PneumocystosisPneumocystosis

Dr.T.V.Rao MDDr.T.V.Rao MD

Pneumocystis Pneumocystis pneumoniapneumonia PCP is a pneumonia caused by the PCP is a pneumonia caused by the

fungal organism fungal organism Pneumocystis carinii Pneumocystis carinii ((now renamed now renamed Pneumocystis jiroveci)Pneumocystis jiroveci). . This organism is common in the This organism is common in the environment and does not cause illness environment and does not cause illness in healthy people. In the 1980s, in healthy people. In the 1980s, biochemical analysis of the nucleic acid biochemical analysis of the nucleic acid composition of composition of PneumocystisPneumocystis rRNA and rRNA and mitochondrial DNA identified the mitochondrial DNA identified the organism as a unicellular fungus rather organism as a unicellular fungus rather than a protozoa. than a protozoa.

Change of Change of NomenclatureNomenclature In 1999, a new binomial classification In 1999, a new binomial classification

renamed human renamed human Pneumocystis cariniiPneumocystis carinii to to Pneumocystis jiroveciPneumocystis jiroveci (after the (after the Czech parasitologist Otto Jiroveci, Czech parasitologist Otto Jiroveci, thought to be the first to describe thought to be the first to describe the organism in humans). The the organism in humans). The designation, designation, Pneumocystis cariniiPneumocystis carinii is is now reserved for one of the two now reserved for one of the two PneumocystisPneumocystis species infecting only species infecting only rats.rats.

SpeciesSpecies

Pneumocystis Pneumocystis carnii found in carnii found in ratsrats

Pneumocystis Pneumocystis jiroveci in jiroveci in humanshumans

Pneumocystis jiroveciPneumocystis jiroveci

Till recently P.Jiroveci was though to be a Till recently P.Jiroveci was though to be a ProtozoanProtozoan

Molecular biology proved that it is a Molecular biology proved that it is a Fungus, related to AscomycetesFungus, related to Ascomycetes

Pneumocystis species are present in the Pneumocystis species are present in the lungs of many animals, Rats, Mice, Dogs, lungs of many animals, Rats, Mice, Dogs, Cats, and Rabbits,Cats, and Rabbits,

Do not cause infections until immuno Do not cause infections until immuno supressed.supressed.

More familiar Pneumocystis carinii is found More familiar Pneumocystis carinii is found only in Rats.only in Rats.

MorphologyMorphology

Spherical, EllipticalSpherical, Elliptical

4- 6 microns, contains 4 4- 6 microns, contains 4 to 8 nuclei to 8 nuclei

Stained with Stained with

Silver stain, toludine Silver stain, toludine blue, Calcoflour whiteblue, Calcoflour white

Trophozites present in a Trophozites present in a tight masstight mass

P.Jiroveci is an extracellular P.Jiroveci is an extracellular pathogenpathogen

T.V.Rao MDT.V.Rao MD

Life Cycle of Life Cycle of PneumocystisPneumocystis

What P.Jiroveci causesWhat P.Jiroveci causes

P.Jiroveci is found in Humans only,P.Jiroveci is found in Humans only, Recent hypothesis P.Jiroveci is obligate Recent hypothesis P.Jiroveci is obligate

member of normal floramember of normal flora Formerly commonly isolated in Interstitial Formerly commonly isolated in Interstitial

plasma cell Pneumonia, also in association plasma cell Pneumonia, also in association withwith

Mal nourished childrenMal nourished children On Corticosteroid therapyOn Corticosteroid therapy Antineoplastic therapyAntineoplastic therapy In transplant recipientsIn transplant recipientsRecently identified as Major cause of Recently identified as Major cause of

Pneumonia in AIDS patients.Pneumonia in AIDS patients.

Impact of Impact of ChemoprophylaxisChemoprophylaxis Major cause of disease in AIDS Major cause of disease in AIDS

patientspatients Chemoprophylaxis had dramtically Chemoprophylaxis had dramtically

reduced the incidence in the recent reduced the incidence in the recent past past

But there is increased incidence of But there is increased incidence of involvement of other organs spleen, involvement of other organs spleen, Lymphnodes,and Bone marrow.Lymphnodes,and Bone marrow.

Pathology and Pathology and PathogenesisPathogenesis In non AIDS patients In non AIDS patients

infiltration of alveolar infiltration of alveolar spaces with plasma spaces with plasma cells can lead to cells can lead to Intestinal plasma cell Intestinal plasma cell Pneumonia.Pneumonia.

But plasma cells are But plasma cells are absent in AIDS absent in AIDS related Pneumocystis related Pneumocystis pneumonia.pneumonia.

Leads to cyanosis Leads to cyanosis with oxygen with oxygen exchange exchange interference.interference.

Spread of Spread of Pneumocystis infectionPneumocystis infection P.jiroveci:P.jiroveci: the infection has a the infection has a

world-wide distribution world-wide distribution and the transmission seems and the transmission seems to occur by airborne route.to occur by airborne route.

P.Jiroveci – P.Jiroveci – predisposed withpredisposed with However, However, Pneumocystis jiroveci Pneumocystis jiroveci can cause can cause

a lung infection in in people with a a lung infection in in people with a weakened immune system due to any of weakened immune system due to any of the following conditions:the following conditions:

Cancer Cancer Chronic use of corticosteroids or other Chronic use of corticosteroids or other

medications that affect the immune medications that affect the immune system system

HIV/HIV/AIDSAIDS Solid organ and/or bone marrow transplant Solid organ and/or bone marrow transplant

Clinical PresentationClinical Presentation

Progressive exertional dyspnea Progressive exertional dyspnea (95%)(95%)

Fever (>80%)Fever (>80%) Nonproductive cough (95%)Nonproductive cough (95%) Chest discomfortChest discomfort Weight lossWeight loss ChillsChills Haemoptysis (rare)Haemoptysis (rare)

Physical presentationPhysical presentation

Like the history, the physical examination findings Like the history, the physical examination findings of PCP are very nonspecific and include the of PCP are very nonspecific and include the following:following:

TachypneaTachypnea FeverFever TachycardiaTachycardia Pulmonary examination may reveal mild crackles Pulmonary examination may reveal mild crackles

and rhonchi but may be normal in up to half of and rhonchi but may be normal in up to half of patients.patients.

Additional findings in children with severe diseaseAdditional findings in children with severe disease– CyanosisCyanosis– Nasal flaringNasal flaring– Intercostal retractionsIntercostal retractions

X ray chest can give X ray chest can give leading cluesleading clues

DiagnosisDiagnosis

Examination of Examination of Bronchoalveloar Bronchoalveloar lavagelavage

Lung BiopsyLung Biopsy Examination of Examination of

induced sputuminduced sputum Examination of cysts Examination of cysts

and Trophozoitesand TrophozoitesYet not possible to Yet not possible to

culture the organismculture the organism

Specimens are Specimens are Examined with StainsExamined with Stains Several special Several special

stains are used for stains are used for identification of identification of Trophozoites and Trophozoites and CystsCysts

Giemasa stainGiemasa stain

Toludine blueToludine blue

Methenamine silverMethenamine silver

Calcoflour whiteCalcoflour white

Appearance of typical Appearance of typical cysts P.Jirovecicysts P.Jiroveci

Monoclonal – Monoclonal – Florescent MethodsFlorescent Methods

Direct Fluorescent Direct Fluorescent methods with use methods with use Monoclonal Monoclonal antibodies emerged antibodies emerged as important, and as important, and rapid method in rapid method in Diagnosis.Diagnosis.

PCR methods are PCR methods are emerging tools in emerging tools in DiagnosisDiagnosis

SerologySerology

Serology is not Serology is not useful in Diagnosing useful in Diagnosing acute infection as acute infection as many posses many posses antibodies to past antibodies to past sub clinical sub clinical infections.infections.

But useful to identify But useful to identify the prevalence in the prevalence in the given localitythe given locality

Immunity - P.JiroveciImmunity - P.Jiroveci

In the absence of Immuno In the absence of Immuno Supression P.Jiroveci do not cause Supression P.Jiroveci do not cause diseasedisease

Cell mediated immunity helps in the Cell mediated immunity helps in the protection from Pneumocystisprotection from Pneumocystis

Infections are prevalent until CDInfections are prevalent until CD44 counts drop below 400/ micro literscounts drop below 400/ micro liters

TreatmentTreatment

Acute cases are treated with Acute cases are treated with Trimethoprim – Sulphmethoxazole Trimethoprim – Sulphmethoxazole

Pentimidum isothionatePentimidum isothionate

ProphylaxisProphylaxis

Use of daily TMP – SMZ or aerolized Use of daily TMP – SMZ or aerolized Pentamidine.Pentamidine.

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