The neurological symptoms of hyperviscosity have been referred to as the Bing-Neal syndrome. Vertigo Hearing loss Paresthesias Ataxia Headaches Seizures Somnolence progressing to stupor and coma Other manifestations may include heart failure, fatigue, and anorexia. Bruises, epistaxis, or gum bleeding may be noted. Ophthalmic examination may reveal decreased visual acuity, dilated retinal veins, sausage-linked retinal veins, or retinal hemorrhages. Neurological examination may reveal various findings, including diminished mental status, confusion, ataxia, or nystagmus.
Serum viscosity is diagnostic in evaluating hyperviscosity syndrome.
The normal range is 1.4-1.8 units. Symptoms usually are not seen before the viscosity reaches 4 units, and hyperviscosity syndrome usually presents with a serum viscosity above 5 units. Obtain a peripheral blood smear. Rouleaux formation is often present with increased serum viscosity. Tailor additional workup to the patient's presentation.