Sarah Klemencic, MD; Jack Perkins, MD


Western J Emerg Med. 2019;20(2):316-322. 

In This Article

Hyperviscosity Syndrome

Hyperviscosity syndrome (HVS) is a rare but potentially catastrophic consequence of increased serum viscosity due to excess serum proteins.[56–59] Hyperviscosity syndrome is the consequence of a significant excess in serum proteins (e.g., Waldenstrὂm's macroglobulinemia [WM] or multiple myeloma) or cellular components (e.g., white blood cells in acute leukemias).[60] Patients with WM are at highest risk for HVS with 40–90% of HVS cases occurring from WM.[61] HVS can also be seen in diseases such as multiple myeloma (second most common cause of HVS), leukemia, and polycythemia.[59] Hyperviscosity syndrome results in relative hypoperfusion, and resultant clinical manifestations represent end-organ dysfunction that may mimic other disease pathology. For example, patients with HVS may complain of visual changes (mistaken for cerebral vascular accident), dyspnea (mistaken for pulmonary embolus or congestive heart failure), or altered mental status (mistaken for sepsis). The classic triad of HVS is mucosal or skin bleeding, visual changes, and focal neurologic deficits; although it is not clear what percentage of patients present with this classic triad.[56–60] The EP should consider this diagnosis in any patient found to have a markedly elevated white blood cell count (i.e., >100 x 104) or hemoglobin (i.e., approaching 20 g/dl) associated with symptoms of hypoperfusion.[61–63] Lab values that will offer the most information include the CMP (total protein and albumin level), CBC (hemoglobin, white blood cell count) with peripheral smear, and coagulation testing (coagulopathy is common in HVS).[63–66] Blood transfusion can significantly worsen HVS and should be avoided if possible. The mainstays of therapy are decreasing serum viscosity through IV fluid resuscitation, plasmapheresis, or leukopheresis.[63–67] Phlebotomy (e.g., polycythemia) or even urgent chemotherapy (e.g., acute leukemia) may also be indicated.[63–67] Evidence for these interventions suggests they do not alter the course of the disease but rather help with symptom alleviation. All patients with HVS will require admission to the hospital and warrant strong consideration for ICU admission.