Community acquired pneumonia

-- days of _ , S/G Onset, W/U/I Progression

  • Sx: fever, productive cough, dyspnea, fatigue, AMS

  • DENIES: chest pain, hemoptysis, recent travel or immobilization, lower extremity swelling, orthopnea, paroxysmal nocturnal dyspnea, wheezing, and sick contacts.

  • pertinent SHx:

  • pertinent DATA on admission:

  • pertinent Micro form past:

  • (NO Prior respiratory MRSA/Pseudomonas colonization, Recent hospitalization and IV antibiotics (≤ 90 days) )

  • DDX:PE, CHF/pulm edema, COPD/asthma exac, PTX, pleural effusion, bronchitis/viral infxn, ACS.

  • Aspiration risk factors include dementia or altered mental status, alcohol or drug use, dysphagia (e.g., stroke), GERD, poor dentition, seizure, impaired gag reflex, and being bedridden.

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→ ANY 1 major OR ≥3 minor = SEVERE (ICU-level care)
Major criteria (just 1 = severe):

  • Respiratory failure → needs mechanical ventilation

  • Septic shock → needs vasopressors
    Minor criteria (need ≥3):

  • RR ≥ 30

  • PaO₂/FiO₂ ≤ 250

  • Multilobar infiltrates

  • Confusion/AMS

  • BUN ≥ 20

  • WBC < 4

  • Plt < 100

  • Temp < 36°C

  • Hypotension (needs fluids)
    --> ICU ?

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WORK UP

  • labs: CBC,BMP, RVP, legionella, strep urine Ag, MRSA nare? BCx only if c/f severe PNA or sepsis

  • imgs: CXR (consolidation), consider CT if c/f PE, diagnosis uncertain, or to look for complications,to assess for empyema, abscess, fungal infection; may be valuable in all immunocompromised patients;

  • Micro: Sputum, Blood, previous cultures?

  • DDX:PE, CHF/pulm edema, COPD/asthma exac, PTX, pleural effusion, bronchitis/viral infxn, ACS.

Plan

  • CTX 2g total 5 days (date***)

  • Azithro 500 mg total 3 days (date***)

  • Severe → cefepime + vancomycin + Azithro

  • Aspiration concern → Ampicillin-sulbactam (Unasyn) + Azithro

  • f/u cultures

  • trend CBC,RFP daily

  • if not improving 48–72 hrs consider adding vanc + cefepime, CT chest/contrast and Cx if not drawn

  • Supportive: acetaminophen PRN, incentive spirometry,

  • hydrocort 50 q6 or prednisone 50 PO daily if sepsis/shock or severe PNA, 4 to 7 days followed by a taper if Course >7 days

  • Afebrile ≥48 hrs and clinically stable → switch to PO: if on CTX + Azithro, change to Amoxicillin 875 mg PO BID and continue Azithro to complete 3 days total. If treated with FQ or for Pseudomonas, switch to Levofloxacin 750 mg PO daily or Ciprofloxacin 750 mg PO BID for 7 days total. If MRSA, use Linezolid 600 mg PO BID for 7–14 days total depending on severity/bacteremia.

  • f/u with PCP in one week after DC

-- Source Control: large parapneumonic effusions and any empyemas will need to be drained via thoracentesis; consider if >10mm, > half hemithorax, suspected to be causing dyspnea

-- Supportive: acetaminophen PRN, incentive spirometry, benzonatate, dextromethorphan

Note
For inpatient CAP, start with CTX + Azithro or Doxy (β-lactam + macrolide; doxy can substitute for macrolide); If unable to take β-lactam + macrolide, use a respiratory FQ such as levofloxacin or moxifloxacin. Add Vanc (per pharm) or Linezolid if MRSA risk (Hx MRSA, recent flu, immunosuppression, IVDU, IV abx in past 3 mo). If Pseudomonas risk (prior Pseudomonas infx, GNR on stain, IV abx in past 3 mo, chronic COPD on steroids), use Cefepime + Levo (or moxi). If risk for both MRSA + Pseudomonas, use Cefepime + Levo/Moxi + Vanc (or Linezolid). For HAP, treat with Cefepime + Vanc. Treat CAP for ≥5 days once clinically stable; uncomplicated MRSA ~7 days; MRSA with bacteremia ≥14 days; Pseudomonas or unusual pathogens 7–14 days (longer if complications). Avoid cephalosporins/carbapenems in severe β-lactam allergy. QT risk is the main concern with macrolides/FQs. Common doses: CTX 1–2 g IV daily; Azithro 500 mg IV/PO daily x 3 ; Doxy 100 mg BID; Levo 750 mg IV/PO daily; Moxi 400 mg IV/PO daily; Cefepime 2 g IV q8h; Cipro 400 mg IV q8h; Linezolid 600 mg IV q12h; Vanc per pharmacy dosing.

  • MRSA risk factors include recent influenza or viral illness, prior MRSA infection or colonization, IV drug use, skin/soft tissue infections (pustules/abscess), cavitary pneumonia, recent hospitalization (especially with IV antibiotics), and a positive MRSA nasal swab.

  • Pseudomonas risk factors include COPD (especially severe or with frequent exacerbations), bronchiectasis, structural lung disease, prior Pseudomonas colonization/infection, recent hospitalization with IV antibiotics, immunosuppression, chronic steroid use, and nursing home or healthcare exposure.

  • Aspiration risk factors include dementia or altered mental status, alcohol or drug use, dysphagia (e.g., stroke), GERD, poor dentition, seizure, impaired gag reflex, and being bedridden.

Notes:

  • Streptococcus pneumoniae (most common bacterial CAP pathogen)

  • in those with comorbidities, older age, or recent antibiotic -> also we cover for Beta-lactamase-producing Haemophilus influenzae, Moraxella catarrhalis_Methicillin-susceptible _Staphylococcus aureus