Prepared by: Dr. Mazen Basheikh

1. Prepared by: Dr. Mazen Basheikh Management of acute crisises of SCA

2. What is SCA ? • It is a chronic disease with acute crises, due to the presence of structurally abnormal Hb (Hb S) in the RBCs which crystallizes on ↓ O2 tension or dehydration. • Although a diagnosis of the disease can be made at birth, clinical abnormalities usually do not occur before age 6 months, when functional asplenia develops.

3. Preventive measures • Folic acid ( 1 mg/ dL ) • Hydroxyurea. • 20 mg/kg/d PO initially; titrate upward by 5 mg/kg/d q12wk to maximal acceptable toxicity . • Education.

4. When to start regular hypertransfusion ?? • Severe or frequent crisis. • After CNS involvement. • After sequestration crisis before splenectomy at the age of 5 years. • May be indicated for ACS for 6 months only.

5. The acute crises: • Painful Crisis (VOC) • Aplastic crisis • Sequestration crisis • Infections • CVA • Acute Chest Syndrome • Priapism

6. VOC Crisis • The most common crisis. • Sudden onset. • Sometimes as a consequence of infection or temperature change. • However, often no precipitating cause can be identified. • Severe deep pain is present in the extremities, involving long bones.

7. VOC Crisis • The abdomen is affected with severe pain resembling acute abdomen. • Pain may be accompanied by fever, malaise, and leukocytosis. • The crisis may last several hours to several days and terminate as abruptly as it began.

8. VOC Crisis • Approximately half the individuals with homozygous Hb S disease experience vasoocclusive crisis. • The frequency of crisis is extremely variable. • Each individual typically has a consistent pattern for crisis frequency.

9. VOC Crisis • VOC is treated with vigorous hydration and analgesics. • Normal saline and 5% dextrose in saline may be used. • Morphine is the drug of choice. • Pethidine should be avoided because patients receiving this have a higher incidence of seizures • Morphine dosing usually (.05-.1) mg/kg/h may be started after a reasonable bolus then adjust according to response. • Dependence seldom occurs, since the duration of sickle pain is brief (5-7 d).

10. Central Nervous System Involvement • This is one of the most devastating aspects of SCD. • It is most prevalent in childhood and adolescence. • The most severe manifestation is stroke, resulting in varying degrees of neurological deficit. • The stroke mostly is thrombotic, but it also may be hemorrhagic. • Vigorous diagnostic and therapeutic efforts may have a beneficial impact on the outcome of this condition. • Having had one stroke, a person is 70-90% more likely to have a recurrence if he was not on regular hypertransfusion program.

11. Central Nervous System Involvement • Strokes are managed with general support and transfusion. • The aim is to lower the concentration of Hb S to less than 30% without rising the total hb to more than 10-12 g/dL. • An exchange transfusion may be required. • Prevention: • Children should be tested using transcranial Doppler ultrasonography. • Those with increased flow are at risk for stroke and should be considered for a chronic transfusion program. • As patients grow into adulthood, the transfusion frequency may be decreased, but whether it can be discontinued remains unclear.

12. Aplastic crisis • This is caused by infection with the Parvovirus B-19. • The virus infects red cell progenitors in bone marrow, resulting in cessation of erythropoiesis. • Coupled with greatly shortened red cell lifespan, usually 10-20 days, a very rapid drop in hemoglobin occurs. • The condition is self-limited, with bone marrow recovery occurring in 7-10 days, followed by brisk reticulocytosis. • May need transfusion only if symptomatic.

13. Sequestration Crisis • The spleen occasionally undergoes a sudden very painful enlargement due to pooling of large numbers of sickled cells. • This can cause a sudden drop in hemoglobin and can be life threatening if not treated promptly. • Early transfusion since it can lead rapidly to shock. Do not allow hb to rise more than 10mg/dL. • Splenectomy may be suggested in case of recurrence.

14. Acute Chest Syndrome • The leading cause of death at the present time. • Consists of chest pain, fever, tachypnea, leukocytosis, and pulmonary infiltrates. • This is a medical emergency and must be treated immediately. • It probably begins with infarction of ribs, leading to chest splinting and atelectasis. • Fat embolism, resulting from bone marrow infarction, plays an important etiological role in the pathogenesis of this syndrome. • If not attended to promptly, it may lead to acute respiratory distress syndrome (ARDS).

15. Acute Chest Syndrome • Managed with analgesics, oxygen, antibiotics, and transfusion. • Antibiotics should provide coverage for S. pneumoniae, H. influenzae type b, Mycoplasma pneumoniae, and Chlamydia pneumoniae . It is recommend to use the combination of cefuroxime and erythromycin. • The aim of the transfusion is to reduce the concentration of Hb S to less than 30%. • If the hematocrit is 30% or higher, an exchange transfusion must be performed.

16. Infections • Pneumococcal infections are common in childhood. • Of special concern is the frequent occurrence of Salmonella osteomyelitis in areas of bone weakened by infarction. • Prevention of infection improves chances of survival in SCD. • Penicillin prophylaxis, Begin at age 2-4 months with 125 mg BID; at 3 years, increase the dose to 250 mg BID .It reduce the incidence and may decrease the mortality rate. • Pneumococcal vaccine at age 2 years, with a booster dose at age 5 years. • All infections must be treated promptly with broad-spectrum antibiotics until a causative organism is identified and therapy is tailored according to its antibiotic sensitivity

17. Priapism • Priapism is a serious complication and tends to occur repeatedly. • When it is prolonged, it may lead to impotence. • Treated with analgesics and hydration. • Persistent priapism may require surgical evacuation of the penile corpora. • The concomitant use of automated red-cell exchange transfusions to reduce the sickle hemoglobin (HbS) level to less than 30% may also be considered, especially if early intervention with irrigation fails. • A nightly dose of pseudoephedrine (30 mg PO) may prevent priapism in some cases.

18. Thank You