Diseases caused by increased number of erythrocytes
EPO) when staying at high altitude, chronic lung disease, right-to-left shunts, methemoglobinaemia.Secondary polyglobulia is mostly compensatory in chronic hypoxia (leads to ↑
The clinical picture
- mainly symptoms of underlying lung/heart disease,
- plethoric appearance, cyanosis,
- headaches, dizziness, visual disturbances.
- ↑ erythrocytes, HTK > 48%, oxygen saturation <92%, ↑ EPO (dif. dg. Polycytaemia vera).
- Stress polycythemia in young people (+ hypertension, obesity = Gaisböck's syndrome)
- Relative polyglobulias in dehydration, extensive burns, etc.
Neonatal polycythemia is defined as a central venous hematocrit > 0,65. Nowever, even with a hematocrit> 0.70, only a small proportion of neonates have clinical signs of hyperviscosity. The clinical picture includes lethargy, hypotension, hyperbilirubinemia and hypoglycemia. Polycythemia may also be involved in the development of convulsions, stroke, renal venous thrombosis and necrotizing eneterocolitis.
Causes of neonatal polycythemia:
- Fetal growth restriction (FGR, IUGR);
- maternal hypertension;
- maternal diabetes;
- chromosomal defects: trisomy 21, 18, 13;
- twin-to-twin transfusion;
- delayed umbilical cord rupture;
- endocrine disorders: tyreotoxicosis, congenital adrenal hyperplasia (CAH).
Treatment is controversial and may not be necessary in neonates with mild symptoms (eg borderline glycaemia, impaired peripheral blood flow). Treatment is indicated in neonates with a hematocrit> 0.65 and symptoms with a potentially severe prognosis (eg refractory hypoglycaemia, neurological symptoms). A partial exchange transfusion is performed with a crystalloid solution (eg physiological solution) with a target hematocrit of 0.55.
- KLENER, P. Vnitřní lékařství. 3. edition. Galén, 2006. ISBN 80-7262-430-X.
- LEDVINA, Miroslav, et al. Biochemie pro studující medicíny. 2. vydání. Praha : Karolinum, 2009. 548 s. s. 85-90. ISBN 978-80-246-1414-4.