Viscosity is discussed in Chapter 3 (Hematology).
(1) The normal relative viscosity is 1.4 to 1.8.
(2) The symptoms of hyperviscosity may begin when the relative viscosity is >= 4.
(3) Viscosity > 6 is usually accompanied by symptoms.
(4) Most symptoms will reverse with reduction in viscosity unless end-organ damage has occurred.
Signs and Symptoms Associated with Hyperviscosity
Weakness and/or fatigue
Anorexia
Weight loss
Coagulopathy (oozing of blood from mucous membranes, nose bleeds, GI bleeding, hematuria, oozing from surgical sites)
Anemia
Visual disturbances (diplopia, partial or complete loss of vision, distended retinal vessels, retinal hemorrhages, papillodema, retinal vein thrombosis)
Distended conjunctival vessels with hemorrhage
Headache
Dizziness and/or vertigo
Nausea
Nystagmus
Ataxia
Decreased mental status (somnolence, stupor, coma)
Psychiatric changes (psychosis, etc.)
Generalized seizures
Hemiparesis
Hearing loss
Postural hypotension
Congestive heart failure
Angina pectoris
Hypotension
Peripheral hypoperfusion, peripheral vascular disease
Hypervolemia (expanded plasma volume)
Impaired renal function (microinfarcts, glomerular deposits, glomerular-tubular dysfunction)