OVERVIEW
Streptococcus pneumoniae is the normal flora of the human nasopharynx, and can cause invasive disease when the body’s immunity is reduced or when new serotypes are acquired. Streptococcus pneumoniae septicemia can be secondary to Streptococcus pneumoniae pneumoniae, otitis media, mastoiditis, pharyngitis, most of the germs from the lungs through the drainage lymphatic pathway through the thoracic duct into the bloodstream, otitis media and mastoiditis, then the Streptococcus pneumoniae can be entered into the bloodstream through the venous sinus, Streptococcus pneumoniae pneumoniae pneumoniae in patients, 20%-30% of the blood culture is positive, and the rate of positivity with the increase of age. The higher incidence in splenectomized patients may be related to the strong phagocytosis and killing of podoconiotic Streptococcus pneumoniae by the mononuclear-phagocytic cell system of the spleen. Patients with other pre-existing severe diseases (e.g., sickle cell anemia and immunocompromised) are susceptible to Streptococcus pneumoniae sepsis.
Etiology
This bacterium is S. pneumoniae. In normal people, although the nasopharynx carries bacteria, but most do not develop, because the cilia of the tracheal mucosa, and the macrophages in the alveoli can remove the invading bacteria; but when the body’s defense function is reduced, the bacteria to colonize, reproduction of the pathway caused by the inflammatory reaction of the local tissues, resulting in the lungs out of the reality of degenerative lesions, such as the bacteria into the bloodstream, then cause sepsis.
Symptoms
Sepsis is the main manifestation. Only when the systemic immune function is seriously impaired can sepsis be caused by this bacterium. For example, patients with malignant tumors of the lymphatic system, liver and kidney failure, splenectomy, and human immunodeficiency virus (HIV) infection; all organs of the body can be attacked and inflammation can occur, and pneumonia, meningitis, pericarditis, osteomyelitis, peritonitis, etc. can occur. Patients may have chills, high fever, headache, generalized pain, nausea, vomiting, irritability, delirium, lethargy, coma. Manifestations of circulatory failure, such as rapid heart rate, weak pulse, cyanosis of lips and fingers, decreased blood pressure, and decreased urine output, may also be present. If there are migratory lesions, such as meningitis and osteomyelitis, the corresponding clinical manifestations may occur.
Examination
1. Blood picture
In systemic infection, blood leukocytes can be significantly increased up to (20-30)×109/L, and neutrophils account for 0.9. In the elderly and immunocompromised patients, the increase of leukocyte count is not obvious, but the classified neutrophils still account for more than 0.8.
2. Bacteriologic examination
Gram stained smear of secretions (e.g. sputum, pus, cerebrospinal fluid) from the patient’s suppurative lesion should be used to find bacteria, and bacterial culture should be done, and blood culture should be done for febrile patients. Acquisition of Streptococcus pneumoniae is the basis for diagnosis.
3. Cerebrospinal fluid examination
The CSF of patients with meningitis shows purulent changes, the appearance is like rice soup, the protein is often more than 1g/L, the leukocytes are more than 500×106/L, multinucleated predominates, and the sugar and chloride are reduced.
4. Immunologic examination
Detection of podoplanet polysaccharide antigen in serum and CSF by latex agglutination test or convection electrophoresis is helpful for the diagnosis of those with negative bacterial culture.
5. X-ray examination
Chest X-ray should be done in those with lung infection. At the beginning, there are only thickening of lung texture and localized faint infiltration images, which can be easily overlooked by fluoroscopy and should be examined by film. Lobar solid changes can be seen after lobar or segmental patchy dense shadow. Translucency increases during the dissipation phase. It takes 2-3 weeks for the shadow to completely dissipate.
Diagnosis
Clinical manifestations and blood changes of pneumonia, meningitis and sepsis caused by Streptococcus pneumoniae infection, results of routine examination of cerebrospinal fluid (CSF), and chest radiographs of patients with pneumonia are not specifically different from those caused by other septic bacteria, so the diagnosis is determined on the basis of the results of bacteriologic examination, especially the results of bacterial culture. If possible, bacterial culture should be performed before antibiotic treatment.
Treatment
1. Symptomatic treatment
For severe cough, expectorant and cough suppressant can be used, such as expectorant spirit, loquat lozenges, compound licorice, etc.; for hypoxia, oxygen inhalation should be given; for hyperthermia, physical cooling can be used appropriately; for meningitis, the main attention should be paid to the prevention and treatment of cerebral edema, and 20% mannitol can be used to drip intravenously; for septic shock, the blood volume should be replenished actively and acidosis should be corrected.
2.Antibiotic treatment
Penicillin is still the first choice in China. Hospitalized patients with pneumonia can be injected with penicillin, and the drug can be stopped after 3 days of fever reduction. If the effect is not good, can be changed to cephalosporin antibiotics. For those who are allergic to penicillin, erythromycin can be used. Meningitis patients need to apply high-dose penicillin intravenous drip. In severe cases, chloramphenicol can be used in combination with intravenous drip. If the effect is not good, the third generation of cephalosporins can be used, such as ceftriaxone sodium, cefotaxime sodium, injected intravenously in divided doses. In case of sepsis, the combination of two antibiotics should be used, for example, penicillin and cefotaxime sodium combined. β-lactams and macrolides combined treatment can reduce the morbidity and mortality of Streptococcus pneumoniae sepsis.