Paraneoplastic syndrome

Overview

Paraneoplastic syndrome of the nervous system occurs when the body’s own immune system that fights cancer, attacks the body’s nervous system which consists of the brain, spinal cord, peripheral nerves or muscle. Other organ systems may also be affected such as the skin, hormones, blood, and joints.  

Paraneoplastic syndrome happens in people who had cancer. It shows symptoms on the part of the nervous system affected and creates deficits on that part. For example, deficits in muscle movement or coordination, sensory perception, memory, thinking or even sleeping.  

Paraneoplastic syndrome of the nervous system commonly occurs in certain types of cancer such as that of the breast, stomach, pancreas, kidney, ovary, lung, testis, lymph node or leukemia.  

Once the cancer has been treated, paraneoplastic syndromes of the nervous system may also be resolved. But, some effects on the nervous system are sometimes irreversible in some cases.

Symptoms

Signs and symptoms of paraneoplastic syndromes of the nervous system develop fast mostly after days or weeks and may start even before the diagnosis of cancer.
The following are signs and symptoms are based on the affected parts of the body:

• Walking instability
• Muscle and abnormal coordination 
• Difficulty in picking up objects or fine motor skills abnormalities  
• Difficulty swallowing 
• Slurred speech or stuttering 
• Cognitive problems or loss of memory  
• Unusual involuntary movements  
• Eyesight abnormalities 
• Sleep disturbances  
• Seizures  
• Hallucinations

Types of paraneoplastic syndromes  

The following are the types of paraneoplastic syndromes of the nervous system:

• Cerebellar ataxia (cerebellar degeneration).
  Deterioration of the nerve cells in the cerebellum. This area part of the brain controls balance, muscle tone and coordination of voluntary movements. Sign and symptoms may include unsteady gait, decreased muscle tone (hypotonia), eye problems (nystagmus), weakened muscle coordination (ataxia).
  
• Limbic encephalitis. Inflammation of the limbic system, limbic area controls emotion, memory and behavior. Sign and symptoms may include personality disorder, memory loss, irritability, seizure.  
• Encephalomyelitis.  Brain and spinal cord inflammation. Sign and symptoms vary depend on the area affected.
• Opsoclonus–myoclonus. A syndrome caused by the deteriorating part of the cerebellum and it controls the part where it will cause irregular eye movements (opsoclonus) and involuntary, chaotic muscle jerks (myoclonus) in the trunk and extremities. 
• Stiff man syndrome.  Also called stiff person syndrome which manifests from muscle rigidity or stiffness that is affects the spine and lower extremities. It also causes muscle spasm which will be painful.
• Myelopathy.  A syndrome of injured the spinal cord. The symptoms depend on the level of spinal cord that affected such as loss of bowel or bladder function, numbness or weakness the area affected. 
• Lambert–Eaton myasthenic syndrome. Is a syndrome of neuromuscular junction that miscommunication between nerves and muscle. Sign and symptoms may include difficulty walking, swallowing problems, blurred vision, muscle weakness, speech impairment. This paraneoplastic syndrome is mostly related to lung cancer. 
• Myasthenia gravis.  Neuromuscular junction abnormalities between the muscles and nerve. It is also often related to thymoma (thymus gland cancer). Sign and symptoms may include weakness of the eye muscle, facial expression abnormalities, difficulty in swallowing, slurred speech, and chewing 
• Neuromyotonia. Also known as Isaac’s syndrome. It impaired nerve cell impulses outside the brain and spinal cord which controls movement of the muscle (peripheral nerve hyperexcitability).
• Peripheral neuropathy. Occurs when nerves are damage and cannot send messages from the brain and spinal cord to the muscle. Symptoms of peripheral neuropathy depend on the site which peripheral nerve are affected.
• Dysautonomia. Is a disorder of the autonomic nervous system (is the part of nervous system that control and regulates the internal organs). Sign and symptoms may include low blood pressure, irregular heartbeat, difficulty breathing. 

Causes

Paraneoplastic syndrome manifest neurological disorders caused by triggered immune system of the body which consists of antibodies and white blood cells called T cells, together with having cancer in its efforts to fight malignancy. The condition is not primarily caused by having cancer, cancer complications or as a side effect of cancer treatment.