Hereditary spherocytosis

The ball -cell anemia ( hereditary spherocytosis ) is an almost exclusively congenital hemolytic anemia (anemia due to pathologically increased destruction of red blood cells). It is the most common hemolytic anemia in Central Europe, the prevalence is at least 1:2000. but is likely to be higher.

Cause

Due to a defect of components of the cytoskeleton ( ankyrin in about 50 % of cases, band 3 and spectrin in each case about 20 %, etc.) results in a loss of the biconcave shape of the red blood cells ( erythrocytes). The erythrocytes assume the energetically more favorable spherical shape ( Sphärozyt ). Such blood cells and increased break down in the spleen. The liberated red blood pigment (hemoglobin ) in the blood is reduced to yellowish bile pigment bilirubin, which is taken up by the liver, glucuronidated and excreted in the bile.

There are different variants of the disease, the inherited different. For the most common variant (65%), it is sufficient that one parent has the disease ( autosomal dominant inheritance ), while the defect is located on chromosome 8 The remaining cases are either spontaneous Neuentstehungen ( new mutations ), or there are variants in which both parents carry the genetic material, but not necessarily have to be ill ( recessive inheritance, 15 %).

Clinical picture

The spherocytes are already metabolically pre-damaged when passing through the spleen and lysed in the sequence partially or completely. The spleen is almost always swells up and it comes to the manifest image of splenomegaly.

In the following passage through the liver occurs through the increased Bilirubinanfall during the further degradation mostly to overload this excretion system. An initial non-infectious jaundice (icterus) is then the result. The stronger the reduction of blood cells, the greater the severity of the disease, ie the stronger anemia (anemia ), and possibly jaundice. The excess of bile pigment can also lead to gallstones.

As a result of the increased iron turnover in the context of the increased degradation of erythrocytes may occur in the course of the disease hemochromatosis (iron accumulation in the liver with cirrhotic remodeling ).

The symptoms of the disease are characterized among other things by the blood (anemia ), fatigue, exhaustion, lack of capacity and resilience, paleness, headache, shortness of breath, difficulty concentrating, and heart palpitations occur. If the disease at an early age, it can also lead to mental and physical developmental disabilities.

Sometimes, especially with certain viral infections (eg, parvovirus B19, the causative agent of fifth disease ), the breakdown of red blood cells is increased massively and it comes to the so-called hemolytic crises, which can also be life-threatening. The replica of the red blood cells in the bone marrow can be greatly reduced (aplasia ). In hemolytic crises will have fever with chills, collapse and Kopf-/Bauch-/Rückenschmerzen and jaundice (icterus).

Methods of investigation

Blood smear: It show characteristic spherical cells ( spherocytes ) that are smaller than normal erythrocytes ( microcytic ) and lacking the central pallor. Furthermore, a polychromasia is present ( modified, " multiform " dyeing ). It can also be increased reticulocyte ( precursor of red blood cells ) and a strong increase in the erythrocyte distribution width in blood.

Laboratory values: hemoglobin (hemoglobin, Hb) decreased to normal, mean corpuscular hemoglobin concentration ( MCHC ) increased median corpuscular volume ( MCV) decreased, increased proportion of hyperchromic erythrocytes ( % HYPER ), lactate dehydrogenase ( LDH) increased, increased indirect bilirubin, haptoglobin decreased.

Special investigations: show spherocytes, compared to normal erythrocytes, decreased osmotic resistance (resistance ). If the spherocytes are introduced into a solution with a lower salt concentration than in the blood ( hypo-osmolar solution, eg Acidified glycerol lysis test, AGLT ), they burst sooner than healthy red blood cells. Using osmotic gradient Ektazytometrie can confirm the disease and its severity can be quantified. Further, the erythrocyte creatine is increased, since the red blood cell population is tapered. Two other tests that are not based on a decreased osmotic fragility, are the flow cytometric detection of reduced binding of eosin -maleimide and the hypertonic Kryohämolyse test.

Therapy

The removal of the spleen ( splenectomy ) is the only measure that can prevent the excessive breakdown of red blood cells. However, the removal of the spleen is connected with an increased risk of infection, so that in general, first the disease is awaited. Only if several hemolytic crises have occurred or blood transfusions were administered or the patient is impaired endurance, the spleen is removed. Earliest possible date for surgery is after the age of 5. This requires a previous vaccination against pneumococcal, meningococcal, and Haemophilus influenzae type B, since after total Milzerntfernung the risk of Postsplenektomie syndrome.

Meanwhile, there is also the possibility, rather than the complete spleen removal to only perform a Teilmilz removal. In this case, a small part of the spleen is left to the above-mentioned To minimize risk of infection.