Topics Respiratory disorders

Respiratory infections

Pneumonia

Respiratory Disorders

50% of consultation with general practitioners or acute illness in young children and a third of consultations in older children

20-35% of acute pediatric admissions to hospital, some of which are life-threatening

Asthma is the most common chronic illness of childhood

Cystic fibrosis is the most common inherited disorder in Caucasians causing chronic disease

Respiratory Infections

The most frequent infections of childhood: 6- 8/year

Pathogens:viruses,bacterial, other pathogens

Host and environmental factors

Classification of respiratory infections

Classification of Respiratory Infections

According to the level of the respiratory tree most involved:

Upper respiratory tract infection

Lower respiratory tract infection

PneumoniaEnmei Liu

Children’s Hospital, CMU

Case -1

Jack, age four months, is sent at home by his general practitioner because of two days of rapid, laboured breathing and poor feeding. He was born at 27 weeks’ gestation, birth weight 979g and was discharged home at three months of age. On examination he was a fever of 37.4C and a respiratory rate of 60 breaths/min. His chest is hyperinflated with marked intercoatal recession. On auscultation there are generalized fine crackles and wheezes.

Question

Do you have any comments or what do you conclude anything from this case?

Case -1

Jack, age four months, is sent at home by his general practitioner because of two days of rapid, laboured breathing and poor feeding. He was born at 27 weeks’ gestation, birth weight 979g and was discharged home at three months of age. On examination he was a fever of 37.4C and a respiratory rate of 60 breaths/min. His chest is hyperinflated with marked intercoatal recession. On auscultation there are generalized fine crackles and wheezes.

Question

What is pneumonia?

Pneumonia is an inflammation of the parenchyma of the lungs.

Definition

Question

How about the prevalence of pneumonia?

Pneumonia accounts for approximately 15% of all respiratory tract infections.

Worldwide, about 3 million children die each year from pneumonia, with the majority of these deaths occurring in developing countries.

Pneumonia remains the most common cause of morbidity in China.

Incidence

Question

How to classify pneumonia in clinic?

Anatomy Pathogens Severity Duration Onset site

Classification

Bronchopneumonia

Lobar or Lobular Pneumonia

Interstitial Pneumonia

Based on anatomy or X-ray manifestation

Based on etiology

Bacterial pneumonia

Viral Pneumonia

Mycoplasma Pneumonia

Chlamydia Pneumonia

Acute Pneumonia

Prolonged Pneumonia

Chronic Pneumonia

Based on the process of pneumonia

Mild Pneumonia

Severe Pneumonia

Based on the severity of pneumonia

Community Acquired Pneumonia (CAP)

Hospital Acquired Pneumonia (HAP)

Based on the onset site of pneumonia

Bronchopneumonia

Question

Why are children likely have bronchopneumonia?

Characters of childhood airway anatomic structure and their respiratory physiology

Immune function of childhood

High risk factors: premature baby, underlying disorders

Question

What cause bronchopneumonia?

• Bacteria: Streptococcus pneumoniae, Haemophilus influenzae

• Viruses

• Mycoplasma

Causes of Bronchopneumonia

Pathology of Pneumonia

Inflammaory exudate

Inflammaory exudate

Pathology of Pneumonia

Question

What are the pathophysiology of pneumonia?

Pathogens

URTI

Bronchitis

Pneumonia

Inflammatory exudate Obstruction of airway

Gas exchange abnormal

Ventilation abnormal

hypoxemia hypercapnia toxinemia

tachypnea

cyanosis

rales

fever

cough

Question

What are the signs and symptoms of pneumonia?

The clinical signs and symptoms of pneumonia depend primarily on the age of the patient, the causative organism, and the severity of the disease.

FeverCough

Cyanosis

Tachypenea

Rales

out breathing in

With inspiration, the side of the nostrils flares outwards

Nasal Flaring

With inspiration, the lower chest wall moves in

Lower Chest Wall Indrawing

out breathing in

FeverCough

Cyanosis

Tachypenea

Rales

Classic findings of pneumonia that occur in adults and older children, such as fever,cough and rales, are often absent in infants and toddlers.

Generally present with nonspecific signs and symptoms including lethargy, irritability, poor feeding, vomiting.

If it appear respiratory failure or other abnormality of other system-severe pneumonia.

Important Points

Complications

Empyema

Pyopneumothorax

Pneumatocele

Lung abscesses

Atelectasis

Laboratory Examination White blood cell count and C-reaction protein

Pathogens examination: 1)Sputum cultures

2)Blood cultures

3)Rapid screening tests for virus or bacterial

Bronchoscopy

Blood gas analysis: hypoxia and/or hypercapnia

Radiograph Evaluation

Typical X-ray manifestation of bronchopneumonia is patchy infiltrates bilaterally

Complication: lung abscesses, empyema, pyopneumothorax, pneumatocele, atelectasis

CT

Normal chest X-ray

Patchy infiltrates

Lobar pneumonia of the right lower zone consolidation

lung abscesses

pyopneumothorax

Question

How to diagnosis pneumonia clinically?

According to the typical clinical manifestation of bronchopneumonia.

According to X-ray manifestation

Pay attention to the atypical manifestation of infants

Evaluate the severity of pneumonia

Find the etiology of pneumonia

Differential Diagnosis

Bronchitis

Foreign Body Inspiration

Tuberculosis

Question

How is pneumonia treated?

Management

Supportive care

Antimicrobials therapy

Hospitalization in selected cases

Supportive Care Adolescents. Respiratory care may range from oxygenation, bronchodilators for wheezing, humidification or mist, suctioning, and postural drainage, intubation and mechanical ventilation.

Hydration (sometimes intravenous) Control of fever

Management of complications

Antimicrobial Therapy Adolescents. Organism Antimicrobial

S. pneumoniae 

Penicillin (if not resistant). third-generation cephalosporin e.g. cefotaxime\ceftriaxone (if resistant to penicillin)

H. influenzae  Azithromycin or Amoxicillin (if not resistant)

Beta lactamase 

Cefuroxime or third-generation cephalosporin (if beta lactamase and resistant)

S. aureusMethicillin (if not resistant) Vancomycin (if MRSA-methicillin resistant S. aureus) if penicillin allergy: vancomycin, clindamycin 

Chlamydia 

Azithromycin (other macrolides e.g erythromycin); alternative, sulfa drugs 

Mycoplasma

Azithromycin (other macrolides); alternative, tetracycline (if older than 8 years) 

RSV  Ribavirin (optional)

Influenza

Amantadine (if severe)

Bacteria Atypical

Viruses

Age Group 

Bacterial  Viral  Empiric Therapy

Neonate (0-28 days)

Group B streptococcus, gram-negative enteric E. coli, Klebsiella, Listeria monocytogenes, S. aureus, other gram-positiv

e)

Cytomegalovirus Herpes simplex

Ampicillin and aminoglycoside (gentamicin or tobramycin or amikacin, or third- generation cephalosporin). Note: Avoid ceftriaxone 2° to b

ilirubin  

Infants 3-16 weeks; afebrile pneumonia

infancy

  Chlamydia trachomatis Ureaplasma urealyticum CytomegalovirusPneumocystis

carinii

Erythromycin Sulfonamide

Infants febrile or

ill appearing

age 1-3 months

Same organisms as for neonate plus S. pneumoniae, H. influ

enzae, S. aureus

Not applicable Antibiotic (nafcillin, oxacillin, or methacillin) Broad-spectrum ceph

alosporin (e.g., cefotaxime)

Toddler or

preschool age

S. pneumoniae, H. influenzae M. pneumoniae, Chlamydia

RSV Parainfluenza Adenovirus Influenz

a

AzithromycinAmoxacillin-clavulanate: not active against atypical organisms (Myc

oplasma, Chlamydia)

Organisms Causing Pneumonia and Empiric Therapy in Pediatric

Question

How about the clinical course of pneumonia ?

With treatment, pneumonia caused by bacteria can usually be cured in 1 or 2 weeks

Pneumonia caused by a virus often lasts longer

Clinical Course Adolescents.

Specific Pneumonias

Brochiolitis

Brochiolitis is the most common serious respiratory infection of infancy

Two to three per cent of all infants are admitted to hospital with the disease each year during annual winter epidemics.

Ninety per cent are aged 1-9 months bronchiolitis is rare after one year old.

Respiratory syncytial virus (RSV) is the pathogen in 75- 80% cases

Clinical Features Coryzal symptoms precede a dry cough and increasing breathlessness. Wheezing is often but not always present. Feeding difficulties associated with increasing dyspnoea are often the reason for admission to hospital. Recurrent apnoea is a serious complication in infants in the first few months of life. Infants born prematurely who develop bronchopulmonary dysplasia and infants with congenital heart disease are more severely affected. The finding on examination are characteristic: Sharp, dry cough Tachypnoea Subcostal and intercostals recession

Hyperinflation of the chest

Investigations

RSV can be identified rapidly using a fluorescent antibody test on nasopharyngeal secretions.

The chest X-ray shows hyperinflation of the lungs due to small airways obstruction and air trapping.

Blood gas analysis, which is required in only the most severe cases, shows lowered arterial oxygen and raised CO2 tension

Hyperinflation of the lungs with flattening of diaphragm

Management Is supportive. Humidified oxygen is delivered into a head- box Mist, antibiotics and steroids are not helpful Nebulised bronchodialators do not reduce the severity or duration of the illness The antiviral drug ribavirin only marginally shortens viral excretion and clinical symptoms, and should be considered only for infants with underlying cardiopulmonary disorders or immunodeficiency Fluids may need to be given by nasogastric tube or intravenously Mechanical ventilation is required in about 2% of infants admitted to hospital

Etiology ： Respiratory syncytial virus (RSV) is the pathogen in 75-80% cases

Clinical features: 1. Age:3-6 month

2. Season

3. Wheezing

4. X-ray

5. Duration:7-10 days

Management:

Bronchiolitis

Staphylococcus aureus . S. aureus is an uncommon but important cause of pneumonia that can occur in any age group. S. aureus is a rapidly progressive fulminant illness S. aureus pneumonia easily occurs complications. Blood cultures are positive in 20-30% of patients . The pleural effusions should be drained by thoracentesis or, if large, by a chest tube. Pneumatoceles are also common and are found in 45- 60% of patients with S. aureus pneumonia.  Methicillin or vancomycin should be administered for 3-4weeks.

Mycoplasma Pneumonia

M pneumoniae is a common cause of symptomatic pneumonia in older children.

Endemic and epidemic infection can occur.

The incubation period is long (2-3weeks), and the onset of symptoms is slow.

Although the lung is the primary infection site, extrapulmonary complications sometimes occur.

Clinical Features

Fever, cough, headache, and malaise are common symptoms as the illness evolves.

Rales are frequently present on chest examination, decreased breath sounds or dullness to percussion over the involved area may be present.

Laboratory findings

The total and differential white blood cell

counts are usually normal.

The cold hemagglutinin titier should be determined, because it may be elevated during the acute presentation. A titer of 1:64 or higher supports the diagnosis.

Imaging

Chest x-rays usually demonstrate intersititial or bronchopneumonic infiltrates, frequently in the middle or lower lobes. Pleural effusions are extremely uncommon.

Complications Extrapulmonary involvement of the blood, CNS, skin, heart, or joints can occur Direct Coombs-positive autoimmune hemolytic anemia,Coagulation defects and thrombocytopenia can also occur A wide variety of skin rashes including erythema multiforma and Stevens-Johnson syndrome

Treatment

Antibiotic therapy with erythromycin for 7- 10 days usually shortens the course of illness.

Supportive measures, including hydration, antipyretics, and bed rest, are helpful.

Chlamydial Pneumonia

Pulmonary disease due to C trachomatis usually evolves gradually as the infection descends the respiratory tract.

Infants may appear quite well despite the presence of significant pulmonary illness.

Appropriate age: 2-12 weeks

Inclusion conjunctivitis, eosinophilia, and elevated immunoglobulins can be seen.

Clinical Features About 50% of patients with chlamydial pneumonia have active inclusion conjunctivitis or a history of it

Rhinopharyngitis with nasal discharge or otitis media may have occurred or may by currently present

Cough is usually present. It can have a staccato character and resemble the cough of pertussis

The infant is usually tachypenic. Scattered inspiraotrt rales are commonly heard, but wheezes rarely

Significant fever suggests a different or additional diagnosis

Laboratory findings

Although patients may frequently be hypoxemic, CO2 retention is not common.

Peripheral blood eosinphilia has been observed in about 75% of patients.

Serum immunloglobulins are usually abnormal. IgM is virtually always elevated, IgG is high in many, and IgA is less frequently abnormal.

C trachomatis can usually be identified in nasopharyngeal washings using fluorescent antibody or culture techniques.

Imaging

Chest x-rays usually reveal diffuse interstitial and patchy alveolar infiltrates, peribronchial thickening, or focal consolidation. A small pleural reaction can be present . Despite the usual absence of wheezes, hyperexpansion is commonly present.

Treatment

Erythromycin or sulfisoxazole therapy should be administered for 14 days.

Oxygen therapy may be required for prolonged periods in some patients.

Summary Pneumonia in pediatric patients encompasses a wide spectrum of etiologies and illness from mild to severe and life threatening.

Therapy should include an antibiotic if a bacteria or atypical bacteria (chlamydia or mycoplasma) is suspected. No antibiotics are necessary for viral pneumonia.

Supportive therapy also includes fever control, maintenance of hydration and respiratory care .

Close follow-up is necessary in order to detect any secondary bacterial infection or the development of complications.

Key Issues

Etiology of pneumonia Pathophysiology of pneumonia Clinical feature of pneumonia Diagnosis and differential diagnosis of

pneumonia Management of pneumonia Several special pneumonias

Case -2

History:

A 9-week old female infant come to see doctor with a 3 week history of rhinorrhea and a 2 week history of cough. The cough is described as explosive and occurring in clusters and it persists as a major clinical symptom. On one occasion, the baby could not seem to catch her breath. She has not had any fever. No one else in this family is ill. At 6 weeks of age, the infant received on DPT.

Physical examination:

On physical examination the infant is alert and in moderate respiratory distress. Her temperature is 37.3C. Pulse 120beats/min, and respiratory rate is 65/min. There are intercostal and subcostal retractions. Ausculation reveals fine inspiratory rales throughout.

Laboratory data:

A complete blood count is normal showing a hemoglobin of 12.5g/dl, the white blood count was 6.2X103/mm3 with 21% polymorphonuclear leukocytes, 20% bands, 50% lymphocytes, and 9% eosinophils. The chest radiograph is shown bilaterally patchy infiltrates, more confluent in the upper lobes without penumothorax or pleural effusions.

Question

1. Please discuss this case.

2. What is the most likely etiology diagnosis?

References Nelson Textbook of PaediatricsPneumonia(Sharon E. Mace, MD,

FACEP, FAA) Current Pediatric Diagnosis and

TreatmentMosby” s Crash CoursePediatrics

Please contact with me:Please contact with me:

Email address: emliu186@hotmail.com

Telephone: 86-23-63624074

Address: Children’s Hospital, CMU

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