Sickle cell disease: Difference between revisions

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== Definition ==
==Background==


* Genetic mutation of the hemoglobin beta? chain
*Genetic mutation of the hemoglobin beta chain, most commonly an E6V substitution, causing the formation of hemoglobin S
*Most common in people with African ancestry, though also occurs in Hispanic, southern European, Middle Eastern, and Indian people
*Life expectancy is 20-30 years shorter


== Crises ==
== Clinical Manifestations ==


* Chronic anemia
* Four major sickle crises:
** Vasoocclusive pain crisis
** Hemolytic crisis
** Aplastic crisis (often associated with parvovirus)
** Splenic sequestration crisis


===Crises===

*Four major sickle crises:
**Vasoocclusive pain crisis
**Hemolytic crisis
**Aplastic crisis (often associated with parvovirus)
**Splenic sequestration crisis

== Diagnosis ==

* Hemoglobin quantification can help to identify the type of sickle cell disease
** HbS is sickle hemoglobin
** HbA is normal adult hemoglobin and HbA<sub>2</sub> is the minor variant of adult hemoglobin
** HbF is fetal hemoglobin
** HbC is a hemoglobin variant that causes sickle cell disease when paired with HbS

{| class="wikitable"
!Genotype
!Hb (g/L)
!HbS (%)
!HbA (%)
!HbA<sub>2</sub> (%)
!HbF (%)
!HbC (%)
|-
|AS (trait)
|normal
|≤40
|>60
|<3.5
|≤1
|
|-
|SS
|60-90
|>90
|
|<3.5
|<10
|
|-
|Sβ<sup>0</sup>-thalassemia
|70-90
|>80
|
|>3.5
|<20
|
|-
|Sβ<sup>+</sup>-thalassemia
|90-120
|>60
|10-30
|>3.5
|<20
|
|-
|SC
|90-140
|50
|
|<3.5
|≤1
|45
|}
[[Category:Hematology]]
[[Category:Hematology]]

Latest revision as of 12:37, 16 August 2020

Background

  • Genetic mutation of the hemoglobin beta chain, most commonly an E6V substitution, causing the formation of hemoglobin S
  • Most common in people with African ancestry, though also occurs in Hispanic, southern European, Middle Eastern, and Indian people
  • Life expectancy is 20-30 years shorter

Clinical Manifestations

  • Chronic anemia

Crises

  • Four major sickle crises:
    • Vasoocclusive pain crisis
    • Hemolytic crisis
    • Aplastic crisis (often associated with parvovirus)
    • Splenic sequestration crisis

Diagnosis

  • Hemoglobin quantification can help to identify the type of sickle cell disease
    • HbS is sickle hemoglobin
    • HbA is normal adult hemoglobin and HbA2 is the minor variant of adult hemoglobin
    • HbF is fetal hemoglobin
    • HbC is a hemoglobin variant that causes sickle cell disease when paired with HbS
Genotype Hb (g/L) HbS (%) HbA (%) HbA2 (%) HbF (%) HbC (%)
AS (trait) normal ≤40 >60 <3.5 ≤1
SS 60-90 >90 <3.5 <10
0-thalassemia 70-90 >80 >3.5 <20
+-thalassemia 90-120 >60 10-30 >3.5 <20
SC 90-140 50 <3.5 ≤1 45