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Interstitial pneumonia with subpleural sparing and weight loss

      1. Introduction

      A 36-years-old man from West Africa was admitted to our ED with respiratory failure and a 15 days history of fatigue and peevish cough. He reported watery diarrhea and a 30 kg weight loss in the last three months. In his clinical history, he did not make any recent trips abroad, nor did he reported any chronic disease, any contact with domestic or wild animals or any drug abuse. He received a complete vaccination course for SARS-CoV-2. On the physical examination we observed low-grade fever, bilateral diffused crackles on chest auscultation, latero-cervical and supra-clavicular lymphadenopathies and a maculopapular rash spread on the upper limbs and trunk. No significant alteration was found at the blood samples (normal leukocyte formula with no leukocytosis and a slight rise of the inflammation markers). SARS-CoV-2 molecular test on nasopharyngeal swab resulted negative.
      Chest CT scan revealed a ground glass thickening involving both lungs with relative sparing of the subpleural regions (Fig. 1). What is the diagnosis?
      Fig 1
      Fig. 1Chest CT scan revealing ground glass thickening involving both lungs with relative sparing of subpleural regions.

      2. Diagnosis

      Pneumocystis Jirovecii pneumonia (PJP) in newly diagnosed AIDS.

      3. Discussion

      A bronchoalveolar lavage was performed, detecting PJP antigens on the samples; HIV antibody test resulted positive.
      PJP is the most frequent opportunistic infection in patients with HIV infection and a low CD4 count. The primary mode of transmission is via the airborne route and it remains dormant unless the patient becomes immunosuppressed; however, this may not account for all cases [
      • Pifer L.L.
      • Hughes W.T.
      • Stagno S.
      • et al.
      Pneumocystis carinii infection: evidence for high prevalence in normal and immunosuppressed children.
      ]. In the 60 s and 70 s its incidence was higher in patients with hematologic malignancies, while in the 80 s the prevalence increased dramatically with the emergence of the HIV epidemic. In recent decades its incidence has drastically decreased among HIV patients, thanks to antiretroviral therapies (ART) and the use of post-exposure antiviral prophylaxis [
      • Hughes W.T.
      • Feldman S.
      • Aur R.J.
      • et al.
      Intensity of immunosuppressive therapy and the incidence of Pneumocystis carinii pneumonitis.
      ,
      • Walzer P.D.
      • Perl D.P.
      • Krogstad D.J.
      • et al.
      Pneumocystis carinii pneumonia in the United States. Epidemiologic, diagnostic, and clinical features.
      ,
      • Sepkowitz K.A.
      Opportunistic infections in patients with and patients without acquired immunodeficiency syndrome.
      ].
      The typical CT findings are characterised by a diffuse interstitial or alveolar ground glass infiltrates involving both lungs with a subpleural sparing. In some cases segmental/lobular infiltrates, solitar/multiple nodules, cysts or pleural effusion can be found.
      Trimethoprim/sulfamethoxazole (for 21 days) is the preferred antimicrobial treatment for PJP. In case of contraindications (allergy, G6P deficiency) alternative regimens can be used (trimethoprim-dapsone, clindamycin-primaquine, atovaquone or pentamidine).
      In HIV patients with PJP, in addition to antibiotics and supportive therapies, the use of steroids for patients with moderate to severe disease is recommended. Given in association with anti-PJP therapy, steroids can decrease the incidence of mortality and respiratory failure, helping in reducing the inflammatory response observed when target therapy is started [
      • Ewald H.
      • Raatz H.
      • Boscacci R.
      • et al.
      Adjunctive corticosteroids for Pneumocystis jiroveci pneumonia in patients with HIV infection.
      ].
      Our patient was treated with oxygen support, trimethoprim/sulfamethoxazole (20 mg/kg/day of trimethoprim and 100 mg/kg/day of sulfamethoxazole) and prednisone (1 mg/kg/day). After clinical improvement, the patient was transferred to the local referral hospital for infectious diseases.

      References

        • Pifer L.L.
        • Hughes W.T.
        • Stagno S.
        • et al.
        Pneumocystis carinii infection: evidence for high prevalence in normal and immunosuppressed children.
        Pediatrics. 1978; 61: 35-41
        • Hughes W.T.
        • Feldman S.
        • Aur R.J.
        • et al.
        Intensity of immunosuppressive therapy and the incidence of Pneumocystis carinii pneumonitis.
        Cancer. 1975; 36: 2004-2009
        • Walzer P.D.
        • Perl D.P.
        • Krogstad D.J.
        • et al.
        Pneumocystis carinii pneumonia in the United States. Epidemiologic, diagnostic, and clinical features.
        Ann Intern Med. 1974; 80: 83-93
        • Sepkowitz K.A.
        Opportunistic infections in patients with and patients without acquired immunodeficiency syndrome.
        Clin Infect Dis. 2002; 15 (34): 1098-1107
        • Ewald H.
        • Raatz H.
        • Boscacci R.
        • et al.
        Adjunctive corticosteroids for Pneumocystis jiroveci pneumonia in patients with HIV infection.
        Cochrane Database Syst Rev. 2015; 2015 (Apr 2)CD006150