Hyperviscosity syndrome
Hyperviscosity Syndrome (HVS) = increased serum viscosity due to high cellular or protein content of blood. Medical emergency that can cause neurological, visual, and cardiorespiratory compromise
🧾 Causes
- 🧬 Waldenström’s macroglobulinaemia (↑ IgM, pentameric → very viscous)
- 🦴 Multiple Myeloma (↑ IgA, IgG paraproteins)
- 🧪 Leukaemias: CLL, CML, ANLL (marked leukocytosis)
- 🩸 Polycythaemia vera (↑ Hb/red cell mass)
- 🧬 Essential thrombocythaemia (↑ platelets)
- 🧪 Myelodysplastic syndromes with extreme leukocytosis
- ❄️ Type I & II Cryoglobulinaemia
- 💙 Cyanotic congenital heart disease (↑ Hb from chronic hypoxia)
- 🧬 HbSS (sickle cell disease → reduced red cell deformability)
- 💉 Iatrogenic: IVIG therapy, IgG4-related disease, HIV infection (polyclonal IgG rise)
🩺 Clinical Features
- 😮💨 Breathlessness, hypoxia, pulmonary infiltrates
- 🧠 Neurological: delirium, headache, dizziness, confusion, seizures
- 👁️ Visual: blurring, diplopia, papilloedema, venous engorgement, retinal haemorrhages
- ❤️ Cardiac failure or priapism (↑ sluggish flow)
- 🩸 Chronic mucosal bleeding: recurrent epistaxis, gum bleeding, GI haemorrhage
🔎 Investigations
- 📈 Hb >180 g/L, WCC >100 × 10⁹/L, Platelets >1000 × 10⁹/L
- 🧪 High paraprotein: IgM >5 g/dL, IgA >6 g/dL, IgG >4 g/dL
- 🧬 Serum electrophoresis: monoclonal or polyclonal immunoglobulin rise
- 💡 Serum viscosity: measured in centipoise (cp)
– Water = 1.0 cp
– Normal serum = 1.4–1.8 cp
– Symptoms usually start at 4.0–5.0 cp
– HVS typically >5.0 cp
💊 Management (involve haematology early)
- 💧 IV fluids to improve perfusion and reduce viscosity
- 🧪 Leucapheresis for hyperleukocytosis
- 🌀 Plasmapheresis: exchange 3–4 L/day with 5% albumin until patient is asymptomatic
- 🩸 If no plasmapheresis: manual plasma exchange (phlebotomy 1–2 units + fluid/albumin replacement)
- 🎗️ Treat underlying cause with chemotherapy (e.g. rituximab in Waldenström’s, myeloma therapy, cytoreduction in leukaemia)
📚 References
