Sickle Cell Disease (SCD)
Excerpts from Social
Security Ruling 17-3p
See the full
text at https://www.ssa.gov/OP_Home/rulings/di/01/SSR2017-03-di-01.html
SCD
is the most common inherited blood disease in the United States, affecting an
estimated 100,000 Americans. SCD is not always
easy to evaluate due to its varying nature and complications. In this SSR, we
provide basic information about SCD and its variants and clarify that sickle
cell trait is not a variant of SCD. We also provide guidance for assessing SCD
under the hematological disorder listings and determining how this impairment
may affect the residual functional capacity finding for adults and the
functional equivalence finding for children.
Policy Interpretation
We consider all
medical evidence when we evaluate a claim for disability benefits. The
following information is in a question and answer format that provides guidance
about SCD and how to consider evidence regarding this impairment. Questions 1
and 2 provide basic background information about SCD and its variants. Question
3 clarifies that sickle cell trait is not a variant of SCD. Question 4
discusses the complications and symptoms of SCD. Questions 5 through 7 explain
how adjudicators should evaluate SCD at various points of the adjudication
process, including the adult and child hematological listings we consider.
SCD
is a type of hemolytic anemia and an inherited hematological disorder that
affects the hemoglobin within a person's red blood cells (RBC). Hemoglobin is
the protein within RBC that carries oxygen. The abnormal hemoglobin makes the
RBC more prone to distortion (“sickling”), which results in blocked blood
vessels and a shortened RBC lifespan. Hemolytic anemia results when the
abnormal RBC are destroyed faster than the body can produce them.
When hemoglobin is normal, a person's RBC are round and easily travel
through blood vessels, bringing oxygen to the body's organs and tissues. SCD
causes sickle-shaped RBC that are not flexible and can stick to vessel walls,
causing blockages (vaso-occlusion) that slow or stop the flow of blood and
oxygen. This blockage may in turn cause pain. Persons with SCD are predisposed
to pain, infection, and other complications. Because people inherit SCD, the
disease is present at birth, but the age when children display symptoms varies.
The different variants of SCD may indicate the severity of complications
and the resulting functional limitations caused by SCD. Laboratory blood tests
such as hemoglobin electrophoresis establish the existence and the variants of
SCD. The following are the most common variants of SCD:
o Hemoglobin (Hb) SS (HbSS) — a person with this form of SCD
inherits one sickle cell gene from each parent. HbSS is the most common and
usually most severe form of SCD.
o
o HbSC — a person inherits one sickle cell gene from one
parent, and another gene for an abnormal hemoglobin called “C” from the other
parent. HbSC is usually a milder type of SCD.
o
o Hb S-beta (Sβ) thalassemia — a person inherits one sickle cell
gene from one parent, and a gene for beta thalassemia from the other parent.
There are two forms of beta thalassemia, sickle beta zero thalassemia (Hb Sβ0
thalassemia) and sickle beta plus thalassemia (Hb Sβ+ thalassemia). Sickle beta
zero thalassemia is usually a more severe form of SCD. People with sickle beta
plus thalassemia tend to have a milder form of SCD.
o
o HbSD, HbSE, and HbSO— people with these variants of SCD
have one sickle cell gene plus another abnormal hemoglobin gene, “D,” “E,” or
“O.” These are rarer types of SCD with varying severity.
o
No. Sickle cell trait is not a variant of SCD. Sickle cell trait occurs
when a person inherits one sickle hemoglobin gene from one parent and a normal
gene from the other parent. People with sickle cell trait rarely have signs and
symptoms associated with SCD and usually do not need treatment. However, in
rare cases and under extreme conditions such as intense exercise, people with
sickle cell trait have a higher risk of severe breakdown of muscle tissue
(exertional rhabdomyolysis) that can lead to serious complications. In spite of this
higher risk, recent evidence indicates that sickle cell trait is not associated
with an increased probability of death.
Sickle cell trait alone is not an impairment. As defined by the Social
Security Act, an impairment must result from anatomical, physiological, or
psychological abnormalities that can be shown by medically acceptable clinical
and laboratory diagnostic techniques. To establish an impairment in this
context, we require objective medical evidence (medical signs and laboratory
findings) from an acceptable medical source of complications from sickle cell
trait. In addition, a person's complications from sickle cell trait must meet
the statutory duration requirement, i.e., be expected to result in death or
last or be expected to last for a continuous period of not less than 12 months.
Therefore, we cannot find a person disabled due to sickle cell trait if there
are no medical signs or laboratory findings of complications from sickle cell
trait and the complications from sickle cell trait do not meet the duration
requirement.
Complications of SCD may include, but are not limited to pain crises,
anemia, osteomyelitis, leg ulcers, pulmonary infections or infarctions, acute
chest syndrome, pulmonary hypertension, chronic heart failure, gallbladder
disease, liver failure, kidney failure, nephritic syndrome, aplastic crisis,
stroke, and mental impairments such as depression. Examples of symptoms that
may stem from these complications include pain, fatigue, malaise, shortness of
breath, and difficulty feeding in infants. The symptoms of SCD vary from person
to person and can change over time.
[Footnotes
omitted.]
This SSR is
applicable on September 15, 2017.
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