Typical symptoms of lobar pneumonia include fever, chills, cough productive of mucopurulent sputum, and pleuritic chest pain. The absence of fever and mucopurulent sputum makes pneumonia an unlikely diagnosis.

CAP caused by Legionella is commonly associated with high fever (above 40° C), multilobar involvement, male sex, neurologic and gastrointestinal sequelae. However, in older patients, symptoms may be more subtle and may present with only altered sensorium.

Medical history should include identification of risk factors such as HIV and COPD. A detailed occupational history, sexual history, recent travel history and animal exposures should be sought to determine the possible risk factor or mode of contraction of the causative agents of the infection. Legionella pneumonia is commonly associated with patients with a history of prolonged stays in hotels and cruise ships.

On physical examination, the patient, particularly the older ones, may be tachypneic, and tachycardic. Breath sounds are often asymmetric with pleural rubs and egophony. Tales and bronchial breath sounds are also commonly heard on auscultation. Furthermore, there is dullness to percussion in the affected area of the chest, with increased tactile vocal fremitus in the same region. The presence of bronchial breath sounds, pleural rubs, and egophony are highly suggestive of pneumonia, however, their absence doesn't exclude pneumonia.

Workup for pneumonia is essential to determine the level of severity of the disease and the treatment plan to be adopted. There are various diagnostic tools employed in the workup for pneumonia. These tools include the PSI/PORT, CURB 65 and the APACHE systems. PSI/PORT is a joint acronym for pneumonia severity index/patient outcome research team score, CURB-65 is also an acronym for confusion, uremia, respiratory rate, blood pressure, and age >65. These indices are measured and used to categorize the patients into groups of varying disease severity and treatment plans. APACHE stands for Acute Physiology And Chronic Health Evaluation, which takes into consideration several laboratory indices for matching disease severity with the appropriate treatment plans.

Baseline laboratory studies required in the diagnosis of pneumonia include serum electrolytes and urea levels, arterial and venous blood gas analyses, complete blood cell count, serum cortisol, serum lactate and acute phase reactants. An oxygen saturation of 90-92% and a high C-reactive protein are highly suggestive of severe lobar pneumonia.

Leukocytosis with a left shift is typical of bacterial infections, however, its absence does not exclude bacterial pneumonia, particularly in the elderly, as leucopenia may indicate sepsis. A high international normalized ratio (INR) is also suggestive of severe lobar pneumonia. However, it points more to an occurrence of imminent disseminated intravascular coagulopathy (DIC).

Blood cultures may be necessary and are best carried out prior to the administration of antibiotics. However, blood cultures are poorly sensitive for pneumonia, being only positive in 40% of the cases. Blood cultures are more sensitive in patients with a severer disease.

Hyponatremia and microhematuria are typically seen in Legionella pneumonia. Furthermore, in Legionella pneumonia, sputum examination using a Legionella-specific fluorescent antibody may be helpful in confirming the diagnosis. Urine antigen testing of serogroup 1 Legionella spp is very accurate and helpful in the diagnosis of Legionella pneumonia caused by serogroup 2, however, these agents account for very few cases of Legionella pneumonia. Serology is also helpful in the diagnosis: serum antibody titer of at least 1:128 strongly suggests it.

Sputum microscopy and cultures are recommended and should be done before antibiotic therapy. On gram staining, a single predominant microorganism is usually observed, although in lobar pneumonia caused by anaerobes, there could be mixed flora on microscopy. The disadvantage of this test is the contamination of the sample by oral materials, making the test result unreliable.

Transtracheal aspiration is recommended in patients being managed in the intensive care unit (ICU). Airway samples are aspirated for gram stain and culture. However, transtracheal lower airway aspiration has been replaced by fiberoptic bronchoscopy.

Imaging studies help to diagnose lobar pneumonia, but in a few cases, they aid in the identification of the causative organism [5] [6]. Chest radiography is the modality of choice in diagnosing pneumonia. The presence of pulmonary infiltrates confirms the diagnosis and other suggestive findings include pleural effusions and parapneumonic pleural fluid. Although not routinely indicated, the computed tomography (CT) scan may determine the presence of pulmonary infections much earlier than a chest X-ray. CT scans may also be beneficial in diagnosing coexisting pulmonary diseases and complications of lobar pneumonia. Furthermore, high resolution CT scan is indicated if plain radiographs yield inconclusive results.

Management of pneumonia including the site of care is determined by the severity of the disease [7] [8] [9] [10]. The PSI is used to guide inpatient care and to prognosticate the disease. All patients with septic shock complicating lobar pneumonia should be admitted to the ICU where intravenous infusion of vasopressors and mechanical ventilation are instituted to correct the cardiopulmonary compromise. Such patients should be stabilized before being transferred to the ward.

Antibiotics constitute the mainstay of treatment of lobar pneumonia. Supportive therapy comprises the rest of the treatment plan. Patients with complicating bronchospasm need inhaled bronchilators which have been proven to be very effective. Pulmonary toileting and correction of electrolyte derangements are all key supportive therapies.

Oral supplemental oxygen via nasal cannula is required in patients who develop mild dyspnea, however, ventilatory support may become necessary if supplemental oxygen is not adequate. In moderate dyspnea, high oxygen concentrations as provided by venti-mask and face mask are required. These devices are to be used with caution in patients with COPD and hypercarbia, as these patients may need endotracheal intubation and ventilation instead. Continuous positive airway pressure (CPAP) may be employed in cases of recalcitrant hypoxemia. However, non-invasive ventilation should be avoided in patients with productive sputum due to a possible impairment in the clearance of airway secretions.

Intravenous crystalloids are to be administered in patients with hypotension and tachycardia. Aggressive fluid resuscitation should be particularly avoided in individuals at risk of volume overload, such as those with comorbid cardiac disease.

Broad spectrum antibiotics are preferred for empirical therapy. However, it should be noted that even with aggressive antibiotic therapy, the mortality rate remains at about 40% in those older than 80 years. There is a general treatment rule which suggests that antibiotic treatment must be commenced within four hours of the patient's arrival at the hospital. Initiating antibiotic treatment after 4 hours after the patient's presentation is associated with a poor prognosis. The patterns of multi-drug resistant organisms in the institution should be determined and should guide antibiotic therapy in cases of hospital-acquired and ventilator-acquired lobar pneumonia. Early mobilization of patients is necessary, as it speeds up the resolution of symptoms.

Uncomplicated pneumonia in otherwise healthy patients doesn't carry significant mortality. Poor prognostic factors for lobar pneumonia include advanced age, respiratory failure, sepsis, neutropenia, comorbid conditions, and the presence of aggressive pathogens such as Klebsiella, Legionella, and S. pneumoniae. If untreated, lobar pneumonia carries a significant general mortality rate of over 30% [4].

Complications of lobar pneumonia include destruction and scarring of the lung parenchyma, respiratory failure, bronchiectasis, empyema, and lung abscess. Lobar pneumonia is also associated with an increased risk of abruptio placentae in gravid patients.

Lobar pneumonia can be caused by lots of agents, however, most cases are caused by a few of these agents. Bacterial causes are the commonest etiological factors responsible for lobar pneumonia. Examples of bacterial causes of lobar pneumonia include Haemophilus influenzae, Klebsiella spp, Staphylococcus spp, Legionella spp, and Streptococcus pneumoniae. These agents may follow a hematogenous spread pattern or infect the lobes by aspiration.

The risk factors for lobar pneumonia include a viral respiratory tract infection and especially an influenza infection. These increase the risk of a secondary bacterial lower respiratory tract infection causing lobar pneumonia. In such cases, S. pneumoniae is the most likely causative agent. Other risk factors include chronic lung diseases such as pulmonary malignancies, bronchiectasis, and chronic obstructive pulmonary disease (COPD). Oral and dental infections also predispose to lobar pneumonia.

Additionally, individuals with an altered mental status due to seizures, drug toxicity, or raised intracranial pressure would have a complicating impaired gag reflex. This, in turn, allows for the aspiration of gastric and oropharyngeal contents, which predispose to aspiration pneumonia.

Acute lower respiratory tract infections are the most frequent infective causes of death in the United States. This group of infections is also associated with a greater morbidity than any other disease worldwide. However, there are statistical variations in the prevalence of the disease and the causative pathogens between countries and geographic regions, thereby limiting data on worldwide epidemiological studies of the disease.

Pneumonia is more common during the winter months and in colder climates. Often, the initial disease is a viral respiratory tract infection which in cold climates. Subsequently, the viral respiratory tract infection becomes superimposed by a bacterial infection.

The commonest cause of community-acquired pneumonia (CAP) is S. pneumoniae, and respiratory viruses are the least common. However, between these extremes, other pathogens are to be encountered, such as M. pneumoniae, H. influenzae, and C. pneumoniae. Ventilator-associated pneumoniae (VAP) occurs in 9-27% of all intubated patients. VAP carries significant morbidity and a high mortality rate at 30-60%.

Mortality from lobar pneumonia is more common among patients of African descent than Caucasian patients. The mortality rate in men of African descent is approximately 26.6 deaths per 100,000 people while the rate in Caucasian women is approximately 23 deaths per 100,000 people.

Although lobar pneumonia is much more common in male than female individuals, pneumonia in women has been associated with a greater number of deaths from the infection. However, age-adjusted mortality rates in higher in men than women.

For individuals aged 65 years old and above, pneumonia and influenza were identified as the sixth commonest cause of deaths recorded in 2005. Furthermore, almost 90% of the deaths from pneumonia occurred among those within this age group. In the United States, a study that analyzed the epidemiology of pneumonia for a period of 20 years revealed that the highest mortality rate of pneumonia occurred in individuals older than 80 years.

Lobar pneumonia progresses in four stages:

1. Congestion: This stage occurs during the first 24 hours of the infection and it is characterized by vascular engorgement, mild neutrophil influx to the lungs, and intra-alveolar fluid, making the lung grossly heavy. The lungs also appear hyperemic at this stage.
2. Red hepatization or consolidation: This stage is characterized by a persistence of the congestion and flow of red blood cells out of the blood vessels into the alveolar sacs. There is also an exudation of neutrophils and fibrin into the air spaces, giving the lungs an appearance of consolidation or solidification. This appearance resembles that of the normal liver, hence it is described as "hepatization".
3. Gray hepatization: At this stage, there is lysis of the red blood cells, but with persistence of the neutrophil exudation and fibrin deposition in the air sacs. While the lung parenchyma is still consolidated at this stage, it appears paler, hence described as "gray" hepatization.
4. Resolution: This is the stage of complete recovery whereby enzymatic activities digest the exudates; the latter may be cleared by the macrophages and drained by the lymphatic system or expectorated by the cough mechanism.

Preventive measures against pneumonia include smoke cessation, avoiding passive smoking, receiving the influenza shot on a yearly basis, proper hand washing, and avoiding crowds in flu seasons.

Lobar pneumonia is an acute pulmonary inflammation localized to one or more lobes. It is characterized by radiographic evidence of fibrinosupparative consolidation of the lungs in response to a bacterial invasion. Lobar pneumonia is also known as non-segmental or focal non-segmental pneumonia.

Bacteria are the most common causes of lobar pneumonia with Streptococcus pneumoniae being the most common cause of lobar pneumonia [1] [2] [3]. Risk factors for the disease include preexisting chronic lung diseases, viral upper or lower respiratory tract infections, and aspiration pneumonitis.

Lobar pneumonia presents with fever, cough productive of mucopurulent sputum, dyspnea, and pleuritic chest pain. Diagnosis of lobar pneumonia is best made with a chest X-ray which could demonstrate typical or pathognomonic findings for certain organisms. Generally, chest X-rays in lobar pneumonia reveal a nonsegmental and homogeneous consolidation of one or more lobes. Homogeneous lobar opacities with air bronchograms are classic findings in lobar pneumonia caused by S. pneumoniae. Other baseline laboratory investigations such as serum electrolytes, urea, and lactate levels are necessary.

The mainstay of treatment of lobar pneumonia is an antibiotic therapy, which is augmented by supportive treatment including oxygen administration, fluid resuscitation, and pulmonary toileting.

The lungs are divided into lobes, each of which is further divided into segments, and then into divisions. Each lobe represents a unique area of the lung, receiving blood and oxygen from a different set of vessels from the others, however all the vessels come from a main trunk. Lobar pneumonia is an inflammation of the lungs, affecting only a lobe and not the whole organ. Sometimes, it could affect more than one lobe.

Lobar pneumonia is mostly caused by germs called bacteria with a certain type, called Staphylococcus pneumoniae, being the commonest cause. Individuals with colds or severe diseases of the lungs are at risk of lobar pneumonia. The hallmark of this disease is the thickening of the lungs, which is medically termed consolidation.

Cough, which is usually productive of a foul-smelling sputum that may appear green, brown, or white, high fever, chest pain, and difficulty in breathing are classic findings of lobar pneumonia. Some patients may also present with fast heart rates.

The diagnosis of lobar pneumonia can be made by taking a chest X-ray of the patient. Other basic investigations include a complete blood cell count and tests for antibodies against specific bacterial organisms. The chest X-ray could reveal certain features which suggest some organisms as the cause of the condition.

Antibiotics are the mainstay of treatment of lobar pneumonia, however, doctors ensure that they determine the risk factors for the disease in that particular individual to determine the best course of antibiotics to be prescribed. Other aspects of the treatment include the administration of oxygen, drainage of the airway mucus, and ventilatory support in those who have severe difficulties in breathing.

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