Article, Hematology

Acute myeloid leukemia presenting as one-and-a-half syndrome

Case Report

Acute myeloid leukemia presenting as one-and-a-half syndrome

Abstract

One-and-a-half syndrome is a clinical disorder featuring Extraocular movements characterized by horizontal conju- gate gaze palsy with internuclear ophthalmoplegia. It usually results from a unilateral lesion of the midbrain, and the most common cause of this syndrome in young women is Multiple sclerosis. We report the case of a 38-year-old woman diagnosed as having acute myeloblastic leukemia presenting with characteristic neurologic and imaging features of one- and-a-half syndrome. Hyperleukocytosis, cancer procoagu- lants, tissue factor expression, and the increased proteolysis of coagulation factors by Leukemic cells may all contribute to the propensity for thrombotic vascular occlusion. The Optimal treatment of acute Brain infarction in acute leukemia patients with hyperleukocytosis remains unclear. However, this patient illustrates that leukapheresis alone can provide rapid and effective relief of visual symptoms without neurologic sequela. To achieve better outcomes and survival, clinicians must maintain a heightened awareness of this distinctly unusual manifestation.

Fig. 2 Axial T2-weightED magnetic resonance imaging of the brain showing a high signal lesion extending from the left paramedian pontine base to the tegmentum (arrow).

Fig. 1 Blood smear showing large numbers of circulating myeloblasts in peripheral blood (Wright-Giemsa stain, original magnification x400).

A 38-year-old woman presented to the emergency department with a 2-day history of Blurred vision and headache. Upon examination, both eyes were spontaneously in neutral position; and visual acuity, light reflex, and accommodation were preserved. During rightward gaze, her left eye did not adduct past the midline and the right eye showed a right beating nystagmus with full abduction. Neither eye was able to move beyond the midline to the left, as demonstrated by complete left lateral conjugate gaze palsy for voluntary, tracking, and oculovestibular move- ments. Vertical gaze remained normal but convergence was limited. Oculocephalic stimulation did not improve the defective visual response. The remainder of the physical examination findings was normal. Laboratory analysis revealed marked leukocytosis (1.7 x 1011/L) with 85% circulating myeloblasts (Fig. 1). Axial T2-weighted mag- netic resonance imaging of the brain confirmed the clinical diagnosis of “one-and-a-half syndrome” as a result of acute

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513.e2 Case Report

brainstem infarction (Fig. 2). The serum levels of D-dimer, fibrinogen, and Fibrin degradation products were normal, and the results of comprehensive studies for hypercoagula- tive disorders were all unremarkable. A bone marrow trephine biopsy was compatible with acute myeloblastic leukemia (M2, French-American-British classification). Immediate leukapheresis completely resolved her neurolo- gic deficits within 3 days. She proceeded with standard cytarabine-based induction chemotherapy.

One-and-a-half syndrome is a clinical disorder featuring extraocular movements characterized by horizontal con- jugate gaze palsy with internuclear ophthalmoplegia. It usually results from a unilateral lesion of the ipsilateral parapontine reticular formation, the internuclear fibers of the ipsilateral medial longitudinal fasciculus, and the abducens nucleus. Demyelinating, vascular, neoplastic, and infectious diseases have all been implicated in the development of this syndrome, and the most common cause in young women is multiple sclerosis [1]. Acute myeloid leukemia (AML) presenting as one-and-a-half syndrome in a young woman is extremely unusual. Besides, the occurrence of Thromboembolic events in the absence of disseminated intravascular coagulation for patients with AML is very rare [2]. Although the major intracranial complication in AML patients with hyperleukocytosis is hemorrhage rather than thrombosis [3,4], hyperleukocytosis can expand the leukemic cell plugs in the microvasculature and compromise tissue perfusion via its deleterious effect on blood rheology [5]. Furthermore, cancer procoagulants, tissue factor expression, and the increased proteolysis of coagulation factors by leukemic cells may also contribute to the propensity for thrombotic vascular occlusion.

The optimal treatment of acute brain infarction in AML patients with hyperleukocytosis remains unclear. Anticoagulant and/or thrombolytic therapy may be inappropriate because catastrophic hemorrhage can occur in the context of insulted blood vessels. This patient illustrates that leukapheresis alone can provide rapid and effective relief of symptoms without neurologic sequela. To achieve better outcomes and survival, clinicians must

maintain a heightened awareness of this distinctly unusual manifestation.

Wen-Hsin Hsu MD Shi-Jye Chu MD

Department of Emergency Medicine Tri-Service General Hospital National Defense Medical Center

Taipei 114, Taiwan, Republic of China

Wei-Chi Tsai MD

Department of Neurology and Neurorehabilitation

Tri-Service General Hospital National Defense Medical Center Taipei 114, Taiwan, Republic of China

Yu-Tzu Tsao MD

Department of Neurology and Neurorehabilitation

Tri-Service General Hospital National Defense Medical Center Taipei 114, Taiwan, Republic of China E-mail address: [email protected]

doi:10.1016/j.ajem.2007.05.014

References

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