ORIGINAL ARTICLE

The prevalence of priapism in children and adolescents with sicklecell disease in Brazil

Paulo Sampaio Furtado • Milena Paiva Costa •

Flavia Ribeiro do Prado Valladares • Leandro Oliveira da Silva •

Maurıcio Lordelo • Isa Lyra • Ubirajara Barroso

Received: 11 June 2011 / Revised: 10 April 2012 / Accepted: 11 April 2012 / Published online: 27 April 2012

� The Japanese Society of Hematology 2012

Abstract To evaluate priapism rates in individuals

\18 years of age with sickle cell disease (SCD) at a referral

center. An evaluation was made of 599 consecutive male

patients with SCD, separated according to type of hemoglo-

binopathy (HbSS, HbSC and HbS-b-thalassemia). Age at first

episode and number of episodes were recorded. Cases of

sickle cell trait were excluded. Mean age was similar in all

groups. Overall, priapism occurred in 3.6 % of patients

(5.6 % of those with HbSS and 1.1 % of those with HbSC;

P = 0.01). In HbSS patients, the prevalence rate of priapism

was from 3.5 (CI 95 % 0.94–13.4) when compared

with patients with HbSC. No patient with b-thalassemia

had priapism. Mean follow-up was 39.7 months (range

1–202 months). Since 91 % of patients with priapism had

HbSS, this group was evaluated separately, revealing a rate of

priapism of 1.6 % in patients\10 years and 8.3 % in those

C10 years of age (P = 0.002). Regarding priapism in HbSS

patients C10 years (8.3 %) when compared with patients

\10 years (1.6 %), the prevalence rate was from 3.3 (CI

95 % 1.1–9.5). Duration of follow-up was not correlated with

priapism (P = 0.774). Forty-seven patients were lost to fol-

low-up. Telephone contact was successful with 14/22

patients with priapism, 50 % of whom had required hospital

treatment. Most episodes (86 %) occurred at night, always

during sleep. Medical interventions were required in 13 cases

as follows: intravenous hydration (n = 4), corpora cavernosa

puncture and drainage (n = 7) and corpus cavernosum–

corpus spongiosum shunts (n = 2). The prevalence of pria-

pism in children\18 years of age with SCD was 3.6 %, lower

than previously reported. Prevalence was higher in HbSS

patients, increasing in patients[10 years of age. Most epi-

sodes occurred at night and half of the patients required some

form of urological procedure.

Keywords Priapism � Sickle cell disease � Children �Hemoglobinopathy

Introduction

Sickle cell anemia (SCA) refers to a heterogeneous group of

genetic hemolytic anemias in which normal hemoglobin A is

substituted by hemoglobin S due to an inherited b-S mutation

(bS). Patients with this abnormality may present with

homozygous sickle cell disease (HbSS) or compound heter-

ozygosity (HbSC, HbS-b-thalassemia, HbSD). The bS

mutation is responsible for changes in the rheology of the

circulating erythrocyte, causing hemolytic anemia, vasooc-

clusion and vascular endothelial dysfunction [1, 2]. Patients

with sickle cell disease (SCD) have a heterogeneous pheno-

type, with acute and chronic clinical complications modu-

lated by genetic, environmental and socioeconomic factors.

Priapism is an involuntary, painful and persistent

erection. Data in the literature reporting the prevalence of

priapism in children are sparse. Within the general pop-

ulation with SCD, the rate of priapism is around 35 %

[3, 4]. The actuarial probability of experiencing priapism

by 20 years of age was found to be 89 %, [5] principally

in cases of HbSS and HbS-b-thalassemia. However, in

most studies the sample population comes from a tertiary

referral center in which the prevalence of priapism would

be expected to be higher. To the best of our knowledge,

this report constitutes the largest published series on the

prevalence of priapism in a pediatric population with

SCD.

P. S. Furtado � M. P. Costa � F. Ribeiro do Prado Valladares �L. Oliveira da Silva � M. Lordelo � I. Lyra � U. Barroso (&)

Bahiana University of Bahia, Salvador, Brazil

e-mail: paulosfurtado@gmail.com

123

Int J Hematol (2012) 95:648–651

DOI 10.1007/s12185-012-1083-0

Methods

A total of 599 consecutive male patients (children and

adolescents \18 years of age), who had been diagnosed

with SCD, were evaluated between October 1990 and May

2008. Patients enrolled to the study were receiving care at a

referral center for hematologic diseases in a Brazilian state

with approximately 14 million inhabitants. Patients were

divided into groups depending on whether they had HbSS,

HbSC or HbS-b-thalassemia and evaluated separately.

Priapism was defined as any involuntary, painful erection.

The age of the patient at the first episode of priapism and

the number of episodes were recorded. Attempts were

made to contact all patients whose medical records indi-

cated a history of priapism by telephone. The patients’

parents were asked about the number of episodes of pria-

pism, the number of episodes that had required hospital

treatment, the date of the first episode, time, the minimum

and maximum duration of the episodes and the type of

treatment received by the patient. The study was approved

by the Internal Review Board of our institution. Statistical

analysis of categorical and continuous data was performed

using the Chi-square test and Student’s t test, respectively.

The Statistical Package for the Social Sciences (SPSS,

version 15.0) was used throughout the statistical analysis.

Differences were considered statistically significant when

p values were \0.05.

Results

The mean age of patients and the prevalence of priapism

are shown in Table 1. There was no difference in the mean

age of patients between the groups. The general prevalence

of priapism was 3.6 %, ranging from 5.6 % in patients with

HbSS to 1.1 % in those with HbSC (P = 0.01). In HbSS

patients, the prevalence rate of priapism was from 3.5 (CI

95 % 0.94–13.4) when compared with patients with HbSC.

Mean follow-up was 39.7 months, ranging from 1 to

202 months. Priapism was not reported by any of the

HbS-b-thalassemia patients. Because 91 % of the patients

who had suffered priapism had HbSS, these patients were

evaluated separately.

The correlation between age and priapism in patients

with HbSS is shown in Table 2. The correlation between

these patients and time of follow-up is shown in Table 3.

No episodes of priapism were detected in patients under

7 years of age. The prevalence of priapism was 1.6 % in

patients under 10 years of age and 8.3 % in those of

10 years of age or older (P = 0.002). Regarding priapism

in HbSS patients C10 years (8.3 %) when compared with

patients \10 years (1.6 %), the prevalence rate was from

3.3 (CI 95 % 1.1–9.5). There was no relationship between

the time of follow-up and priapism (P = 0.774). Forty-

seven patients were lost to follow-up.

Telephone contact was successful in fourteen of the

patients with a history of priapism. The mean age of these

patients was 13.4 years, ranging from 7 to 18 years. Three

patients had had only one episode, while one patient had

two episodes, one had three and the other patients had had

Table 1 Distribution of mean age in years, time of follow-up in months and prevalence of priapism in HbS patients

HbSS (%) HbSC (%) HbS-b-thalassemia Other hemoglobinopathy P value

Mean age 10.37 ± 4.27 10.48 ± 4.42 10.33 ± 5.12 9.66 ± 5.00 NS

Priapism 20 (5.6 %) 2 (1.1 %) 0 0 0.01

Total 388 178 11 22

Regarding priapism in HbSS patients, the prevalence rate was from 3.5 (CI 95 % 0.94–13.4) when compared with patients with HbSC

Table 2 Prevalence of priapism in patients with HbSS by age in

years

Priapism Total

No Yes

Age

1 5 0 5

2 5 0 5

3 10 0 10

4 13 0 13

5 26 0 26

6 27 0 27

7 41 2 43

8 32 1 33

9 25 0 25

10 24 2 26

11 31 2 33

12 21 1 22

13 24 2 26

14 17 2 19

15 20 1 21

16 18 1 19

17 17 3 20

18 12 3 15

Total 368 20 388

Regarding priapism in HbSS patients C10 years (8.3 %) when com-

pared with patients \10 years (1.6 %), the prevalence rate was from

3.3 (CI 95 % 1.1–9.5)

The prevalence of priapism in children and adolescents with sickle cell disease 649

123

more than three episodes of priapism. Half of the patients

required hospital treatment. The minimum duration of the

episodes of priapism was 2 min and the maximum 3 days.

The patient whose episode of priapism lasted for 2 min had

a well characterized, painful erection. Most episodes

(86 %) occurred at night and always when the patient was

asleep. In thirteen patients, a procedure was necessary

following the failure of more conservative approaches. In

four cases, the episode of priapism was successfully

resolved by intravenous hydration. Seven patients required

corpora cavernosa puncture and drainage, and in two cases

a surgical procedure (corpus cavernosum–corpus spongio-

sum shunt) was performed following the failure of more

conservative approaches.

In 10 cases of patients who were unable to be reached by

telephone, their charts were reviewed. Six patients had had

[3 episodes of priapism, while three had had only one

episode and information was missing regarding the number

of episodes of priapism in the case of the remaining patient.

Discussion

To the best of our knowledge, this is the largest series to

evaluate the prevalence of priapism in children with SCD.

The rate of priapism found here was lower (3.6 %) than

rates reported in the literature for children and adults with

SCD [3–6]. If this evaluation was limited exclusively to

those patients with HbSS, the rate of priapism would still

be low (5.6 %). The rate of priapism in HbSS patients was

almost fivefold higher compared to the group of patients

with HbSC. Gbadoe et al. [6] interviewed a group of 115

patients over 5 years of age, most of whom were adults,

and reported a rate of priapism of 26 % in patients with

SCD. Adeyoju et al. [4] reported acute episodes of pria-

pism in 25 % of 130 patients with SCD and a mean age of

25 years. Mantadakis et al. [5] evaluated the rate of pria-

pism in a group of 98 patients B20 years of age with SCD.

The patients were interviewed during a scheduled

outpatient visit to the sickle cell clinic of the Children’s

Medical Center, Dallas. Overall, 27 % reported at least one

episode of priapism. The actuarial probability of a patient

experiencing priapism by 20 years of age was 89 %.

One of the strengths of this study is that the data were

collected at the only referral center for SCD in a state of 14

million inhabitants. Therefore, the possibility of a selection

bias is slight in this population. In studies in which the

population comes from a tertiary center, the prevalence of

priapism is expectedly higher. Other explanations for the

low rate of priapism found in the present study include:

(a) the fact that the analysis was retrospective and the

episodes of priapism may have been underreported in the

charts; (b) differences in this sample population; and

(c) more rigorous follow-up of patients (regular use of

medication reduces vascular episodes).

Although the analysis of these data was retrospective,

priapism is a mandatory question in the follow-up inter-

view of any patient with SCD. Furthermore, acute priapism

is an extremely memorable event and is often reported

spontaneously by the parents, since it is generally severe

enough to cause the family to seek hospital treatment for

the patient. Therefore, it is believed that few cases of pri-

apism failed to be included in the study. However, even so,

since the percentage of patients evaluated is high, this

would not have resulted in any significant change in the

prevalence rate.

A difference in the clinical course of SCD in this sample

population may justify the lower rate of priapism. The

gamut of symptoms experienced by patients with SCD may

vary greatly, ranging from minimal clinical manifestations

to the most severe forms of the disease. Many factors may

influence the heterogeneity of these manifestations including

environmental, socioeconomic, cultural and psychological

variables [7].

The haplotypes of the b-globin genes, which may affect

fetal hemoglobin levels, are used as genetic markers to

identify specific segments of chromosomes in population

studies [8]. A high level of fetal hemoglobin inhibits HbS

polymerization and has been associated with a more benign

course of the disease. Five main haplotypes of SCA have

been described according to the geographical area where

they are most common: Benin, Senegal, Bantu, Cameroon

and Arab-Indian. The Benin and Bantu haplotypes, the

variants that are predominant in Brazil, are associated with

lower fetal hemoglobin levels, while the Senegal and Arab-

Indian variants are associated with higher risks of priapism

[9, 10]. In this country, 20 % of individuals of African

descent are heterozygous for a-thalassemia because of a

deficiency in a gene (a3.7 kb) [11]. This reduces hemolysis,

increases hemoglobin levels and reduces the mean cor-

puscular volume of the red blood cells as well as the

number of reticulocytes when compared to the HbSS

Table 3 Correlation between time of follow-up in years and priapism

in patients with HbSS

Priapism Total

No Yes

Time of follow-up

0–3 173 8 181

4–6 77 5 82

C7 73 5 78

Lost of follow-up 45 2 47

Total 368 20 388

P = 0.774

650 P. S. Furtado et al.

123

individual who has no alpha genes. The beneficial effects

of this association in the clinical course of the patient

include fewer limb ulcers, cerebrovascular accidents and

possibly priapism. In this particular region of the country, a

high level of miscegenation is characteristic. However,

based on the findings of the present study, the hypothesis

that this could influence the way in which the disease

manifests itself remains unproven.

Finally, rigorous follow-up may affect the rate of com-

plications in SCD. Control of anemia, good hydration and

regular use of medication will result in a reduction in

vascular episodes. In this institute, patients are reminded of

their follow-up visits by telephone or letter in an attempt to

improve compliance. This service is the only referral center

for SCD treatment in the state. Few patients miss their

follow-up visits, particularly symptomatic patients.

Fowler et al. [3] reported a 33 % incidence of priapism

in patients with HbS-b-thalassemia. In the present study, no

cases were found in this specific group. However, the

number of patients in the present sample who had this type

of SCD is too small to allow any conclusion to be reached.

It is widely known that patients with HbS-b-thalassemia

are clinically similar to those with HbSS; therefore, pria-

pism is also a concern in this group of patients. Although in

the present study, HbS-b-thalassemia was not divided into

its two subtypes: Hb b and Hb b?, Hb-b-thalassemia is

known to be the more aggressive type.

According to the findings of the present study on pria-

pism in SCA, recurrent episodes are common; however,

only half of the patients required hospital treatment. Most

episodes (86 %) occurred at night and always when the

patient was asleep. Around 14 % of the patients with pri-

apism required a corpus cavernosum–corpus spongiosum

shunt.

In conclusion, the prevalence of priapism in children

\18 years of age with SCD was 3.6 %. This rate was

higher in HbSS patients and more prevalent after 10 years

of age. Mean duration of follow-up was 39.7 months. Most

episodes occurred at night and half of the patients needed

some type of urological procedure.

Conflict of interest None.

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