Introduction: The opsoclonic-myoclonic-ataxic syndrome (OMAS) is that in which there are at least two of the cardinal signs (opsoclonus, myoclonus and ataxia).
Objectives: To report three cases, their evolution and aetiology, and discuss the main physiopathological basis and guidelines for treatment.
Clinical cases: We present three cases admitted to the Internal Medicine Department with the diagnosis of OMAS. The investigations included standard biochemical and haematological tests, a full study of the cerebrospinal fluid, computerized axial tomography of the skull and thorax, and magnetic resonance. We describe the clinical presentation, evolution, aetiology and treatment given. The results of the complementary tests are shown in the form of tables. Finally we consider the diagnosis of this condition. Three patients, two men and one woman, aged between 43 and 78 were diagnosed as having OMAS. The causes were: paraneoplasia, acute diffuse encephalomyelitis and probable multiple sclerosis. The patient with lung cancer died whilst the other two showed almost complete recovery on the treatment given.
Conclusions: Our cases show that OMAS may be a feature of a diffuse process affecting the brainstem and cerebellum. The commonest causes found are multiple sclerosis, acute diffuse encephalomyelitis and as a paraneoplastic feature of a tumour. It may improve with treatment, but depending on the aetiology, death may occur. Immunomodulation treatment is vital even though symptomatic treatment may be given.