Priapism at Diagnosis of Pediatric Chronic Myeloid Leukemia: Data Derived from a Large Cohort of Children and Teenagers and a Narrative Review on Priapism Management

Abstract

Pediatric chronic myeloid leukemia (CML) is a very rare malignancy (age-related incidence 0.1/100,000) typically presenting with leucocyte counts >100,000/µL. However, clinical signs of leukostasis are observed at diagnosis in only approximately 10% of all cases and among these, priapism is infrequent. Here, we analyze data from pediatric CML registries on the occurrence of priapism heralding diagnosis of CML in 16/491 (3.2%) boys (median age 13.5 years, range 4-18) with pediatric CML. In the cohort investigated, duration of priapism resulting in a diagnosis of CML was not reported in 5 patients, and in the remaining 11 patients, occurred as stuttering priapism over 3 months (n = 1), over 6 weeks (n = 1), over 1-2 weeks (n = 2), over several days (n = 2), or 24 h (n = 1), while the remaining 4 boys reported continuous erection lasting over 11-12 h. All patients exhibited splenomegaly and massive leukocytosis (median WBC 470,000/µL, range 236,700-899,000). Interventions to treat priapism were unknown in 5 patients, and in the remaining cohort, comprised intravenous fluids ± heparin (n = 2), penile puncture (n = 5) ± injection of sympathomimetics (n = 4) ± intracavernous shunt operation (n = 1) paralleled by leukocyte-reductive measures. Management without penile puncture by leukapheresis or exchange transfusion was performed in 3 boys. In total, 7 out 15 (47%) long-term survivors (median age 20 years, range 19-25) responded to a questionnaire. All had maintained full erectile function; however, 5/7 had presented with stuttering priapism while in the remaining 2 patients priapism had lasted <12 h until intervention. At its extreme, low-flow priapism lasting for longer than 24 h may result in partial or total impotence by erectile dysfunction. This physical disability can exert a large psychological impact on patients' lives. In a narrative review fashion, we analyzed the literature on priapism in boys with CML which is by categorization stuttering or persisting as mostly painful, ischemic (low-flow) priapism. Details on the pathophysiology are discussed on the background of the different blood rheology of hyperleukocytosis in acute and chronic leukemias. In addition to the data collected, instructive case vignettes demonstrate the diagnostic and treatment approaches and the outcome of boys presenting with priapism. An algorithm for management of priapism in a stepwise fashion is presented. All approaches must be performed in parallel with cytoreductive treatment of leukostasis in CML which comprises leukapheresis and exchange transfusions ± cytotoxic chemotherapy.

Keywords: chronic myeloid leukemia; exchange transfusion; hyperleukocytosis; leukapheresis; leukostasis; pediatric CML; pediatric CML registry; penile puncture; priapism.

Figure 3

Algorithms for diagnostic procedures and therapeutic management of priapism in patients with pediatric CML (Modified from [23,24,25,96,97,98,99]). For details see text. Abbreviations: BCR::ABL1 = Breakpoint cluster region-Ableson leukemia 1 (chromosomal rearrangement representing the hall mark of CML), BGA = blood gas analysis, CML = chronic myeloid leukemia, hrs = hours, TKI = tyrosine kinase inhibitor, WBC = whole blood count.

Figure 1

Schematic cross-sectional diagram of the anatomy of the penis. The smooth muscles of the corpora cavernosi and the arterial and arteriolar walls play a predominant role in the erectile process. Following sexual stimulation, these flat muscles relax causing dilatation and increased blood flow. The blood is trapped when the subtunical venular plexus are compressed between the tunica albuginea and the peripheral sinusoids. Note the interconnections between the left and right corpus cavernosum (in this schematic diagram only one interconnection is shown) which enable blood exchange in such way that only unilateral aspiration is sufficient when low flow priapism is treated (for details see text, modified from [25]).

Figure 2

Age distribution of patients with priapism at diagnosis of pediatric CML.

Figure 4

Technique of corporal blood aspiration with a butterfly needle. Insertion is performed laterally at a middle position of the shaft to avoid damaging the corpus spongiosum/urethra or the dorsal neurovascular bundles. In cases of low flow priapism, unilateral aspiration is sufficient as interconnections exist between the left and right corpus cavernosum. A three-way tap is connected to the tube of the butterfly needle allowing irrigation and aspiration (Modified from [24]).