Abstract
Tinnitus is the sensation of sound inside the head and is a common symptom encountered daily by otorhinolaryngologists. Pulsatile tinnitus sufferers hear rhythmical noise at the same rate as a heartbeat and can present a diagnostic challenge. In this report, we present a 32-year-old patient with pulsatile tinnitus that led to the diagnosis of essential thrombocythemia. The symptom of pulsatile tinnitus allowed an early diagnosis of essential thrombocythemia and a more favorable prognosis. The case demonstrates the importance of blood tests for all patients who present with pulsatile tinnitus of unknown origin.
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Case report
A 32-year-old man presented at our hospital on October 25, 2006, with bilateral pulsatile tinnitus that had started 2 weeks previously. The tinnitus volume had become increasingly loud and was described as a “pa-hyu, pa-hyu” sound that was synchronized to the patient’s heartbeat and changed in tone when he turned his neck. There were no associated findings such as otorrhea, otalgia, hearing loss, or vertigo.
Microscopic inspection revealed no abnormalities in either of the tympanic membranes or the external auditory canals. Pure-tone audiometric examination, tympanometry, stapedial reflex, Bekesy audiometry, and x-ray examination of the ears also failed to show abnormal findings; and the patient’s blood pressure was normal at 133/74 mm Hg. A blood test was performed including a full cell count, liver function, and cholesterol value. Although most results were normal, the platelet count was abnormally high at 1866 × 10 9 cells per liter. Leukocyte counts were slightly high at 12 100/ μ L, and there were megakaryocytes and primitive leukocytes in the peripheral blood.
The patient was admitted to a hematology and oncology specialist on October 27, 2006; and on the same day, bone marrow aspiration and chromosomal testing were performed to rule out chronic myeloid leukemia and essential thrombocythemia. Ten days later, the patient was diagnosed with essential thrombocythemia from the results of the blood test, bone marrow test, and chromosomal test . On the day the platelet count increased to 2010 × 10 9 cells per liter, the hematologic specialist administered ranimustine, an antineoplastic alkylating agent, to prevent the development of thrombosis and bleeding by reducing the number of platelets. Aspirin medication was started for antiplatelet therapy.
The medication, platelet count, and the subjective tinnitus loudness level (0–10, minimum–maximum) are shown along a time course in Fig. 1 . Two months later, the platelet count decreased to 935 × 10 9 cells per liter and thereafter rebounded to 1056 × 10 9 cells per liter. A second dose of ranimustine was administered on December 22, 2006; and 3 months later, the platelet count again began to increase. Continuous intermittent oral administration of hydroxyurea was carried out from March 16, 2007; and thereafter, the platelet count stabilized around 600 × 10 9 cells per liter. As the platelet count decreased, the subjective tinnitus also diminished and finally disappeared until now (February 1, 2010). It therefore appears that the platelet count increase was the cause of the pulsatile tinnitus ( Fig. 1 ).
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Discussion
Pulsatile tinnitus is unique in that it is rhythmic and synchronous with the patient’s pulse. It can be caused by vascular diseases, such as arteriovenous shunt or fistula, arteriovenous malformation, arteriosclerosis, high jugular bulb, and benign intracranial hypertension; it can also be due to intracranial lesions, such as glomus tumors, meningioma, and hemangioma, or systemic diseases, such as anemia and hypertension .
Common patient subjective expressions of pulsatile tinnitus are represented as “dok, dok”; “za, za”; “jin, jin”; “zak, zak”; or “shu, shu.” In this case, the patient expressed the sound as “pa-hyu, pa-hyu,” suggesting a rare symptom probably caused by the increase in blood viscosity due to essential thrombocythemia.
The World Health Organization classification recognizes essential thrombocythemia as a chronic myeloproliferative disease characterized by a high platelet count (greater than 600 × 10 9 cells per liter). Diagnosis in these patients is confirmed by invasive evaluation (diagnostic bone marrow biopsy, absence of Philadelphia chromosome on bone marrow culture, and absence of the bcr/abl fusion gene). In essential thrombocythemia, bone marrow findings are remarkable for the presence of large, but mature-appearing, megakaryocytes with deeply lobulated nuclei that are most often dispersed throughout the biopsy sections, but sometimes also found in loose clusters .
Essential thrombocythemia generally shows a slight female preponderance (1:1.5–2.1, male to female ratio) . The availability of a unique medical record system for essential thrombocythemia in Olmsted County, Minnesota, has supported population-based epidemiologic data that report the age- and sex-adjusted annual incidence rate to be 2.53 per 100 000 population . As life expectancy appears to be normal in essential thrombocythemia, the prevalence of the disease is much higher and has been estimated at 24 total cases per 100 000 population . The median age at diagnosis is 60 years, although the diagnostic age range is very wide (18-90 years). Approximately half of patients are asymptomatic, whereas the other half has vasomotor, thrombotic, or hemorrhagic disturbances. Pulsatile tinnitus has never before been reported as a symptom of essential thrombocythemia, and we believe that detailed medical interviews should be carried out in all cases of pulsatile tinnitus to assess the likelihood of essential thrombocythemia .
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