Progressive Multifocalleukoencephalopathy - Causes, Symptoms and Treatments

Progressive multifocalleukoencephalopathy (PML) is a rare disorder of the nervous system that primarily affects individuals with suppressed immune systems (such as those with cancers such as leukemia or lymphoma, or acquired immunodeficiency syndrome [AIDS]). The disorder, which is caused by a virus, is characterized by demyelination or destruction of the myelin sheath that covers nerve cells, specifically oligodendrocytes. The myelin sheath is the fatty covering­which acts as an insulator - of nerve fibers in the brain.

Though rare, PML occurs more frequently in people whose immunity is compromised by HIV, usually in those with CD4+ counts of less than 100 cells/ul of blood, and is rapidly progressive. The interval between first neurologic symptoms and death may be as short as 3 to 4 months; in rare cases, remission has occurred and patients have survived for several years. In general, however, PML is an incurable, fatal disease.

Causes of Progressive multifocalleukoencephalopathy:

PML is caused by the opportunistic JC virus (JCV), a member of the papovavirus family. (The name JC comes from the initials of a patient with the disorder.) PML is believed to be caused by reactivation of latent JCV infection, resulting in demyelination of the central nervous system. Initial brain lesions occur around blood vessels, suggesting dissemination via the blood.

Signs and symptoms of Progressive multifocalleukoencephalopathy:

Symptoms include mental status changes followed by speech or language deficits, visual deficits, and generalized or focal weakness. Neurologic signs include lack of coordination (weakness of one limb or one side of the body), cranial nerve palsies, loss of vision on one side, sensory loss in one limb or one side of the body, language disturbance, and unsteadiness.

Diagnosis of Progressive multifocalleukoencephalopathy:

Definitive diagnosis of PML requires a brain biopsy. Clinically, detecting focal lesions and abnormalities of the white matter on computed tomography scan or magnetic resonance imaging suggests the diagnosis. Recently, DNA of the JC virus has been detected in the cerebral spinal fluid, and used as a diagnostic tool.

Because of the neurological symptoms that occur with PML, differential diagnosis should include toxoplasmosis, central nervous system (CNS) lymphoma, cerebral vascular disease, HIV encephalopathy, HIV dementia, CNS infection, lymphoma, and tuberculosis.

Treatment of Progressive multifocalleukoencephalopathy:

There is no accepted treatment regimen for PML, other than highly aggressive antiretroviral therapy. Cortieosteroids may be utilized if the patient is having difficulty with edema. Supportive care for the patient's activities of daily living, nutrition, safety and prevention of further neurologic accident or head injury are important.

Special considerations and Prevention tips of Progressive multifocalleukoencephalopathy:

• Observe the patient with PML closely for antiretroviral therapy response.
• Family members and care providers should be included in the evaluation of the therapy. Depending on the patient's memory and mentation, they may need a great deal of support.
• Stress the importance of taking the medications on schedule.

When a diagnosis of PML has been established or suggested due to a clinical picture of neurologic deterioration, the nurse must initiate a discussion of plans for terminal care (including wills, advance directives, and supportive care and services) with the patient and caregiver. Supportive treatment will be necessary for an undetermined period of time, and hospice referral should be considered if the patient doesn't respond to a highly aggressive antiretroviral regimen.