30 Flashcards
Common procedures for young individuals with sickle cell disease 2
Tonsillectomy
Lymphoidal-tissue hypertrophy involving Waldeyer’s ring is common in children with sickle cell disease.
Excessive snoring may be observed, as well as obstructive sleep apnea.
Some physicians think tonsillar hypertrophy may relate to desaturation of hemoglobin and increase the risk of sickling.
Tonsillectomy with adenoidectomy will improve the obstructive apnea for most patients.
Cholecystectomy
Bilirubin gallstones occur frequently in all patients with hemolytic anemias—including sickle cell disease—the result of increased release of hemoglobin during breakdown of abnormal red blood cells.
Although rare in the first five years of life, an increasing number of children are found to have gallstones during adolescent ages.
Although many children with sickle cell disease may have evidence of gallstones on screening ultrasounds, management is conservative and cholecystectomies are reserved for patients who are symptomatic.
If symptoms require it, cholecystectomy preferably is done as an elective procedure, with preoperative transfusions of packed red blood cells (pRBCs) given to reduce the chances of acute chest syndrome or other complications following the surgery due to the time under anesthesia.
Cholecystitis can be a serious infection to treat, so treatment is warranted if there are any symptoms from the cholelithiasis.
Risk of sepsis in sickle cell disease is increased by what organisms 3
Prophylaxis
Infants and young children with SCD are at greatly increased risk for sepsis.
The decreased splenic function leads to decreased resistance to infection with encapsulated organisms (Streptococcus pneumoniae, Haemophilus influenzae type b, Neisseria meningitidis).
When given to infants with sickling disorders, penicillin significantly decreases the risk of mortality from overwhelming sepsis.
Penicillin is usually continued until the child is 5 or 6 years of age; after this age there is little data to support its use except in patients who have had documented sepsis and bacteremia, or who have had their spleens removed.
Expected complications for children with sickle cell disease 4
Jaundice
With increased breakdown of the red blood cells, sickle cell disease leads to jaundice.
Anemia
The anemia that is seen in sickle cell disease can cause some fatigue, and can sometimes be more severe due to myelosuppression from infections such as Parvovirus or from hypersplenism when the spleen enlarges and traps blood cells.
Stroke
Children with sickle cell are at risk of stroke: 10% by the age of 15 years.
Respiratory Problems
The lungs are a site of occasional sickling problems.
This can occur in the form of pneumonia, because of the increased tendency to infections.
It may also occur as a result of vaso-occlusion in the lung parenchyma. This process, called acute chest syndrome, is a medical emergency requiring supplemental oxygen and transfusion therapy.
Sickle cell disease:
Trans cranial doppler
Transfusion therapy
Transcranial Doppler (TCD) Studies
Stroke occurs in approximately 10% of children with sickle cell disease.
Evaluation of cerebral blood-vessel flow by TCD has been shown to be a useful screening tool for predicting the risk of patients for stroke.
A TCD can help in evaluating which patients might benefit from prophylactic transfusion of RBCs.
TCD studies are now recommended in children 2-15 years of age to determine their risk for stroke.
Transfusion Therapy
It is important to ask about blood transfusions as part of the history in all children with sickling disorders, especially if the patient is new to you. Knowing about transfusions gives clues to the severity of some of the complications associated with sickle cell disease, and about the potential for the development of antibodies (alloimmunization) to minor blood-group antigens.
Blood-group minor antigens (Kell, Duffy, Kidd, etc.) are known to be clustered along racial and ethnic lines.
Exposure to blood that is cross-matched for the major A, B, and O and Rh antigens may still be mismatched for minor antigens.
These minor antigens can induce the development of weak antibodies that can then react with future transfused blood.
For patients who may be requiring transfusions with some frequency—such as those with sickle cell disease—it is recommended that when a transfusion is first indicated, the patient have a complete RBC antigen phenotype of his own red blood cells. That way, the treating physicians will know which RBC antigens the patient has and does not have on his/her red blood cells, and can use blood that is “phenotypically matched” for the patient’s specific antigens. If this is done (and it may not be possible in an emergency transfusion), the chances of the patient developing alloimmunization to minor antigens is decreased.
Benefit
Chronic transfusion therapy in children with elevated TCD blood flow has been shown to significantly decrease the risk of stroke. It is not known how long this transfusion therapy needs to continue; this question is currently under study.
Risks
Chronic transfusion has the risk of iron overload, which may require the use of deferasirox or deferoxamine (iron chelators).
Chronic transfusion increases the risk of alloimmunization and other transfusion reactions.
Immunization recommendations for children with sickle cell disease 2
The current immunization recommendations have helped to prevent serious infections in children with sickle cell disease.
The Haemophilus influenzae type b conjugate vaccine and 13-valent pneumococcal conjugate vaccine (Prevnar 13)—given at 2, 4 and 6 months—have aided in protection against two bacteria that have been major leaders in morbidity and mortality in children with sickle cell disease.
Conjugation
In a child under the age of 2 years, the immune system has a suboptimal response to purely polysaccharide vaccine. Conjugating the antigens to a protein allows an infant’s immune system to make antibodies.
Pneumococcal Vaccine
The 13-valent pneumococcal conjugate vaccine given in the first year of life provides protection against the 13 serotypes contained in the vaccine.
To expand antibody coverage beyond the 13 initial serotypes, children with sickling disorders receive the 23-valent pneumococcal polysaccharide vaccine at two and five years of age.
Meningococcal Vaccine
Children with anatomic or functional asplenia should also receive the meningococcal conjugate vaccine at age 2 years.
Unless they have a milder genotype than Gerardo’s Hgb SS, most children with sickle cell will have functional asplenia. They will receive a booster dose 3-5 years later.
And, of course, while all children should receive influenza vaccine annually, children with sickle cell disease are at higher risk and should be immunized against this also.
Inheritance of sickle cell disease
Growth
Autosomal recessive
Impairment of growth is common in children with sickle cell disease. This is probably multifactorial and may be due to any one or combination of the following:
Chronic anemia Poor nutrition Painful crises Endocrine dysfunction Poor pulmonary function
Baseline hgb in sickle cell disease
Children with sickle cell disease frequently have baseline hemoglobins between 6 and 9 g/dL (60-90 g/L). They accommodate to this level of hemoglobin very well, but the lower the baseline hemoglobin, the more difficult it is for the patient to withstand any acute change.
When to seek emergency care for patients with scd
Fever
Fever in children with sickle cell disease is a medical emergency.
It is sometimes the only sign of serious infection.
Splenic enlargement
Massive enlargement or rapid change in size can indicate splenic sequestration crisis.
Slurred speech
Slurred speech can indicate a stroke and should be rapidly evaluated.
An exchange transfusion may be indicated to lower the hemoglobin-S level to help prevent progression and to prevent recurrent stroke.
Chest pain
Tachypnea and chest pain may indicate acute chest syndrome, and either one warrants emergency evaluation.
Rapid breathing
Tachypnea and chest pain may indicate acute chest syndrome, and either one warrants emergency evaluation.
Increased pallor
Pallor is a typical finding from the anemia of SCD, and does not constitute an emergency.
However, an increase in pallor can be caused by splenic sequestration, increased hemolysis (as discussed above) or a temporary inhibition of erythroid production (aplastic crisis).
Increased jaundice
Baseline jaundice is typical in sickle cell disease, so on its own is not an emergency.
Marked increase in the level of jaundice may indicate an increase in the degree of hemolysis and a need for transfusion (may be associated with a viral illness).
Priapism
Priapism from sickling in the penile arteries can cause permanent damage.
Diff dx for fever, respiratory distress and CP in child with SCD 5
Acute chest syndrome (ACS)
ACS often develops in children admitted for a painful vaso-occlusive crisis. It is one of the most common causes of death in patients with sickle cell disease.
Clinical features of ACS include:
Fever
Cough
Chest pain (this can lead to difficulty with expansion of the lower lung and result in atelectasis)
Shortness of breath
Decreased oxygenation
Pericarditis
Typically presents with tachypnea and fever.
Uncommonly causes chest pain.
The increased splenomegaly speaks against this diagnosis.
Congestive heart failure (CHF)
CHF can occur in patients with sickle cell disease and chronic anemia.
Tachypnea is one of the most common signs of CHF in children.
Usually does not cause chest pain on its own.
Rib infarction
A rib infarction should always be suspected when child with sickle cell disease presents with chest pain.
Fever may be present with a vaso-occlusive crisis.
Tachypnea may be due to the need to avoid taking deep breaths.
Rhonchi are not consistent with this diagnosis.
Sepsis
Sepsis can happen at any time with sickle cell disease and must be a consideration.
Because sepsis is usually non-focal, however, it is unlikely that chest pain would be present.
Findings in car in scd in patient with chest pain, respiratory distress and fever 5
Acute chest syndrome (ACS) Findings in ACS may be due either to fat embolism or to vaso-occlusion of pulmonary vasculature. Findings include, but are not limited to:
Multilobar infiltrates (more commonly lower and middle lobes)
Effusions
Atelectasis
It is always difficult to distinguish whether an infiltrate in the lung of a child with sickle cell disease represents an infectious process (pneumonia) or atelectasis from infarction or pulmonary fat embolus.
Pericarditis
Pericarditis can present with effusion and infiltrate on chest x-ray.
Congestive heart failure (CHF)
Lower lobe infiltrates and cardiomegaly are both consistent with a diagnosis of CHF.
Rib infarction
While there would not be pulmonary infiltrates, a pleural effusion might happen as a sequela of rib infarction.
Also, cardiomegaly and hypoxia would not usually be present (though patients with sickle cell disease may have baseline cardiomegaly).
Sepsis
Cardiomegaly would be present only if patient was in cardiogenic shock (although, as noted above, patients with sickle cell disease may have cardiomegaly at baseline).
New infiltrates would not be a usual finding unless the sepsis leads to acquired/adult respiratory distress syndrome (ARDS).
CBC finding in SCD 2
Patients with sickle cell disease frequently demonstrate an exaggerated leukocytosis and thrombocytosis in response to stress.
CBC findings do not definitively help to identify if pneumonia or other cause of ACS is present.
Treatment of pain crisis in SCD
Intravenous fluids, NSAIDs (anti inflammatory properties), and intravenous narcotics (morphine or derivatives of morphine) are frequently required to control the pain.
Watch for respiratory depression
RBC transfusion and antibiotics in acute chest syndrome
An RBC transfusion is the only way to directly reduce or reverse the sickling process which is the underlying cause of the acute chest syndrome. Indications for RBC transfusion in ACS are not precise, but if a child experiences one of the following, a transfusion of packed red cells is recommended:
A fall in hemoglobin from baseline Increasing respiratory rate Worsening chest symptoms Declining O2 sats Progressive infiltrates on chest x-ray It should be noted that the vast majority of sickle cell patients with acute chest syndrome will have one or more of these findings.
Exchange transfusion (erythrocytapheresis) should be reserved for especially severe disease and/or hypoxemia not corrected by oxygen therapy.
Antibiotics in Acute Chest Syndrome
Practice guidelines and clinical data support the use of antibiotics in children with acute chest syndrome. Unfortunately, the clinical and laboratory features of ACS do not allow one to easily distinguish whether the cause is pulmonary fat embolism and/or infarction from acute infectious pneumonitis.
Various infectious agents have been reported in ACS including:
Viruses Chlamydia Mycoplasma Bacteria One large prospective study treated all ACS patients with a third-generation cephalosporin and a macrolide antibiotic. However, the overall rate of positive cultures was < 10%.
As every community has different rates and patterns of antimicrobial resistance, it is important to understand antibiotic choices selected by sickle cell hematologists at local centers.
Tx for SCD 2
Stem Cell Transplantation
Hematopoietic stem cell transplantation provides the only known curative therapy for sickle cell disease. This is a high-risk procedure with a significant mortality rate (around 5%) in the early post-transplant period. For most, myeloablative therapy is used prior to the transplant, causing a large percentage of the reported deaths. It is appropriate in children with major complications associated with sickle cell disease. The decision to proceed with transplant should be undertaken in conjunction with a pediatric hematologist familiar with both sickle cell disease and hematopoietic stem cell transplants. A recent Cochrane Systematic Review noted, however, there were no randomized, clinical trials published and the group recommended more research.
Another opportunity is the use of stem cell research to treat children with genetic conditions such as severe sickle cell disease. One treatment involves bone marrow transplant. Unfortunately, less than 15% of children with sickle cell disease have healthy, haploidentical siblings who can act as donors. Alternative sources for a matched sibling donor for patients with sickle cell disease are being investigated, including matched unrelated donors and cord blood units. In addition, instead of completely replacing the patient’s marrow with donor stem cells, using reduced intensity treatment regimens with a goal of reaching a chimeric bone marrow is also being investigated.
Hydroxyurea
Another promising therapy is the use of hydroxyurea. Administration of hydroxyurea, a chemotherapeutic agent, has been shown to decrease the severity and frequency of the sickling disorders when administered daily to patients with more severe disease.
Hydroxyurea inhibits ribonucleotide reductase, increases fetal hemoglobin (HgF), and also may have other effects, such as:
Improved nitric oxide metabolism
Reduced RBC endothelial interaction
Decreased erythrocyte density.
Prophylaxis in SCD
When given to infants with sickling disorders, penicillin significantly decreases the risk of mortality from overwhelming sepsis. Prophylaxis is usually continued until the child is five or six years of age (after this, there is little data to support its use except in patients who have had documented sepsis and bacteremia, or who have had their spleens removed).
