1.What is Guillain-Barre syndrome?

Guillain-Barre syndrome is a disorder in which the body's immune system attacks part of the peripheral nervous system.
The first symptoms of this disorder include varying degrees of weakness or tingling sensations in the legs. In many instances the weakness and abnormal sensations spread to the arms and upper body.

2.Causes Guillain-Barre syndrome

The immune system starts to destroy the myelin sheath that surrounds the axons of many peripheral nerves, or even the axons themselves (axons are long, thin extensions of the nerve cells; they carry nerve signals). The myelin sheath surrounding the axon speeds up the transmission of nerve signals and allows the transmission of signals over long distances.
3.Symptoms of Guillain-Barre syndrome

Weakness, typically beginning in the legs and progressing upward. The weakness is accompanied by decreased feeling (paresthesia). Reflexes are lost, for example, the hammer to the front of the knee will not induce a kick. In severe cases breathing can be affected enough to require a ventilator and rarely the heart can be affected.

4.Diagnose Guillain-Barre syndrome

Guillain-Barre is called a syndrome rather than a disease because it is not clear that a specific disease-causing agent is involved. A syndrome is a medical condition characterized by a collection of symptoms (what the patient feels) and signs (what a doctor can observe or measure). The signs and symptoms of the syndrome can be quite varied, so doctors may, on rare occasions, find it difficult to diagnose Guillain-Barré in its earliest stages.
Several disorders have symptoms similar to those found in Guillain-Barré, so doctors examine and question patients carefully before making a diagnosis. Collectively, the signs and symptoms form a certain pattern that helps doctors differentiate Guillain-Barré from other disorders. For example, physicians will note whether the symptoms appear on both sides of the body (most common in Guillain-Barré) and the quickness with which the symptoms appear (in other disorders, muscle weakness may progress over months rather than days or weeks). In Guillain-Barré, reflexes such as knee jerks are usually lost. Because the signals traveling along the nerve are slower, a nerve conduction velocity (NCV) test can give a doctor clues to aid the diagnosis. In Guillain-Barré patients, the cerebrospinal fluid that bathes the spinal cord and brain contains more protein than usual. Therefore a physician may decide to perform a spinal tap, a procedure in which the doctor inserts a needle into the patient's lower back to draw cerebrospinal fluid from the spinal column.

Further reading:
http://www.ninds.nih.gov/disorders/gbs/gbs.htm
http://en.wikipedia.org/wiki/Guillain-Barré_syndrome
http://www.mayoclinic.com/health/gui...ndrome/DS00413