What Is Pneumonia? Types, Causes, Diagnosis And Treatment
What Is Pneumonia ? Despite its lyrical and exotic sounding name, not to mention difficult to spell, Pneumonia is responsible for about 0.4 million hospitalizations annually in the United States, with an even higher number of patient prevalence i.e. estimated to be about 0.9 million. Every year, about 5 to 7% of Americans (about 50,622) die as a result of this disease. Pneumonia, therefore, presents a great economic and social burden to the society. But what exactly is this disease all about? Read on to find out.
Like in most basic diseases, the causative agent boils down to microorganisms, either bacteria, viruses or fungi. Pneumonia is no different and is classified as an infection caused by any of the aforementioned microorganisms that affect part of a lung, or rarely, both the lungs, and causes the air sacs to fill with fluid or pus. Needless to say, this makes breathing difficult, and causes productive cough i.e. cough with sputum; breathing becomes painful and there is a decreased amount of oxygen exchange in the lungs.
According to the World Health Organization, pneumonia is largest infectious cause of children’s death throughout the world.
When just a part or lobe of the lung is affected by disease, it is called lobar pneumonia. On the other hand, when there are diffused patches of diseased areas in the lung, especially the terminal parts of the airway, it is called broncho-pneumonia or bronchial pneumonia. Another way to classify pneumonia is based on the causative microorganism, for example, bacterial pneumonia, viral pneumonia etc. The prognosis and treatment of pneumonia are also based on the causative agent.
What Is Pneumonia? What Are Symptoms Of Pneumonia?
The disease manifestation of pneumonia varies from mild to severe, and also depends on the causative organism. Other variants that may have an impact on the symptoms of the patient can include the age, gender and the overall health of the patient. Typically the disease starts with high grade fever, which may be accompanied by chills and rigors, productive cough i.e. cough with sputum, shortness of breath. Chest pain is also a symptom of pneumonia, what is typically called the pleuritic chest pain.
Sometimes patients experience gastrointestinal symptoms like nausea, diarrhea and/or vomiting as well. Rapid breathing (more than 18 breaths/min), altered mental status, central cyanosis, increased pulse rate (more than 100 beats per min), decreased pulse rate (less than 60 beats per min), harsh breath sounds, swollen lymph nodes, crackles and bronchial breath sounds (on stethoscope) are also seen.
Patient can feel breathless and cyanosed; he may need to put an effort into breathing and drag in air, this is typically seen in the form of nasal flaring and hunched shoulders, when accessory muscles of breathing are used.
At the extremes of age—in the infants and the elderly, symptoms are less specific. For example, there is non-productive cough, confusion, restlessness, cyanosis, and absence of fever. Because of the presence of these atypical and non-specific symptoms, disease tends to be smore severe in such patients, as it may not be diagnosed timely. It is not uncommon to hospitalize such patients and monitor them carefully to prevent complications.
Moreover, in the elderly patients there tend to be other comorbid illnesses as well, for example, ischemic heart disease, diabetes mellitus , cerebrovascular disease, and these conditions need constant monitoring as well. Most physicians therefore find it prudent to treat such individuals as in-patients.
Types Of Pneumonia
Many forms of classifications are used to categorize pneumonia. It can be based on the causative agent as well as the areas of the lungs it affects, and another category is community-acquired or hospital acquired.
Let us first look at the microorganism-based disease:
What Is Bacterial Pneumonia?
This is the most common form of pneumonia. According to the National Heart, Lung And Blood Institute, the most notorious bacteria responsible for affecting most adults in the United States is the Streptococcus pneumoniae. Despite its dangerous name, Streptococcus also known as Strep pneumoniae does not cause disease in the body unless the defenses of the body are weakened in some way—for example after a recent illness, use of antibiotics that change the normal flora of the respiratory tract, post-operative patients, alcoholics, malnourished patients, the elderly patients, cigarette smokers, or people having Chronic Obstructive Pulmonary Diseases(COPD).
In some individuals with weak immunity—like the cancer patients—there is an endogenous source of pathogens, e.g. sinusitis, nasal carriers, gastric colonization, oropharynx etc.
Apart from Strep Pneumoniae, there are some other culprits of pneumonia as well: Haemophilus Influenza, C.Pneumoniae.
What Is Viral Pneumonia?
Even though viral pneumonia is less common than bacterial pneumonia and is generally milder, it is still a nuisance. The common pathogens responsible include the ever present Influenza or flu virus, respiratory syncytial virus (RSV) in children, human metapneumovirus (HMPV), human parainfluenza virus (HPIV), and rhinovirus.
Viruses cause about half of the cases of pneumonia; their presentation is similar to bacterial illness but there is generally more coughing involved. Moreover, viral pneumonia usually gets better on its own in a couple of weeks, but it can make the patient susceptible to super-added bacterial infection.
Mycoplasma pneumoniae or Mycoplasma Pneumonia is an “atypical” bacterium Mycoplasma organisms are not viruses or bacteria, but they have traits common to both. They are the smallest agents of disease that affect humans. Mycoplasmas generally cause mild cases of pneumonia, most often in older children and young adults.
Mycoplasma pneumoniae infections are sometimes referred to as “walking pneumonia.” Some experts estimate that between 1 and 10 out of every 50 cases of community-acquired pneumonia (lung infections developed outside of a hospital) in the United States is caused by M. pneumoniae. However, not everyone who is exposed to M. pneumoniae develops pneumonia.
Fungal infections are a cause of serious concern because they typically occur in the immunocompromised, like the HIV patients, people on chemotherapy or immune-suppressant drugs. Some of the common pathogens behind fungal pneumonia in the United States include:
- Coccidioidomycosis: This is a Californian fungus, found mostly in Southern California, and the Southwestern desert.
- Histoplasmosis: found in the River Valleys of Mississippi and Ohio.
- Cryptococcus: found in bird droppings and soil contaminated with bird droppings throughout the US.
Pneumonia, based on its location in the lungs can be classified as:
This is when a lobe(s) in one or both lungs is affected by disease. Usually the cause of disease is Strep Pneumoniae, with an acute onset, high grade fever and productive cough with rusty sputum.
When disease is present in the form of diffused or scattered small patches of lung tissue. Such a disease pattern is characteristic of many bacterial pathogens, with an insidious attack on the body. The disease is usually accompanied by mild fever but productive cough of yellowish/green sputum.
Interstitial pneumonia is also present in the form of small, scattered patches in the lung tissue. It is mostly caused by viral and fungal pathogens like influenza or cryptococcus. The different thing about its presentation is that patient has a non-productive hacking cough, with headache and myalgias.
Community Acquired Pneumonia
this type of pneumonia is the most common, and the most prevalent form. It is a contagious pneumonia and infectious disease. The most common pathogen involved is again, Strep Pneumoniae, but other pathogen including H.influenzae, Staphylococcus aureus, Pseudomonas aeruginosa are not uncommon. In flu outbreaks, influenza virus is a major cause of CAP, serious enough to warrant hospital stay. The use of vaccines against Strep pneumoniae has decreased the frequency of CAP, but it still remains a common cause of infectious lung diseases in the United States.
The incidence of CAP varies with the age of the patient, as well as the geographical location. Worldwide, the incidence of CAP increases with age, being not only more common, but also more serious in those aged 65 and above. In Europe and North America, about 5 to 11 people per 1000 suffer from CAP, and the rate of hospitalization increases to 13.5 per 1000, from 3.6-8.5 per 1000, in those aged above 65 years.
Hospital Acquired Pneumonia
This type of pneumonia occurs in the hospitalized patients (after about 48 hours of admission), who show no signs of disease at the time of admission, but develop it later, after exposure to pathogens in the hospital. It is most commonly found in mechanically ventilated patients, but even the non-intubated patients can contract it.
The main cause of disease is when the pathogens find their way to the alveoli and overwhelm the defenses of the host. This can be as a result of aspiration of pathogens, hematogenous spread, contaminated aerosol, use of fibrobronchoscopes, and oropharyngeal aspiration etc.
This type of pneumonia has a poor prognosis because of the co-morbidities.
Health Care-Asociated Pneumonia
Health care-asociated pneumonia occurs in the residents of a nursing facility who have had undergone some sort of procedure in the past 30 days. The causative organisms are similar to community acquired pneumonia, in addition to some other bugs. Typically the symptoms of this type of pneumonia are the same as other types but the elderly may exhibit less prominent signs.
Aspiration Pneumonia occurs in the severely ill, patients suffering from cerebrovascular disorders, and comatose patients etc. who aspirate the gastric contents which causes inflammation of alveoli and aspiration pneumonitis.
What Is Pneumonia? How To Diagnose Pneumonia
Apart from the physical examination, there are some investigations that can help the doctor make a conclusive diagnosis. These investigations include:
-Chest X-ray: patchy consolidation is seen on chest x-ray in case of pneumonia.
-Blood tests: –
These can include a complete blood count (CBC) with ESR, and blood culture. CBC can show an elevated white blood count i.e. the hallmark of bacterial infection. A blood culture can help identify the pathogen in the bloodstream. An arterial blood gas (ABG) sample can help measure the oxygen levels in the blood and help calculate the severity of the disease.
-Sputum culture: identifies the pathogen in the sputum.
-Chest Computed tomography (CT): shows a more detailed picture of the lungs than the chest x-ray.
-Pleural fluid culture: fluid from between the pleural cavity (space between the lungs and chest cavity) is taken out through a needle (a process called thoracocentesis), and analyzed for the presence of pathogens.
-Pulse oximetry: it is a sensor that shows the blood oxygen level when attached to a finger. It is a non-invasive method. It also helps calculate severity of disease.
-Bronchoscopy: is a more invasive approach that is used in severe cases of disease. If the patient is not responding to medication and therapy, a bronchoscopy may need to be performed to look inside the lungs.
Despite the number of investigations that help make the diagnosis of pneumonia, the best predictors of pneumonia diagnosis according to a research are high grade fever (temperature more than 100°F and abnormal breath sounds. Interestingly, the same research shows that about 35% of patients diagnosed with pneumonia had a negative chest x-ray.
Causes Of Pneumonia
The main causative agents of pneumonia are the bugs we discussed above. Strep pneumoniae, h.influenza, staph aureus, legionella, mycoplasma, aspiration of gastric/lower respiratory tract contents, respiratory syncytial virus etc. are what cause the disease. But there are certain other factors that not only make invasion by pathogens possible, but also make the intruders feel at home. Some of these causes include:
- Cerebral palsy
- Cigarette smoking
- Heart disease
- Malignant disease
- Liver disease like cirrhosis
- Chronic lung conditions like cystic fibrosis or COPD
- Living in a nursing home
- Inability to swallow properly, as in stroke patients
- Recent viral infection
- Recent trauma or surgery
- Travelers who spend time in a crowded setting or go to countries where pneumococcal diseases are prevalent
- Immunocompromised patients such as those on steroid medication, cancer patients, patients with autoimmune disorders, diabetics etc.
Treatment Of Pneumonia
As mentioned before, treatment of pneumonia is dependent on the causative agent of disease, as well as the severity of disease. The first question that the clinician asks himself is inpatient or outpatient treatment. For community acquired pneumonia, most people can be treated as out patients. Only those who have severe disease, co-existing illnesses or are at extremes of ages, usually require hospitalization. In-patients are at higher risk of getting hospital-acquired pneumonia, it is therefore very important to justify admitting the patient in the first place.
Bacterial pneumonia: the mainstay of treatment for bacterial pneumonia is antibiotic therapy. Proper duration of antibiotic therapy must be completed to prevent any relapse. Macrolides or doxycycline is given in most cases of CAP.
Viral pneumonia: viral illnesses do not respond to antibiotics. Moreover, viral pneumonia is usually milder and of shorter duration. Sometimes viral pneumonia is self-limiting, and gets better in 1 to 3 weeks. However, in some cases taking an antiviral may become necessary.
Fungal/atypical or severe pneumonia: patients with severe symptoms may need aggressive treatment and hospital care. Intravenous antibiotics, or oxygen therapy may be needed to provide relief to the patient. Sometimes ICU care may also be needed to provide ventilatory support, depending on the severity of disease.
Proper medical care and treatment plan is needed for the treatment of pneumonia.
How Long Does Pneumonia Last?
When it comes to pneumonia, there is no certain time limit that can be given for the patient to recover. Rather, many factors affect the prognostic journey of the patient. Usually it takes as little as 1 to 3 day period for symptoms to appear. Factors which can affect disease duration include:
- Health and age of the patient: naturally those are in better shape, will manage to kick out the bug earlier than the feeble.
- Quick diagnosis
- Immunity of the patient
- Bacterial or viral disease: bacterial pneumonia tends to be more severe than viral.
In the health individuals, pneumonia can clear up with treatment in 1 to 2 weeks. Even then it is not unnatural to feel weak or have some lingering symptoms like cough for the next few weeks. A cohort study in Canada found persistence of symptoms in patients even at 2 and 6 weeks after antimicrobial therapy.
How To Manage Pneumonia
- Get enough rest
- Hydrate, hydrate and hydrate. Drinking water and fluids can help break down and bring out the sticky phlegm so that it no longer damages the delicate air sacs.
- Take the medication as prescribed by the doctor. In case of antibiotic therapy, try to be as regular as possible and not skip a dose.
- Increasing physical activity can help in quick recovery.
- Practicing breathing exercises can improve the lung function
- Vitamin c can help boost the immunity of the body
- In case of fever, an over the counter antipyretic like aspirin or acetaminophen can be helpful. (Aspirin should not be given to children).
- Follow-up care should not be neglected. Do not think that if you have the disease under control, you have managed to get rid of the bug as well. It could easily be hiding in the body, biding its time.
- Avoid contact with other people during the time you have pneumonia. Remember, pneumonia is a contagious disease and giving it to others will probably make you feel worse (unless it’s your arch enemy, in that case feel free to be happy). Coughing, sneezing, not sharing the items of daily use like towels and hand washing can be helpful in limiting the spread of disease.
The Centers for Disease Control And Prevention, has some advice regarding protection from pneumonia:
- Get vaccinated against pneumonia with the fancy Pneumococcal vaccine, the 23-valent pneumococcal polysaccharide vaccine (PPSV23). PPSV23 is particularly recommended for adults aged 65 years and above and also for smokers.
- PCV-13 is the vaccine recommended for children aged 6 to 18 years.
- For children younger than 6, routinely receiving 4 doses of a different pneumococcal vaccine is recommended.
- Vaccination against influenza virus is also beneficial especially for the elderly; studies have shown a decrease of 30-50% in hospitalizations as well as a decrease in mortality, with its use. Every individual receives one flu shot every year in USA.
- Vaccinate against Influenza, in children under 5 years old only or asplenic/sickle cell patients.
- Hand washing, avoiding exposure to people suffering from respiratory infections, covering the mouth and nose while sneezing are also recommended practices.
- Also avoid sharing eating utensils or items of daily use like towels with people who are sick.
Pneumonia During Pregnancy
Pneumonia poses a certain risk to the pregnant mother and child, with increased morbidity and mortality compared to women who are not pregnant. Women with a history of smoking or respiratory disease are particularly susceptible to pneumonia. Even though the presentation of disease is not very different for bacterial pneumonia in the pregnant and non-pregnant individuals, many complications of pneumonia are attributed to delayed diagnosis. One of the reasons of delayed diagnosis is that pregnant women view shortness of breath as a result of pregnancy instead of disease.
Moreover, coexisting anemia and asthma also increase the risk of a pregnant woman getting pneumonia. Even after delivery, the chances of pneumonia are slightly higher due to aspiration.
Community acquired pneumonia remains the commonest pneumonia, even in pregnant women. The choice of antibiotic therapy depends on the severity of disease, the presence of a co-existing illness, and basically the same principle as any other non-pregnant individual.
However, the choice of antibiotic should take into consideration the well-being of the fetus, teratogenicity, toxicity and the excretion of drug in breast milk. Macrolides and Beta-lactam are considered safe for treating CAP in a pregnant woman.
In addition, current respiratory and anti-viral therapies are also helpful in reducing maternal morbidity and mortality. During the flu season, vaccinating the mother with influenza vaccine can also help prevent/shorten the duration of disease.
Pneumonia And Nutrition
According to the American Society for Clinical Nutrition, Zinc deficiency is a serious health problem, especially when it comes to infectious diseases like diarrhea and pneumonia. In a study, it was found that Zinc intake, along with antimicrobial therapy, helped significantly reduce the duration of disease in children, especially those aged more than 6 months.
Probiotic-rich food can also help reduce the duration of disease; a balanced diet with vegetables, grains and lean proteins is recommended. Certain foods like flour, high-fructose corn syrup and artificial sweeteners can have an adverse effect on the inflammatory areas of the body. Vitamin c intake can have a kick-ass effect by improving the immunity of the individual.
Other dietary recommendations for those suffering from pneumonia include the intake of a light meal, which would neither worsen the shortness of breath, nor the cough while swallowing. Broth, egg white, whey and milk are acceptable items. However, starchy and saccharine food should be avoided during the acute attack. The idea should be to provide a nutritive yet easily digestible diet to the patient.