Platelet cold agglutinins and thrombocytopenia: A diagnostic dilemma in the intensive care unit
A 32-year-old lady was admitted with a 3 day history of bilateral upper and lower limb weakness. A diagnosis of Guillain-Barre syndrome (GBS) was suspected and patient was shifted to the ICU. The nerve conduction studies were consistent with that of acute motor axonal neuropathy type of GBS. The patient received a 5 day course of intravenous immunoglobulin (Ig). The platelet count at admission was 60,000. The white blood cells and red blood cell (RBC) counts were found to be normal. Repeated counts were on the lower side ranging from 3,000 to 15,000. However, the patient was not symptomatic and had no evidence of bleeding.\nClinical hematology opinion was sought and a suspicion of sepsis, heparin induced thrombocytopenia, drug/immune mediated thrombocytopenia and dengue were entertained. Accordingly patient was extensively worked up. Immunological work-up including titers of anti-neutrophilic cytoplasmic antibody/anti-nuclear antibody and other investigations such as dengue serology were obtained. However, this extensive work-up did not reveal anything.\nA review of the treatment chart was done to exclude any drug induced low platelet count. The patient was on supportive measures and medications as directed by ICU protocol. The patient received ranitidine for stress ulcer prophylaxis and multi-vitamins. These are not known to cause thrombocytopenia. Noinvasive procedures were undertaken in the interim period and deep venous thrombosis (DVT) prophylaxis with heparin was discontinued in view of the suspicion of heparin induced thrombocytopenia. Mechanical prophylaxis was instituted for DVT.\nThe hematologist was consulted and it was found that there was in-vitro clumping of platelets with ethylene diamine tetra acetic acid (EDTA). After further discussion and in accordance with the hematologist's suggestion, EDTA, citrate and heparinized samples were dispatched to the lab. The problem of clumping; however, persisted. The hematologist suspected the presence of cold agglutinins against platelets and analyzed the count by raising the temperature and this revealed a normal platelet count. The count thus obtained was 213,000. The hematologist made a diagnosis of spontaneous EDTA independent platelet agglutination and these platelet cold agglutinins were responsible for considerable diagnostic confusion.