COMMUNITY

ACQUIRED
PNEUMONIA (CAP)

PRESENTED BY DR M. KAZEVU
“The ability to breath is a gift”
 KEY COMPONENTS OF PULMONARY
DEFENSE
Mucociliary clearance Immune response: A
(escalator): a dynamic complex interplay of innate
process involving and adaptive immune cells,
coordinated movement of antibodies (e.g., mucosal IgA)
cilia to propel mucus, and inflammatory mediators
entrapping inhaled particles to combat infections and
& pathogens towards the maintain tissue homeostasis.
upper airway for elimination.

Alveolar macrophages: Cough reflex: A protective

resident phagocytic immune mechanism that forcefully
cells within the lung alveoli expels mucus, irritants and
that engulf and destroy pathogens from the airways
pathogens, particulates and
cellular debris.
PNEUMONIA
• This is inflammation of the lung parenchyma (distal
to the terminal bronchioles).
• This includes respiratory bronchioles, alveolar ducts,
alveolar spaces and interstitial tissue.
• Can be classified in many ways, a few include:
• Etiologically: infectious vs non-infectious
• According to setting acquired
• Community acquired
• Hospital acquired & health care associated pneumonia (includes
cases caused by multidrug resistant pathogen associated with
HAP)
• Ventilator associated
• Anatomic/morphology: Lobar, bronchopneumonia,
interstitial
CAP
• Diagnosis of CAP:
• 2 or more signs e.g.,
temperature >38 °C or
<36 °C; leukocyte count
<4000/ML or >10000/
ML) or symptoms (eg,
new or increased cough
or dyspnea) of pneumonia
in conjunction with
consistent radiographic
findings without an
alternative explanation.
PREDISPOSING FACTORS
• Preceding respiratory viral infections (superadded
bacterial infections)
• Alcoholism
• Cigarette smoking (effect of Tar on cilia)
• Underlying diseases such as heart failure, COPD
• Age extremes
• Immunosuppressive therapy and disorders
• Decreased consciousness, coma, seizure etc.
• Surgery and aspiration of secretions
COMMON PATHOGENS (GLOBAL
PERSPECTIVE)
 INFECTIOUS ETIOLOGY
• Bacterial: • Viral:
• Streptococcus • Influenza viruses (A and B)
pneumoniae/pneumococcus (50%) • Respiratory syncytial virus
• Haemophilus influenzae (7%) (RSV)
• Klebsiella pneumoniae • Parainfluenza virus
• Pseudomonas aeruginosa • Human metapneumovirus
• Cold viruses: adenovirus,
• Legionella pneumophilia (3%)
coronavirus (including SARS-
• Staphylococcus aureus (2%)
CoV-2), Astrovirus
• Moraxella catarrhalis (2%)
• Mycoplasma pneumoniae (atypical • Fungal/Parasitic
pneumonia)
• Pneumocystis Jirovercii
• Chlamydophila pneumoniae
pneumonia
• Chlamydophila psittaci • Histoplasma capsulatum
• Coxiella burnetti (Q fever) • Blastomyces dermatitidis
• Coccidiodes immitis
• Aspergillosis
ZAMBIA ETIOLOGY PERSPECTIVE
• Among people living with HIV, Mycobacterium
tuberculosis was found to be a common cause of
pneumonia (Mateyo KJ et al.,2014)
• PJP had low prevalence of 4.4%.

• Not so many studies on etiological diversity in

CAP in Zambia.
COMMON CAP
ETIOLOGY (UTH)
TAKE AWAY POINTS
• The most common pathogen was Mycobacterium tuberculosis, found in 19.6%
of the participants and it was associated with increased 30-day mortality.
• Candida species were isolated in 17.5% of sputum samples and co-infection
with Mycobacterium tuberculosis was seen in 23% of these. (?Synergist
growth of Candida in PTB)
• Gram-negative organisms were the most common bacterial isolates other than
Mycobacterium tuberculosis and were altogether identified in about 30% of
the isolates.
• The commonest gram-negative organism isolated was Klebsiella pneumoniae, with
a frequency (12.1%) similar to that found by Mateyo et al. in HIV-infected patients
• A rare opportunistic organism called Pseudomonas alcaligenes was isolated in
4.9% of the patients, of which only 55% had HIV infection
• Streptococcus pneumoniae was only isolated in 1.8% of the samples tested, in
sharp contrast with previous studies where S. pneumoniae was the most
common cause of CAP (could be much higher as most cases are managed
adequately at lower facility level)
RURAL
PERSPECTIVE
• Main focus: viral
surveillance program
(2018-2019)
• Pathogens isolated
(63.2% of samples from
671 participants with
influenza like illness):
• Influenza virus (18.3%)
• RSV (11.8%)
• Rhinovirus (26.4%)
• Coronavirus (6.0%)
• 6.4% with multiple Macha Hospital in Southern Province, Zambia
respiratory pathogens
RURAL PERSPECTIVE
CLINICAL SYMPTOMS
• Fever and chills: can be as high as 39.5- 40.5O C.
• Swinging fevers often suggest empyema.
• Cough: dry or productive with hemoptysis..
• Chest pain: pleuritic in nature due to inflammation of
pleura (mediated by bradykinin and prostaglandin E2 ).
• Breathlessness.
• In the elderly community acquire pneumonia (CAP) can
present with confusion or nonspecific symptoms such as
recurrent falls. CAP should always be considered in
the differential diagnosis of sick elderly patients
given their frequently atypical presentation.
CLINICAL SIGNS
• Tachypnea and increased pulse rate
• Cyanosis may be present
• There will be dullness to percussion
• Bronchial breath sounds over areas of consolidated
lung.
• Coarse crepitations.
• A pleural rub may be heard early on in the illness
• Elevated WBC count.
• Extrapulmonary manifestation: may be indicative of
causative agent.
CLINICAL FEATURES
30-DAY MORTALITY
ROUTINE LABS
• May not be useful in diagnosis but help with risk stratification:
• Serum chemistry panel (sodium, potassium, bicarbonate, blood urea nitrogen [BUN], creatinine,
glucose)
• Arterial blood gas (ABG) determination (serum pH, arterial oxygen saturation, arterial partial
pressure of oxygen and carbon dioxide) – Hypoxia and respiratory acidosis may be present.
• Venous blood gas determination (central venous oxygen saturation)
• Full blood cell (CBC) count with differential:
• leukopenia ominous clinical sign of impending sepsis
• Leukocytosis with a left shift may be observed in any bacterial infection
• Serum free cortisol value
• Serum lactate level
• Blood culture: positive in around 40%
• Note: pulse oximetry finding of less than 90-92% indicates significant hypoxia,
and an elevated C-reactive protein (CRP) level may be predictive of more serious
disease
• Pleural fluid analysis if there is a significant pleural effusion may be helpful (a
diagnostic pleural tap will be helpful), Gastric lavage
KEEP IN MIND
• Strep pneumoniae: WBC> 15 x10 9 /L (90%
polymorphonuclear leukocytosis), ESR>
100mm/hour, CRP> 100mg/L.
• Mycoplasma: WBC is usually normal. In the
presence of anemia, hemolysis should be ruled out
(direct Coomb’s test and measurement of cold
agglutinins).
• Legionella: there is Lymphopenia without marked
leukocytosis, hyponatremia, hypoalbuminemia and
high serum levels of liver aminotransferases.
SPUTUM
• Sputum Gram stain and culture should be done before antibiotic
therapy
• Good-quality, contaminant-sparse specimen containing < 10 squamous
epithelial cells per low-power field should be obtained
• The white blood cell (WBC) count should be more than 25 per low-
power field in non-immunosuppressed patients.
• A single predominant microbe should be noted at Gram staining.
• Mixed flora may be observed with anaerobic infections.
• Many specimens are often contaminated by oral materials making
results unreliable.
• Note: to be accurate, only specimens that have been examined
microscopically and that have satisfied the criteria for good quality
sample should be cultured.
INVESTIGATIONS
• Chest X-ray:
• Strep. Pneumoniae: consolidation with
air bronchograms, effusions and
collapse due to retention of secretions
can all be seen.
• Radiological abnormalities can lag
behind clinical signs.
• A normal CXR on presentation should
be repeated after 2-3 days where
community acquired pneumonia is
suspected.
• Mycoplasma: Usually one lobe is
involved but infection can be bilateral
and extensive
• Legionella: There is lobar and then
multi-lobar shadowing with the
occasional small pleural effusion.
Cavitation is rare.
CURRENT RECOMMENDATIONS
• Blood cultures are generally not recommended for
outpatients or most hospitalized adults with community-
acquired pneumonia (CAP).
• Pre-treatment cultures recommended for (one of):
• Is currently receiving empiric treatment for MRSA or P aeruginosa
• Previously had MRSA or P aeruginosa infection, especially of the
respiratory tract
• Was hospitalized within the preceding 90 days and received parenteral
antibiotics for any reason
• Urine antigen testing for pneumococcus is also generally
not recommended unless the CAP is severe.
• Antibiotic therapy should be started in adults with
clinically suspected and radiographically confirmed CAP,
regardless of procalcitonin levels.

The Infectious Diseases Society of America (IDSA) and American Thoracic Society (ATS)
TREATMENT
• Hospitalization in adults with CAP should be based on:
• Clinical judgement + validated clinical prediction rule for prognosis.
• The Pneumonia Severity Index (PSI) is preferred over the CURB-65.
• The duration of antibiotic therapy should be guided by a
validated measure of clinical stability.
• Antibiotics should be continued until stability is achieved, for a
total antibiotic duration of at least 5 days.
• Routine follow-up chest imaging is not recommended in adults
with CAP whose symptoms have resolved within 5 to 7 days.
• Routine corticosteroid treatment is not recommended in adults
with CAP (regardless of severity) or severe influenza
pneumonia (some studies suggest otherwise)

The Infectious Diseases Society of America (IDSA) and American Thoracic Society (ATS)
PSI
ANTIMICROBIALS
• Adult patients with CAP who are otherwise healthy:
• Amoxicillin 1 g three times daily OR
• Doxycycline 100 mg twice daily OR
• In areas with pneumococcal resistance to macrolides < 25%: a macrolide
(azithromycin 500 mg on day one and then 250 mg daily or clarithromycin
500 mg twice daily or clarithromycin extended-release 1,000 mg daily)
• Outpatient adults with CAP who have comorbidities:
• Combination therapy:
• Amoxicillin/clavulanate 500 mg/125 mg 3 times daily or amoxicillin/clavulanate
875 mg/125 mg twice daily or 2,000 mg/125 mg twice daily or a cephalosporin
(cefpodoxime 200 mg twice daily or cefuroxime 500 mg twice daily) AND
• A macrolide (azithromycin 500 mg on day one then 250 mg daily or clarithromycin
[500 mg twice daily or extended release 1,000 mg once daily]) or doxycycline 100
mg twice daily OR
• Monotherapy :
• Respiratory fluoroquinolone (levofloxacin 750 mg daily, moxifloxacin 400 mg daily,
OR gemifloxacin 320 mg daily)
ANTIMICROBIALS
• Inpatient adults with non-severe CAP who do not have risk factors for
MRSA or P aeruginosa:
• Combination therapy:
• A beta-lactam (ampicillin plus sulbactam 1.5-3 g every 6 hours or cefotaxime 1-2 g
every 8 hours or ceftriaxone 1-2 g daily or ceftaroline 600 mg every 12
hours) AND
• A macrolide (azithromycin 500 mg daily or clarithromycin 500 mg twice daily) OR
• Monotherapy with a respiratory fluoroquinolone (levofloxacin 750 mg daily,
moxifloxacin 400 mg daily)
• If macrolides and fluoroquinolones are contraindicated: A beta-lactam
as above AND doxycycline
• The following regimens are recommended among inpatient adults with
severe CAP who have no risk factors for MRSA or P aeruginosa (agents
and doses as above):
• A beta-lactam plus a macrolide OR
• A beta-lactam plus a respiratory fluoroquinolone
NOTE
• Empiric coverage for MRSA or P aeruginosa is recommended in adults with
CAP only in the presence of locally validated risk factors.
• Possible empiric treatment for MRSA includes:
• vancomycin (15 mg per kilogram every 12 hours, adjusted according to levels) or
linezolid (600 mg every 12 hours).
• Empiric treatment choices for P aeruginosa include:
• Piperacillin-tazobactam (4.5 g every 6 hours),
• Cefepime (2 g every 8 hours),
• Ceftazidime (2 g every 8 hours),
• Aztreonam (2 g every 8 hours),
• Meropenem (1 g every 8 hours), or imipenem (500 mg every 6 hours).
• If empiric coverage for MRSA or P aeruginosa is being administered to adults
with CAP based on published risk factors without local etiological data, empiric
coverage should be continued while culture data are obtained.
• Routine addition of anaerobic coverage for suspected aspiration pneumonia is
not recommended except when lung abscess or empyema is suspected.
HYDROCORTISONE
SUPPORTIVE MANAGEMENT
• Oxygen: supplemental oxygen should be administered to
maintain saturations between 94% and 98% provided the
patient is not at risk of carbon dioxide retention due to loss of
hypoxic drive in COPD.
• Intravenous fluids: required in hypotensive patients showing
evidence of volume depletion.
• Thromboprophylaxis if admitted for more than 12 hours
subcutaneous low molecular weight heparin should be prescribed
unless contraindications exist.
• Physiotherapy: chest physiotherapy is not needed unless sputum
retention is an issue.
• Nutritional supplementation
• Analgesia should be given
PNEUMONIA COMPLICATIONS
• S-Septicemia
• L-Lung abscess
• A-ARDS
• P-Para-pneumonia effusions
• H-Hypotension
• E-empyema
• R-Respiratory failure/Renal failure
DISTANT COMPLICATIONS
• Septic arthritis
• Meningitis
• Pneumonia can progress to sepsis, sometimes
with septic shock
• Heart failure (Cor pulmonale)
REFERENCES AND FURTHER
READING
• Dequin P-F et al. DOl: 10.1056/NE(Moa2215145)
• Gamache, J., 2024. Bacteria Pneumonia. [Online]
Available at: https://emedicine.medscape.com/article/300157-overview#a1
[Accessed 5 February 2025].
• Loevinsohn, G. et al., 2020. Respiratory pathogen diversity and co-infections in rural
Zambia. International Journal of Infectious Diseases, Volume 102, pp. 291-298.
• Loscalzo, J. et al., 2022. Harrison's Priciples of Internal Medicine. 21st ed. New York:
Mc Graw Hill.
• Mateyo KJ, Lakhi S, Guffey B, Chi B, Mweemba A, Andrews B. 2014; Pulmonary
disease in HIV-infected Patients at the University Teaching Hospital, Lusaka, Zambia.
Med J Zambia. 41(2):48–57.
• Vaughn, V. M., Dickson, R. P. & Horowitz, J. K., 2024. Community-Acquired Pneumonia
(A Review). JAMA, Volume 332, pp. 1282-1295.
• Ziko LM, Hoffman TW, Fwoloshi S, Chanda D, Nampungwe YM, Patel D, et al. (2022)
Aetiology and prognosis of community-acquired pneumonia at the Adult University
Teaching Hospital in Zambia. PLoS ONE 17(7): e0271449.
https://doi.org/10.1371/journal.pone.0271449
THANK YOU