RESULTS
From 2000 to 2020, 40 patients were diagnosed with erythrocytosis at the
center, in a male-to-female ratio of 7 to 1. Their mean age was 15.31 ±
2.49 years (8.34–17.92) years at diagnosis and 17.92 ± 2.96 years
(11.43–27.17) at data collection, and the median follow-up time was 9
months, ranging from 6 months to 13.80 years. Thirty-two (80.0%)
patients had been referred in the past 24 months due to full-blood count
screening performed in schools. In terms of family relatedness, two of
the patients were siblings. Table 1 summarizes the demographic and
laboratory characteristics of the patients.
The medical histories of the patients involved no other diseases, and
patients generally seemed to be healthy. Seventeen families (43.58%)
had relatives with erythrocytosis, or relatives who regularly received
phlebotomies, and in seven and five families, fathers and siblings were
also affected, respectively. In 11 families (28.20%), 15–48-year-old
relatives had experienced myocardial infarction, stroke, and/or sudden
death.
Physical examination revealed that 14 (35.0%) patients had plethora,
while none had splenomegaly or any other pathological findings. The Hgb
levels, age, and sex of the patients at diagnosis appear in Figure 1;
mean Hgb at diagnosis was 17.40 ± 1.34 g/dL (14.63–23.0 g/dL). All
patients’ leukocyte counts, platelet counts, venous blood gas levels,
capillary oxygen saturation levels (>95%), and results of
Hgb electrophoresis (i.e., with high-performance liquid chromatography)
were within normal limits. To analyze EPOR mutations, the blood samples
of the first seven patients had been sent to Portugal, but results
revealed only a previously identified heterozygous EPOR nonsense
mutation c.1316G>A (p.Trp439Term) in two
siblings.13 No patient exhibited a JAK2mutation or splenomegaly, thrombocytosis and/or leukocytosis which are
characteristic findings of myeloproliferative disease.
Recurrent phlebotomies (i.e., 1–12 times/year) had been performed on
demand in all patients in the presence of symptoms of hyperviscosity,
and all patients had reported symptom relief after the procedure (Table
1). Many patients had been prescribed acetylsalicylic acid as an
antiaggregant but had demonstrated poor compliance. All patients had
been informed about potential bleeding and thrombosis at diagnosis, and
good hydration, an active lifestyle, and abstinence from smoking,
mountain climbing, and scuba diving had been recommended. No thrombotic
episodes had occurred in any patients during follow-up.
Symptoms and signs of CE detected in the patients are listed in Table 2.
The most common presenting symptoms were headache (80.0%), numbness and
tingling in the hands and feet (45.0%), and pruritus (37.5%). At least
one gastrointestinal symptom (e.g., nausea, vomiting, abdominal pain,
and rectal bleeding) was reported in 40.0% of patients.
Gastrointestinal symptoms were prominent, and patients reported visiting
numerous pediatricians for years in search of a diagnosis. Six cases of
CE (15.0%), despite being asymptomatic at diagnosis, were detected
during routine whole blood screening.