Case Report
A 64-year-old male patient was admitted to hospital on April 21st, 2021 (Day 1, hereafter referred as D1) with 3-day-paroxysmal abdominal cramps, accompanied by diarrhea, nausea as well as vomiting. The diagnosis was transverse colon perforation on admission, with rectal mass, septic shock and hypokalemia. An emergency surgery was performed to repair laparotomy perforation as well as radical treatment of rectal cancer. After the operation, he was transferred to intensive care unit (ICU) (D1). The score of the sequential organ failure assessment9, acute physiology and chronic health evaluation10, and Richmond agitation-sedation scale11 was 8, 19 and -2 scores, respectively. For surviving sepsis, ICU physicians implemented bundle strategies as antimicrobial therapy (imipenem and cilastatin sodium for injection, 0.5g q6h), fluid resuscitation (20% human albumin, 40g; crystoloid solution, 3000ml) and sedation therapy (remifentanil, propofol, midazolam).
During the ICU hospitalization (D1-D9), his blood routine examinations, body temperature, and procalcitonin are shown in Table 1. On D2, vancomycin (1g, q12h) was administrated intravenously combined with imipenem and cilastatin sodium, due to an operative recording showing a serious fecal contamination in his abdominal cavity. Unexpectedly, his platelets count (7 × 109/L) severely decreased on D4 (Figure 1). According to the blood routine test (Table 1) and medical history, we roughly excluded common blood diseases and autoimmune diseases. Meanwhile, hepatic failure and disseminated intravascular coagulation (DIC) were put aside. Thus, idiopathic thrombocytopenic purpura (ITP) was a major concern which might be caused by infection or medications, etc. After transfusion of platelets (1 U) and blood cells (2 U) on D4, his platelets count recovered a little (26 × 109/L). However, it went down again in the morning of D5 (14 × 109/L). The severe infection, as the first factor suspected to thrombocytopenia was alleviating at the same moment. Among all the medication used between D1-D5, vancomycin aroused suspicion and was discontinued (with its trough concentration being as 11 ug/ml). And a platelet transfusion (1U) was given to prevent hemorrhage.
In the evening of D5, as the body temperature increased to 38.7℃, the patient had to re-administered vancomycin. As a result, his platelets count was reduced from 61 × 109/L to 3 × 109/L within 8 hours. He had to receive a platelets (2U) transfusion again in the morning of D6. As drainage fluid culture suggested only Escherichia Coli (ESBL-) infection, we completely discontinued vancomycin but kept on imipenem and cilastatin sodium. The platelets count backed to 135 × 109/L on D7 and never dropped again since then. He was transferred back to the general ward after being extubated (D9). On D14, he stopped using antibiotics and was discharged with a better health condition. According to the Naranjo adverse reaction evaluation scale (Table 2)12, the total score was 6, and the relationship between vancomycin and thrombocytopenia was judged as ”probably”.