Streptococcus pneumoniae



OVERVIEW

Definition.

Acute inflammation of the lungs due to opportunistic invasion of the respiratory tract by Streptococcus pneumoniae.

Pathogenesis

Streptococcus pneumoniae is the common causative agent in community-acquired pneumonia in adults in this country.

The annual incidence of Streptococcus pneumoniae pneumonia in the United States is approximately 68/100,000 to 260/100,000, and there is a lack of epidemiologic data in this country.

Causes

Causes

Streptococcus pneumoniae infection

Streptococcus pneumoniae is a normal parasitic bacterium in the human body and can be isolated from the nasopharynx of some healthy people.

When the host’s immune function is impaired, Streptococcus pneumoniae colonizing the host’s nasopharynx can opportunistically invade the respiratory tract and cause acute inflammation of the lungs.

Predisposing Factors

The following factors can induce impaired host immune function and cause Streptococcus pneumoniae pneumonia.

Exposure to cold and rain.

Alcohol abuse, fatigue.

Upper respiratory tract infection.

Risk factors

People with the following risk factors are susceptible to Streptococcus pneumoniae.

Children under 2 years of age and people over 65 years of age.

Malnourished people.

Underlying diseases such as diabetes mellitus, liver cirrhosis, renal insufficiency, malignant tumors, leukemia, uremia, and AIDS.

Long-term use of glucocorticoids or immunosuppressants, undergoing radiotherapy.

Granulocyte deficiency or dysfunction.

Organ transplant patients, alcoholics.

Symptoms

Main Symptoms

High fever, chills

Obvious high fever and chills may occur, and the body temperature may be as high as 39～40℃.

The peak of body temperature is often in the afternoon or evening, mostly in the form of fever, and the pulse rate increases with the rise of body temperature.

Cough and sputum

Cough is more frequent.

Often accompanied by coughing up sputum, there may be rust-colored sputum or blood in the sputum.

Chest pain

Chest pain may be present on the affected side.

Chest pain may radiate to the shoulder or abdomen.

Chest pain may worsen with coughing and deep breathing.

Prodromal symptoms

Symptoms of upper respiratory tract infection such as generalized body aches and nasal congestion often precede the onset of the disease.

Other symptoms

Gastrointestinal symptoms such as nausea, vomiting, abdominal pain, poor appetite, and diarrhea may occur.

In severe cases, symptoms of infection poisoning such as drowsiness, irritability, convulsions and shock may occur.

Complications

Streptococcus pneumoniae may lead to the following complications.

Septicemia, infectious shock

Streptococcus pneumoniae can enter the blood circulation after infecting the lungs, causing systemic infection and leading to septicemia, which can lead to infectious shock in severe cases.

Patients may have high fever that does not go away, decreased blood pressure, wet and cold extremities, little or no urine, consciousness disorder, convulsions and other manifestations.

It can further induce dysfunction of multiple vital organs such as heart, liver, kidney, etc., leading to multi-organ failure threatening the patient’s life.

Pseudothorax

About 5% to 10% of patients with Streptococcus pneumoniae may be complicated by pyothorax.

The patient may have high fever and worsening dyspnea.

Extrapulmonary infection

About 10% to 20% of patients with Streptococcus pneumoniae may enter the blood circulation through lymphatic vessels and thoracic ducts, causing symptoms of infection in other parts of the body outside the lungs, such as meningitis, otitis media, pericarditis, endocarditis, arthritis, and so on.

Depending on the site of infection, symptoms such as dizziness, headache, impaired consciousness, convulsions, earache, vertigo, palpitations, dyspnea, and joint pain may occur.

Consultation

Department of Medicine

Respiratory Medicine

When the patient develops fever, cough, sputum, chest pain, etc., it is recommended to consult a doctor promptly.

Pediatrics

Patients under the age of 14 may consult the Department of Pediatrics when they develop the above symptoms.

Emergency Department

When the patient develops persistent high fever, chills, dyspnea, cyanosis, clammy extremities, impaired consciousness, shock, etc., it is recommended to consult the Emergency Department or call 120 emergency immediately.

Preparation for medical treatment

Preparation for medical consultation: registration, preparation of information, common problems

Tips for seeking medical treatment

Physical cooling, such as warm water baths, can be used to reduce fever before seeking medical treatment, and self-medication is generally not recommended.

If you have fever, monitor your body temperature and keep a record of it.

Preparation checklist for seeking medical treatment

Its need to pay attention to the time of onset of symptoms, special performance, etc.

Are there any symptoms such as coughing and phlegm? If so, what is the nature of the phlegm?

Are there any symptoms such as fever, chills, etc., and what is the highest body temperature? Is there a pattern of temperature change?

Is there any chest pain, shoulder or back pain, abdominal pain, etc.?

Are there any gastrointestinal symptoms such as nausea, vomiting, abdominal pain, poor appetite, diarrhea, etc.?

Is there dyspnea, cyanosis, clammy extremities, impaired consciousness, shock, etc.?

How long have these symptoms been present?

Are there any underlying diseases such as diabetes mellitus, cirrhosis of the liver, renal insufficiency, malignant tumors, leukemia, uremia, AIDS, etc.?

Are there any respiratory diseases such as chronic bronchitis, bronchial asthma, chronic obstructive pulmonary disease, bronchiectasis, etc.?

Are there any long-term use of glucocorticoids, immunosuppressants and other drugs?

Any cold, rain, fatigue, intoxication, etc. before the onset of illness?

Examination results in the past six months, which can be brought to the doctor’s office.

Imaging tests: chest radiograph, chest CT, etc.

Laboratory tests: blood routine, C-reactive protein, etc.

Medication in the last 3 months, if available in boxes or packages, bring with you to the doctor’s office

Antibiotics: e.g. levofloxacin, cefaclor, etc.

Expectorant drugs: e.g. Ambroxol, Bromhexine, etc.

Antipyretics and analgesics: e.g., ibuprofen, acetaminophen, etc.

Diagnosis

Diagnostic basis

The diagnosis of Streptococcus pneumoniae is mainly based on the history, signs and auxiliary examinations, among which the bacteriologic examination is the basis for confirming the diagnosis.

Medical history

It occurs in children, the elderly, and people with immunocompromised immunity, such as those with underlying diseases and long-term use of glucocorticoids and immunosuppressants.

Clinical manifestations

The onset of the disease is often preceded by cold, rain, fatigue, alcoholism, upper respiratory tract infection and other triggers.

Symptoms such as high fever, chills, cough, rust-colored sputum or bloody sputum, chest pain, generalized body aches and pains are often present.

There may be nausea, vomiting, abdominal pain, poor appetite, diarrhea and other digestive symptoms.

Early lung signs are not obviously abnormal.

With the progression of the disease, lung auscultation may have weakened respiratory sounds, and wet rales and pleural friction sounds may be heard. When solid lung lesions appear, there may be turbidity of lung percussion, increased palpation tremor, and bronchial breath sounds may be heard.

Fever is often accompanied by increased heart rate, sometimes with arrhythmia. Acute febrile face may appear: burning, dry skin, scarlet cheeks, flaring nose, herpes simplex at the corners of the mouth and around the nose.

Some patients may have signs of epigastric tenderness, and in severe cases, intestinal distension may manifest.

Combined with septicemia, patients may have skin and mucous membrane hemorrhagic spots, and sclera yellow stain.

When combined with infectious shock, there may be a drop in blood pressure, cold and wet extremities, mental depression and other manifestations.

Chest imaging

Chest X-ray and chest CT are commonly used, which are the preferred examinations and are important for the diagnosis of Streptococcus pneumoniae.

In the early stage of the disease, only the thickening of lung texture or the blurring of the affected lung segments and lobes is often seen.

With the progression of the disease, chest imaging may show a large inflammatory infiltrate shadow or solid shadow in the lungs, and bronchial insufflation may be seen in some of the solid shadows, and a small amount of pleural effusion may be seen in some patients.

Laboratory tests

The presence and severity of infection can be assessed.

Leukocytes are often elevated, and the percentage of neutrophils is often increased to more than 80%, which may be accompanied by a leftward shift of the nucleus.

In immunocompromised patients, the blood count may not be high in leukocytes, but the neutrophil percentage usually remains elevated.

A decrease in the total number of leukocytes is indicative of severe disease.

Serum C-reactive protein values tend to rise.

Calcitoninogen may be elevated and may fall rapidly when anti-infective therapy is effective.

It can clarify what kind of pathogenic bacteria the patient is infected with, which is important for the diagnosis of Streptococcus pneumoniae pneumonia.

If the sputum smear sees typical Gram-staining-positive, pod-bearing diplococci or streptococci, a preliminary pathogenetic diagnosis can be made.

Collect sputum, alveolar lavage fluid, pleural effusion, pus or blood specimens, etc., and conduct bacterial culture for 24-48 hours to determine the pathogen.

Polymerase chain reaction (PCR) and fluorescent-labeled antibody testing can improve the rate of pathogenic diagnosis.

The presence of respiratory failure, acid-base imbalance, and electrolyte disorders can be known.

The severity of the patient’s condition can be assessed.

Respiratory failure, acidosis, and electrolyte disorders may be present in severe cases.

Differential Diagnosis

Streptococcus pneumoniae needs to be differentiated from acute bronchitis, cough variant asthma, tuberculosis, bronchial foreign bodies, pulmonary embolism, and pneumonia due to other pathogens:

Acute bronchitis

Similarities: both can lead to cough and sputum symptoms.

Differences:

Acute bronchitis patients have no fever or only low fever, good general condition, cough mainly dry cough, some patients can cough a small amount of sputum, the lungs can be heard wet and dry rales, mostly not fixed. Chest imaging may show enhanced lung texture.

Streptococcus pneumonia patients have high fever, accompanied by chills, in addition to coughing often cough rust-colored sputum or blood sputum, lung auscultation can be heard wet rales, chest imaging can be seen in the lungs of a large inflammatory infiltrate shadow or solid shadow.

Tuberculosis

Similarity: Both can cause cough and fever.

Differences:

Patients with tuberculosis usually have a history of tuberculosis-related exposure, mostly low-grade fever, which often occurs in the late afternoon, accompanied by night sweats, unremarkable lung rales on auscultation, tuberculosis foci in the lungs on chest imaging, a positive tuberculin test, and mostly normal blood tests.

Patients with Streptococcus pneumoniae have high fever, accompanied by chills, coughing rust-colored sputum or bloody sputum in addition to coughing, and wet rales can be heard on lung auscultation, and chest imaging shows large inflammatory infiltrate shadows or solid shadows in the lungs.

Pulmonary embolism

Similarity: Both can cause chest pain, dyspnea, hemoptysis and other symptoms.

Differences:

Patients with pulmonary embolism usually do not have fever, dyspnea symptoms are more obvious, lung auscultation can be heard on the affected side of the decreased breath sounds, chest imaging can be seen embolic foci in the lungs, D-dimer examination is often elevated.

Patients with Streptococcus pneumoniae have high fever, accompanied by chills, coughing rust-colored sputum or blood sputum in addition to coughing, lung auscultation can be heard wet rales, chest imaging can be seen in the lungs of a large inflammatory infiltrate shadows or solid shadows. d-dimer may not be high.

Pneumonia caused by other pathogens

Similarity: Both of them can cause fever, cough, sputum and other symptoms, and inflammatory exudation in the lungs is common on chest imaging.

Differences: It is sometimes difficult to differentiate pneumonia caused by different pathogenic bacteria only based on the history, physical signs and imaging manifestations, and pathogenetic examination is of great value in differentiating pneumonia caused by different pathogenic bacteria.

Treatment

Aim of treatment: control the infection as soon as possible, improve the ventilation function, and at the same time, protect the function of important organs and prevent complications.

Principle of treatment: drug treatment is the mainstay, at the same time with oxygen, nutritional support and other symptomatic supportive therapy for comprehensive treatment, if necessary, surgery.

General treatment

Rest

In the acute stage, bed rest should be provided and activities should be reduced.

Oxygen therapy

For arterial oxygen partial pressure less than 60mmHg or cyanosis in the middle and severe patients need oxygen.

Low-flow oxygen is the mainstay, and it is advisable to maintain the patient’s oxygenation above 90%.

Patients with severe respiratory failure may be mechanically ventilated.

Airway management

Remove oral and nasal secretions in time, and suction sputum when necessary to keep the airway open and improve ventilation.

Nebulized inhalation can be given to humidify the airway and promote sputum elimination.

If necessary, tracheal intubation is feasible to facilitate the removal of sputum.

Maintaining water-electrolyte balance

Encourage drinking 1～2L of water per day.

Intravenous rehydration can be given if necessary to maintain stable water electrolytes.

Nutritional support

Supplement sufficient protein, vitamins and calories.

Patients who have difficulty in eating can be given parenteral nutrition support.

Fasting and drinking

Some patients with severe infection may have paralytic intestinal obstruction, and should be forbidden to eat and drink temporarily.

Gastrointestinal decompression can be given to these patients if necessary.

Medication

Antibiotics

Effective antibiotics should be used to control the infection as soon as possible and in sufficient quantity. Initially, they can be chosen empirically, and sensitive antibiotics should be used immediately after culture results are obtained.

Penicillin is preferred, and those who are allergic to penicillin or infected with penicillin-resistant strains can choose drugs such as levofloxacin, moxifloxacin, cefotaxime and ceftriaxone.

Patients infected with multi-drug-resistant strains can choose vancomycin, linezolid and other sensitive drugs according to the results of drug sensitivity.

Expectorant drugs

They can dilute the sputum of patients and promote the discharge of sputum.

Commonly used are Ambroxol, Bromhexine, Acetylcysteine and so on.

Antipyretic and analgesic drugs

Non-steroidal drugs can be used to control the patient’s body temperature when the temperature is more than 38.5℃, and these drugs have analgesic effect, which can relieve the patient’s chest pain symptoms.

Commonly used are ibuprofen, acetaminophen and so on.

Glucocorticoid

Glucocorticosteroids can reduce the morbidity and mortality of patients with severe pneumonia combined with infectious shock, and hydrocortisone succinate is recommended.

Surgery

Pleurodesis or closed chest drainage

When pyothorax develops or when pleural effusion is high.

When pus is low, pleurodesis is indicated to extract the pus.

If there is more pus or pleural effusion, it is advisable to perform closed pleural drainage to drain the pus and effusion adequately.

Presence of coagulation dysfunction, bleeding tendency, when it has not been corrected.

Poor general condition, critical condition, unable to tolerate puncture surgery.

Allergy to anesthetic drugs.

Presence of infection in the operative area or nearby skin.

Presence of mental illness or uncooperative individuals.

Prognosis

Cure

The overall prognosis is favorable.

Younger patients, patients without underlying disease, and mildly ill patients are most likely to be cured with early and aggressive treatment.

Elderly, immunocompromised people and severely ill patients may develop severe complications such as sepsis and infectious shock, which can be life-threatening in severe cases.

Daily

Daily Management

Dietary management

Eat as little or no spicy food as possible, such as chili, mustard, pepper, etc., so as not to irritate the respiratory tract and aggravate the symptoms of cough and phlegm.

Eat as little or no greasy food as possible, such as animal offal, fatty meat, fried food, so as not to aggravate the burden on the stomach and intestines and affect the digestive function.

You can eat fluid or semi-fluid diet rich in high quality protein and vitamins, easy to digest, such as lean meat, fresh fruits and vegetables, etc. You can drink more water as appropriate.

Life management

Keep indoor air circulation.

Ensure sufficient rest.

Disease monitoring

If the patient has received surgical treatment such as thoracocentesis, closed chest drainage, etc., pay attention to ensure that the wounds and dressings are clean and dry after the operation, and pay attention to observing whether the drainage tubes are open, the amount and nature of the drainage material, etc.

Pay attention to the change of condition. If there is persistent high fever, dyspnea, cyanosis, depression, wet and cold extremities, etc., consult a doctor immediately.

Follow-up examination

Regular follow-ups as prescribed by the doctor can detect and treat recurrence of pneumonia and complications in time and improve the prognosis.

Review of routine blood tests, C-reactive protein, calcitoninogen, chest imaging and other tests will help to understand the changes in the condition of the patient.

Prevention

Strengthening immunity, reducing risk factors, practicing good hygiene and timely vaccination are effective measures to prevent Streptococcus pneumoniae.

Strengthen immunity and reduce risk factors

Pay attention to balanced diet and nutrition, and live a regular life.

Take appropriate physical exercise to enhance immunity.

Quit smoking and avoid excessive alcohol consumption.

Add more clothes to keep warm when the weather gets cooler to avoid getting cold.

Adopt good hygiene habits

Pay attention to maintaining oral hygiene to avoid bacterial chance to cause disease.

Wear a good mask when you go out in spring and winter, take good personal protection and avoid going to places where people gather.

Timely vaccination

Those who are older than 65 years old can receive influenza vaccination to prevent influenza.

Pneumococcal vaccine is available for those who are older than 65 or younger than 65 but have cardiovascular disease, pulmonary disease, diabetes, alcoholism, cirrhosis of the liver and immunosuppression.