Female Infant\Purpura\Bone Marrow Puncture?

A 2-month-old baby girl presented with purpura. The following is the complete blood count report. Specimen type: Whole blood Department: Hematology Clinic Clinical diagnosis: Thrombocytopenia 1 The following items use this methodology: <Five-part differential> 2 White blood cell count 7.6×10⁹/L 3 Lymphocytes 68.9% ↑ 4 Monocytes 9.4% 5 Neutrophils 18.0% ↓ 6 Eosinophils 3.6% 7 Basophils 0.1% 8 Lymphocyte# 5.2×10⁹/L 9 Monocyte# 0.7×10⁹/L 10 Neutrophil# 1.4×10⁹/L 11 Eosinophil# 0.27×10⁹/L 13 Red blood cell count 3.30×10¹²/L 14 Hemoglobin 100.0 g/L 15 Hematocrit 30.4% 16 Mean corpuscular volume 92 fL 17 Mean corpuscular hemoglobin 32.3 pg 18 Mean corpuscular hemoglobin concentration 329 g/L 19 Red cell distribution width 14.9% 20 Platelet count 34×10⁹/L ↓↓ 21 Mean platelet volume --- The above is the complete blood count report. Main abnormalities noted (for reference): Lymphocyte percentage elevated (68.9% ↑) Neutrophil percentage decreased (18.0% ↓) Platelet count markedly decreased (34 ×10⁹/L; normal reference range 100-550 ×10⁹/L) Hemoglobin and hematocrit mildly reduced The doctor recommended proceeding with a bone marrow puncture. On further questioning, it was learned that the infant had received a pentavalent vaccine (diphtheria + tetanus + pertussis + poliomyelitis + Haemophilus influenzae type b) approximately two weeks earlier. The author advised that the purpura could be observed to see if it would resolve spontaneously. Nevertheless, the elderly family members took the infant for the bone marrow puncture. While awaiting the bone marrow puncture report, the purpura gradually faded.