wsmithv's version from 2015-11-08 01:26

General and Presentation

Question Answer
CAP defpneumonia occuring before hospitalization OR within 48 h of hospital admission
Stats CAP is most comon infectious cause of death in US and S Penumoniae is most common cause of CAP
CAP Pathogens and Their AssociationH Flu = COPD, S Aureus = Recent viral Infection (influenza), Klebsiella Pneumoniae = Alcoholism, diabetes, Anaerobes = poor dentition, aspiration, Mycoplasma pneumoniae = young & health paitents, Chlamydophila pneumoniae = hoarseness (often in young & healthy), Legionella = contaminated water sources, air conditioning, ventilation systems, Chlamydia Psittaci = bird-contact, Coxella burnetii = Animals at the time of giving birth, veterinarians, farmers
PresentationAll Present with FEVER and COUGH; ONLY SEVERE present associated with dyspnea and distinguished by abnormalities of vital signs (tachycardia, hypotension, tachypnea) or abnormalities of mental status
Differentiate Pneumoniae from BronchitisDyspnea, high fever, and abnormal Chest Xray are possible in penumoniae but unlikely in bronchitis
Other Key Indications on Presentation of particular etiology or stateabdominal pain or diarrhea can occur with infection in lower lobes irritating intestines through diaphragm (Legionella is particularly known for causing diarrhea); chills or 'rigors' are sometimes a sign of BACTEREMIA (S Pneumo is most common pneumo associated with bacteremia); chest pain (often pleuritic) can occur from inflammation of pleura; hypothermia is as abad as fever in terms of pathologic significance
Breath soundsDullness --> effusion; 'bronchial' breath sounds and egophony --> consolidation of airspaces
CAP Pathogen-Specific Associations on PresentationK. Pneumoniae = hemoptysis from necrotizing disease (called "current jelly" sputum); Anaerobes = foul-smelling sputum ("rotten eggs"); Mycoplasma Pneumoniae = dry cough, rarely sever, bullous myringitis; Legionella = gastrointestinal symptoms (abdominal pain, diarrhea) or CNS symptoms such as headache and confusion; pneumocystis = AIDS with CD4 < 200
Dry or non-productive coughmycoplasma, viruses, coxiella, pneumocystis, chlamydia. These infections preferentially invovle the interstitial space in lung, leaving air spaces of alveoli empty and healthy (and hence less sputum production); lobar, bacterial pneumonia leaves alveoli filled with puss hence leading to sputum; sputum colors are useless in determining etiology


Question Answer
Best Initial Dx testChest X-ray is best for ALL RESPIRATORY INFECTIONS (can't determine specific etiology); Sputum Gram stain and culture are best initial determination of etiology (but many organisms can't be detected this way)
Atypical pneumoniaInclude mycoplasma, chlamydophia, legionella, coxiella and viruses. These are nto visible on Gram stain and not culturable on standard blood agar. BUT THESE AGENTS ACCOUNT FOR 30-50% of CAP
Chest Xray imagesRight middle lob infiltrate = minor fissure is shown separating middle and upper lobes and dense infilitrates will obscure right heart border. Bilateral interstitial infiltrates = atypical pneumonias (mycoplasma viruses, coxiella, pneumocystis, and chlamydia. The same organisms that typically present with nonproductive cough; Xray findings lag behind clinical findings). NOTE 1ST CHEST XRAY IS FALSE NEGATIVE IN 10-20% OF CASES -- ESPECIALLY IN ATYPICAL PNEUMO. Meniscus sign = pleural effusion. If effusion is mobile, then a lateral decubitous xray will show a fluid layering. If not mobile, then it wont. If it doesn't, that is concern for infection (AKA empyema) and Loculation. Hydropneumothorax = air and fluid in pleural space; suggestive of empyema
TestingChest CT and MRI show greater definition than Xray but cannot determine specific etiology. IN INFECTIOUS DISEASES THE RADIOLOGICAL TEST IS ALMOST NEVER THE MOST ACCURATE
Blood CulturesPositive in 5-15% of CAP, particular with S Pneumo; Sputum Gram stain is "adequate" if >25 WBCs and < 10 epithelial cells; (otherwise may be mostly saliva and not indicative of lung)
Tests in Severe Disease with Unclear Etiology or in Those Not Responding to TXThoracentesis, Bronchoscopy
ThoracentesisAny new large effusion should be tapped to determine if empyema is present. Empyema is infected pleural effusion (acts like abscess but improves rapidly if drained)
Etiology of Pleural EffusionsTransudative (secondary to either increased in PCWP or decrease in intravascular oncotic pressure. CAPILLARIES ARE WORKING FINE, BUT STARLING FORCES FAVOR EXIST FROM VESSELS INTO INTERSTITIAL AND THEN PLEURAL SPACE) Versus Exudative (secondary to increased vascular permeability. DAMAGE TO VESSEL WALLS WHICH THEN LEAK INTO PLEURAL SPACE)
EmpyemaDefined as infection of pleural fluid. Dx Criteria include LDH > 60% of serum level OR protein > 50% of serum level. OTHER CRITERIA = A white cell count > 1000 or pH < 7.2 or + gram stain or +culture or frank puss in fluid. TX = Drainage by Chest tube or Thoracostomy
BronchoscopyOnly needed if sputum stain and Cx and Blood Cx don't yeild organism and patient's condition is worsening despite empiric therapy. Exception is pneumocystis penumonia (which is hard to grow without bronch)
CAP/Organism Specific TestsS Pneumo = urine antigen; mycoplasma = PCR, Cold agglutinins, Serology, special culture media; Chlamydophila, Chlamydia psittaci, and Coxiella burnetti = rising serologic titers; Legionella = urine antigen OR Culture on Charcoal-Yeast Extract; Pnumocystis = Bronchoalveolar Lavage (BAL)
CAP Tx General Rulesrare to have specific organism identified at initiation of Tx; if organism is identified, use that to direct treatement; most important step is determine SEVERITY -- determines where to treat and drives initial therapy (ETIOLOGY DOES NOT)
Mycoplasma and ChlamydophilaRarely confirmed b/c usually just treated empirically


Question Answer
Outpatient Tx AlgorithmIf previously health OR no ABX in past 3 months AND mild symptoms --> MACROLIDE (AZITHROMYCIN OR CLARITHROMYCIN) OR DOXY; if comorbidities or ABX in past 3 months --> respiratory floroquinolone (levo or moxifloxacin)
Inpatient TxRespiratory Floroquinolone (Levo or Moxifloxacin) or (more commonly) CEFTRIAXONE AND AZITHROMYCIN
Reasons to Hospitalize80% are safely treated outpatient with oral ABX. Patients with SEVERE dz must be hospitalized.
What is SEVERE PNEUMOSEVERE = any combination of hypotension (systolic <90); RR > 30; p02 < 60 OR pH <7.35; Elevated BUN > 30 OR Na <130 or Glucose > 250; Pulse >125; Confusion; FEVER > 104; 65 or older or comorbidities (cancer, COPD, CHF, renal failure, or liver disease)
CURB 65Confusion, Uremia, Respiratory Distress, BP low, >65. Any one is sufficient for admission
Pneumo Vax Criteria23 Polyvalent vaccine. Everyone > 65. Everyone with chronic heart, liver, kidney, or lung disease (including asthma) should be vaccinated as such as underlying disease is apparent (regardless of age). Other reasons: functional or anatomic asplenia (e.g., sickle cell), hematologic malignancy (leukemia, lymphoma), immunosuppression (diabetes mellitus, alcoholics, corticosteroid users, AIDS or HIV; CSF leak and cochlear implantation recipients.
Pneumo Vax MethodIf healthy --> single dose at 65. If first fax before 65 or with other conditions previously described --> second dose 5 years after 1st dose. Healthcare workers do NOT need pneumo vax