True about Pneumocystis carinii (Pneumocystis jerovecii) is the following EXCEPT

Ans. d (| arterial O2 gradient (PAO2-PaO2)) (Ref: Harrison's Internal medicine 17th edition, p. 1267)ABG in PCP:# | alveolar arterial O2 gradient (Normal < 15 mm H2O 20-30 )# | PaO2 When,When,PAO2 - PaO2 < 35 mm Hg:- PAO2 - PaO2 > 35 mm Hg and PaO2 < 60 mm Hg:- Mild infection- Severe infection- No need to add steroids- Add steroid for 14-21 days.Pneumocystis JiroveciiFungus - Ribosomal genetic make-up and RNA resembles to that of fungus, but lacks mycolic acid in cell-wall.# When it occurs? -CD4 count < 200/mcc in HIV patients# When to suspect? -Fever > 2 weeksDry cough > 2 weeksPresence of oropharyngeal/oesophageal Candida# Clinical features: Dry cough, Dyspnea, Tachycardia, Fever, Cyanosis# RS examination: Auscultation reveals only few abnormalities# CXR: Most common reticulonodular infiltrates starting at hillum involving MZ and LZ with sparing of apex and CP angle (perihilar ground-glass haziness is earliest radiological change in PCP).# Rarest - pleural effusion.# Pneumothroax especially receiving (5-10% cases) aerosolized pentamidine.# Diffusion capacity of lung# Other sites of P Jirovecii infection- Lymph node (most common extrapulmonary site)0- Spleen- Liver- Bone Marrow# Treatment- DOC - Septran- Other Drugs: Dapsone, Pentamidine, Clindamycin and Atovaquone.Summary - Pneumocystis jirovecii:# Yeast (originally classified as protozoan). Inhaled. Most inf asymptomatic. Immunosuppression (AIDS) pre- disposes.# Causes Pneumocystis pneumonia (PCP), a diffuse interstitial pneumonia.# Diffuse, bilateral CXR appearance. Diagnosed by lung biopsy or lavage. Disc-shaped yeast forms on meth- enamine silver stain of lung tissue.# Treatment/prophylaxis: TMP-SMX, pentamidine, dapsone (prophylaxis only), atovaquone (prophylaxis only). Start prophylaxis when CD4 count drops < 200 cells/mm3 in HIV patients.Also Know:Conditions where diffusion capacity of Lung increasedEarly LVFIntra-alveolar hemorrhage