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  • Updated 02.07.2024
  • Released 08.28.2007
  • Expires For CME 02.07.2027

Leukemia: neurologic complications



Leukemias are hematologic neoplasms originating from myeloid or lymphoid cells. Acute leukemias consist of immature cells, and chronic leukemias consist of mature cells.

The estimated incidence rate is 14.0 per 100,000, with a lifetime risk of 1.6%, making leukemia the eleventh most common cancer in the United States. Induction protocols reduced the incidence of central nervous involvement sevenfold (16). The 5-year relative survival rate has dramatically improved to 66.7% with new treatments (NIH Cancer Stat Facts: Leukemia).

Leukemia causes neurologic morbidity through infiltration of the central nervous system or through vascular, metabolic, infectious, paraneoplastic, and treatment-related complications.

Key points

• Leukemia is a group of hematologic neoplasms that can present with neurologic complications either by direct or indirect mechanisms.

• The direct effects of leukemia on the nervous system include leptomeningeal infiltration of leukemic cells, formation of mass lesions (chloroma, granulocytic sarcoma), and conversion of chronic lymphoid leukemia to non-Hodgkin lymphoma (Richter syndrome).

• Systemic effects of leukemia include hematologic or vascular complications, metabolic anomalies, infections, and paraneoplastic syndromes.

• Treatment-related complications include the effects of chemotherapy and radiation therapy, the unique effects of bone marrow or stem cell transplantation, and CAR-T.

Historical note and terminology

Leukemias are neoplasms of the hematopoietic stem cells and their progenitors. They are divided into four subgroups according to the lineage and the maturity of the cells involved. Myeloid lineage encompasses granulocytes (neutrophils, eosinophils, basophils), monocytes, erythrocytes, and megakaryocyte cells, whereas lymphoid lineage encompasses T, B, and NK lymphocytes. Acute leukemias have an acute onset and involve immature precursor cells (blasts), whereas chronic leukemias have a more subacute or chronic onset and involve mature precursors (16). The four broad categories of leukemia are acute lymphoid leukemia, acute myeloid leukemia, chronic lymphoid leukemia, and chronic myeloid leukemia (03).

Leukemias are usually diagnosed with a blood analysis, flow cytometry, and bone marrow sampling. Magnetic resonance imaging typically detects central nervous system involvement (18).

CNS involvement is defined as the presence of leukemic cells in the CNS, either discovered by clinical, radiological, or paraclinical (eg, lumbar puncture) findings. Recognition of neurologic complications is important as they require emergent diagnosis and treatment to prevent long-term sequela and often confer a poor prognosis (03).

Leukemias can have a heterogeneous neurologic presentation depending on the structures affected (03; 14; 07). In many cases, patients report no neurologic symptoms. CNS involvement can cause headache, unsteadiness, loss of consciousness, seizures, or intracranial hypertension. Cranial nerve involvement can cause diplopia, facial hypoesthesia or asymetria, hypoacusis, vision loss, and dysphagia. Rarely, hypothalamic syndromes resulting in obesity can be seen. Spinal cord involvement can cause pain, hypoesthesia, paresis, and loss of bladder control (07).

Treatment of leukemias involves the use of radiotherapy and chemotherapeutic agents, such as methotrexate and cytarabine, which can have significant neurotoxicities and can induce a prolonged period of neutropenia predisposing to serious CNS infections (03). Other treatment options include allogeneic stem cell transplant and monoclonal antibodies (18). Newer treatment options, such as CD19- or CD22-targeted chimeric antigen receptor-engineered T-cell therapy, have led to complete remission in up to 60% to 90% of children with relapsed acute lymphoid leukemia (23).

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