How would I assess a patient with suspected sickle cell disease?

Assessment of a Patient with Suspected Sickle Cell Disease

A comprehensive diagnostic approach for suspected sickle cell disease should include laboratory testing, clinical evaluation, and screening for complications, with hemoglobin electrophoresis being the definitive diagnostic test.

Initial Diagnostic Workup

• Complete blood count (CBC) with reticulocyte count to assess for normocytic normochromic anemia and elevated reticulocytes, which are hallmarks of hemolysis in SCD 1
• Hemoglobin electrophoresis to confirm the presence of hemoglobin S and determine the specific genotype (HbSS, HbSC, HbS/β-thalassemia) 1
• Peripheral blood smear to identify sickle-shaped red blood cells 1, 2
• Basic metabolic panel to evaluate renal function, as SCD can affect the kidneys 3
• Liver function tests to assess for hepatic involvement 3
• Urinalysis to screen for proteinuria, particularly in patients over 10 years of age 3

Clinical Assessment

• Vital signs with special attention to:

  • Blood pressure (may be lower than age-specific norms in SCD patients) 3
  • Oxygen saturation (track over time for changes) 3
  • Temperature (to identify potential infections) 4

• Physical examination focusing on:

  • Growth parameters and development (SCD can affect growth) 3
  • Spleen palpation (to detect splenomegaly or assess for functional asplenia) 3
  • Cardiopulmonary assessment (to identify signs of acute chest syndrome) 3
  • Neurological examination (to detect any neurological deficits suggesting stroke) 1
  • Skin examination (for pallor, jaundice, or leg ulcers) 2

Age-Specific Screening

• For children aged 2 years and older with HbSS or HbSβ0-thalassemia:

  • Transcranial Doppler ultrasonography to assess stroke risk 3

• For patients 10 years and older (all genotypes):

  • Annual dilated fundoscopic examination for retinopathy 3
  • Annual urinary protein evaluation 3

Evaluation for Common Complications

• Pain assessment using validated pain scales to evaluate for vaso-occlusive crisis 5
• Chest radiography if respiratory symptoms are present to evaluate for acute chest syndrome 1
• Pulse oximetry to assess for hypoxemia, which may indicate acute chest syndrome 3
• Neurological symptoms warrant urgent evaluation, including brain MRI/MRA to assess for stroke or silent cerebral infarcts 3
• Assessment of school performance and neurodevelopment, as SCD can affect cognitive function 3

Special Considerations

• Preoperative assessment should include hemoglobin levels, with a target of >9 g/dL before surgery 3
• For patients receiving chronic transfusions, monitor for iron overload with:
  • Serial ferritin levels 3
  • Consider liver MRI (R2, T2*, or R2*) every 1-2 years if ferritin >1000 ng/mL 3
  • Consider cardiac T2* MRI only in patients with high iron burden (liver iron content >15 mg/g) for 2+ years 3

Pitfalls to Avoid

• Failing to distinguish between sickle cell trait and sickle cell disease 2
• Attributing all pain to SCD without considering other etiologies 5
• Overlooking the risk of infection due to functional asplenia, which can begin as early as 3 months of age 1
• Delaying treatment for acute chest syndrome, which can rapidly progress 1
• Missing silent cerebral infarcts, which require MRI for detection and can affect cognitive function 3

Multidisciplinary Approach

• Involve both a pediatrician/primary care provider and a multidisciplinary SCD clinic team for comprehensive care 3
• Consider referral to specialized centers for:
  • Patients with pulmonary hypertension confirmed by right-heart catheterization 3
  • Complex cases requiring expertise in SCD management 3
  • Patients with cardiac T2* abnormalities requiring specialized monitoring 3

By following this systematic approach, clinicians can effectively assess patients with suspected sickle cell disease and identify complications requiring intervention, ultimately improving morbidity, mortality, and quality of life outcomes.