Pathophysiology

Pathophysiology Study Guide

©2018 of 131 defects, are due to the species of Pjivoreci infection, S pneumoniae, P aeruginosa, Legionella pneumophila, L monocytogenes, Nocardia species, Mycobacterium species, fungi, VZV, HSV, CMV, Epstein-Barr virus (EBV), respiratory viral infections, Toxoplasma species, cryptosporidia, Strongyloides species, encapsulated bacteria, Candida, Mycobacterium avium-intracellulare complex, and herpesviruses. Phagocyte deficiency makes the host vulnerable to S aureus, Nocardia species, P aeruginosa, Serratia species, streptococci, other enteric organisms, and Candida, Burkholderia, Aspergillus, and Chromobacterium species. Further, there are certain infections that become fatal for immune-compromised hosts, which include infectious diarrhea, pneumonia, tuberculosis, measles, malaria, salmonellosis, P jiroveci infection, and HIV. The immune-compromised host must look for interventions that help prevent the occurrence of infections so that they do not become fatal or severe. These preventive interventions can be categorized as pre-emptive measures and concurrent measures. Some pre-emptive measures include identification and correction of risk factors for the occurrence of infections, increasing the resistance power of the host to fight infectious pathogens, and avoiding hospitalization. In contrast, some concurrent measures that one can adopt include keeping away from exogenous pathogens, and the reduction of endogenous flora and antimicrobial prophylaxis. Transplantation Reactions Sometimes, when a tissue or organ is damaged, doctor's resort to replacing the damaged tissue or organ with a donated organ or tissue, performing transplantation surgery. It is important that the immune system of the host accepts the new transplanted/donated organ or tissue. If the immune system considers the organ foreign, it is likely that a transplantation reaction occurs. Complications arising from transplantation reactions are explained below. Graft Versus Host Disease Graft versus host disease is a complication that may occur when a bone marrow transplantation or stem cell transplantation does not succeed. In this reaction, cells of the donor do not get accepted by the body of the host, but instead, attack the body of the recipient. When cells of the other person are transplanted, it is known as allogeneic, while when the cells of the recipient are transplanted back to him, it is known as autologous. It should be noted that the probability of graft versus host disease changes based on if the tissues and cells of the donor match closely with the recipient. GVHD can be acute or chronic depending on the magnitude of symptoms. Symptoms include abdominal pain, cramping in the abdomen, nausea, vomiting, diarrhea, liver troubles (jaundice), rash on skin, itching, and redness on the skin. Symptoms of chronic GVHD may be lifelong and may include changes in vision, dryness and patches in the mouth, fatigue, weakness in muscles, chronic pain, pain and stiffness in joints, a rash with discolored and thickened skin, breathlessness, and weight loss. Rejection When the immune system of the recipient does not accept the organ or tissue and attacks back at the transplanted organ or tissue, it is known as transplant rejection. The cause of rejection is that the immune system of the host recognizes the transplanted organ or tissue as foreign. This is because the Achieve Page 37