A NEUROLOGIST'S APPROACH TO THE IMMUNOSUPPRESSED PATIENT

Abstract

It is not unusual to be asked for a neurological assessment of a patient with some form of immune suppression. Most patients will have an acquired disorder of the immune system and are the focus of this review (table 1). We shall not discuss the neurological consequences of HIV, as this is the subject of a separate article in this supplement (see p i29), nor those with rarer inherited immune deficiency as their investigation and treatment is such a highly specialised area.View this table:In this windowIn a new window Table 1 Classification of immune deficient conditions Acquired immune suppression may be a deliberate goal of medical treatment where the aim is to reduce an inappropriate immune response, such as treating myasthenia with steroids and azathioprine. It may be a recognised undesired effect of treatment for another condition—for example, in a patient on anti-neoplastic chemotherapy. Less obviously immunosuppression can occur in disorders that impair the effectiveness of the immune system—for example, systemic lupus erythematosus (SLE), diabetes, renal failure. In all these situations the condition being treated with immunosuppression, or the process causing the immune suppression, may have their own inherent neurological manifestations additional to suppression of the immune response. Examples include non-metastatic effects of malignancy, such as limbic encephalitis, or a systemic condition such as SLE that leads to direct involvement of the central nervous system (CNS) presenting as neuropsychiatric illness. Alternatively, treatments for malignancy also have direct and unwanted effects on the CNS and neuromuscular system—for example, the neurotoxic side effects of cytotoxic drugs. Immunosuppression changes the normal relationships to the microorganisms so: innocuous organisms in the immune competent individuals become pathogenic infections evolve rapidly the usual clinical and laboratory manifestations and markers of infection may not be seen or detected. This alters the clinical presentation and features of infection, both systemic and neurological. Immunosuppressed patients are susceptible to …