Pneumocystis jiroveci Pneumonia

Pneumocystis jiroveci Pneumonia

Q. 1

A 31 year old HIV-positive man develops a severe pneumonia. Lower respiratory tract secretions obtained by fiberoptic bronchoscopy with bronchoalveolar lavage and stained with methenamine silver stain demonstrate cup-shaped cysts with sharply outlined walls. Which of the following organisms is the most likely pathogen in this case?

 A

Candida albicans

 B

Giardia lamblia

 C

Haemophilus influenzae

 D

Pneumocystis carinii

Q. 1

A 31 year old HIV-positive man develops a severe pneumonia. Lower respiratory tract secretions obtained by fiberoptic bronchoscopy with bronchoalveolar lavage and stained with methenamine silver stain demonstrate cup-shaped cysts with sharply outlined walls. Which of the following organisms is the most likely pathogen in this case?

 A

Candida albicans

 B

Giardia lamblia

 C

Haemophilus influenzae

 D

Pneumocystis carinii

Ans. D

Explanation:

The organism described is Pneumocystis carinii, which is an opportunistic parasite that appears to be more closely related to fungi than to protozoa.
Its cyst form, when stained with silver stains, has the distinctive appearance described in the question stem, and is typically found in frothy material that occupies the lumen of alveoli.
The trophozoites are smaller and much harder to recognize.
Bronchoalveolar lavage is considered much more reliable than induced sputum as a diagnostic specimen.

Pneumocystis pneumonia is a common infection among AIDS patients, and is very uncommon in other clinical settings.

Formerly, many AIDS patients died with Pneumocystis pneumonia, but the combination of early drug treatment (with trimethoprim/sulfamethoxazole or pentamidine) and prophylaxis (usually with trimethoprim/sulfamethoxazole) has decreased the number of fatal infections. In severe cases, Pneumocystis infection can sometimes be demonstrated in extrapulmonary sites.
 
Candida albicans(choice A) can infect the lung and stain with methenamine silver, but the description of the lavage material would probably include the terms fungal hyphae and yeast forms.
 
Giardia lamblia (choice B) causes diarrhea, rather than pneumonia.
 
Haemophilus influenzae(choice C) and Streptococcus pneumoniae(choice E) are bacteria and would not stain with silver stains.
 
Ref: Levinson W. (2012). Chapter 52. Blood & Tissue Protozoa. In W. Levinson (Ed),Review of Medical Microbiology & Immunology, 12e.

Q. 2

An AIDS patient with clinical pneumonia has a bronchoalveolar lavage that demonstrates small, “hat- shaped” structures in alveoli that are about the size of an erythrocyte and stain with silver stains. The microorganism involved is most likely which of the following?

 A

Aspergillus fumigatus

 B

Blastomyces dermatitidis

 C

Mycobacterium avium

 D

Pneumocystis carinii

Q. 2

An AIDS patient with clinical pneumonia has a bronchoalveolar lavage that demonstrates small, “hat- shaped” structures in alveoli that are about the size of an erythrocyte and stain with silver stains. The microorganism involved is most likely which of the following?

 A

Aspergillus fumigatus

 B

Blastomyces dermatitidis

 C

Mycobacterium avium

 D

Pneumocystis carinii

Ans. D

Explanation:

This is the classic appearance of Pneumocystis cysts. Pneumocystis is a common (and dangerous) cause of pneumonia in AIDS patients
. The diagnosis is now frequently made by bronchoalveolar lavage, which is much more effective at demonstrating the organism than is either sputum or blood culture.
 
Aspergillus fumigatus is a typical fungus, and hyphae would probably have been seen in the lavage material.
 
Blastomycosis is caused by a dimorphic fungus that grows in mammalian tissues as a round, multinucleate, budding cell 8-15 micrometers in diameter.
 
Mycobacteria  are small, acid-fast rods.
 
Ref: Ray C.G., Ryan K.J. (2010). Chapter 45. Candida, Aspergillus, Pneumocystis,and Other Opportunistic Fungi. In C.G. Ray, K.J. Ryan (Eds), Sherris Medical Microbiology, 5e.

Q. 3

A person having CD4 count of 200 presents with difficulty of breathing. The most probable diagnosis is?

 A

Tuberculosis

 B

Histoplasmosis

 C

Candidiasis

 D

Pneumocystis jiroveci

Q. 3

A person having CD4 count of 200 presents with difficulty of breathing. The most probable diagnosis is?

 A

Tuberculosis

 B

Histoplasmosis

 C

Candidiasis

 D

Pneumocystis jiroveci

Ans. D

Explanation:

Pneumocystis pneumonia is the most common opportunistic infection associated with AIDS. The risk of Pneumocystis jiroveci pneumonia among HIV- infected patients rises markedly when circulating CD4+ T cell counts fall below 200 cells/L.

Tuberculosis in HIV patients occur when CD4 count is 100 cells/L.

Ref: Manual of Emergency Medicine edited by Jon L. Jenkins, G. Richard Braen, 2004, Page 302 ; Harrison’s Principles of Internal Medicine, Volume 2, Page 1267 ; Harrison’s 17th ed chapter 182

Q. 4

In HIV infection the prophylaxis for pneumocystis jiroveci may be stopped after HAART if the CD4 count persists more than 200 for what duration?

 A

1 month

 B

2 month

 C

3 month

 D

6 month

Q. 4

In HIV infection the prophylaxis for pneumocystis jiroveci may be stopped after HAART if the CD4 count persists more than 200 for what duration?

 A

1 month

 B

2 month

 C

3 month

 D

6 month

Ans. C

Explanation:

Pneumocystis jiroveci – Prophylaxis should be started if the patient has

1. CD4+ T cell count OR
2. Oropharyngeal candidiasis OR
3. Prior bout of PCP
 
DRUG used: Trimethoprim/sulfamethoxazole (TMP/SMX), 1 double strength tablet once daily
The prophylaxis may be stopped if CD4+ T cell count >200  for 3 months
Ref: Harrison, Edition-18, Page-1544.

Q. 5

An AIDS patient develops symptoms of pneumonia, and Pneumocystis carinii is suspected as the causative organism. Bronchial lavage is performed. Which of the following stains would be most helpful in demonstrating the organism’s cysts on slides made from the lavage fluid?

 A

Alcian blue

 B

Hematoxylin and eosin

 C

Methenamine silver

 D

Prussian blue

Q. 5

An AIDS patient develops symptoms of pneumonia, and Pneumocystis carinii is suspected as the causative organism. Bronchial lavage is performed. Which of the following stains would be most helpful in demonstrating the organism’s cysts on slides made from the lavage fluid?

 A

Alcian blue

 B

Hematoxylin and eosin

 C

Methenamine silver

 D

Prussian blue

Ans. C

Explanation:

The appropriate stain is methenamine silver, and the requisition slip when submitting the wash fluid should have a reference to either Pneumocystis or methenamine silver, since routine hematoxylin and eosin does not adequately demonstrate the organisms. The cysts, when stained with methenamine silver, have a characteristic cup or boat shape; the trophozoites are difficult to demonstrate without electron microscopy. It is also worth knowing that sputum samples are not nearly as effective as bronchial washes in demonstrating the organisms.

Alcian blue is good for demonstrating mucopolysaccharides.
Hematoxylin and eosin is the routine tissue stain used in pathology laboratories. Prussian blue is good for demonstrating iron.
 

Q. 6

Which organism cannot be cultured ‑

 A

Klebsiella rhinoscleromatis

 B

Klebsiella ozaenae

 C

Klebsiella granulomatis

 D

Pneumocystis jiroveci

Q. 6

Which organism cannot be cultured ‑

 A

Klebsiella rhinoscleromatis

 B

Klebsiella ozaenae

 C

Klebsiella granulomatis

 D

Pneumocystis jiroveci

Ans. D

Explanation:

Ans. is ‘d’ i.e., Pneumocytstis jiroveci

“The life cycle of pneumocystis probably involves sexual and asexual reproduction, although definitive proof awaits the development of a reliable culture system”. – Harrison

“Rhinosporidium seeberi has not been cultivated in media”. – Ananthnarayan.


Q. 7

Pneumocystis carinii is a fungus because ‑

 A

rRNA, mitochondrial protein gene sequence & presence of thymidylate synthase

 B

Cell wall contains glucans

 C

Angifungals are effective against P. carini

 D

All

Q. 7

Pneumocystis carinii is a fungus because ‑

 A

rRNA, mitochondrial protein gene sequence & presence of thymidylate synthase

 B

Cell wall contains glucans

 C

Angifungals are effective against P. carini

 D

All

Ans. D

Explanation:

Ans. is ‘a’ i.e., rRNA, Mitochondrial protein gene sequence & presence thymidylate synthase; `b’ i.e., Cell wall contains glucans; ‘c’ i.e., Antifungals are effective against p. carinii

.  The taxonomic classification of Pneumocystis as a fungus is based on factors:

1.   Analysis of gene sequence for ribosomal RNA, mitochondria! proteins and major enzymes.

2.   Presence of b-1, 3 glucan in the cell wall.

3.   The efficacy of antifungal drugs that inhibit b-glucan synthesis.

.    In contrast to most fungi.

1.   Pneumocystis lacks ergosterol

2.   Not susceptible to antifungal drugs that inhibit ergosterol synthesis.


Q. 8

Pneumocystis carinii is a –

 A

Fungi

 B

Protozoa

 C

Gram negative

 D

All

Q. 8

Pneumocystis carinii is a –

 A

Fungi

 B

Protozoa

 C

Gram negative

 D

All

Ans. A

Explanation:

Ans. is ‘a’ i.e., Fungi

Pneumocystis jirovcci (P. carinii)

.   Pneumocystis is an opportunistic fungal pulmonary pathogen.

.         Developmental stages

  1. Pleomorphic trophic form
  2. Thick walled cyst
  3. Precyst – an intermediate stage

.    Risk factors

  1. HIV (CD4 T cell <200 mL)
  2. Immunosuppressive therapy (particularly glucocorticoids)
  3. Primary immunodeficiency diseases
  4. Premature malnourished infants.

    – Tachycardia – Cynosis

Chest X-ray

–  Bilateral diffuse infiltrates beginning in the perihilar regions —> classical finding.

– Upper lobe infiltrates who receive aerosolized pentamidine.

– Pneumothorax.

. Hypoxemia is most widely used prognostic factor for P carinii pneumonia.

.   Pneumocystosis cannot be cultured :‑

. ”The life cycle of pneumocystis probably involves sexual and asexual reproduction, although definitive proof awaits the development of a reliable culture system”.


Q. 9

Which of the following is a fungus –

 A

Klebsiella

 B

Clostridia

 C

Pneumocystis jerovecii

 D

Listeria

Q. 9

Which of the following is a fungus –

 A

Klebsiella

 B

Clostridia

 C

Pneumocystis jerovecii

 D

Listeria

Ans. C

Explanation:

Ans. is ‘c’ i.e., Pneumocystis jiroveci

.   Pneumocystis is an opportunistic fungal pulmonary pathogen.


Q. 10

Pneumocystis carinii is diagnosed by –

 A

Sputum examination for trophozoites and cyst under microscope

 B

Culture

 C

Positive serology

 D

Growth on artificial media

Q. 10

Pneumocystis carinii is diagnosed by –

 A

Sputum examination for trophozoites and cyst under microscope

 B

Culture

 C

Positive serology

 D

Growth on artificial media

Ans. A

Explanation:

Ans. is ‘a’ i.e., Sputum examination for trophozoites and cyst under microscope


Q. 11

A patient suffering from AIDS presents with history of dyspnea and non- productive cough x-ray shows bilateral perihilar opacities without pleural effusion and lymphaden-opathy. Most probable etiological agent is :

 A

Tuberculosis

 B

CMV

 C

Kaposis sarcoma

 D

Pneumocystis carinii

Q. 11

A patient suffering from AIDS presents with history of dyspnea and non- productive cough x-ray shows bilateral perihilar opacities without pleural effusion and lymphaden-opathy. Most probable etiological agent is :

 A

Tuberculosis

 B

CMV

 C

Kaposis sarcoma

 D

Pneumocystis carinii

Ans. D

Explanation:

D i.e. Pneumocystic carinii


Q. 12

A 45 year old, HIV positive patient presents with features of pneumonia. Characteristic histopathological features suggesting pneumocystis carinii pneumonia is:

 A

Prominent Interstitial Pneumonitis

 B

Eosinophilic Alveolar Exudates

 C

Prominent mononuclear cells in Alveolar exudates

 D

Neutrophilic infiltration of alveolar interstitium

Q. 12

A 45 year old, HIV positive patient presents with features of pneumonia. Characteristic histopathological features suggesting pneumocystis carinii pneumonia is:

 A

Prominent Interstitial Pneumonitis

 B

Eosinophilic Alveolar Exudates

 C

Prominent mononuclear cells in Alveolar exudates

 D

Neutrophilic infiltration of alveolar interstitium

Ans. B

Explanation:

Answer is B (Eosinophilic Alveolar Exudate):

The most characteristic histoputhological feature of pneumocystis carinii pneumonia in adults is predominantly alveolar, foamy vacuoloted, eosinophilic exudates.

Interstitial pneumonitis is usually mild and shows infiltration with PML and mononuclear cells.


Q. 13

All of the following statements about Pneumocystis Jiroveci are true Except:

 A

Usually associated with CMV infection

 B

May be associated with Pneumatocele

 C

Usually diagnosed by sputum examination

 D

Causes disease only in the immunocompromised host

Q. 13

All of the following statements about Pneumocystis Jiroveci are true Except:

 A

Usually associated with CMV infection

 B

May be associated with Pneumatocele

 C

Usually diagnosed by sputum examination

 D

Causes disease only in the immunocompromised host

Ans. A

Explanation:

 

Answer is A (Usually associated with CMV infection):

Pneumocystis Jiroveci may be associated with CMV infection but it is not usually associated with CMV infection.

Pneumocystis Jiroveci is the new nomenclature for human infection with Pneumocystic carini (which is now used for organisms found in rats)

Pneumocystis infection in Humans : P. Jiroveci

Pneumocystis infection in Rats : P. Carini

Pneumocystic Jiroveci disease and immunosupression  `Pneumocystis Jiroveci does not cause disease in the absence of immuno supression’

Note

Pneumocystic Jiroveci may infect immunocompetent hosts but the disease (pneumocvstis pneumonia) occurs only when the host is immunosupressed

Most individuals are infected in early childhood But pneumonia occurs in immunocompromised patients only either due to reactivation or new infection.

Persons at risk for Pneumocystic disease (Pneumocystosis)

  • Acquired Immunodeficiency Disease (eg AIDS)
  • Patients Recieving Immunosupressive therapy (especially Glucocorticoids) for cancer, organ transplantation etc.
  • Children with primary immunodeficiency diseases
  • Premature malnourished infants (immunodeficient)
  • Pneumocystic Pneumonia : Diagnosis

Diagnosis of Pneumocystic Pneumonia is based on specific identification of organism in respiratory specimen with appropriate histological staining

Pneumocystis infection is usually diagnosed by sputum examination

Sputum samples should always be obtained by induction (with hypertonic saline)

Routine sputum specimen is often inadequate (Washington manual of Pulmonary medicine)

BAL forms the mainstay of diagnosis for Pneumocvstic Pneumonia

If organisms are not seen on induced sputum examination a Bronchoalveolar lavage specimen should be obtained. BAL forms the mainstay of diagnosis for Pneumocystic Pneumonia – Harrisons 16th

Pne imocvstic Pneumonia and CMV infection (Pneumocystic Pneumonia’ by Wolzer & Cushion 3rd/418) `Several studies have indicated that CMV is a risk factor for Pneumocystis Pneumonia in Renal transplant patients

These is however no convincing evidence to show a direct effect of the CMV virion on Pneumocystis’

Thus we conclude

Pneumocystic may be associated with CMV infection but in a few selected cases and special circumstances like Renal tansplantation. CMV is not usually associated with pneumocystic pneumonia.

Pneumocvstis Pneumonia and Pneumatocele

Pneumocystic Pneumonia may be associated with pneumotocele formation but Pneumatoceles are not associated in all cases of Pneumocystic pneumonia

Pneumatocele: Differential Diagnosis (CT scan of the body by Mathias /362)

  • Post infectious (Staphylococcal° and other bacterial infections)
  • Pneumocystic
  • Post traumatic (Laceration )
  • After treatment of metastasis (rare)

 


Q. 14

Indication for prophylaxis in pneumocystis carini pneumonia include

 A

CD4 count < 200 /p1

 B

Tuberculosis

 C

Oral candidiasis

 D

a and c both are correct

Q. 14

Indication for prophylaxis in pneumocystis carini pneumonia include

 A

CD4 count < 200 /p1

 B

Tuberculosis

 C

Oral candidiasis

 D

a and c both are correct

Ans. D

Explanation:

Answer is A and C

Indications for prophylaxis against Pneumocystic carinii

  • An absolute CD4 count <200/pt (CD4percentage
  • Oropharyngeal candidiasis (Primary prophylaxis)
  • Prior Pneumocystic carinii pneumonia (Secondary prophylaxis)

Remember

Criteria for discontinuing primary prophylaxis CD4 + Tcell count > 200, for 3 months

The drug of choice for primary and secondary prophylaxis is TM P- SMX

 

 

 


Q. 15

All the following are used in the treatment of Pneumocystis carinii except:

 A

Pentamidine

 B

Dapsone

 C

Cotrimoxazole

 D

Fluoroquinolones

Q. 15

All the following are used in the treatment of Pneumocystis carinii except:

 A

Pentamidine

 B

Dapsone

 C

Cotrimoxazole

 D

Fluoroquinolones

Ans. D

Explanation:

Answer is D (Fluoroquinolones):

Fluoroquinolones are not used in the treatment (#. P. carinii infection. Drugs used for treatment of Pneumocystis carinii infection include:

Agent

Disease

First choice drug

Second choice

Third choice

Pneumocystis carinii

Mild to moderate

pneumonia

Trimethoprim

Sulfamethoxazole

Trimethoprim — Dapsone

Clindamycin — Primaquine

Atovaquone

Sever pneumonia

Trimethoprim

Sulfamethoxazole

Pentamidene

Clindamycin-Primaquine

Trimetroxate

Drug of choice for all forms of pneumocystosis: Trimethoprim-Sulfamethoxazole (Cotrimoxazole)


Q. 16

Drug of choice for pneumocystis carinii is:

 A

Doxycycline

 B

Cotrimoxazole

 C

Tetracycline

 D

Dapsone

Q. 16

Drug of choice for pneumocystis carinii is:

 A

Doxycycline

 B

Cotrimoxazole

 C

Tetracycline

 D

Dapsone

Ans. B

Explanation:

Answer is B (Cotrimoxazole):

Trimethoprim/sulfamethoxazole or Cotrimoxazole is the drug of choice for all firms of Pneumocystis Pneumonias.

‘Trimethoprim-Sulfamethoxazole which acts by inhibiting folic acid synthesis is considered the drug of choice for all forms of Pneumocystis Pneumonias. Therapy is continued for 14 days in Non-HIV-Infected patients and for 21 days in HIV-Infected patients’ – Harrison 18th/1672


Q. 17

All are seen with Pneumocystis carini in AIDS except

 A

Pneumonia

 B

Otic polypoid mass

 C

Ophthalmic choroid lesion

 D

Meningitis

Q. 17

All are seen with Pneumocystis carini in AIDS except

 A

Pneumonia

 B

Otic polypoid mass

 C

Ophthalmic choroid lesion

 D

Meningitis

Ans. D

Explanation:

Ans. is ‘d’ i.e., Meningitis


Q. 18

Indication for prophylaxis in pneumocystis carini pneumonia include

 A

CD4 count < 200

 B

Tuberculosis

 C

Viral load > 25,000 copies/ml

 D

Oral candidiasis

Q. 18

Indication for prophylaxis in pneumocystis carini pneumonia include

 A

CD4 count < 200

 B

Tuberculosis

 C

Viral load > 25,000 copies/ml

 D

Oral candidiasis

Ans. A

Explanation:

Ans. is ‘a’ i.e., CD4 count < 200

PROPHYLAXIS OF PNEUMOCYSTIC CARINH PNEUMONL4

Primary prophylaxis is indicated for

  • Patients with CD4- cell counts of< 200/4
  • History of oropharyngeal candidiasis

Secondary prophylaxis is indicated for

  • Both HIV infected and non HIV infected patients.
  • Who have recovered from pneumocystosis.

Primary and secondary prophylaxis may be discontinued in HIV infected persons once.

  • CD4+ counts have risen to > 200/p1 and remained at that level for 3 months.

Also know

First choice agent for prophylaxis

  • Trimethoprim, sulphamethoxazole.

Other agents used in prophylaxis.

  • Dapsone, pentamidine.


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