What Are the Causes of Acute Progressive Weakness?

Acute progressive weakness is a sudden-onset muscular weakness that rapidly becomes more severe over several hours or days. It is usually the result of something attacking the nerve or muscle cells. Diseases affecting the nervous system this way are rare.

Guillain-Barre

• Guillain-Barre syndrome is an autoimmune disorder. The body's immune response because confused and mistakes cells of the peripheral nervous system for foreign invaders. This causes the body to attack these cells, causing progressive weakness. Guillain-Barre usually appears after a viral infection, but it also can be triggered by surgery or vaccinations. It starts with mild weakness in the lower legs, which rapidly progresses to full-body paralysis and respiratory failure.

  Guillain-Barre cannot be cured, but there are treatments to reduce the severity of symptoms and prevent death. Plasmapheresis is the treatment of choice because it removes the offending antibodies, lessening the severity of the disease.

Myasthenia Gravis

• Myasthenia gravis is a neuromuscular disorder that causes weakness by blocking nerve-to-muscle communication. Like Guillain-Barre, myasthenia gravis is an autoimmune disease. Its causes are generally unknown, but it is sometimes triggered by a thymoma or other tumor of the thymus.

  Muscle weakness that becomes progressively worse with activity is the main symptom of myasthenia gravis. Most other symptoms are the result of this muscle weakness. They include difficulties performing everyday tasks, such as climbing stairs, lifting objects, eating and even breathing. Plasmapheresis and intravenous immunoglobulin therapy can help reduce symptoms of myasthenia gravis for an extended period of time, but as yet there is no cure. Removing the cancerous tumor on the thymus leads to a permanent reduction or remission in symptoms for some people.

Acute Intermittent Porphyria

• Acute intermittent porphyria is a genetic disorder that causes an array of symptoms due to deficiencies in certain enzymes needed for porphyrin metabolism. Although intense abdominal pain is its most common symptom, acute intermittent porphyria also involves muscle weakness, which rapidly progresses to flaccid paralysis. The weakness and paralysis continue to get worse until porphyria is treated. Untreated, respiratory failure from the paralysis can result in death. Other symptoms include changes in mental status, including paranoia, delirium and psychosis, and, rarely, seizures.

  Episodes of porphyria are triggered mainly by certain types of drugs, especially barbiturates and sulfonamides, but they can also be triggered by alcohol, caloric restriction, and stress to the body, such as with infection. Mild cases are treated with intravenous glucose, while more severe cases usually respond to three to four days of treatment with hematin. Most people are symptom-free between acute attacks.

Other Causes

• Spinal chondromyxoid fibroma and other spinal tumors can cause muscle weakness as they press against the spinal cord. The resulting muscle weakness gets worse as the tumor grows bigger, applying more pressure to the spinal cord. Electrolyte disturbances, such as hypokalemia, can also cause progressive weakness.

  Although most cases of electrolyte imbalance occur over an extended period of time, some conditions, including caffeine intoxication, can cause an acute disturbance that results in more-severe symptoms. Other autoimmune disorders, such as amyotrophic lateral sclerosis, multiple sclerosis and polymyositis, cause muscle weakness because of the body's attack of the central nervous system or connective tissues.