Neglected vitamin K deficiency causing coagulation dysfunction in an older patient with pneumonia: a case report

BACKGROUND: The development of coagulation disorders can be dangerous and fatal in the older people, especially those with multiple medical conditions. Vitamin K-dependent coagulation disorders are easily overlooked when anticoagulant drugs are not used and the patient shows no signs of bleeding. CASE PRESENTATION: We report a case of a 71-year-old male suffering from pulmonary infection with severe coagulation disorder without bleeding symptoms. He also had a history of Parkinson’s disease, Alzheimer’s disease and cardiac insufficiency. Coagulation tests were normal at the time of admission, prothrombin time (PT) is 13.9 (normal, 9.5–13.1) seconds and the activated partial thromboplastin time (APTT) is 30.2 (normal, 25.1–36.5) seconds. But it turned severely abnormal after 20 days (PT: 136.1 s, APTT: 54.8 s). However, no anticoagulants such as warfarin was used and no bleeding symptoms were observed. Subsequent mixing studies with normal plasma showed a decrease in prothrombin times. Vitamin K deficiency was thought to be the cause of coagulation disorders considering long-term antibiotic therapy, especially cephalosporins, inadequate diet and abnormal liver function. After supplementation with 20 mg of vitamin K, coagulation dysfunction was rescued the next day and serious consequences were effectively prevented. CONCLUSIONS: Overall, timely vitamin K supplementation with antimicrobials that affect vitamin K metabolism requires clinician attention, especially in older patients who are multimorbid, frail or nutritionally compromised, and are admitted to hospital because of an infection that needs antimicrobial therapy are at risk of clotting disorders due to abnormal vitamin K metabolism secondary to altered gut flora, which can exacerbate existing nutritional deficiencies.