Can a patient's elevated white blood cell (WBC) count, from leukocytosis to a higher level of leukocytosis, be attributed to steroid-induced effects, given the resolution of septic arthritis symptoms after treatment with corticosteroids (steroids) and antibiotics?

From the Guidelines

The elevated white blood cell count (from 17.20 to 21.12) could be steroid-induced leukocytosis, especially since the patient is clinically improving with no remaining signs of septic arthritis. Corticosteroids commonly cause increased white blood cell counts by demarginating neutrophils from blood vessel walls and delaying their migration out of the bloodstream 1. The typical duration of corticosteroid treatment is 7-14 days, or less for those who are rapidly improving, and inflammation may recur after discontinuing corticosteroid therapy, especially when it is stopped abruptly 1.

Key Considerations

• The patient's clinical status should be carefully monitored after discontinuing corticosteroids.
• If the patient deteriorates after stopping corticosteroids, reinitiating corticosteroid therapy could be helpful.
• Corticosteroid-induced adrenal suppression is probably duration-dependent, and patients who receive longer courses of corticosteroids might be particularly likely to benefit from a taper before discontinuing.

Recommendations

• I recommend rechecking the white blood cell count 3-5 days after discontinuing steroid therapy to allow time for the medication effect to wear off and the count to normalize.
• If steroids must be continued for other reasons, the white count can be monitored weekly while recognizing that elevation may persist throughout treatment.
• When interpreting follow-up results, focus on the patient's clinical status rather than laboratory values alone.
• If the patient develops new fever, joint pain, or other concerning symptoms despite the improving clinical picture, earlier reassessment of both laboratory values and clinical status would be warranted. The steroid-induced leukocytosis is typically benign and self-limiting once the medication is discontinued 1.

From the Research

Steroid-Induced Leukocytosis

• The patient's elevated white blood cell count from 17.20 to 21.12 after steroid administration could be attributed to steroid-induced leukocytosis, as supported by studies 2, 3, 4.
• Corticosteroids are known to cause leukocytosis, with the degree of increase related to the dosage administered 3.
• The increase in white blood cell count can be seen as early as 48 hours after high-dose steroid administration, with a mean increase of up to 4.84 × 10^9/L cells 2.

Timing of White Blood Cell Count Recheck

• The white blood cell count can peak at 48 hours after steroid administration, and it is recommended to recheck the count after this period to assess the effect of steroids on leukocytosis 2.
• However, the optimal timing for rechecking the white blood cell count is not explicitly stated in the provided studies, and clinical judgment should be used to determine the appropriate timing.

Differential Diagnosis

• It is essential to consider other causes of leukocytosis, such as infection, when interpreting elevated white blood cell counts in patients on steroids 3, 4.
• A shift to the left in the peripheral white blood cells, toxic granulation, and other clinical features can help differentiate between steroid-induced leukocytosis and infection 3.