Sickle Cell Disease Flashcards
Acute sickle cell chest syndrome presentation
chest pain, cough, pulmonary infiltrates, hypoxemia, fever, lung crackles
in a sickle cell pt
Treatment of acute sickle cell chest syndrome
supplemental oxygen, broad spectrum abx, IVF and pain control
If acute chest syndrome is mild (SaO2>90% and single lobar infiltrate) what do you do?
0-2 units of RBC TRANSFUSION
If acute chest syndrome is moderate (with SaO2>85% and <2 lobes on CXR w/ pulmonary infiltrate), what do you do?
2-3 units of pRBC TRANSFUSION
If acute chest syndrome is (SaO2<85% or >2 lobes w/ pulm infiltrate) is severe, what do you do?
exchange transfusion. to prevent hemoconcentration or hyperviscosity.
Do we use steroids in acute chest syndrome?
No because it can cause rebound vaso occlusive events and increased risk for avascular necrosis and there’s an association with hemoragic stroke
When do we use hydoxyurea for acute chest syndrome?
Never used in acute setting. only used as a way to decrease frequency of pain crises and acute chest syndrome in the chronic setting.
What must you do if you see pulmonary infiltrates in someone with sickle cell and acute pain?
they have acute chest syndrome, need to measure oxygen and start empiric abx. May need transfusions or exchange transfusion.
what is priapism
> 2-4 hr penile or clitoral erection that is not associated with sexual stimulation or desire
can be seen as a serious side effect of people with sickle cell disease and seen up to 45% of pts.
why does priapism occur in sickle cell dx pts?
due to decreased oxygen levels in corpora cavernosa which leads to sickling and blockage of penile venous outflow
can have ischemic changes that can occur in the penile tissue if priapism is not corrected after 4 hrs resulting in fibrosis and ED.
how to treat sickle cell disease patients with priapism with milder symptoms <2 hrs
increased fluid intake oral analgesics and attempted urination once erection subsides
priapism lasting more than 2 hrs with more significant symptoms need
IV pain meds and IVFs, blood aspiration of the corpus canvernosum with saline irrigation and intracavernosal injection of sympathomimetics (phenylephrine and epinephrine) to restore penile venous outflow. (done by a urologist)
priaprism that lasts for >12 hrs may need (what for treatment)
surgical shunting and glans-spongiosum shunt to bypass blood from corpus cavernosum to corpus spongiosum and relieve occlusion.
what Hgb target is aimed for with pts who have sickle cell disease and acute pain crisis?
exchange transufsions should help increase hgb level rapidly and the goal Hgb target is <10g/dl. we do not aim for higher because this can cause neurological complications like headaches, seizures, obtundation requiring ventilatory support.
Sickle cell trait patients can present with;
recurrent gross hematuria - make sure that urinalysis lacks active urinary sediment which would make glomerular causes more likely.
Normal U?s means no structural kidney lesion , kidney stone or UTI less likely.
two renal pathology that you will see with a sickle cell trait patient
hematuria and impaired ability to make maximally concentrated urine
why does a sickle cell trait patient have abnormal renal function?
because the renal papilla is in a naturally hypoxic and hypertonic environment and so papillary blood flow velocity is is relatively slow and this all favors sickling of cells and this leads to renal papillary infarction and possibly papillary necrosis
what is seen on labs of sickle cell crisis or vasoocclusive phenomena ?
acidosis, hypovolumia, and hypoxia
Tx with aggressive IV hydration and opioid pain control.
Parvo B19 infection with sickle cell dx?
pts can develop severe anemia from red cell aplasia due to underlying viral infection like parvovirus B19.
Can see fatigue, rhinorrhea, macular exanthems (slapped cheeks) and myalgias.
what does parvovirus B19 do to bone marrow in sickle cell pts?
causes can cause a aplastic anemia in sickle pts.
See cessation of RBC production temporarily and can caused reticulopenia (starts about 5 days after exposure and can continue for 7-10 days) and can see a drop in Hgb that may need transfusions.
When should a sickle cell pt get a RBC exchange transfusion?
acute chest syndrome, CVA, TIA, or priapism.
what are the causes of acute severe anemia in a sickle cell dx pt?
splenic sequestration crisis
aplastic crisis
hyperhemolytic crisis
What is a splenic sequestration crisis?
this is vasoocclusion in spleen causing pooling of RBCs.
see markedly low hgb, high reticulocytosis, and rapidly enlarging spleen
where do we see splenic sequestration crisis?
seen in sickle cell children before autosplenectomy (where this sequestration crisis leads to splenic infarction in different areas)
what is done to prevent splenic sequestration crisis?
splenectomy to prevent reoccurrences.
By the time sickle cell pt is an adult, they will have functional asplenia as their spleen will have completely infarcted.
Aplastic crisis features
transient arrest of erythropoiesis with markedly low bone marrow RBC precursors, markedly low Hgb, and low reticulocytes.
Usually due to infection (Parvo B19, EBV, Strep pneumoniae, and Salmonella)
Recurrent dx is rare due to immunity
What is hyperhemolytic crisis?
sudden worsening of anemia with increased reticulocytosis
unclear etiology but possibly delayed transfusion reaction in tps with multiple transfusions
what causes aplastic crisis
transient bone marrow arrest leading to decrase erythropoiesis and decreased hgb (<4) and little to no reticulocytosis.
see profound anemia, pallor, weakness, lethargy, dyspnea.
What is treatment for aplastic crisis?
supportive with transfusions, rest, analgesics, hydration, and oxygenation. recurrent aplastic anemia is rare due to immunity to viral illness.
difference between hyperhemolytic and splenic sequestration and aplastic anemia crisis?
both hyperhemolytic crisis and splenic sequestration present with reticulocytosis
aplastic crisis presents with little or no reticulocytosis
side effects of hydroxyurea:
myelosuppression and leukopenia and neutropenia. can also cause thrombocytopenia.
what is also associated with sickle cell dx?
Iron deficiency anemia - seen in 20% of SCD due to increased urinary excretion of iron loss but ferritin is <25.
Acute chest syndrome is defined as:
new infiltrate on CXR + any of the following: fever, chest pain or respiratory symptoms like cough, wheezing, decreased oxygen saturation, tachypnea, or accessory muscle usage.
causes of acute chest syndrome
infection
asthma
hypoventilation
pulmonary vasoocclusion from fat emboli
if sickle cell dx pt is admitted for acute pain crisis and their CXR is negative does that mean they don’t have acute chest syndrome?
No. Negative CXR obtained at initial presentation do not rule out subsequent development of acute chest syndrome
ACS develops within 48-72 hrs after admission for acute pain crisis.
Pts admitted for sickle crisis should be considered to be in prodromal phases of acute chest syndrome
What are some measures that could be done to prevent a pt in sickle cell crisis from developing acute chest syndrome?
prophylactic measures are: close pulmonary monitoring, cautious hydration, optimal pain control and incentive spirometry
What empiric antibiotics should be started for someone with acute chest syndrome:
they need to cover atypical organisms like Chlamydia and Mycoplasma (azithromycin)
What type of fluids should be started for a patient in acute sickle cell crisis?
hypotonic 1/2 normal saline or D5 1/2 normal saline.
Complications of sickle cell TRAIT
renal disease
hematuria, increased UTI, renal medullary carcinoma
Thrombosis:
splenic infarct, VTE, and priapism
pts with sickle cell trait are
asymptomatic and don’t have complications of sickle cell dx like vasoocclusive crisis and hemolysis,
But they can have hematuria from infarction of renal medullary blood vessels
can see splenic infarct in strenuous exercise or exposure to hypoxic conditions - if infarction occurs in portion of spleen next to diaphgram can see small pleural effusion with radiation of pain to shoulder top.
splenic infarct is seen with
what’s it’s presentation?
sickle cell trait pts
can see splenic infarct in strenuous exercise or exposure to hypoxic conditions - if infarction occurs in portion of spleen next to diaphgram can see small pleural effusion with radiation of pain to shoulder top.
Treatment of splenic infarct in sickle cell trait pts
Tx is supportive care and analgesia.
how to prevent secondary stroke in a patient with sickle cell disease
need to get monthly erythrocyte transfusions.
70% of new stroke and subsequent stroke without intervention.
