Community – Acquired Pneumonia ( CAP )

Community – Acquired Pneumonia ( CAP )
Adel Khattab
Prof.of Pulmonary Medicine
Ain Shams University
Community – acquired pneumonia is an acute inflammation or infection of the lung parenchyma characterized by clinical and radiological signs of consolidation of part or parts of one or both lungs. According to WHO reports , it is the third leading cause of death. The most common cause are bacteria : Streptococcus pneumonia 20 – 60 % , H. influenza 3 -10 % , atypical ( Mycoplasma , Chlamydia and Legionella ) 10 – 20 % and viruses 5 – 15 %. In 40 – 60 % no causes are identified. Community – acquired pneumonia is more common in patients with DM , asthma , COPD , heart disease , malignancy , renal failure , neurological disorders and liver diseases.
Regarding investigations recommended , for the outpatient CXR is mandatory while for the inpatients many investigations are needed. Beside CXR , sputum
( Gram stain and culture ) , blood cultures , CBC , blood glucose renal and liver functions , procalcitonin and serology. In cases with pleural effusion , thoracocentesis and pleural fluid analysis is indicated. In progressive and un-resolving cases , bronchoscopy is required. CXR is essential to establish diagnosis , for evaluation of severity , to assess pattern of consolidation and to look for co-existing conditions. Features of atypical pneumonia are gradual onset , cough is usually dry scanty or mucoid , fever is low grade and chest physical signs are often
minimal while general symptoms
( headache , body aches )
are common. While in typical pneumonia , the onset is sudden , cough is productive and purulent , fever is high grade and chest physical signs are more evident while the general symptoms are rare and mild.
Regarding the site of care decisions , many scoring CAP severity are available. The most simple one is CURB 65 score. Five variables ( Confusion , BUN more than 20 mg / dl , RR more than 30 , BP systolic less than 90 diastolic less than 60 and age more than 65 )
CURB 0-1 , treat at home . CURB 2 , short hospital stay or supervised outpatient treatment. CURB 3 , hospitalization in the medical ward. CURB 4-5 , ICU care.
Choice for antibiotics for treatment is usually empirical. The start of empirical antibiotic treatment should not be delayed due to the need for performing diagnostic sampling for microbiological studies. An "appropriate" empirical treatment refers to the use of antibiotic to witch the possible microorganism(s) are sensitive. "Adequate" treatment
refers to the use of appropriate antibiotic at the ( correct dosage ) , with ( good penetration ) at the site of infection and when( indicated ) in ( combination ).
Adherence to guidelines either national or international improve the survival by 10 %. The most widely used guidelines in management of CAP is IDSA/ATS 2007.Antibiotic recommended depends on the severity of the case :
1)For previously healthy outpatients use new oral macrolides.
2)If antibiotic within past 3 months or presence of comorbidities in outpatients : either
– Respiratory Quinolone or
- Combination Macrolide + Beta - lactam.
3) For inpatients ( in the ward), parenteral antibiotics are recommended , either :
- Respiratory Quinolone or
- Combination Macrolide + Beta lactam.
4)For inpatients ( in the ICU )
-No risk of Pseudomonas : IV Beta-lactam + IV Macrolide or IV Quinolone.
-Risk of Pseudomonas : IV antipseudomonas Beta-lactam + IV antipseudomonas Quinolone. Or
IV antipseudomonal Beta – lactam + IV Aminoglycoside + IV Macrolide or IV antipseudomonal Quinolone.
Switch from IV to oral antibiotics is economically mandatory for improving inpatients. There should be improvement in cough and dyspnea , no fever , decreasing WBC and functioning GIT. Switch from IV to oral antibiotics , either :
1)Step – down therapy : conversion from one antibiotic given IV to one given orally.
2)Transitional – therapy : conversion from one antibiotic given IV to same given orally but not at the same dosage or strength.
3)Sequential – therapy : conversion from same antibiotic given IV to oral form at the same dosage and strength.
Antibiotics are given for a minimum of 5 days and patients should be afebrile for 48 – 72 hours.
For prevention of CAP , ask for smoking cessation beside Influenza and Pneumococcal vaccination in indicated patients.