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 Table of Contents  
Year : 2022  |  Volume : 12  |  Issue : 1  |  Page : 1-2

Sickle cell anemia and its complications

Department of Medicine, Assam Medical College and Hospital, Dibrugarh, Assam, India

Date of Submission16-Mar-2022
Date of Acceptance17-Mar-2022
Date of Web Publication18-Apr-2022

Correspondence Address:
Anupam Dutta
Assistance Editor, Department of Medicine, Assam Medical College and Hospital, Revti House, Purnananda Road, Shantipara, Dibrugarh 786001, Assam
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2278-8239.343425

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How to cite this article:
Dutta A. Sickle cell anemia and its complications. Assam J Intern Med 2022;12:1-2

How to cite this URL:
Dutta A. Sickle cell anemia and its complications. Assam J Intern Med [serial online] 2022 [cited 2023 Jun 1];12:1-2. Available from: http://www.ajimedicine.com/text.asp?2022/12/1/1/343425

  Introduction Top

Anemia may be defined as a reduction below the normal values of the total red cell mass. Anemia has been defined by the World Health Organization as a reduction of hematocrit value below the normal limits or anemia is considered to exist in adults whose hemoglobin levels are lower than 13 g/dL (males) or 12 g/dL (females).[1]

Sickle cell disease (SCD) is a major world health problem. It is estimated to affect at least 20% of the world population and approximately 0%–18% in northeastern India. In SCD, the RBCs contain an abnormal hemoglobin called sickle hemoglobin, which causes these cells to change to a stiff, sticky, curved shape like sickle or crescent moon. Sickle cell dies prematurely causing anemia. They also pile up, and form plugs in blood vessels causing micro- and macrovascular complications.

SCD causes an activated adhesive endothelium. These vasculopathy abnormalities are attributable to ischemia-reperfusion injury, hemostatic activation, microvascular occlusion, and formation of a procoagulant milieu. Vasculopathy of SCD has been implicated in the development of pulmonary hypertension, stroke, leg ulceration, and priapism, particularly associated with hemolytic severity and reported also in other severe hemolytic disorders. This vasculopathy might also play a role in other chronic organ dysfunction in patients with SCD.

  Pathophysiology Top

Hemoglobin is a molecule that is responsible for carrying oxygen to all the tissues of the body from the lungs. Normal human hemoglobin is a tetramer formed by two pairs of globin chain attached to heme. There are four types of globin chain (α, β, δ, and γ) chains. Normal adult hemoglobin consists of two α and two β chains (α2β2). Hemoglobin A22δ2) is a minor component which is less than 3.3% and less than 1% is HbF (α2γ2)

SCD occurs when there is a point mutation in the sixth position of globin chain of hemoglobin where glutamic acid is replaced by valine from the N terminal end of the chain. Whenever there is hypoxia and stress the β-globin chain promotes the non-covalent polymerization of hemoglobin, which distorts red blood cells into a sickle shape and decreases their elasticity. These cells fail to return to normal shape when normal oxygen tension is restored. As a consequence, these sickle cells are unable to deform as they pass through narrow capillaries, leading to vessel occlusion and ischemia.

  Complications in Sickle Cell Disease Top

Pulmonary complications

Acute chest syndrome

Acute chest syndrome usually refers to acute lung injury syndrome. Usually, patients present with chest pain, tachycardia, tachypnea, cough fever, and hypoxemia.[2],[3]

Radiological finding shows consolidation of Alveoli. Prevalence is approximately 29%.

Restrictive lung disease

Restrictive lung disease in SCD patients is a complication of acute chest syndrome. Radiological analysis shows area of fibrosis at the basal areas of the lungs.

Diagnosis can be confirmed by spirometry where FEV1/FVC is normal or mildly raised. The development of advanced chronic lung disease in patients with SCD has been called sickle cell chronic lung disease.[4]


The prevalence of asthma/reactive airway disease appears to be the same in SCD patients within pediatric age group (though in adult the percentage is less).[5]

Studies have suggested the association between ACS and asthma in SCD patients as in asthma due to ventilation-perfusion mismatched there will be increased chances of sickling of RBCs.

Pulmonary hypertension

PH is an increasingly recognized common complication of SCD and other hereditary or acquired hemolytic anemias.[6] The associated mortality rate is very high. Each increase of 10 mm Hg in mPAP is associated with a 1.7-fold increase in the rate of death of SCD patient. Diagnosis of PH is confirmed by using Doppler echocardiography. An elevated pulmonary artery systolic pressure calculated from the TRV of greater than 2.5 m/s was prospectively defined as abnormal.

Other complications


Anemia present as pallor, easy fatigability, irritability, loss of appetite, and poor growth.


Young patients with SCD can present with extremely life-threatening infection like pneumonia, sepsis, meningitis, and osteomyelitis.

Body organ damage and failure

All organs are vulnerable, including the kidneys, liver, spleen, heart, and eyes, for tissue damage due to deprivation of blood and its nutrients and of oxygen due to repetitive plugging of blood vessels by sickle cells.


Stroke is one of the most catastrophic and frequent medical problem encountered in SCD.

Hand foot syndrome

Commonly encountered in patients of pediatric age group.


Bilirubin, which is a breakdown product of RBCs, causes gallstones which on impaction of gallbladder duct causes cholecystitis and if untreated may lead to life-threatening condition like sepsis. The presenting symptoms are similar to jaundice.

Leg ulcer

More commonly seen in males aged between 10 and 50. Typically, they are open elevated sores with surrounding skin redness and thinning, located within patches of hyperpigmentation. Most commonly seen on ankle and can be single or multiple.

Avascular necrosis

It commonly involves the hip joint and patients present with painful limbs. Other vulnerable joints are the shoulders.

Renal and bladder involvement

Kidney and bladder infections are quite common in SCD. Patients present with painful and frequent micturation, incontinence, fever, lower abdominal pain, and backache. Due to repetitive clogging of the blood vessels of the kidneys renal failure can be developed.

Priapism and impotence

Men with sickle cell anemia may present with priapism. Overtime, priapism can damage the penis and lead to impotence.

Eye involvement

Eye involvement is the sequlee of microvascular complication that usually affects the retina but rarely causes blindness.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Allen JB, Allen FB The minimum acceptable level of hemoglobin. Int Anesthesiol Clin 1982;20:1-22.  Back to cited text no. 1
Gladwin MT, Vichinsky E Pulmonary complications of sickle cell disease. N Engl J Med 2008;359:2254-65.  Back to cited text no. 2
Platt OS The acute chest syndrome of sickle cell disease. N Engl J Med 2000;342:1904-7.  Back to cited text no. 3
Powars D, Weidman JA, Odom-Maryon T, Niland JC, Johnson C Sickle cell chronic lung disease: Prior morbidity and the risk of pulmonary failure. Medicine (Baltimore) 1988;67:66-76.  Back to cited text no. 4
Anthi A, Machado RF, Jison ML, Taveira-Dasilva AM, Rubin LJ, Hunter L Hemodynamic and functional assessment of patients with sickle cell disease and pulmonary hypertension. Am J RespirCrit Care Med 2007;175:1272-9.  Back to cited text no. 5
Jison ML, Gladwin MT Hemolytic anemia-associated pulmonary hypertension of sickle cell disease and the nitric oxide/arginine pathway. Am J RespirCrit Care Med 2003;168:3-4.  Back to cited text no. 6


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