Related articles: Drepanocytosis
Definition
Drepanocytosis is a form of chronic hemolytic anemia, characterized by an alteration typical of red blood cells. In particular, under certain conditions, the red blood cells take on a sickle conformation due to the presence of an abnormal hemoglobin, called Hb S (where "S" stands for "sikle", meaning "sickle" in English).
The red blood cells thus deformed are less flexible and, during their transit, they adhere to the vascular endothelium, triggering the occlusion of the small arterioles and capillaries. This predisposes to thrombosis and focal ischemic phenomena (sometimes heart attacks) in various organs and tissues.
The sickle cell disease is caused by a point mutation of the beta-globin gene, transmitted in an autosomal recessive manner, which involves the insertion of the amino acid valine instead of the glutamic acid, with the production of the pathological hemoglobin S (Hb S).
Most symptoms occur only in homozygous patients.
Most common symptoms and signs *
- Anemia
- anisocytosis
- Asthenia
- Chills
- Cardiomegaly
- Cyanosis
- dactylitis
- Diarrhea
- Erectile dysfunction
- Dehydration
- Dyspnoea
- Abdominal pain
- Chest pain
- Bone pain
- Hepatomegaly
- Temperature
- Shortness of breath
- Hypoxia
- Hypotension
- Jaundice
- Backache
- Headache
- Pallor
- Polyuria
- Priapism
- Rheumatism
- Growth delay
- Heart murmur
- splenomegaly
- Fainting
- Tachycardia
- Skin Ulcers
- Pleural effusion
- Dizziness
- He retched
Further indications
The clinical manifestations of sickle cell disease vary in their characteristics and onset times. However, the disease generally produces chronic hemolysis and acute vaso-occlusive episodes (or sickle crises), with local ischemic damage.
Chronic hemolytic anemia develops generally after the post-natal physiological decline of Hb F; this condition generally does not require chronic transfusion support. Some patients present with variable jaundice, pallor, bilirubin stones and chronic ulcers of the perimalleolar region. In children, acute sequestration of the sickle cell in the spleen can occur, an event that aggravates anemia.
Vaso-occlusive episodes are determined by entrapment of erythrocytes in the peripheral microcirculation during the deoxygenation phase of Hb S; these acute crises can be triggered by infectious episodes, pregnancy, cold exposure and dehydration. Vaso-occlusive ischemic accidents typically occur in the musculoskeletal system, but also in the spleen, central nervous system, lungs or kidneys, with severe pain associated with fever and tachycardia. Over time, these phenomena can compromise the functionality of any fabric or organ.
The long-term consequences of sickle cell disease include growth and developmental delay. Many individuals develop hypogonadism and priapism, a serious complication due to cavernous body blockage, which can cause erectile dysfunction. In children, hepatosplenomegaly is frequent; in the adult, however, due to repeated infarcts that resolve into fibrosis, the spleen is usually very small. Drepanositosi can cause genitourinary symptoms, such as haematuria, renal papillary necrosis and reduced ability to concentrate urine (hypostenuria).
Bone marrow infections and aplasia can develop as acute complications and be fatal. In sickle cell disease, infectious conditions can cause leukocytosis, fever, vomiting, diarrhea with dehydration and tissue fusion. These episodes may also be responsible for osteomyelitis and meningitis.
An acute thoracic syndrome resulting from obstruction of the pulmonary microcirculation is one of the major causes of death. This complication occurs at any age, but is more common in childhood and involves the sudden appearance of fever, chest pain and dyspnea. Repeated episodes predispose to chronic pulmonary hypertension. Furthermore, in the context of drepanocytosis, cardiomegaly and systolic ejection murmurs are frequent.
The diagnosis is based on clinical evidence, on the analysis of hemoglobin by electrophoretic examination, on the blood smear and on molecular analysis.
The treatment of drepanocytosis may include regular or occasional transfusions, analgesics and other symptomatic therapies. Hydroxyurea can reduce the frequency of seizures.
