Pneumocystis jirovecii pneumonia in an immunocompetent host

Abstract

Pneumocystis jirovecii pneumonia (PCP) is a potentially life-threatening infection, which predominantly occurs in the immuno-compromised host. It has been rarely reported in immunocompetent subjects. In them, the infection presents with fulminant respiratory failure along with fever and dry cough in contrast to an indolent course in the immuno-compromised population. The most significant risk factors for PCP in non-HIV infected hosts are glucocorticoid use and cell mediated immunity defects. We report a rare case of Pneumocystis jirovecii pneumonia in an immunocompetent patient.

Keywords: Immunocompetent host, pneumocystis jirovecii, pneumonia

How to cite this article:
Koshy G, Koshy JM, John M, Deodhar D. Pneumocystis jirovecii pneumonia in an immunocompetent host. Ann Trop Med Public Health 2015;8:122-4
How to cite this URL:
Koshy G, Koshy JM, John M, Deodhar D. Pneumocystis jirovecii pneumonia in an immunocompetent host. Ann Trop Med Public Health [serial online] 2015 [cited 2021 Apr 14];8:122-4. Available from: https://www.atmph.org/text.asp?2015/8/4/122/162374
Introduction

Pneumocystis jirovecii pneumonia (PCP) is a potentially life-threatening infection, which predominantly occurs in the immunocompromised host. However, individuals with normal immune systems may also harbor asymptomatic lung colonization and may serve as a reservoir for the spread of Pneumocystis[1] We report a case of PCP in an immunocompetent patient.

Case Report

A 56-year-old male of Indian race from Qatar, while on holiday in North India, presented with cough for 1 month, and dyspnea and hemoptysis for 7 days prior to admission. He was a diagnosed case of systemic hypertension and type 2 diabetes mellitus. He had been diagnosed with tuberculoid leprosy 35 years ago, and was treated with dapsone for 6 years after which he had done well.

On examination, he was found to be tachypneic, with a respiratory rate of 26 breaths/min and examination of the respiratory system revealed bilateral crepitations. His saturation, on room air, was 70%. An initial arterial blood gas done on oxygen via a mask revealed type I respiratory failure with oxygen saturation of 90.4% and partial pressure of oxygen (PO 2 ) of 63.4 mmHg. Chest radiography had nonhomogenous opacities in the bilateral middle and lower zones [Figure 1]. Initial investigations were unremarkable except for leucocytosis (11,000/mm 3 ) and glycated hemoglobin (Hba1c) of 7.4%.

Figure 1: Chest X ray revealing bilateral non homogenous opacity

Click here to view

He was initiated on treatment for community-acquired bronchopneumonia and atypical pneumonia. Treatment for influenza A virus (H1N1) infection was also initiated as there were reports of similar infections in the community. Noninvasive ventilation was initiated with which he maintained 95% saturation.

On the second day, in spite of treatment, he did not maintain saturation off oxygen and further testing of induced sputum was sent for Gram staining, Ziehl-Neelsen staining, modified acid-fast bacilli (AFB) staining, and silver methylamine preparation to look for PCP. Oocysts of Pneumocystis jirovecii were isolated on silver methenamine staining. He was initiated on co-trimoxazole (trimethoprim/sulphamethoxazole two tablets three times a day), along with steroids (prednisolone tablets 40 mg twice a day, which was gradually tapered off). His condition improved and he was switched over to oxygen via a mask by the third day.

Large areas of ground-glass appearance in bilateral lung fields with interstitial septal thickening consistent with PCP were seen on a high-resolution computed tomography (HRCT) of the chest, done on the seventh day [Figure 2]. Fourth-generation human immunodeficiency virus (HIV) enzyme-linked immunosorbent assay (ELISA) was done, which was negative. Western blot analysis also was done for confirmation, which was also negative. A cluster of differentiation (CD4) count done at that point was 296 cells/MCL.

Figure 2: HRCT of the chest depicting ground glass opacities suggestive of interstitial pneumonia

Click here to view

The patient gradually improved and started maintaining saturation off oxygen by the 10th day. A repeat chest x-ray [Figure 3] done on the 14th day revealed marked clearing of the lung lesions. He was discharged in a stable condition on the 15th day and co-trimoxazole was continued for a total of 21 days, along with steroids. CD4 done 1 month later was 984 cells/MCL, implicating that the low CD4 count was a transient decrease due to the illness.

Figure 3: Chest radiography revealing resolution of pulmonary infiltrates after treatment

Click here to view

Discussion

PCP has been rarely reported in immunocompetent subjects. [2] It is speculated to result either from an infection de novo or from reactivation of a latent childhood infection. [3] In spite of the absence of HIV infection, the individuals can be predisposed to PCP. In them, the infection presents with fulminant respiratory failure, along with fever and dry cough as was in our case; this is in contrast to an indolent course in the immunocompromised population. [4] Experiments have shown that the Pneumocystis organisms can replicate in the lung alveolus of immunocompetent hosts and remain infectious; hence, this organism is found even in healthy adults in a normal community. [5]

Immunocompetent individuals might harbor a short-lived infection and when immunosuppressed and susceptible, may cause the development of clinical PCP infection. [6] The most significant risk factors for PCP in non-HIV-infected hosts are glucocorticoid use and cell-mediated immunity defects, which lead to alterations in the lung surfactant, thereby predisposing to pneumonia. [4],[5]

Individuals who have been affected with Hansen’s disease have shown wide-ranging immunity, from strong cellular immunity in paucibacillary type to poor cellular immunity (with potent humoral immunity) in multibacillary type. [7] Historically, this patient had tuberculoid leprosy, implicating a strong cellular immunity.

This case was unusual as this patient was neither HIV infected nor on glucocorticoid or immunosuppressants. The only risk factor in him was that he was a diabetic. The restoration of immune status as indicated by normal CD4 counts a month later also implicates that the patient’s baseline immune status was normal.

Conclusion

PCP should always be considered in patients, even in non-HIV settings, who present with dry cough and dyspnea with type 1 respiratory failure. Since these patients have nonproductive cough, it is important to get induced sputum for examination as the oocysts of pneumocystis are attached to the type 2 pneumocytes. High index of suspicion is required to diagnose these cases.

Acknowledgment

We would like to acknowledge the help of the Department of Microbiology, Christian Medical College & Hospital, Ludhiana, Punjab, India.

References
1.
Thomas CF Jr, Limper AH. Pneumocystis pneumonia. N Engl J Med 2004;350:2487-98.
2.
Harris K, Maroun R, Chalhoub M, Elsayegh D. Unusual presentation of pneumocystis pneumonia in an immunocompetent patient diagnosed by open lung biopsy. Heart Lung Circ 2012;21:221-4.
3.
Sing A, Roggenkamp A, Autenrieth IB, Heesemann J. Pneumocystis carinii Carriage in immunocompetent patients with primary pulmonary disorders as detected by single or nested PCR. J Clin Microbiol 1999;37:3409-10.
4.
Yale SH, Limper AH. Pneumocystis carinii pneumonia in patients without acquired immunodeficiency syndrome: Associated illness and prior corticosteroid therapy. Mayo Clin Proc 1996;71:5-13.
5.
Chabé M, Dei-Cas E, Creusy C, Fleurisse L, Respaldiza N, Camus D, et al. Immunocompetent host as a reservoir of Pneumocystis organism: Histological and rt-PCR data demonstrate active replication. Eur J Clin Microbiol Infect Dis 2004;23:89-97.
6.
Gigliotti F, Harmsen AG, Haidaris CG, Haidaris PJ. Pneumocystis carinii is not universally transmissible between mammalian species. Infect Immun 1993;61:2886-90.
7.
Duthie MS, Goto W, Ireton GC, Reece ST, Sampaio LH, Grassi AB, et al. Antigen-specific T-cell responses of leprosy patients. Clin Vaccine Immunol 2008;15:1659-65.

Source of Support: None, Conflict of Interest: None

Check


DOI: 10.4103/1755-6783.162374

Figures

[Figure 1], [Figure 2], [Figure 3]

Paul Mies has now been involved with test reports and comparing products for a decade. He is a highly sought-after specialist in these areas as well as in general health and nutrition advice. With this expertise and the team behind atmph.org, they test, compare and report on all sought-after products on the Internet around the topics of health, slimming, beauty and more. The results are ultimately summarized and disclosed to readers.

LEAVE A REPLY

Please enter your comment!
Please enter your name here