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  1. 1. Pneumocystosis Dr.T.V.Rao MD
  2. 2. Pneumocystis pneumonia <ul><li>PCP is a pneumonia caused by the fungal organism Pneumocystis carinii ( now renamed Pneumocystis jiroveci) . This organism is common in the environment and does not cause illness in healthy people. In the 1980s, biochemical analysis of the nucleic acid composition of Pneumocystis rRNA and mitochondrial DNA identified the organism as a unicellular fungus rather than a protozoa. </li></ul>
  3. 3. Change of Nomenclature <ul><li>In 1999, a new binomial classification renamed human Pneumocystis carinii to Pneumocystis jiroveci (after the Czech parasitologist Otto Jiroveci, thought to be the first to describe the organism in humans). The designation, Pneumocystis carinii is now reserved for one of the two Pneumocystis species infecting only rats. </li></ul>
  4. 4. Species <ul><li>Pneumocystis carnii found in rats </li></ul><ul><li>Pneumocystis jiroveci in humans </li></ul>
  5. 5. Pneumocystis jiroveci <ul><li>Till recently P.Jiroveci was though to be a Protozoan </li></ul><ul><li>Molecular biology proved that it is a Fungus, related to Ascomycetes </li></ul><ul><li>Pneumocystis species are present in the lungs of many animals, Rats, Mice, Dogs, Cats, and Rabbits, </li></ul><ul><li>Do not cause infections until immuno supressed. </li></ul><ul><li>More familiar Pneumocystis carinii is found only in Rats. </li></ul>
  6. 6. Morphology <ul><li>Spherical, Elliptical </li></ul><ul><li>4- 6 microns, contains 4 to 8 nuclei </li></ul><ul><li>Stained with </li></ul><ul><li>Silver stain, toludine blue, Calcoflour white </li></ul><ul><li>Trophozites present in a tight mass </li></ul><ul><li>P.Jiroveci is an extracellular pathogen </li></ul><ul><li>T.V.Rao MD </li></ul>
  7. 7. Life Cycle of Pneumocystis
  8. 8. What P.Jiroveci causes <ul><li>P.Jiroveci is found in Humans only, </li></ul><ul><li>Recent hypothesis P.Jiroveci is obligate member of normal flora </li></ul><ul><li>Formerly commonly isolated in Interstitial plasma cell Pneumonia, also in association with </li></ul><ul><li>Mal nourished children </li></ul><ul><li>On Corticosteroid therapy </li></ul><ul><li>Antineoplastic therapy </li></ul><ul><li>In transplant recipients </li></ul><ul><li>Recently identified as Major cause of Pneumonia in AIDS patients. </li></ul>
  9. 9. Impact of Chemoprophylaxis <ul><li>Major cause of disease in AIDS patients </li></ul><ul><li>Chemoprophylaxis had dramtically reduced the incidence in the recent past </li></ul><ul><li>But there is increased incidence of involvement of other organs spleen, Lymphnodes,and Bone marrow. </li></ul>
  10. 10. Pathology and Pathogenesis <ul><li>In non AIDS patients infiltration of alveolar spaces with plasma cells can lead to Intestinal plasma cell Pneumonia. </li></ul><ul><li>But plasma cells are absent in AIDS related Pneumocystis pneumonia. </li></ul><ul><li>Leads to cyanosis with oxygen exchange interference. </li></ul>
  11. 11. Spread of Pneumocystis infection <ul><li>P.jiroveci: the infection has a world-wide distribution  and the transmission seems to occur by airborne route. </li></ul>
  12. 12. P.Jiroveci – predisposed with <ul><li>However, Pneumocystis jiroveci can cause a lung infection in in people with a weakened immune system due to any of the following conditions: </li></ul><ul><li>Cancer </li></ul><ul><li>Chronic use of corticosteroids or other medications that affect the immune system </li></ul><ul><li>HIV/ AIDS </li></ul><ul><li>Solid organ and/or bone marrow transplant </li></ul>
  13. 13. Clinical Presentation <ul><li>Progressive exertional dyspnea (95%) </li></ul><ul><li>Fever (>80%) </li></ul><ul><li>Nonproductive cough (95%) </li></ul><ul><li>Chest discomfort </li></ul><ul><li>Weight loss </li></ul><ul><li>Chills </li></ul><ul><li>Haemoptysis (rare) </li></ul>
  14. 14. Physical presentation <ul><li>Like the history, the physical examination findings of PCP are very nonspecific and include the following: </li></ul><ul><li>Tachypnea </li></ul><ul><li>Fever </li></ul><ul><li>Tachycardia </li></ul><ul><li>Pulmonary examination may reveal mild crackles and rhonchi but may be normal in up to half of patients. </li></ul><ul><li>Additional findings in children with severe disease </li></ul><ul><ul><li>Cyanosis </li></ul></ul><ul><ul><li>Nasal flaring </li></ul></ul><ul><ul><li>Intercostal retractions </li></ul></ul>
  15. 15. X ray chest can give leading clues
  16. 16. Diagnosis <ul><li>Examination of Bronchoalveloar lavage </li></ul><ul><li>Lung Biopsy </li></ul><ul><li>Examination of induced sputum </li></ul><ul><li>Examination of cysts and Trophozoites </li></ul><ul><li>Yet not possible to culture the organism </li></ul>
  17. 17. Specimens are Examined with Stains <ul><li>Several special stains are used for identification of Trophozoites and Cysts </li></ul><ul><li>Giemasa stain </li></ul><ul><li>Toludine blue </li></ul><ul><li>Methenamine silver </li></ul><ul><li>Calcoflour white </li></ul>
  18. 18. Appearance of typical cysts P.Jiroveci
  19. 19. Monoclonal – Florescent Methods <ul><li>Direct Fluorescent methods with use Monoclonal antibodies emerged as important, and rapid method in Diagnosis. </li></ul><ul><li>PCR methods are emerging tools in Diagnosis </li></ul>
  20. 20. Serology <ul><li>Serology is not useful in Diagnosing acute infection as many posses antibodies to past sub clinical infections. </li></ul><ul><li>But useful to identify the prevalence in the given locality </li></ul>
  21. 21. Immunity - P.Jiroveci <ul><li>In the absence of Immuno Supression P.Jiroveci do not cause disease </li></ul><ul><li>Cell mediated immunity helps in the protection from Pneumocystis </li></ul><ul><li>Infections are prevalent until CD 4 counts drop below 400/ micro liters </li></ul>
  22. 22. Treatment <ul><li>Acute cases are treated with Trimethoprim – Sulphmethoxazole </li></ul><ul><li>Pentimidum isothionate </li></ul>
  23. 23. Prophylaxis <ul><li>Use of daily TMP – SMZ or aerolized Pentamidine. </li></ul>
  24. 24. Created for Medical Education for Graduate Medical Students Dr.T.V.Rao MD Email [email_address]