pneumonic plague



OVERVIEW

Definition

Plague is a natural epidemic disease caused by Yersinia pestis (plague bacillus), pneumonic plague is a kind of plague, others also include adenomatous plague, septicemic plague and so on.

Pneumonic plague is highly contagious, with a high case fatality rate, it is one of the most serious virulent infectious diseases endangering human beings, and it is an international quarantine infectious disease.

Types

According to the different ways of infection, pneumonic plague can be divided into primary and secondary types.

Primary pneumonic plague

Mostly caused by inhalation of droplets containing plague bacilli, it is the most serious clinical type, with a high case fatality rate and the greatest epidemiological harm.

Secondary pneumonic plague

It is caused by the progression of the disease to the lungs on the basis of adenomatous plague and septicemic plague.

Incidence

Pneumonic plague tends to be endemic after October.

Plague is a natural epidemic disease, and its natural sources are distributed in more than 60 countries and regions in Asia, Africa and America. Twelve types of natural sources of plague exist in China [1].

Causes

Pathogenesis

It is mainly caused by Yersinia pestis infection, and the basic conditions leading to the epidemic are the following three aspects.

Source of infection

Animals naturally infected with plague can serve as a source of infection (according to statistics, there are more than 300 species in the world), most notably rodents, such as rats and dryads.

Patients with pneumonic plague are infectious in the early stages of the disease.

Septicemic plague, glandular plague patients whose adenomas have broken down can also be used as a source of infection.

Transmission pathway

Through flea bites.

Transmission by droplet, pneumonic plague patients or animal respiratory secretions contain a large number of plague bacilli, through breathing, coughing plague bacilli into the surrounding air, the formation of bacterial particles and aerosols, resulting in the spread of pneumonic plague.

Laboratory infection, plague laboratory workers due to poor protection, improper operation and laboratory accidents, can be infected with pneumonic plague through inhalation and other ways.

Susceptible people

The population is generally susceptible.

Symptoms

Main symptoms

Primary pneumonic plague

The incubation period is short, about 1-3 days.

The main manifestations are acute onset of illness, chills, high fever, body temperature up to 40~41℃, and increased respiratory rate.

Initially, there may be dry cough, followed by coughing up thin foamy sputum, there may be blood in the sputum or coughing up pure blood sputum.

There may be facial flushing, conjunctival congestion, lips, face, limbs and the whole body skin cyanosis.

If effective treatment is not given in time, the patient mostly dies of toxic shock, respiratory failure and heart failure after 2~3 days.

Secondary pneumonic plague

Before the onset of the disease, there are symptoms of adenomatous plague or septicemic plague, such as enlarged lymph nodes in the infested area, severe pain, high fever, confusion, and extensive bleeding.

When secondary pneumonic plague occurs, it often manifests as a sudden worsening of the condition, with coughing, chest pain, dyspnea, and coughing up bright red foamy blood sputum.

Consultation

Department of Medicine

Department of Infectious Diseases

If you have traveled to a plague-endemic area or come into contact with a confirmed plague patient and have symptoms such as fever, cough, coughing up bloody sputum, chest pain, enlarged lymph nodes, and subcutaneous hemorrhage, it is recommended that you consult a doctor promptly.

Emergency Department

When there are emergencies such as high fever convulsions, respiratory distress, blurred consciousness, massive hemoptysis, etc., it is recommended to consult the Emergency Department immediately.

Preparation for medical treatment

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

Tips for seeking medical treatment

Before seeking medical treatment, patients with high fever can first use physical cooling, such as applying cold compresses to the forehead and wiping the armpits, hands and feet with warm water.

Wear a mask and avoid crowded places.

Preparation checklist for seeking medical treatment

In particular, you need to pay attention to the time of onset of symptoms, special manifestations, etc.

Is there fever? What is the highest temperature?

Is there cough, sputum, hemoptysis?

Are there swollen lymph nodes in the groin, armpits, etc.?

Are there any subcutaneous hemorrhages, nosebleeds, etc.?

When did the above symptoms appear?

Any history of close contact with plague patients?

Do you have a history of living in a plague-endemic area?

Have you been in contact with plague-infected animals, such as rats and otters?

Any flea bites?

Any history of food or drug allergy?

Test results in the past month, which can be brought to the doctor’s office.

Laboratory tests: blood test, blood biochemistry, coagulation function, etc.

Imaging tests: Chest X-ray, Chest CT, etc.

Medications used in the last 1 month, you may bring the box or package with you to the doctor if available

Antipyretic and analgesic drugs: ibuprofen, acetaminophen, etc.

Anti-infective drugs: streptomycin, doxycycline, etc.

Diagnosis

Diagnosis is based on

Medical history

The following history of pneumonic plague may be present within 10 days prior to the onset of the disease.

A visit to a plague-endemic area.

History of close contact with plague-affected animals or plague patients.

History of flea bites.

Clinical manifestations

There may be chills, high fever, shortness of breath, chest pain, blood in the sputum or coughing up pure blood sputum, conjunctival congestion, cyanosis of the lips, face, limbs and skin of the whole body.

When the doctor examines the body, the lungs can be detected by percussion with limited turbidity, and the turbidity boundary gradually expands with the aggravation of the disease. Scattered rales may be detected on auscultation of the lungs [1].

On cardiac examination, the physician may find enlarged heart borders, arrhythmia, and sometimes a systolic murmur.

Laboratory tests

The total number of peripheral blood leukocytes may be elevated, often above (20-30) × 109/L, with neutrophils predominating; a decrease in erythrocytes, hemoglobin, and platelets may also be seen.

The examination of alanine aminotransferase (ALT), azalea transaminase (AST), lactate dehydrogenase (LDH), phosphocreatine kinase (CK/CK-MB), creatinine (Cr), urea nitrogen (BUN) and other indexes can be carried out, which can understand the degree of hepatic and renal function and myocardial injury.

When accompanied by liver function injury, there may be ALT, AST and other elevations; when accompanied by kidney function injury, there may be Cr, BUN and other elevations; when accompanied by myocardial injury, there may be CK, CK-MB and other elevations.

When diffuse intravascular coagulation (DIC) occurs, it can be manifested as a decrease in the concentration of fibrinogen, a significant prolongation of prothrombin time, and a significant increase in D-dimer and fibrinogen degradation products.

Detection of plague-specific genes by polymerase chain reaction (PCR) method.

Isolation and culture of plague bacteria and phage lysis test.

Reverse phase indirect hemagglutination test (RHIA) for plague F1 antigen.

Enzyme-linked immunosorbent assay (ELISA) for detection of plague F1 antigen.

Colloidal gold chromatographic method on paper for the detection of plague F1 antigen.

Indirect hemagglutination test (HIA) for detection of Plague F1 antibody.

Enzyme-linked immunosorbent assay (ELISA) for detection of Plague F1 antibody.

Colloidal gold chromatography on paper for detection of plague F1 antibody.

Imaging

Chest X-ray and chest CT.

In the early stage, single or multiple high-density shadows can be seen in the lungs, distributed in multiple lobes; as the disease progresses, it can rapidly develop into a large solid lesion in both lungs, or even “white lungs”.

Differential diagnosis

Pneumonic plague needs to be differentiated from lobar pneumonia and inhalation anthrax. The differentiation is mainly based on the clinical manifestations and the pathogenic examination of sputum.

Lobar pneumonia

Most of the patients with lobar pneumonia have no history of contact with dead animals and domestic animals, and the clinical manifestation is coughing rust-colored sputum, and there may be Streptococcus pneumoniae in the sputum; the lungs may have signs of pulmonary solid lesions, and the chest X-ray examination may show large patchy shadows.

Pneumonic plague is hemorrhagic pneumonia with hemoptysis as the main manifestation, sputum and pharyngeal secretion can be detected plague bacillus.

Inhalation anthrax

After the onset of inhalational anthrax, there are low fever, fatigue and pressure discomfort in precordial region, which lasts for 2~3 days, and then the condition can be suddenly aggravated, and there can be chest tightness, chest pain, chills, high fever, respiratory distress, cough, cyanosis and bloody sputum.

The clinical manifestations of pneumonic plague are heavy, mostly within 24~36 hours of the onset of severe chest pain, coughing, coughing up a large amount of frothy bloody sputum or bright red sputum, shortness of breath, and rapid onset of dyspnea and cyanosis.

Treatment

Treatment goal: to reduce the symptoms of patients, reduce the occurrence of complications, and reduce the morbidity and mortality rate.

Treatment principle: suspected or confirmed infected patients should be isolated and receive antibacterial treatment as soon as possible.

General treatment

Patients should be strictly isolated in an isolation hospital or isolation ward, which must be free of rats and fleas.

Hygienic treatment (dressing, flea control and disinfection) is required upon admission.

The sick area and indoor area should be disinfected regularly, and patients’ excreta and secretions should be thoroughly disinfected with chlorinated lime or cresol soap solution.

Patients with pneumonic plague need to be isolated until symptoms disappear, local secretions, blood or sputum bacterial culture every 3 days, 6 consecutive times of negative germs, can be released from isolation and discharged.

Bed rest, pay attention to water and electrolyte balance.

Patients with high fever can be given ice packs, alcohol baths and other physical cooling measures.

Antibacterial treatment

Streptomycin (SM) is still preferred for the treatment of pneumonic plague, and the dosing strategy of early, adequate and total control is emphasized.

When applying streptomycin treatment, other types of antibiotics, such as quinolones, doxycycline, and β-lactams, are often combined in order to achieve a better prognosis.

If streptomycin cannot be used due to allergy or other reasons, gentamicin, chloramphenicol, tetracycline, doxycycline, ciprofloxacin, etc. can be considered.

Drugs must be applied under the guidance of a doctor.

Anti-shock treatment

When the patient is in shock, anti-shock treatment is needed, such as replenishing blood volume, correcting acidosis, and applying vasoactive drugs.

Respiratory support

Patients with pneumonic plague need to be frequently monitored for changes in blood oxygen saturation (SpO2), and a decrease in SpO2 is found to be an early manifestation of respiratory failure, which should be given prompt treatment, such as oxygen intake by mask or ventilator-assisted ventilation.

Other treatments

If the fever is >38.5℃, or the generalized aches and pains are obvious, antipyretic and analgesic drugs can be used, such as acetaminophen, ibuprofen and so on.

In the case of concurrent cardiac insufficiency, cardiotonic drugs can be used, such as trichoside C.

If diffuse intravascular coagulation (DIC) is present, heparin anticoagulation is given along with platelets, fresh frozen plasma and fibrinogen for replacement therapy, and coagulation function is closely monitored.

Prognosis

Cure

Pneumonic plague has a high morbidity and mortality rate, and if effective treatment is not given in time, patients mostly die of toxic shock, respiratory failure and heart failure 2~3 days after the onset of the disease.

Hazard

It may be combined with shock, respiratory failure, heart failure, etc., and can be life-threatening in case of untimely treatment.

Patients with pneumonic plague can cause human-to-human transmission through droplets, causing plague epidemics or pandemics and affecting the health of the population.

Daily

Daily management

Suspected or confirmed patients and direct contacts need to be isolated separately.

During the isolation period, pay attention to hygiene, healthy diet, appropriate exercise, and maintain a good psychological state.

Prevention

Do not travel to areas where plague is endemic.

Do not hunt infected animals privately and do not strip-feed infected animals.

Travelers should use insect repellent products to prevent flea bites. Anti-mosquito measures can also prevent flea and other blood-sucking insects from biting.

Anyone in contact with plague or suspected plague patients should take enhanced protection. Healthcare workers entering the ward should wear a full set of personal protective equipment (PPE), mainly including protective eyewear, protective clothing, N95 masks, gloves and shoe covers.

The following groups of people need prophylactic treatment.