Guillain-Barré syndrome (GBS) can take several different forms, including:

• Acute inflammatory demyelinating polyneuropathy (AIDP). Condition that damages the myelin sheath, the fatty protective covering surrounding the nerves’ axons. Motor and sensory nerves of the peripheral nervous system may be affected, slowing transmission of signals to and from the brain. Symptoms include muscle weakness and paralysis that begins in the legs and feet and moves up to the arms and hands. The vast majority of cases of GBS in the United States are of this type. Often, when people speak of GBS, they are referring to AIDP.
  
  
• Miller Fisher syndrome (MFS). MFS affects facial and cranial nerves and includes a distinctive triad of ataxia (loss of coordination), eye muscle paralysis (ophthalmoplegia), and the absence of body reflexes (e.g., knee-jerk). MFS may also include generalized weakness as well as difficulty speaking or swallowing. Unlike other forms of GBS, weakness associated with MFS typically begins in the upper body and descends to the lower body.
  
  
• Acute motor axonal neuropathy (AMAN). AMAN usually involves damage to the nerve axons, especially those affecting movement. Symptoms are similar but more severe than those of AIDP and recovery can take much longer. For example, patients with AMAN are more likely to experience weakness or paralysis of breathing muscles, resulting in respiratory failure. Outbreaks of this type of GBS have occurred in northern China.
  
  
• Acute motor-sensory axonal neuropathy (AMSAN). This type of GBS is similar to AMAN, except that this type also includes sensory symptoms, such as loss of reflexes and burning or tingling sensations (paresthesia).  The axons of both motor and sensory nerves may be damaged. This type of GBS may last longer than AMAN.  

Chronic inflammatory demyelinating polyneuropathy (CIDP) is similar to AIDP, although CIDP is not considered a type of GBS. Unlike AIDP, which is characterized by an acute (sudden and severe) onset of symptoms, CIDP develops slowly and lasts longer.