| The clinical manifestations of sickle cell anemia | | | | during the neonatal period and early part of |
| vary markedly in severity and frequency. The | | | | infancy, it may not be recognized until the toddler |
| most acute symptoms of the disease occur | | | | and preschool period. It is frequently first |
| during periods of exacerbation called crises. There | | | | diagnosed during a crisis, after an acute upper |
| are four types of episodic crises vaso-occlusive, | | | | respiratory or gastrointestinal infection. Crisis, after |
| splenic sequestion, aplastic, and hyperhemolytic | | | | an acute upper respiratory or gastrointestinal |
| crises. | | | | infection. |
| Vaso-occlussive crises are the most common and | | | | Several tests are available for detecting sickle cell |
| the only painful ones. They are the result of | | | | anemia. Although most of the routine |
| sickled cells obstructing the blood vessels, causing | | | | hematological tests described are done primarily |
| occlusion, ischemia, and potentially necrosis. The | | | | to evaluated the anemia, this discussion focuses |
| major symptoms of this crisis are fever, acute | | | | on the four tests specifically used to detect the |
| abdominal pain from visceral hypoxia, hand-foot | | | | homozygous or heterozygous for of the disease. |
| syndrome, and arthralgia, without an exacerbation | | | | For screening purposes either the sickling test of |
| of anemia. | | | | the sickledex is commonly used. If the test is |
| Splenic sequestration crises are caused by the | | | | positive, hemoglobin electrophoresis is necessary |
| spleen sequestering (pooling) large quantities of | | | | to distinguish between those children with the trait |
| blood, causing a precipitous drop in blood volume | | | | and those with the disease. Screening for sickle |
| and ultimately shock. The crisis may be acute or | | | | cell trait has become a controversial subject, |
| chronic. The chronic manifestation is termed | | | | especially among the black community, since |
| functional asplenia. The acute form occurs most | | | | there is no method of preventing the disease |
| commonly in children between 8 months and 5 | | | | other than selective birth procedures. |
| years of age and may result in death from | | | | Stained blood smear |
| profound anemia and cardiovascular collapse. | | | | Examination of the stained smear of blood may |
| Aplastic crisis is diminished red blood cell | | | | reveal a few sickled red blood cells. However, |
| production, usually triggered by a viral or other | | | | since the erythrocyte assumes its normal discoid |
| infection. When superimposed on the existing rapid | | | | shape under adequate oxygenation, non-sickled |
| destruction of red blood cells, a profound anemia | | | | cells may be present even in the homozygous |
| results. | | | | form of the disease. Whenever sickle cells are |
| Another type of bone marrow crisis is | | | | found, the diagnosis is usually positive for sickle |
| megaloblastic anemia, which is attributed to an | | | | cell anemia, not sickle cell trait. |
| excess nutritional need for folic acid/ or vitamin | | | | Sickling test (sickle cell slide preparation) |
| B12 during periods of pronounced erythropoiesis. | | | | The simplest method to detect sickling is to place |
| Since infection is not always antecedent to | | | | a drop of blood on a slide and cover it with a |
| aplastic or hypoplastic crises, it is possible that folic | | | | sealed cover slip to produce de-oxygenation. |
| acid deficiency is a causative agent. | | | | Eventually sickling of the red blood cell occurs. |
| Hyperhemolytic crisis occurs when there is an | | | | Unfortunately this test may take several hours |
| even greater rate of red blood cell destruction. It | | | | before results are obtained, and it is not specific |
| is characterized by anemia, jaundice, and | | | | for the disease or trait. False negatives for the |
| reticulocytosis. It is a rare complication and | | | | trait can occur if the blood contains a very small |
| frequently suggests other coexisting abnormalities, | | | | amount of hemoglobin S. |
| such as glucose-6-phosphate dehydrogenase | | | | Hemoglobin electrophoresis ("fingerprinting") |
| deficiency, which is also common in black persons. | | | | In this test, the blood is specially prepared and |
| Diagnostic evaluation | | | | separated into various hemoglobin by high-voltage |
| Although sickle cell anemia has been reported | | | | electrophoresis. |