Pediatric emergency medicine trisk 555

an acute exacerbation may require steroids as part of their management; however, a
taper beyond the standard 5-day course is necessary.

Stroke
Initial Assessment
The combined incidence of ischemic and hemorrhagic stroke is nearly 300-fold higher
in patients with sickle cell disease compared with all children. Eleven percent of all
sickle cell anemia patients will suffer a stroke, with occurrence at a median age of 20
years. Fatalities with ischemic strokes are less likely than with hemorrhagic stroke;
however, neurologic sequelae are common with both. Typical presenting symptoms and
signs for ischemic stroke include focal weakness, dysarthria, aphasia, and seizure.
Hemorrhagic strokes present with evidence of increased intracranial pressure including
severe headache, vomiting, impaired mental status, bradycardia, nuchal rigidity, coma,
focal neurologic deficits, and seizure. Risk factors include young age, low baseline
hemoglobin concentration, and high leukocyte count. Historical risk factors include
previous stroke, moyamoya, cerebral aneurysms, acute chest syndrome, acute
hypertension, hypertransfusion, and recent corticosteroid use. Cerebral aneurysms occur
with increased frequency in patients with sickle cell disease. The origin of this
complication, which is usually detected in teenagers or adults, remains obscure but may
relate to local vessel damage. The severe morbidity and high mortality associated with
ruptured cerebral aneurysms require careful evaluation of patients with sickle cell
disease and headaches or other neurologic findings (vertigo, syncope, nystagmus, ptosis,
meningismus, or photophobia). Unfortunately, the aneurysm often escapes detection
until after major, and often fatal, subarachnoid or intracerebral bleeding.
Management/Diagnostic Testing
Use CT for initial evaluation of sickle cell patients with concern for stroke. MRI can
assist in early diagnosis in ischemic strokes (within 2 to 4 hours of symptoms) that may
not be apparent on CT. A 1.5 to 2 times volume exchange transfusion should begin
immediately for ischemic strokes. This reduces the likelihood of further intravascular
sickling and may prevent extension of cortical damage. MRA should be performed in
patients with identified intracranial hemorrhage to guide further diagnosis and

management. If an accessible aneurysm is identified and bleeding persists, surgical or
interventional radiology intervention should follow radiologic confirmation.

Anemia
Initial Assessment/H&P
The baseline anemia of a patient with sickle cell disease may worsen acutely due to
acute hemolysis triggered by a viral or bacterial infection or by an aplastic crisis usually
in the setting of infection with parvovirus B19 halting RBC production for 2 to 4 days.


In both cases, patients will present with fatigue, pallor (or jaundice if hemolysis is
present), and tachycardia.
Management/Diagnostic Testing
Laboratory studies will demonstrate a fall in the hemoglobin from baseline. Patients
with a hemolytic crisis will typically have scleral icterus, jaundice, and a reticulocytosis.
Both hemolytic and aplastic crises are usually self-limited; once the infection clears, the
patient recovers. Patients with severe symptoms such as altered mental status, impaired
oxygen delivery, and significant tachycardia should receive a transfusion of pRBCs.
Transfusion volume should be calculated to target the patient’s baseline hemoglobin
level and not exceed 10 to 11 g/dL.

Splenic Sequestration
Initial Assessment/H&P
Splenic sequestration, a potentially life-threatening event, usually presents in children
younger than 5 years of age before the spleen has completely fibrosed. The lifetime risk
is 20%. It may be the first presenting symptom of sickle cell disease in children less than
2 years. Patients with HbSC and sickle β-thalassemia have less splenic fibrosis and may
experience splenic sequestration at any age. During sequestration, the spleen becomes
acutely engorged in some cases with a significant portion of the blood volume. Patients
will present with acute onset of left upper quadrant abdominal pain, progressive pallor,

increasing tachycardia, and lethargy over several hours. The spleen is palpable and may
be tender. A prominent reticulocytosis is usually present. Hypotension and
cardiovascular collapse can occur with a 10% to 15% mortality rate.
Management/Diagnostic Testing
The mainstay of treatment is replenishment of the intravascular volume for patients in
hypovolemic shock. Resuscitation with crystalloid is used to stabilize perfusion
emergently. However, aggressive crystalloid use can compromise tissue oxygenation
due to dilutional worsening of anemia. Transfuse pRBCs for patients in shock (5 to 10
mL/kg; begin carefully with 2 to 3 mL/kg). Since RBCs will be released from the spleen
as the sequestration reverses, do not overcorrect the hemoglobin (return it to patient’s
baseline) with initial transfusion to avoid complications of circulatory overload and
erythrocytosis. Reversal of shock and a rising hemoglobin level signal improvement of a
sequestration crisis. The spleen becomes less firm and smaller over the course of days.
For milder cases, admission for serial splenic examinations and establishing trend of
hemoglobin is appropriate.

Papillary Necrosis
Initial Assessment/H&P


Papillary necrosis in the kidneys causes hematuria that is usually sudden and painless
and often persistent. A history of recent trauma, streptococcal infection, or recurrent
urinary tract infection should alert the physician to other causes of hematuria. Similarly,
hypertension suggests the presence of nephritis rather than simple vasoocclusion.
Management/Diagnostic Testing
Laboratory evaluation should include CBC, reticulocyte count, type and cross,
electrolytes, BUN/Cr, and urinalysis. In papillary necrosis, microscopic examination of
the urine shows numerous RBCs but RBC casts are rarely seen. Pyuria and proteinuria
in excess of what might be attributed to the blood in the urine are not found in papillary
necrosis and may indicate nephritis. Renal ultrasound may be obtained to confirm the

diagnosis or evaluate for alternative etiologies for the hematuria. Admission to the
hospital is often required for IV hydration. In severe hematuria, significant anemia may
necessitate RBC transfusion. Simple or exchange transfusion may also shorten the
course of ongoing hematuria. The lifetime risk of renal failure is 11%.

Avascular Necrosis
Sickle cell disease is the most common cause of pediatric femoral head avascular
necrosis. This complication is even more common in patients with HbSC disease. The
lifetime risk of avascular necrosis is 21%. Risk factors include a high baseline
hematocrit and a clinical history of frequent or severe painful crises.
Management/Diagnostic Testing
Treatment options are limited. Bed rest and core decompression are the initial
approaches. Total hip replacement may become necessary.

Transfusions
Patients with sickle cell disease may receive many transfusions throughout their lives
and are at risk for developing alloantibodies. Perform extended RBC antigen testing
before their first transfusion; their primary hematologist usually performs this during
routine outpatient monitoring. Alloantibodies make future cross-matching more
challenging and increase the risk of a hemolytic transfusion reaction. Ensure that local
blood banks communicate with the blood bank at patient’s primary institution. The
volume of simple transfusion should be calculated to avoid raising the patient’s
hemoglobin level above 10 to 11 g/dL. Exchange transfusion may be needed in some
clinical settings, as discussed in the complication sections above; this procedure requires
adequate large-bore IV access, or central venous access, and often requires a
plasmapheresis machine. Infants may be exchange transfused with simple syringes in
consultation with a hematologist. If sophisticated blood banking services are not
available, consider transferring the patient to an appropriate center.
Clinical Indications for Discharge or Admission

For patients with vasoocclusive crises, admit for IV analgesics if their pain is
inadequately managed with an oral pain regimen. Additionally, admit patients who are
unable to maintain adequate oral intake and are at risk of dehydration. Ill-appearing
patients or those with clinical concern for acute chest syndrome, sepsis, splenic
sequestration, or stroke require hospitalization and potentially intensive care
management. Consider hospitalization for febrile patients who are well appearing but
are younger than 6 months, underimmunized, if there is a concern for the reliability of
follow-up, and in those with more than 5% (absolute) drop in hematocrit below baseline,
or a Hb <6 g/dL. Febrile nontoxic patients with sickle cell disease may be discharged
following blood cultures and antibiotic administration if they are able to follow up
within 24 hours.

NEUTROPENIA
Goals of Treatment
Prompt evaluation and treatment of neutropenic patients is essential to decreasing
morbidity and mortality associated with infection. Cultures should be obtained but
should not delay empiric antibiotic treatment. Numerous quality improvement initiatives
in pediatric emergency medicine have shown improvement in time to initiation of
antibiotic therapy in patient populations known to be at risk of neutropenia.
CLINICAL PEARLS AND PITFALLS
Neutropenia is defined as an absolute neutrophil count (ANC) less than
1,500/μL, with severe neutropenia <500/μL.
Severe neutropenia increases the risk for serious infection due to increased
susceptibility to bacterial and fungal infections, but not typically to viral or
parasitic infections.
Risk of serious infection in neutropenic patients varies depending on the
etiology of the neutropenia and patient comorbidities.
Incidental neutropenia identified in a previously healthy child likely represents
viral suppression.

Current Evidence
Neutrophils are an essential component of host defense against invasive organisms
including bacteria and fungi. Neutropenia or defects in neutrophil function can result in
clinically significant immunocompromise.

Clinical Considerations
Asymptomatic neutropenia has multiple etiologies and diagnostic evaluation can occur
as an outpatient. In febrile patients, obtain blood and urine cultures, along with