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 Table of Contents  
CASE REPORT
Year : 2014  |  Volume : 16  |  Issue : 2  |  Page : 81-83

Cryptococcus neoformans : Need to consider in the differential diagnosis of acute bronchopneumonia in acquired immunodeficiency syndrome


Department of Microbiology, Bharati Vidyapeeth Medical College, Dhankawadi, Pune, Maharashtra, India

Date of Web Publication14-Nov-2014

Correspondence Address:
Vrushali Harsh Thakar
Department of Microbiology, Bharati Vidyapeeth Medical College, Dhankawadi, Pune, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-1282.144722

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  Abstract 

The most common presentation of Cryptococcus infection in immunocompromised patients is meningitis. Here, we report a patient with acquired immunodeficiency syndrome who developed pulmonary cryptococcosis due to infection with a poorly capsulated C. neoformans. Poorly capsulated strains of C. neoformans have been reported from HIV sero-positive patients. Patient had no history of any underlying chronic lung infection. Chest X-ray showed bilateral inhomogeneous haziness in middle and lower zones suggestive of acute bronchopneumonia. Diagnosis was based on culture findings and detection of cryptococcal capsular antigen by latex agglutination test. Unfortunately, patient died due to lack of clinical suspicion and delay in systemic antifungal treatment. This case highlights the importance of pulmonary cryptococcosis as a differential diagnosis while treating acute bronchopneumonia in immunocompromised hosts.

Keywords: Acquired immunodeficiency syndrome, bronchopneumonia, Cryptococcus neoformans


How to cite this article:
Thakar VH, Dalal B, Maushami, Modak M. Cryptococcus neoformans : Need to consider in the differential diagnosis of acute bronchopneumonia in acquired immunodeficiency syndrome. J Acad Clin Microbiol 2014;16:81-3

How to cite this URL:
Thakar VH, Dalal B, Maushami, Modak M. Cryptococcus neoformans : Need to consider in the differential diagnosis of acute bronchopneumonia in acquired immunodeficiency syndrome. J Acad Clin Microbiol [serial online] 2014 [cited 2020 Apr 5];16:81-3. Available from: http://www.jacmjournal.org/text.asp?2014/16/2/81/144722


  Introduction Top


Life-threatening infections caused by the encapsulated fungal pathogen Cryptococcus neoformans have been increasing steadily over the past 10 years because of the onset of acquired immunodeficiency syndrome (AIDS) and the expanded use of immunosuppressive drugs. [1] Cryptococcosis is a chronic, subacute or acute pulmonary, systemic or meningitic infection caused by an encapsulated yeast C. neoformans. The radiographic finding of pulmonary cryptococcosis manifest infiltrates, nodules or mass-like lesion. [2] Capsule deficient or poorly encapsulated C. neoformans strains are frequently isolated from patients suffering from AIDS. [3] There are a few reports of capsulated C. neoformans causing acute bronchopneumonia in AIDs. [4] However, poorly encapsulated strains causing acute respiratory failure is rare. The pathogenicity of C. neoformans depends on the interplay between the immune status of the host and the virulence of the infecting strain. It can range from asymptomatic lung colonization in the immunocompetent host to rapidly progressive meningitis in immunocompromised patients. [5] Here, we would like to report a case of acute bronchopneumonia caused by poorly encapsulated C. neoformans strain in an adult suffering from AIDS.


  Case report Top


A 47-year-old man came to the outpatient department with a history of a dry cough and fever. Patient was apparently alright till 2 weeks back when he started complaining of white patches in the oral mucosa and irritation in the mouth. After 1 week, he started having fever that was intermittent and low grade in nature associated with dry cough and throat irritation. Patient had no major illness in the past except piles since 2 years. Patient was admitted as a case of oral candidiasis and pyrexia of an unknown origin. Tablet fluconazole (200 mg) was started for oral candidiasis. On examination, patient was conscious and oriented. Pulse was 116/min. Blood pressure was 90 mm Hg systolic.

Investigations

Blood: Total leucocyte count - 4700/cumm, platelet count - 2 lacs/cumm, malarial parasites-negative.

Liver function tests - normal, renal function tests - normal, HIV-positive for HIV 1 antibodies by Tridot, Retroquick and Chemiluminescent immunoassay (ABBOT Architect HIV Ag/Ab Combo assay), HBsAg - negative.

Chest X-ray-inhomogenous haziness was noted in bilateral mid and lower zones suggestive of pneumonitis.

After 2 days, the patient became breathless and developed high-grade fever. He showed a drop in SpO 2 even after oxygen supplementation and was shifted in intensive care unit (ICU). The patient was nebulized. Injection ceftriaxone was started. Oseltamivir was also started on suspicion of H1N1 infection.

Chest X-ray showed increase in haziness and changes s/o bilateral bronchopneumonia [Figure 1]. Bronchoscopy showed widespread erythematous change with multiple, white, plaque like lesions in trachea and throughout the bronchial tree.
Figure 1: Chest X-ray showing bilateral inhomogeneous haziness s/o acute bronchopneumonia

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Sputum, bronchoalveolar lavage (BAL) and blood samples were sent for culture and sensitivity testing. Sputum and BAL cultures were inoculated on blood agar, chocolate agar and Sabouraud's dextrose agar. Throat swab was sent for H1N1 examination. H1N1 was negative.

Bronchoalveolar lavage fluid showed neutrophils 55%, macrophages 39% and lymphocytes 7%. BAL was negative for acid fast bacilli. Gram-stain of sputum, BAL fluid showed 3-5 μm sized Gram-positive, non-capsulated budding yeast cells [Figure 2]. India ink showed a small capsule around some yeast cells [Figure 3].
Figure 2: Gram's-stain showing Gram-positive budding yeast cells

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Figure 3: India ink preparation showing poor capsule

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Blood Bactec 9050 (BD diagnostics) showed a peep after 48 h of incubation. All three samples were negative for any significant bacterial pathogen.

After 48 h of incubation, white, smooth colonies were grown on blood agar, chocolate agar and Sabouraud's dextrose agar. Gram's-stain of colonies showed 3-5 μm sized Gram-positive non-capsulated circular yeast cells. India ink showed small capsule around some yeast cells. The strain was urease positive, showed growth at 37°C, produced black coloured colonies on Bird seed agar [Figure 4] and was positive for capsular antigen detected by Cryptococcus latex agglutination test (Wellcogen Cryptococcus latex agglutination Kit). So, it was diagnosed as C. neoformans.
Figure 4: Black coloured colonies on Bird seed agar

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Gram's-stain report was informed to clinician. Unfortunately, patient developed tachypnea and was put on a ventilator. The patient expired on the 2 nd day of admission in ICU before the culture result. Hence, systemic antifungal drugs could not be started and investigations like CD4 count, lung biopsy could not be done.


  Discussion Top


Cryptococcus neoformans is an encapsulated fungus that can cause fatal infection in immunocompromised hosts. Patients with T-cell deficiencies are more susceptible to infection. [5]

It is the only pathogenic fungus that produces capsular material. When encapsulated yeasts are grown in culture and recognized histologically, a diagnosis is established. [6] Capsule deficient cryptococci were once believed to cause pulmonary infections exclusively in immunocompetent patients. However, increasing numbers of infections due to capsule deficient cryptococci have been reported in AIDS patients. Thus, it is obvious that poorly encapsulated, or capsule deficient strains may be seen in both immunocompetent and immunodeficient patients. [7],[8]

Common chest X-ray findings in pulmonary cryptococcosis are nodular infiltrates resembling carcinoma. [9] A few authors have reported capsulated C. neoformans causing acute bronchopneumonia in AIDS. All these patients developed disseminated cryptococcosis despite antifungal treatment and died due to acute respiratory failure. [4] Our patient developed acute bronchopneumonia due to poorly encapsulated C. neoformans. This is a rare case as poorly encapsulated strain has caused life-threatening acute bronchopneumonia in AIDs. Patient died due to acute respiratory failure and delay in systemic antifungal treatment.

So, pulmonary cryptococcosis should be kept in mind while treating acute bronchopneumonia in immunocompromised hosts.

 
  References Top

1.
Buchanan KL, Murphy JW. What makes Cryptococcus neoformans a pathogen? Emerg Infect Dis 1998;4:71-83.  Back to cited text no. 1
    
2.
Kimura M, Kaufman L, Maekura S, Teramura K, Satou T, Hashimoto S. Pulmonary cryptococcosis due to a capsule-deficient strain confused with metastatic lung cancer. Mycopathologia 1997;140:65-8.  Back to cited text no. 2
    
3.
Lacaz C. Meningoencephalitis due to nonencapsulated Cryptococcus neoformans: Case report. Arq Neuropsiquiatr 1993;51:395-8.  Back to cited text no. 3
    
4.
Lee KH, Chang UI, Kim HW, Kim G, Kim SK, Yoo J, et al. Acute respiratory failure associated with cryptococcal pneumonia and disseminated cryptococcosis in an AIDS patient. Korean J Intern Med 2006;21:39-42.  Back to cited text no. 4
    
5.
Boyton RJ, Altmann DM, Wright A, Kon OM. Pulmonary infection with Cryptococcus neoformans in the face of underlying sarcoidosis. Respiration 2007;74:462-6.  Back to cited text no. 5
    
6.
de Klerk AA, Bezuidenhout J, Bolliger CT. A young healthy woman presenting with acute meningitis and a large pleural-based mass. Respiration 2003;70:655-7.  Back to cited text no. 6
    
7.
Denning DW, Stevens DA, Hamilton JR. Comparison of Guizotia abyssinica seed extract (birdseed) agar with conventional media for selective identification of Cryptococcus neoformans in patients with acquired immunodeficiency syndrome. J Clin Microbiol 1990;28:2565-7.  Back to cited text no. 7
    
8.
Chandler FW, Watts JC. Cryptococcosis. In: Chandler FW, Watts JC, editors. Pathologic Diagnosis of Fungal Infections. Chicago: ASCP Press; 1987. p. 161-75.  Back to cited text no. 8
    
9.
Gordonson J, Birnbaum W, Jacobson G, Sargent EN. Pulmonary cryptococcosis. Radiology 1974;112:557-61.  Back to cited text no. 9
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]



 

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