Chronic myeloid leukemia (CML), also known as chronic myelogenous leukemia or chronic granulocytic leukemia, affects about 15% of the adult population, starting in the hematopoietic cells of the bone marrow and spreading into the blood. The disease progresses through three phases: chronic, blast, and accelerated. In most cases, adult patients with CML are asymptomatic, with the majority of patients in the chronic phase, and the disease is discovered incidentally during a routine complete blood count that reveals an elevated white blood cell count.

Despite claims of an asymptomatic course of the disease, there are specific symptoms that should be noted. These include fatigue, weight loss, exercise intolerance, fever and increased sweating, early satiety, decreased food intake, and pain in the right and/or left upper quadrant of the abdomen due to liver and/or spleen enlargement. In addition to the typical and established manifestations of CML, cases with atypical symptoms have been reported. For example, although hearing loss is associated with acute leukemia and is less common in patients with late-stage CML, increasing evidence suggests sudden hearing loss in patients with CML.

Given the rarity of cases and the complex nature of the combination of these two health conditions, my colleagues and I reviewed CML studies that reported cases of hearing loss between 2013 and 2023. After applying additional eligibility criteria, we analyzed 13 studies published between 2013 and 2023. Of these studies, one was a case series, 11 were case reports, and one was an observational cross-sectional study. Essentially, all of the CML cases described were in the chronic phase at diagnosis.

Of included studies, 84.6% of the included studies reported sudden bilateral onset of hearing loss. Most clinical cases were reported in Nigeria, followed by the United States, with a mean age of 38.9 years, and most cases were reported among male patients. Further studies showed that sudden hearing loss was the first manifestation before CML diagnosis in more than half of the studies. No studies have shown normal or less than 200 white blood cells in CML patients at diagnosis with hearing loss, confirming possible strong correlation between hearing loss and white blood cell count.

We also examined the causes of sudden hearing loss proposed by the authors of the included studies, which were considered as the main pathological factors. Rapid cochlear damage due to hyperleukocytosis was identified as the leading pathological cause of sudden hearing loss in six reported cases, consistent with previous findings. Cochlear ossification has also been reported in patients with CML, leading to persistent bilateral hearing loss. Additional explanations included leukocytosis and an inflammatory process ending in labyrinthitis, as well as central hearing loss due to a hemorrhagic complication in the temporal and/or temporoparietal lobe. Another study reported a case of sudden hearing loss in a patient due to intracranial hemorrhage and inflammation around the mastoid process. This can be explained by data suggesting that leukocytosis with increased blood viscosity in small vessels can lead to vascular rupture and tissue hemorrhage, causing damage to the auditory complex, disruption of fiber projection from the medial geniculate bodies to the central auditory area, and, consequently, central hearing loss.

Taking into consideration, the clinical presentation of hearing loss described in the included studies and earlier data, it can be reiterated that hematological malignancies should be considered as a differential diagnosis in any case of acute sudden hearing loss. Indeed, in some of the cases studied, an association with ocular toxicity (vision loss) was also reported. However, the latter may be associated with hyperleukocytosis, congestion and/or a hyper viscosity state causing occlusion of retinal vessels such as the vestibular vessels with subsequent ischemic retinal damage, or with increased intracranial pressure, retinal hemorrhage or localized nerve infarction.

The cumulative summary of this study led my colleagues and me to conclude that bilateral irreversible hearing loss, predominantly in middle-aged men, is a characteristic feature of most published studies of CML. Alas, reversibility of hearing loss is not improved by intensive leukoreduction or leukapheresis, despite the fact that early treatment of CML can prevent further problems and disease spread.