Priapism is a complication rarely seen in leukemia. We report a 21-year-old man presented with persistent painful erection of penis for 19 hours at home. The patient had undergone immediate irrigation and decompression of priapism by urologist at emergency department . This approach resulted in a flaccid penis later. During hospitalization, peripheral blood smear and bone marrow aspiration was confirmatory of chronic myeloid leukemia. No impotency nor other sequela was noted after his discharge. This case illustrates the importance of all physicians in the diagnosis and management of patients with priapism.
(Chang Gung Med J 2003;26:288-92)

Key words:
priapism, chronic myeloid leukemia, emergency department, impotency.

CASE REPORT

A previously healthy 21-year-old man was referred from local hospital for treatment of priapism and hyperleukocytosis. His penis remained erect, painful, and swelling when he arrived at emergency department (ED). There was no history of trauma, malaise, night sweats, joint pain, and cough. However, body weight loss about 9 Kg and bleeding tendencies during recent 3 months were noted himself. The vital signs revealed a body temperature 38.2oC, pulse 109 beats/minute, and blood pressure 137/64 mmHg, respirations 21 beats/minute. He was alert and oriented. The physical examination revealed that the liver was palpable 6 cm below the right costal margin, and spleen was 7 cm below the left costal margin. His conjunctiva was pale but no jaundice. The penis was erect, firm, and tender with superficial venous engorgement. Laboratory data showed hemoglobin (Hb) 8.3 g/dl, hematocrit 25.7%, white blood count (WBC) 216,800/mm3, and Platelet 1746,000/mm3. Serum chemistries were unremarkable for uric acid 452 痠ol/L, creatinine 70.7 痠ol/L. Treatment of the priapism was initiated performed by cavernosa aspiration and epinephrine irrigation at ED under the impression of low flow type priapism because of his history and physical examination. The erection was relieved later by these procedures. For hyperleukocytosis, he was admitted to hematological ward and was diagnosed as a case of chronic myeloid leukemia on the basis of peripheral blood smear and bone marrow examination (Fig.1). The Philadelphia chromosome was illustrated in the patient. He was started on hydroxyurea tablets at 1.5 grams per day and one vial of interferon alfa-2a (6 MIU/vial) subcutaneously daily. Allopurinol 300mg daily with adequate hydration was also started for potential tumor lysis syndrome. Before discharge, his WBC dropped to 82900/ mm3 and Hb raised to 9.7 g/dl. Recurrent priapism was not happened to him during his admission period. The patient continues to report to us without any erectile dysfunction till date.

DISCUSSION

Priapism is an involuntary prolonged erection unrelated to sexual activity and cannot be relieved by ejaculation. Most priapism is painful but not all cases. Priapism is defined as either low-flow (ischemic) or high-flow (non-ischemic).(4) Low-flow or ischemic priapism results from pathologically decreased penile venous outflow that eventuates in stasis. Intracavernosal blood sampling reveals acidosis and a decrease in oxygen tension.(5) Clinically, low-flow priapism manifests as a painful, rigid erection. This type is more common and represents an actual emergency because irreversible cellular damage and fibrosis occur if treatment is not administered within 24 to 48 hours.(6) It will result in long-term sequela of erectile dysfunction or predisposition to frequent, prolonged episodes of priapism.(7) The cause of low-flow priapism including idiopathic, hematologic disorders,(8-9) tumor infiltrate,(10) or drugs induced.(11-12) High-flow or arterial priapism differs in that it results from increased arterial inflow into the cavernosal sinusoids, which overwhelms venous outflow and clinical presentation was painless. In contrast to low-flow priapism, intracavernosal blood sampling from patients with high-flow priapism reveals bright red oxygenated blood,(5) and thus irreversible cellular damage and fibrosis are rare.(6) The type of priapism is usually due to penis or perineum trauma that results in injury to the internal pudendal artery.(13-15) This establishes a fistula between the cavernosal artery and the corpus cavernosum that unregulated inflow occur. It is not an actual emergency in patients with high-flow priapism, and treatment can be on an elective basis.
Priapism can occur at any age and two peaks in age distribution is described.(16) A pediatric peak, 5-10 years old, is noted owing to sickle cell disease in black patients. The secondary peak occurs in patients with active sexual activity age of 20-50 years old. Idiopathic priapism is the most common (64%) while approximately 20% are related to hematologic disorders.(1,16) In CML, priapism is an unusual presentation and seldom to encounter. Hyperleukocytosis is though to be the cause of priapism in patients with leukemia.(4) Four different mechanism is described: (1) venous congestion of the corpora cavernosa resulting from mechanical pressure on the abdominal veins by the splenomegaly (2) Sludging of leukemic cells in the corpora cavernosa and the dorsal veins of penis (3) infiltration of the sacral nerves with leukemic cells (4) infiltration of the central nerve system. In our case, significant leukocytosis with hepatosplenomegaly supports the first mechanism in the pathogenesis. An important aspect of priapism is that most physicians will never encounter. The poor experience will result in delay of treatment and irreversible squeal. So all physicians should understand that long-term sequela can be avoided with prompt diagnosis and treatment.
To diagnose the underlying pathophysiology of priapism, the distinction between low and high flow priapism is important because their associated treatment and prognosis differ. Differentiating between low-flow and high-flow priapism can be achieved with a detailed history, physical examination, gas analysis of the blood within the corpora cavernosa,(15) and penile Doppler ultrasound study. Detailed history includes medications, malignant diseases, trauma, sickle cell disease, and the use of intracavernosal agents, all of which provide clues about the type of priapism. On physical examination, patients with low-flow priapism usually have a rigid, painful penile shaft with a soft glans, whereas in those with high-flow priapism ,the entire penis is partially rigid and painless. Intracavernosal blood gas analysis is helpful in differentiating between high and low flow priapism. Low-flow priapism have an intracavernosal blood pH < 7.00,(11) a PCO2 > 60 mmHg, and a PO2 < 30 mmHg.(17) These values vary depending on the duration of the low-flow state. High-flow priapism patients have normal blood gas analysis values. Doppler ultrasonography can be used to detect the presence of an arterial-to-cavernosum fistula in the patients with high-flow priapism. Besides, the initial work-up should includes complete blood count, hemoglobin electrophoresis, serum chemistries, coagulopathy state, and drugs screen if indicated.
About the management of priapism, there have been many methods described in the literature in the world. Spinal anesthesia, ice water enema, ice packs, fibrinolytic agents and anticoagulants have been tried but no significant success rate obtained. To relieve the painful erection of the patient, immediate aspiration and irrigation of the corpora cavernosa as well as injection of a-adrenergic agents were performed. The penis should be cleansed and 2% xylocaine is used to anesthetize the glans penis and septum between glans and corpora; general or spinal anesthesia is an alternative. To reduce the anesthesia risk, we did these procedures under sedation and local anesthesia. So this intervention can be done by any physician at anywhere with appropriate preparation. After preparation, repeated intracavernous aspirations through an 18-22 gauge needle into the corpora cavernosa and gentle normal saline irrigation were performed with a 10 ml syringe. The sluggish bloods were removed and the intracavernous pressure was reduced. Erect penis may relieve by these procedures along. However, it is more effective with an additional injection of a-adrenergic agents such as phenylephrine or epinephrine. If the erection persists for 24-48 hours, the patient should have a surgical shunt performed to reduce the priapism. The purpose of surgical procedures is to establish a new venous outflow and restore normal arterial flow to the corpora cavernosa. The Urologists should also involve in the early intervention because of their familiar with the management and complication of the priapism.
The importance of prompt diagnosis and treatment of priapism cannot be overemphasized, as there is definite incidence of impotence following this condition. One study cited 35% and 60% impotence rates for patients priapistic for 5 days and 10 days, respectively.(18) So decompression of the penis should be done as frequently as possible during the first 24 hours.(2)
Besides the initial relief of priapism, the further workup and management of the underlying disease are more important. In our case, with use of a combined urological therapy and oncological treatment to priapism, the patient was recovery and had restored long-term potency. In conclusion, priapism is an uncommon presentation in CML that all physicians should be aware of the disorders and the need for early intervention and management.

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From the Department of Emergency Medicine, 1Division of Hematology-Oncology, Chang Gung Memorial Hospital, Taipei.
Received: Mar. 20, 2002
Accepted: Aug. 20, 2002
Address for reprints: Dr. Shy-Shin Chang, Department of Emergency Medicine, Chang Gung Memorial Hospital. 5, Fushing Street, Gueishan Shiang, Taoyuan, Taiwan 333, R.O.C.
Tel.: 886-3-3281200 ext. 2505
Fax: 886-3-3287715
E-mail: sschang@cgmh.org.tw