<P> In high doses, hydrocortisone (cortisol) and those glucocorticoids with appreciable mineralocorticoid potency can exert a mineralocorticoid effect as well, although in physiologic doses this is prevented by rapid degradation of cortisol by 11β - hydroxysteroid dehydrogenase isoenzyme 2 (11β - HSD2) in mineralocorticoid target tissues . Mineralocorticoid effects can include salt and water retention, extracellular fluid volume expansion, hypertension, potassium depletion, and metabolic alkalosis . </P> <P> Glucocorticoids cause immunosuppression, decreasing the function and / or numbers of neutrophils, lymphocytes (including both B cells and T cells), monocytes, macrophages, and the anatomical barrier function of the skin . This suppression, if large enough, can cause manifestations of immunodeficiency, including T cell deficiency, humoral immune deficiency and neutropenia . </P> <Table> Main pathogens of concern in glucocorticoid - induced immunodeficiency: <Tr> <Th> Bacteria </Th> <Td> <Ul> <Li> Enterobacteriaceae </Li> <Li> Legionella micdadei </Li> <Li> Listeria monocytogenes </Li> <Li> Mycobacterium tuberculosis </Li> <Li> Nontuberculous mycobacteria </Li> <Li> Nocardia asteroides </Li> <Li> Rhodococcus equi </Li> <Li> Salmonella species </Li> <Li> Staphylococcus aureus </Li> <Li> Streptococci </Li> </Ul> </Td> </Tr> <Tr> <Th> Fungi </Th> <Td> <Ul> <Li> Aspergillus </Li> <Li> Blastomyces </Li> <Li> Candida albicans and nonalbicans species </Li> <Li> Coccidioides immitis </Li> <Li> Cryptococcus neoformans </Li> <Li> Fusarium species </Li> <Li> Histoplasma capsulatum </Li> <Li> Penicillium marneffei </Li> <Li> Pseudallescheria boydii </Li> <Li> Zygomycosis </Li> </Ul> </Td> </Tr> <Tr> <Th> Viruses </Th> <Td> <Ul> <Li> Adenovirus </Li> <Li> Cytomegalovirus </Li> <Li> Herpes simplex virus </Li> <Li> Human papillomavirus </Li> <Li> Influenza / parainfluenza </Li> <Li> Respiratory syncytial virus </Li> <Li> Varicella zoster </Li> </Ul> </Td> </Tr> <Tr> <Th> Other </Th> <Td> <Ul> <Li> Cryptosporidiosis / Isospora belli </Li> <Li> Pneumocystis carinii </Li> <Li> Strongyloides stercoralis </Li> <Li> Toxoplasma gondii </Li> </Ul> </Td> </Tr> </Table> <Tr> <Th> Bacteria </Th> <Td> <Ul> <Li> Enterobacteriaceae </Li> <Li> Legionella micdadei </Li> <Li> Listeria monocytogenes </Li> <Li> Mycobacterium tuberculosis </Li> <Li> Nontuberculous mycobacteria </Li> <Li> Nocardia asteroides </Li> <Li> Rhodococcus equi </Li> <Li> Salmonella species </Li> <Li> Staphylococcus aureus </Li> <Li> Streptococci </Li> </Ul> </Td> </Tr>

What is the mechanism of action of steroids