More on priapism
Hindawi Publishing Corporation
Advances in Urology
Volume 2008, Article ID 549861, 3 pages
doi:10.1155/2008/549861
Idiopathic Low-Flow Priapism in Prepuberty:
A Case Report and a Review of Literature
Ihab A. Hekal1 and Eric J. H. Meuleman2
1Urology Department, Urology and Nephrology Center, Mansoura 35516, Egypt
2Urology Department, Free University Medical Center, 1007 MB Amsterdam, The Netherlands
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Priapism is a condition first described by Tripe in 1845.
It has been defined as a pathological condition of
penile erection that persists beyond or is unrelated to sexual
stimulation .
In children and prepubertal boys as well as in adults,
it can be classified according to the aetiology into low-flow
(ischemic) and high-flow priapism. Most common causes
of the former are the use of medications and hematological
conditions. Several medications have been implicated in
ischemic priapism. Most notably, psychiatric drugs as a class
are over represented. Antipsychotics such as chlorpromazine,
phenothiazine, and clozapine are known culprits as well are
the antidepressants such as trazodone [5]. Olanzapine or
methylphenidate therapy (drugs used for attention deficit
hyperactivity disorder) is reported to cause priapism in
children [6]. Total parenteral nutrition, with its high fat
content, is also believed to cause priapism [7].Hematological
diseases that are accompanied by hyperviscosity such as
sickle cell disease or trait and leukemia are well-known causes
of ischemic priapism in children [8].
High-flow (nonischemic) priapism was firstly described
over 40 years ago [9]. It is always the result of a straddle injury
of the corpora cavernosal resulting in an arteriocavernosal
fistula, which on its turn results in an uncontrolled arterial
inflow into the cavernosal sinusoids. Because the cavernosal
smooth muscle is contracted and well oxygenated (on
aspiration, bright red blood with a high PO2 is encountered),
the erection is semirigid and not painful [8].
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In low-flow priapism, venous outflow is blocked due
to a complete paralysis of the cavernous smooth muscle.
Due to ischemia, the erection is painful. .
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Various histological studies have been performed to
define the histological changes in relation with the duration
of ischemia. In the early stages at less than 12 hours,
interstitial edema and thickening are the most common
findings. From 12 to 24 hours, thrombocytes start to adhere
to the endothelium such that by 48 hours necrosis of
cavernosal smooth muscle cells and fibroblast proliferation
has occurred. The end result is loss of smooth muscle and
fibrosis of the corpora cavernosa [12].
Low-flow priapism has been described in men of all ages
including newborns. The peak incidence is bimodal with the
highest incidence occurring between the ages of 5–10, and
20–50 years. Generally in the younger age group, priapism is
secondary to a neoplasm or sickle cell anemia [8]
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