64 S. Singh et al.
Discussion
Homozygous SCA usually presents with signs and
symptoms of pallor, fever, and abdominal and joint
pains within the first year of life [3]. First presentation
in adult age group is rare [4]. Our case also presented
with complaints of joint swelling and bone pains for
past 10 years.
Abnormal red cell rheology leads to erythrostasis
in SCA, because of which there is ischemia and
infarction throughout body, involving spleen,
bone marrow, bone, lungs, etc. [1]. Process of
autosplenectomy due to repeated episodes of infarc-
tion starts at 2 years of age and is complete by the
age of 8 years. Although splenomegaly is known
in children, spleen is not palpable in adults [2,4].
However, our patient had palpable spleen 5 cm
below costal margin, which is rare at the age of
22 years. Recent study suggests that the persistence of
spleen may be due to chronic malaria or improved
clinical care [5]. This does not explain persistent
splenomegaly in our case as our patient did not show
evidence of chronic malarial infection and was not
under any treatment.
Figure 1. Peripheralsmear showingnormocyticnormochromicRBCs
along with irreversibly sickled RBCs (long arrows), Giemsa, 400x.
test for sickling with 2% sodium metabisuphite was
positive. Starch gel hemoglobin electrophoresis at pH
8.6 showed single band in a hemoglobin S, D, and G
region with no band in the HbA and HbA2 region
(Figure 2). HbF was 0% and HbA2 was 2.0%.
Laboratory investigations revealed total serum bilir-
ubin of 5.4 g/dl (direct 4.2 g/dl), total serum proteins
— 6.2g m/dl, serum albumin — 4.7 g/dl and serum
globulin — 1.5 g/dl (A:G ratio–3.3:1). Her brother
had not being worked up before his death, and hence
his diagnosis was not known.
Causes of persistent splenomegaly in sickle cell
disease include HbSD, HbSb thalassemia and splenic
sequestration crisis. The former two were excluded in
our case due to the positive sickling, HbA2 ,3.5%
and 0% HbF [2]. Splenic sequestration crisis is
defined by a decrease in steady state hemoglobin
concentration of at least 2 g/dl, evidence of marrow
erythropoiesis and an acutely enlarged spleen [4].
Sequestration crises usually present in infants and
young children whose spleens are chronically enlarged
before autoinfarction and fibrosis have occurred
leading to autosplenectomy. It is characterized by
sudden occurrence of massive splenomegaly at the
expense of blood volume. Circulatory collapse and
even death can occur within few hours [6]. High index
of suspicion is needed as it may present with sudden
drop of hemoglobin even without palpable spleen [7].
Although persistence of spleen is rare in adult cases of
sickle cell disease, chances of sequestration crises in
such cases do remain a possibility.
Since double heterozygotes for HbSD do not show
sickling on peripheral smear and HbS/b thalassemia
show HbA2 . 3.5% [2], the final diagnosis of
homozygous SCA (HbSS) with persistence of spleno-
megaly was made. The patient refused further
treatment and went back to her native village.
Walker et al. reported the presence of focal
hypoechoeic lesion in spleen of SCA in children [8].
Our patient also showed similar lesions in spleen. The
differential diagnoses of focal hypoechoeic splenic
lesions comprise of splenic abscess, lymphoma [8,9]
and metastasis [8,10]. Our patient did not have any
features of these conditions. Walker et al. emphasized
the benign course of such lesions with no need for
further investigation for malignant disease [8]. These
hypoechoeic lesions on ultrasonography have imaging
characteristics of normal spleen on MRI, thus
allowing for a correct diagnosis. They are probably
“preserved functioning splenic tissue” in an otherwise
fibrosed and calcified spleen [11].
Figure 2. Hemoglobin electrophoresis demonstrating a slow-
moving band in the region of HbS and the absence of band in region
of HbA and HbA2 (C and P denote point of application of control
and patient, respectively), starch gel electrophoresis, pH 8.6.
Singh, Vijay
