Natriuretic peptides are peptic hormones produced by atrial and ventricular myocytes, and by endothelium of blood vessels, that take part in homeostatic control of water and sodium levels, but also potassium transport, lipolysis in adipocytes and blood pressure regulation.   Three different natriuretic peptides are distinguished: atrial natriuretic peptide (ANP), b-type natriuretic peptide (BNP) and c-type natriuretic peptide (CNP). Those peptides are responsible mostly for water-sodium homeostasis and regulation of blood pressure. Levels of natriuretic peptides increase significantly in diseases and disorders such as congestive heart failure and pulmonary hypertension, that is why natriuretic peptides were found useful in diagnosis and monitoring of said diseases. In clinical practise, BNP and NT-proBNP levels are mostly used.

Introduction: Cotard's syndrome (CS) is a rare set of psychopathological symptoms, the main symptom of which is nihilistic delusions concerning the negation of the existence of internal organs or the entire bodyAim, material and methodology: The aim of the study is to present a case of a patient treated for postpartum depression who developed Cotard's syndrome. The patient's symptoms began immediately after her daughter. The clinical picture was dominated by anxiety and apathy, nihilistic delusions about the atrophy of the urethra and other lower abdominal organs, and olfactory hallucinations - she could smell rot.Discussion: The available literature on Cotard’s Syndrome does not allow us to indicate a certain reason for its development. Perhaps the birth of the first child - the woman doubted herself as a mother, she was afraid that she would hurt the cause of the disorders observed and described by us was transient ischemia of the CNS during delivery.Conclusions: Cotard's syndrome can develop in the course of many mental and somatoform disorders. The described case is, to our knowledge, the first description of Cotard’s Syndrome in the deprivation period. Difficulties in establishing the etiopathogenesis and pathophysiology of Cotard’s Syndrome translate into therapeutic problems. It has been suggested that the treatment of the underlying disorder on the basis of which CS is developed remains the most effective method of therapy.