mainly from cholesterol
  • Transport and fate of adrenal hormones
  • Cortisol combines in blood mainly with a globulin called cortisol binding globulin or trancortin and to a lesser extent with albumin.
  • Aldosterone combines only loosely with plasma proteins.
  • In general , the hormones become fixed in target tissues or destroyed within one or two hours for cotisol and 30 mnts for aldosterone.
  • Adrenal steroids are degraded mainly in liver. 25 % of this is excreted in bile & feces & remaining 75 % in bile & urine.
  • Blood concentration of aldosterone : 6 ng/dl
  • Secretory rate of aldosterone            :  150 – 250 μg/day.
  • Blood concentration of cortisol : 12μg/dl
  • Secretory rate of cortisol           :  15 – 20 mg/day.

Function
Adrenal cortex secretes three types of steroid hormones known as corticosteroids.

  1. Mineralocorticoids
  2. Glucocorticoids
  3. Androgens,Estrogens and Progestins

Mineralocorticids are essential to life because they regulate the amount of mineral salts(also called electrolytes that are retained in the body. A proper balance of water and salts in blood and tissues is essential to the normal functioning of the body. Most important mineralocorticoid hormone is called Aldosterone.Its secretion by Adrena cortex increases the reabsorption in to the blood stream of sodium by the kidney tubules. At the same time, Aldosterone stimulates the secretion of another electrolyte called potassium.Secretion of Aldosterone increases manifold in the face of severe sodium restricted diet,thereby enabling the body to hold needed salt in the blood stream.

Glucocorticoids  are steroid hormones having an important influence on the metabolism of sugars,fats and proteins within all body cells. It  also has a powerful antinflammatory effect. Cortisol is the most important glucocorticoid hormone ,also called hydrocortisone. Cortisol increases the ability of cells to make new sugars out of fats and proteins (gluconeogenesis) and regulates the quantity of sugars,fats and proteins in the blood and cells. Cortisone is a hormone very similar to cortisol and can be prepared synthetically. Cortisone is useful in treating inflammatory conditions such as Rheumaoid arthritis.

Androgens,estrogens and progestins are male and female hormones that maintain the secondary sex characteristics such as beard and breast development and are necessary for reproduction. These hormones are also produced in ovaries and testes. Excess adrenal androgen secretion in females leads to Virilism (development of male characteristics) and excess adrenal estrogen and progestin secretion in males produce feminization (development of feminine characteristics)

Adrenal medulla
Adrenal medulla secretes two types of catecholamine hormones.

  • 1.  Epinephrine (Adrenaline)
  • 2.  Norepinephrine (noradrenaline)

Epinephrine increases cardiac rate,dilates bronchial tubes,and stimulates the production glucose from a storage substance called glycogen when glucose is needed by the body. Norepinephrine constricts vessels and raises blood pressure.

Both epinephrine and norepinephrine are called sympathomimetic agents because they mimic,or copy the action of the sympathetic nervous system.  During times of stress,these hormones are secreted by adrenal medulla in response to nervous stimulation. They help the body respond to crisis situations by raising the blood pressure,increasing the heart beat and respiration and bringing sugar out of storage in cells. 

Hyper secretion of adrenal glands

  • Glucocorticoid excess
  • Group of symptoms due to excess cortisol from adrenal cortex.

CLASSIFICATION

  1. ACTH dependent
  • Iatrogenic (ACTH therapy)
  • Pituitary dependent bilateral adrenal hyperplasia (cushing’s disease)
  • Ectopic ACTH syndrome (due to small cell carcinoma, bronchus)
  1. Non-ACTH dependent
  • Adrenal carcinoma
  • Adrenal adenoma

Cushing’s syndrome

Clinical Features
Obesity,moon like fullness of face,excess of deposition of fat in the thoracic region of the back (called buffalo hump) ,hyperglycemia,hypernatraemia,hypokalaemia,osteoporosis and hypertension occur with excess cortisol secretion. Etiology may be excess ACTH secretion or tumor of adrenal cortex.

Gonadal dysfunction is very common, with menstrual irregularity in females and loss of libido in males. Hirsutism is frequently found in female patients, as is acne. All these features tend to be present more often in patients with adenoma than in those with bilateral adrenal hyperplasia.

Psychiatric abnormalities have been reported.Depression and lethargy are among the commonest problems.

The typical red-purple livid striae of the syndrome are found most frequently on the abdomen but may also be present on the upper thighs and arms. They are very common in younger patients and less so in those over 50.

The myopathy of Cushing’s involves the proximal muscles of lower limb and shoulder girdle.

Nelson’s syndrome
Association of a locally invasive pituitary tumour with very high levels of ACTH and hyperpigmentation which may occur in some patients with Cushing’s disease following bilateral adrenalectomy.

Carney’s syndrome
This is an autosomal dominant condition comprising mesenchymal tumours (especially atrial myxomas), spotty skin pigmentation, peripheral nerve tumours, and various endocrine tumours, one of which may be Cushing’s syndrome. The adrenals then contain multiple, small, pigmented nodules.

Mccune-ALBRIGHT SYNDROME
In this condition fibrous dysplasia and cutaneous pigmentation may be associated with pituitary, thyroid, adrenal, and gonadal hyperfunction. The adrenal hypersecretion may produce Cushing’s syndrome.

Gastric inhibitory polypeptide (GIP) hypersensitivity
This food-dependent form of Cushing’s syndrome resulted from the normal increase in GIP after eating. Not surprisingly, the clinical syndrome is related to food intake. Fasting can produce adrenal insufficiency.

Diagnostic tests

  • Circadian rhythm of plasma cortisol
  • Urinary free cortisol excretion
  • Dexamethasone suppression tests
  • Insulin tolerance test

Differential diagnostic tests

  • Plasma ACTH
  • Determining the molecular species of ACTH by chromatography or by immunoradiometric assay
  • Plasma potassium (See also  Chapter 20.2.3 291)
  • High-dose dexamethasone suppression test
  • Metyrapone test 

Hypofunction of adrenal gland

Adrenocortical insufficiency

 Primary :           Addison’s disease
Congenital / Acquired enzyme defects

Secondary         :    Hypothalamic / Pituitory disease
Glucocorticoid therapy

Primary adrenocortical insufficiency – Addison’s disease

  • Glucocorticoid and mineralocorticoid decreased.
  • Loss of Adrenal androgen production
  • Increased ACTH secretion

CAUSES
Common

  • Autoimmune
  • Sporadic
  • Polyglandular deficiency
  • Tuberculosis
  • Bilateral adrenalectomy

Rare

  • Metastatic tumors, lymphomas
  • Intra adrenal hemorrhage (Water House Friderickson Syndrome following meningococcal infection)
  • Haemochromatosis
  • Amyloid
  • Adrenal infections

Clinical features
Due to Glucocorticoid deficiency-weight loss,malaise,anorexia,weakness,nausea,vomiting,diarrhea,constipation,postural hypotension,hypoglycaemia

  • Due to mineralocorticoid deficiency-hypotension
  • Due to increased ACTH secretion-pigmentation
  • Due to loss of adrenal androgen-decrease in body hair,especially in female

Investigations

ACTH stimulation test

  • Plasma ACTH measurement
  • Plasma electrolytes
  • Blood glucose

Management

            Glucocoticoid replacement therapy

 Adrenal crisis
Patient may present in shock with severe hypotension,hyponatraemia,hyperkalaemia and hypoglycaemia. Muscle cramps,nausea,vomiting,diarrhea and unexplained fever present.It is a medical emergency and need IV fluid and intravenous hydrocortisone.

Secondary adrenocortical insufficiency :  Due to hypothalamic or pituitary disease.

Mineralocorticoid excess :  Overproduction of aldosterone, the major salt -retaining hormone

Primary hyper aldosteronism/ conn’s syndrome 

Patients are almost invariably hypersensitive.This is discovered only by detailed biochemical investigations.In classic cases,overproduction of aldosterone either by an adenoma or bilateral zona glomerulosa hyperplasia is associated with hypertension and hypokalaemia.

Secondary hyperaldosteronism : Due to increased activity of rennin-angiotensin system.It can be due to physiological reasons like salt depletion and pathological reasons like nephritic syndrome, cirrhosis with ascites and congestive cardiac failure.

Catacholamine excess

Pheochromocytoma
Rare tumor of chromaffin tissue which secretes catacholamines and is responsible for less than 1% hypertension. It may arise from any part of sympathetic chain but 90% is from adrenal medulla.

In MEN type two A,phaeochromocytoma is associated with medullary carcinoma thyroid and hyperparathyroidism. In MEN type two B,the same abnormality is associated with marfanoid body habits,bumpy lips and  mucosal neuromas of tongue,eyelids and cornea.Both this arise spontaneously or inherited as autosomal dominant.

CLINICAL FEATURES

  • Hyprtension (usually paroxysmal)
  • Pallor,palpitation,sweating headache
  • Anxiety
  • Abdominal pain,vomiting,constipation,weight loss,glucose intolerance

Screening test

  • 24 hours urine for VMA (vinyl mandelic acid)
  •  24 hours free urinary catecholamines

Management :   Excision of tumor

Repertorial representation

Addisons disease

  • 1) [Complete ] [Mind]Torpor:Addisons disease, in:
  • 2) [Complete ] [Mind]Work:Aversion to mental:Addisons disease, in:
  • 3) [Complete ] [Kidneys]Addisons disease:
  • 4) [Complete ] [Generalities]Convulsions:Addisons disease, in:
  • 5) [Complete ] [Generalities]Faintness, fainting:Tendency:Addisons diseas e, in:
  • 6) [Complete ] [Generalities]Lassitude:Tendency:Addisons disease, in:
  • 7) [Complete ] [Generalities]Weakness, enervation, exhaustion, prostration, infirmity:Addisons disease, in:
  • 8) [Kent ] [Kidney]Addison’s disease:
  • 9) [Kent ] [Generalities]Convulsions:Addison’s disease,in:
  • 10) [Boericke ] [Generalities]Addison’s disease:
  • 11) [Clarke ] [Clinical]Addison’s disease:
  • 12) [Knerr ] [Mind and Disposition]Apathy:Addison’s disease, in:
  • 13) [Knerr ] [Mind and Disposition]Cross:Spells, with depression (addison’s disease):
  • 14) [Knerr ] [Mind and Disposition]Depressed (dejected, despondent):Irritability:And crossness (addison’s disease):
  • 15) [Knerr ] [Inner Head]Headache (undefined):Addison’s disease, in:
  • 16) [Knerr ] [Sensorium]Vertigo:Addison’s disease, in:
  • 17) [Knerr ] [Mind and Disposition]Work:Aversion to:Addison’s disease, in:
  • 18) [Knerr ] [Mind and Disposition]Torpor:Addison’s disease, in:
  • 19) [Knerr ] [Mind and Disposition]Irritable:Depression, with, addison’s disease:
  • 20) [Knerr ] [Outer Head]Hair:Color, disposition to change:Red hair turns to chestnut brown (addison’s disease):
  • 21) [Knerr ] [Upper Face]Yellow:Earthy color, in addison’s disease:
  • 22) [Knerr ] [Desires, Aversion Appetite, Thirst]Hunger:Excessive:Addison’s disease, in:
  • 23) [Knerr ] [Hiccough, Belching, Nausea and Vomiting]Vomiting:Constant:Addison’s disease, in:
  • 24) [Knerr ] [Serobiculum and Stomach]Stomach:Acidity:Phthisis, in, or add ison’s disease:
  • 25) [Knerr ] [Serobiculum and Stomach]Stomach:Gastralgia:Addison’s disease, in, frequent attacks:
  • 26) [Knerr ] [Serobiculum and Stomach]Stomach:Pain (undefined):Addison’s disease, in:
  • 27) [Knerr ] [Hypochondria]Hypochondria:Pain:Left, in, in addison’s diseas e:
  • 28) [Knerr ] [Abdomen]Oppression:Pain (undefined):Addison’s disease:
  • 29) [Knerr ] [Abdomen]Sensitiveness (externally):Pressure, to, in addison’s disease:
  • 30) [Knerr ] [Stool and Rectum]Constipation:Addison’s, in, disease:
  • 31) [Knerr ] [Urinary Organs]Kidney:Addison’s disease:
  • 32) [Knerr ] [Urinary Organs]Kidney:Drawing:In addison’s disease:
  • 33) [Knerr ] [Urinary Organs]Kidney:Pressing sensation:In addison’s diseas e:
  • 34) [Knerr ] [Neck and Back]Lumbar region:Heat:Renal region, in, (addisons disease) morbus brightii (diabetes):
  • 35) [Knerr ] [Neck and Back]Lumbar region:Pressing feeling:Addison’s disease, in:
  • 36) [Knerr ] [Neck and Back]Lumbar region:Tension:Addison’s disease, in, morbus brightii, and diabetes:
  • 37) [Knerr ] [Nerves]Convulsions:Addison’s disease:
  • 38) [Knerr ] [Nerves]Convulsions:Epileptic:Addison’s disease, in:
  • 39) [Knerr ] [Nerves]Fainting (syncope):Addison’s disease:
  • 40) [Knerr ] [Nerves]Lassitude (fatigue, loss of energy, indolence, languor, tiredness, weariness):Addison’s, in, disease:
  • 41) [Knerr ] [Nerves]Paralysis:Addison’s, in, disease:
  • 42) [Knerr ] [Nerves]Trembling:Muscles:Addison’s disease, in:
  • 43) [Knerr ] [Nerves]Twitching (jactitation, jerking, subsultus tendinum):Addison’s, in, disease:
  • 44) [Knerr ] [Nerves]Weakness (debility, exhaustion, feebleness, prostration, loss of strength, vital power diminished, etc.):Addison’s, in, disease:
  • 45) [Knerr ] [Skin]Brown:Addison’s disease, in:
  • 46) [Knerr ] [Skin]Brown:Yellowish color into brown, sudden turning of, asif smoked (addison’s disease):
  • 47) [Knerr ] [Skin]Dark:Addison’s disease, in:
  • 48) [Knerr ] [Skin]Desquamation:Scales, peels off and shows loosened, a fatty transpiration (addison’s disease):
  • 49) [Knerr ] [Skin]Dry:Parchment like, in addison’s disease:
  • 50) [Knerr ] [Skin]Hypertrophy:Thickening, in addison’s disease:
  • 51) [Phatak ] [Phatak A-Z]Addison’s disease:
  • 52) [Special ] [Bio-chemic]Addison’s disease: 

Adrenal affections

  • 1) [Complete ] [Kidneys]Inflammation:Adrenal ( 1) : 1 mark = Alloxanum
  • 2) [Clarke ] [Clinical]Adrenal neuralgia (1) : 2 marks = Adrenalinum

Cushing’s disease

  • Complete : Generalities > Cushing’s disease (1) : 1 mark = Chlorpromazinum

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