Hearing loss is an uncommon symptom in hematological
diseases. There are only few case reports with regarding
hearing loss in leukemias. The pathogenesis is not well
established. In some cases, postmortem lesions in the inner ear
were reported. Nageris et al
6 reported a CLL case with
sudden hearing loss in 1993. In that case, the hearing loss was
also sensorineural and improved dramatically after
chemotherapy. This unique observation was associated with
decrease of the circulating CLL cells, which corresponded to a
partial response, and lasted three years. Chae et al
9 reported
a similar observation in 2002. The hearing loss in a chronic
myelogenous leukemia was resolved after leukoapheresis.
They presumed that cochlear vessel occlusion, as a result of
elevated blood viscosity was responsible for the hearing loss.
Harada et al
10 also reported a case with unilateral
sensorineural hearing loss in a patient with acute lymphoblastic
leukemia. The hearing loss was reversible.
There are also some cases with blindness due to retinal
vein occlusion as a result of hyperviscosity syndrome. Serum
viscosity can increase with large molecules such as IgM or IgA
dimers, which usually occur in plasma cell discrasias. In vivo
this can cause sludging of capillary blood flow and so vision
disturbances, and some clotting disorders. The pathogenesis of
the clinical features of leukemic hyperleukocytosis is complex.
Multiple factors may involved including number, size, and
deformability proliferation rate; vascular adhesion/invasion
ability of leukemic cells, release of tissue harmful substances
by different leukocyte types, specific characteristics of the
microcirculation and competition of leukocytes and tissue cells
for O2 1,3,11,12. Hyperviscous blood becomes an important
factor if leukocyte is above 15ml/dl, which contributes injury
at the microcirculatory level. The mechanisms may change
depending on the leukemia type. The increased leucocytes
result in small aggregates and/or leukocyte thrombi, that lead
to tissue infarctions or vascular and tissue invasion with
hemorrhage 1,3. However, in some postmortem series in
CLL patients, thrombi and aggregated leukocytes have been
seen described 13.
In our case, the bilaterally sensorineural type hearing loss
resolved after chemotherapy, within three weeks.
)
)
)