It is a comprehensive article where we will learn symptoms, causes, diagnosis, treatment and vaccines for pneumonia. Pneumonia is a infectious condition which can cause cough, chest pain and high grade fever.
Signs & Symptoms of Pneumonia
Bacterial Pneumonia usually presents with following signs and symptoms
- Sputum production,
- Chest pain.
It can be either productive cough or dry cough depending upon the bugs that caused pneumonia in the first place. The interstitial pneumonia caused usually by atypical organisms like Peumocystis, viruses, mycoplasma and sometimes often legionella results in dry cough.
The quality and degree of sputum production tells us what maybe the cause of pneumonia. Streptococcus pneumoniae, Klebsiella and Haemophilus have significant purulent sputum production.
Strept pneumoniae: Rusty colored sputum ( gets its color from oxidation of blood)
Klebsiella: Currant Jelly sputum, has a mucoid characteristic (from the thick mucoplysaccharide coating of the bacteria)
Usually worsens with taking deep breath and most of the time associated with lobar pneumonia from strep pneumoniae.
Some Specific Signs and Symptoms due to Specific Organism
Mycoplasma: Dry cough, chest soreness, Anemia (hemolysis from cold agglutinin)
Legionella: Confusion, headache, lethargy, diarrhea and abdominal pain
Peumocystis: Marked breathlessness, and cough. Usually in HIV positive patients with CD4 count less that 200/uL.
Causes of Pneumonia
Pneumonia can be caused by bacteria, bacteria like organisms, viruses and fungi.
Most common cause of Pneumonia is bacteria especially Streptococcus Pneumoniae which is the number one cause of pneumonia in all age groups expect for children less than 5 years where virus is the most common cause of pneumonia.
The typical agents responsible for pneumonia are strept pneumoniae, haemophilus and moraxella.
The atypical agents like Legionella, mycoplasma and chlamydia can cause pneumonia as well.
Other than that virus are responsible for mild pneumonia. Some influenza virus may case serious type of pneumonia known as SARS (sudden acute respiratory syndrome) which can be fatal at times.
It is important to know that you can get exposed to these germs in certain predisposing conditions. The history of your work, travel and recent contact may be important in knowing the type of germs causing pneumonia. I have illustrated few examples below.
- Smokers, people with chronic respiratory disease: Haemophilus Influenza
Young and health people: Mycoplasma (Walking Pneumonia)
- Old aged smokers with history of living around infected water source like coolers : Legionella
- HIV positive with CD4 count less that 200/uL and not taking prophylactic meds: Pneumocystis Jeroveci
- Exposure to animals especially at the time they are giving birth: Coxiella Burnatti (Q Fever)
- Alcoholics: Klebsiella
- Following influenza viral infection: Staph Aureus
- Exposure to birds: Chlamydia Psittaci
- Exposure to bat or bird droppings especially if you do recreational cave exploration: Histoplasma Capsulatum
- Hunters, exposure to rabbits: Francisella tularensis
- Travel to South east Asia: SARS, Avian Influenza
- Hospital Stay more than 48 hours : Klebsiella, Pseudomonas, E.coli, Staph Aureus
- Inhibited gag reflux due to brain injury, swallowing problem, or excessive use of alcohol or drugs: Klebsiella causing Aspiration Pneumonia.
- Decreased immunity, decreased neutrophils, steroid overuse: Aspergillus
How To Diagnose Pneumonia
Pneumonia can be suspected initially on the basis of clinical signs and symptoms like fever, cough with sputum, breathlessness, chest pain. There maybe some atypical signs like absence of fever if the patient is immuno-compromised or malnourished. Cough maybe dry, depending upon the cause of pneumonia. There might be confusion, lethargy, abdominal pain and lethargy if it pneumonia is due to legionella. Past history of exposure and occupational history might give some clue about cause of pneumonia.
As far as tests are concerned chest x-ray is the single most initial test which not only tells about the presence of disease but also initial clue to determining the diagnosis. On the basis of chest X-ray it can be determine if the disease is restricted to one lobe (Lobar Pneumonia) or it is bilaterally present in both the lungs with interstitial infiltrates. X-ray also helps in finding out if pneumonia is associated with plural effusion or not.
Lobar Pneumonia is mainly caused by typical agents like s.pneumoniae, haemophilus, morexella.
Interstitial Infiltrates : Seen mainly in pneumonia caused by pneumocyctis, mycoplasma, chlamydia, coxiella and sometimes legionella.
Sputum also helps in diagnosing pneumonia, it might be rusty colored if caused by s.pneumoniae or currant jelly if the causative organism is klebsiella. The sputum culture is the most specific test for diagnosing lobar pneumonia as the other atypical organisms do not produce enough sputum and also difficult to show up on Grams stain or regular bacterial culture.
Sometimes invasive tests are required to diagnose pneumonia like bronchoscopy, thoracentesis, pleural biopsy, or culture of pleural fluid.
Most specific test for diagnosing pneumonia is with open lung biopsy which is almost never performed.
Specific diagnostic methods for diagnosing pneumonia based on causative organism
- Mycoplasma : antibody titre. Cold agglutinins can also be performed but it has limited sensitivity and specificity.
- Peumocyctis Jiroveci: Bronchioalveolar lavage. Increased LDH.
- Coxiella, Chlamydia (Pneumoniae and Psittaci), coccidioidomycoses : specific antibody titres.
- Legionella: Bacteria can be cultured in charcoal yeast extract, urine antigen test, direct fluorescent antibodies and specific antibody titers.
Treatment of Pneumonia
Treatment of Pneumonia depends on two major factors:
- Severity of the disease: Patient needs hospitalization or not
- Type of pneumonia: Is it community acquired or Hospital Acquired.
Severity of the disease
Mild pneumonia can be treated without admitting the patient, however if the disease is sever the patient has to be admitted to undergo treatment. There are major determinants of severity. Read signs & symptoms of pneumonia to understand better.
Degree of hypoxia (Deprivation of oxygen supply)- If the partial pressure of oxygen is less than 60 mm of HG, oxygen saturation is below 94 percent on room air, respiratory rate above 30/minute, confusion or disorientation, uremia (building up of nitrogenous waste in the body due to renal failure caused by hypoxia in this case).
Hypotension– Systolic below 90 and diastolic below 60 mm of HG
Other markers of severity:
High fever, hypothermia, leucopenia (decrease in WBC) , usually less than 4000/ cubic mm, rapid pulse >125/min, hyponatremia (decrease in sodium content of the body), dehydration.
Patients with serious underlying illness are also needed to be hospitalized. These co-morbid conditions include cancer, renal disease, liver disease or chronic lung disease.
Treatment of Community Acquired Pneumonia:
Antibiotics are used to treat pneumonia. The specific causative germ or bacteria is not known at the time of the start of the treatment, so treatment is started with emperical therapy.
If the there is no need to admit the patient the antibiotic of choice for “Outpatient Community Acquired Pneumonia” is Macrolides (Azithromycin or Clarithromycin)
New Flouroquinolones (levofloxacin or gatifloxacin)can also be used and are generally second line drug of choice.
Macrolides or New flouroquinolones
Since mild cases of community acquired pneumonia are usually mycoplasma and chlamydia pneumoniae we do not use 2nd and 3rd gen cephalosporis as they do not cover all the atypical agents.
Hospitalized patients are usually treated with new fluoroquinolones or 2nd or 3rd generation cephalosporins (cefuroxime or ceftriaxone) combined with a macrolide or doxcycline
New Fluoroquinolones or 2nd-3rd gen cephalosporins +Macrolide / Doxycycline
Treatment of Hospital Acquired Pneumonia
Some patients might develop pneumonia while there stay in hospital usually after 48 hours of stay. Main causes of hospital acquired pneumonia are
1-Gram negative bacilli (Pseudomonas, Klebsiella, E.coli)
2-Gram positive bacilli (Methicillin resistant Staph Aureus)- MRSA
The empirical therapy is done usually with 3rd generation cephalosporins with anipseudomonal activity (Ceftazidime or cefotaxime) or carbepenems (imipenem) or beta lactam/beta lactamase inhibitor combination (piperacillin/tazobactam) with coverage of MRSA by Vancomycin or linezolid.
3gen cephalosporin/carbepenem/b-lactam,lactamase inhibitor + Vancomycin
Aminoglycosides like amikacin, gentamycin is added to prevent drug resistance, synergistic effect and to make better gram negative coverage.
Once the result of sputum culture or bronchoalveolar lavage or pleural fluid culture is out, we can adjust the antibiotics accordingly. Read diagnosing pneumonia for better understanding.
Special bugs need special antibiotics
1-Pneumocystis: Trimethoprim Sulfamethoxazole (TMP/SMZ). Steroids should be used if the infection is severe (arterial PO2 is less than 70mmof HG or A-a gradient is greater than 35 mm of HG). If patient is allergic to TMP/SMZ, I.V pentamidine or atovaquone can be used. Dapsone or atovaquone can be used prophylactically.
2- Coxiella Brunetti (Q-Fever)- usually treated with doxycycline or erythromycin as an alternative.
3-Coccidioidomycoses- no need for treatment for primary pulmonary disease. Treatment is required only for disseminated disease or if the patient is immunocompromised. Life threatening disease is treated with amphotericin while milder form is treated with fluconazole or itraconazole.
Those patients who are at risk for pneumonia should receive pneumococcal vaccine.
Prevention of Pneumonia: Pneumonia Vaccine
Pneumococaal vaccine is used to prevent disease caused by Streptococcus Pneumoniae, which includes disease of blood (septicemia) brain (meningitis) and Lungs (Pneumonia). Pneumococcal vaccines are generally of two types:
- Pneumococcal Polysaccahride Vaccine 23 (PPSV 23): Made from 23 strains of bacteria.
- Pneumococcal Conjugate Vaccine 13 (PCV 13): Used in children and recently approved by FDA to be used in adults aged 50 and above.
Pneumococcal Polysaccahride Vaccine 23 (PPSV 23)
It usually given to age groups between 19 and 64 years old with medical conditions or risk factors like:
- Lung disease
- Cardiac disease
- Kidney Disease
- Cigarette smoker
- Immunocompromised patient
- HIV positive
- Any medical condition that weakens immune system
Booster shot is given after 5 years
All patients older than 65 years without any contraindication to the vaccine or if its more than 5 years since they received there last dose. Booster dose is given after 5 years
Pneumococcal Conjugate Vaccine 13 (PCV 13)
PCV 13 is recommended for adults more than 19 years old with medical condition like asplenia (non functional spleen) splenectomy (spleen has been removed), Sickle cell anemia, CSF leaks or any type of implants in ear, especially cochlear implants.
If doctor recommends both vaccine, usually PCV 13 is given first followed by PPSV23 after two months. If the patient has already taken PPSV 23 shot and needs PCV 13 there should be a gap of at least one year
Contraindications for the Pneumococcal Vaccine:
Life threatening allergy to the vaccine
Allergic reaction to any of the components of the vaccine
Moderately or severely Ill : Might have to wait until you recover.
Pneumococcal Vaccine can be given if you have mild fever or cold
Pregnancy: Pregnant women should get vaccinated only if they need it. There is no data that shows that the vaccine is safe in pregnancy but mother who received shots of pneumococcal vaccine early in pregnancy not knowing that they were pregnant did not caused any harm to the baby
Side Effects of Pneumococcal Vaccine
1-Mild redness and swelling at the place where shot was given
2-Mild Fever, Marked swelling and redness at the site of vaccination, body ache and weakness (Only in 1% of cases)
3-Allergic reaction to Pneumococcal Vaccine: This could be life threatening and you should immediately seek medical attention as soon as you notice any of the following signs and symptoms of allergic reaction:
- Breathing difficulty
- High fever
- Generalized skin rash and redness
- Hoarseness of voice
- Dizziness, weakness
- Increased heart beat.