Endocrinology Made Simple : Acute Adrenal Insufficiency

Acute Adrenal Insufficiency:

This is of two main types

Primary adrenal insufficiency

This occurs due to impairment of the adrenal glands.

80% are due to an autoimmune disease called Addison's disease or autoimmune adrenalitis.

One subtype is called idiopathic, or of unknown cause.

Other cases are due to congenital adrenal hyperplasia or an adenoma (tumor) of the adrenal gland.

Secondary adrenal insufficiency

This is caused by impairment of the pituitary gland or hypothalamus.

This also takes place in setting of long term exposure to glucocorticoids medications that can cause chronic suppression of hypothalamic-pituitary adrenal axis resulting in secondary or tertiary adrenal insufficiency due to decrease in plasma ACTH and cortisol levels respectively.

Pathophysiology And Clinical Features:

Signs and symptoms include:

Hypoglycemia

Dehydration

Weight loss

Disorientation.

Weakness

Tiredness

Dizziness

Low blood pressure that falls further when standing (orthostatic hypotension),

Cardiovascular collapse

Muscle aches

Nausea,

Vomiting

Diarrhea.

These problems may develop gradually and insidiously.

ACTH doesnot control release of mineralocorticoids from zona glomerulosa of the adrenal glands and hence patients have normal plasma aldosterone levels and are normotensive.

However such patients can develop vascular collapse under stressful situations such as infection due to decrease in cortisol which is hormone responsible for maintenance of vascular tone.

Cortisol also promotes synthesis of catecholamines in adrenal medulla,cortisol deficient patients are unable to mount a good pressor response during stress.

Hypotension in this patient should respond to fluid repletion and stress dose of corticosteroids.

In secondary and tertiary adrenal failure,there is no significant abnormal mineralocorticoid levels.

Management

Primary goal of treatment in patients with acute adrenal insufficiency is to reverse the hypotension,correct the electrolyte abnormality and replace cortisol.

Prompt administration of intravenous steroids is indicated without watching for confirmation of the diagnosis.

Intravenous dexamethasone is preferred because it is long acting and doe snot interfere with measurement of serum or urinary steroids during subsequent cosyntropin stimulation test ACTH

Computer Studies Made Simple : Open System Interconnection Model / OSI

Open System Interconnection Model / OSI :

This model allows communications between two systems with different architecture.

Composition of OSI

It consists of seven layers.

These are as follows:

1.       Physical Layer

2.       Data Link Layer

3.       Network Layer

4.       Transport Layer

5.       Session Layer

6.       Presentation Layer

7.       Application Layer

Physical Layer

This is the bottom layer of OSI Model.

It is responsible for transmission of bits and data and determines the control signals.

It also defines the characteristics and type of transmission medium.

It also defines the type of encoding

It determines the data rate or number of bits that should be sent per second.

Data Link Layer

This layer divides stream of bits into small easily handled units called frames.

It ensures system to control rate of transmission of data such that there remains a balance between rate of receiving and transmission of data.

It also detects damaged frames  and prevents duplication of frames.

Network Layer:

This layer manages the establishment,maintenance and termination of network layers.

It determines a path between sender and the receiver and manages the delivery of data from source to destination.

Transport Layer:

This layer is responsible for ensuring efficient data transmission takes place between the sender and the recipient.

It eliminates errors in the messages and divides larger data packets into smaller ones for efficiency in data transmission.

Session layer:

This layer pertains with users management.

It helps in establishing,managing and terminating connections between users.

Presentation Layer

This layer plays a role in changing data and formatting it such that it canbe transmitted between the sender and recipient effectively.

It can also compress a large sized data into smaller size a process called compression.

Application Layer:

This layer provide services to the users such as emails,network sharing etc.

     

   

Endocrinology Made Simple : Normal Functions Of Somatostatin

Normal Functions Of Somatostatin :

Somatostatin has following normal functions in human body:

1. Inhibit the release of growth hormone from Anterior pituitary gland

2. Inhibit the release of thyroid-stimulating hormone (TSH)

3. Suppression of release of following gastrointestinal hormones : Gastrin, Cholecystokinin          (CCK),Secretin,Motilin,Vasoactive intestinal peptide (VIP),Gastric inhibitory polypeptide (GIP),Enteroglucagon

4. Reducing the rate of gastric emptying, and

5. Reducing smooth muscle contractions and blood flow within the intestine

6. Suppressing the release of pancreatic hormones

7. Inhibiting the release of insulin and glucagon

8. Suppressing the exocrine secretory action of pancreas

Endocrinology Made Simple : Somatostatinomas

Somatostatinomas

Theses are tumors arising from Delta cells in the pancreas.

Some tumors may arise from somatostatin secreting cells of duodenum

Clinical features:

Classical triad of somatostatinomas is

Gall stones

Diabetes

Malabsorption

They cause Diabetes by inhibiting insulin secretion.

Gallstones are caused by inhibitory effect of somatostatin on gall bladder motility.

Malabsorption occurs due to inhibition of pancreatic secretion.

Investigations:

Fasting Somatostatin Levels are obtained to confirm a Diagnosis of Somatostatinomas.

Fasting Somatostatin Levels of more than 160 pg/ml are diagnostic of somatostatinomas.

After biochemical diagnosis has been confirmed,next step is localization of tumor by Imaging studies such as CT Scan of abdomen.

Management :

This includes a combination of Chemotherapy and Surgery

Chemotherapy with streptozocin, dacarbazine, doxorubicin

Surgical debulking via Whipple procedure and other resections of other affected  gastrointestinal organs .

Computer Studies Made Simple : Uses and Advantages of Computers

Uses and Advantages of Computers:

1 . Storage of large amounts of information and retrieval of data for subsequent uses.

2 . Work with great speed executing functions rapidly and able to do tasks repeatedly.

3 . Undertake complex calculations with high accuracy.

4. Follow the instructions given with consistency