Upper respiratory tract Cricoid cartilage Lower respiratory tract

Common diseases Upper respiratory tract: Lower respiratory tract: Influenza Tonsillitis laryngitis Lower respiratory tract: bronchitis Asthma Pneumonia

Ventilation and perfusion

Ventilation Perfusion Rate Ventilation and perfusion Ventilation Perfusion Rate Alveolar space O2 CO2 70% 100%

Pathophysiology

According to WHO’s report: Among all the pediatric patients, 90% suffered from infectious diseases; Among all these patients with infectious diseases, 90% are diagnosed as URI. Among all these URI patients, 90% are infected by virus.

Pneumonia Pneumonia is termed as infections of the alveoli caused by microorganisms or other noninfectious factors. Pneumonia still carries a high mortality rate in infants who are not treated promptly and properly.

There are many different causes of pneumonia in children There are many different causes of pneumonia in children. The most common causes are germs. Viruses are usually the cause in 90% of pneumonia infants and young children. Children with a viral pneumonia may have a better chance of developing a bacterial pneumonia, too.

Pneumonia can also be caused by foreign material such as food or stomach acid, especially in newborn and infants. These materials are aspirated (inhaled) into the lungs.

Common causes Viruses group B Streptococcus Newborns group B Streptococcus respiratory syncytial virus Infants Viruses parainfluenza viruses, influenza virus, adenovirus Atypical organisms Chlamydia trachomatis, Pneumocystis carinii Bacterial B. pertussis, Streptococcus pneumoniae, Haemo-philus influenzae

Common causes Young children Viruses parainfluenza viruses, influenza virus, adenovirus Atypical organisms Mycoplasma pneumoniae Bacterial Pneumococcus, mycobaterial tuberculosis Older children and adolescents Mycoplasma pneumoniae, Chlamydia trachomatis Pneumococcus, B. pertussis, mycobaterial tuberculosis

Bacterial pneumonia Viral pneumonia Mycoplasmal pneumonia

Common Signs and symptoms Cough Breathing pattern Cyanosis Respiratory Sound

Cough A cough is a voluntary or involuntary explosive expiration. The cough reflex is initiated by the stimulation of subepithelial mechanoreceptors in the trachea, bronchi and interstitium.

Cough Paroxysm: A series of coughs that is difficult to stop. It is due to pertussis, viral infection and asthma, etc. During paroxysm of coughing, headache, vomitting, conjuctival hemorrhage may be induced by the increased intracranial pressure. An acute cough may be benefit to eliminate the obstruction or facilitate mucociliary clearance when foreign bodies or excess mucus is present. A chronic cough may be harmful to cause complications, such as chest pain.

breath with Severe pneumonia Breathing pattern Normal breath breath with Severe pneumonia

Cyanosis When maximal respiratory efforts cannot provide sufficient ventilation to saturate the blood fully and the amount of unoxygenated Hb exceeds 50g/L, the children will appear cyanotic.

Respiratory sounds Breath sounds are influenced by the depth of breathing, velocity of the air flow, position of the patients and the fluid in the air space. The pitch of breath sounds depends on the size of the orifices or the diameter of the airway: the smaller the orifice or the airway, the higher the pitch.

Symptoms of different pneumonia Viral pneumonia The respiratory syncytial virus is the most common agent. It is often accompanied by a skin rash and unresponsive to antibiotics. Adenovirus may produce viral pneumonia in children and young adults. It more commonly causes upper respiratory tract disease with prominent rhinitis.

RSV Pneumonia Respiratory syncytial virus is the major respiratory pathogen of young children, causing lower respiratory tract disease in infants. Infection may occur at any time but is least frequent in the summer, accounting for 20 to 25% of hospital admissions for pneumonia of young infants and children.

RSV Pneumonia lower respiratory diseases, primarily, pneumonia, bronchiolitis and tracheobronchitis occurs in 25-40% of cases onset is gradual with rhinorrhoea, low-grade fever, cough, wheezing and mild systemic symptoms tachypnoea, dyspnoea, frank hypoxia, cyanosis and apnoea may develop in severe cases wheezing and crackles may be heard on auscultation there may be an accompanying skin rash

Bacterial Pneumonia pneumococcal pneumonia usually a history of preceding upper respiratory tract viral infection. more common in winter months with sudden onset marked fever; febrile convulsions in preschool children cough - initially dry but replaced by a productive cough with rusty-coloured sputum after 24 - 48 hours breathing - rapid and shallow; diminished movement on the affected side may be signs of consolidation and a friction rub

Bacterial Pneumonia staphylococcal pneumonia usually a history of preceding upper respiratory tract viral infection. more common in winter months with sudden onset marked fever; febrile convulsions in preschool children cough - initially dry but replaced by a productive cough with rusty-coloured sputum after 24 - 48 hours breathing - rapid and shallow; diminished movement on the affected side may be signs of consolidation and a friction rub

Mycoplasmal pneumonia peak rate of infection in autumn and early winter initial influenza-like disease with headache, fever, malaise, myalgia, diarrhea and fatigue - often develop several days before the onset of respiratory problems; the malaise and fatigue may persist for long after the acute illness wide variety of respiratory and non-respiratory complications

cough - initially dry and often insignificant; usually becomes productive with a mucoid and purulent sputum; often paroxysmal, disturbing sleep; may be absent in one-third of cases isolated crackles or areas of wheezing may be heard over one of the lower lobes subsegmental atelectasis and small effusions often detectable in the absence of prominent chest symptoms

Radiology RSV pneumonia Radiologic features are variable depending upon the extent of the infection. Chest radiology may show hyperexpansion, peribronchial thickening, and infiltrates ranging from diffuse interstitial infiltrates to segmental or lobar consolidation.

pneumococcal pneumonia classically, shows consolidation with a lobular distribution note that radiological changes may lag behind the clinical course of the disease and conversely, radiologic features may persist for several weeks after being cured.

staphylococcal pneumonia The chest radiograph often appears cavitated. Infection starts in the bronchi, causing areas of patchy consolidation in one or more lobes. These break down to form multiple thin walled abscesses – pneumatocoeles - which appear as cysts.

Mycoplasma pneumoniae Chest radiology is highly variable. The most frequent pattern is one of bronchial thickening with areas of interstitial infiltration and subsegmental atelectasis involving one of the lower lobes; sometimes, there may be dramatic shadowing in both lower lobes. Often there is no correlation between radiologic appearance and the clinical state of the patient.

Lab tests RSV pneumonia Diagnosis is established by isolation of RSV from respiratory secretions, particularly, sputum or throat swabs. Immunologic reactions such as ELISA are then used to detect the virus in tissue culture.

Techniques based on complement fixation or neutralisation of antibody titers are more valuable in older children and adults. A bedside immunoassay kit is now available which detects RSV; confirmation should be sought with the laboratory tests detailed above.

Lab tests pneumococcal pneumonia white cells - raised; often greater than 15 x 109 per litre ESR - raised; may exceed 100 mm in an hour CRP - raised

Sputum examination, sputum and blood culture- positive in 25-40% of cases, are essential in management of a patient with pneumonia. It may possible to demonstrate pneumococcal antigen in both blood and sputum.

Lab tests staphylococcal pneumonia sputum examination and culture blood culture - positive in 20 - 30% of cases full blood count ESR CRP

Lab tests Mycoplasma pneumoniae White cell count is usually normal but ESR may be raised and C reactive proteins may be elevated. a rise of specific antibody titre - occurs in most instances, but, obviously, requires paired samples separated by a week or more, and is therefore not useful in the inital diagnosis

cold haemagglutination serology - present in about 50% of cases but may produce false positives in measles, infectious mononucleosis, adenovirus pneumonias, certain tropical diseases and collagen vascular disease.

RSV pneumonia Treatment is largely symptomatic. Intubation and ventilatory assistance are given if there is severe hypoxia. Humidified oxygen may be required if arterial oxygen tension is low. Ribavarin, a nucleoside analogue which is active in vitro against RSV, has been shown to relieve lower respiratory tract illness in children. It is used by inhalation since oral administration is associated with liver and bone marrow toxicity. Studies have yet to be conducted in adults.

pneumococcal pneumonia Pneumococcal pneumonia is generally treated with amoxycillin, ampicillin or co-amoxiclav. For severe infections: intravenous antibiotics e.g. ampicillin or co-amoxiclav. Oral amoxycillin or augmentin can be used when the pneumonia is resolving clinically and the patient is apyrexial.

For mild-moderate infections: amoxycillin 500mg tids for 10-14 days. Alternative treatments in penicillin allergy include erythromycin or cefuroxime (but note 10% cross-sensitivity). Prophylaxis: pneumococcal vaccination

staphylococcal pneumonia Antibiotic treatment should be started after blood and sputum has been taken for culture. Initial therapy is often blind. Consult with a bacteriologist about appropriate drug treatment if in doubt: penicillin-sensitive first choice: benzylpenicillin alternative: erythromycin penicillinase producing first choice: flucloxacillin alternative: dependent on local sensitivities

Mycoplasma pneumoniae Treatment is with either erythromycin or tetracycline: erythromycin or other macrolide e.g. clarithromycin or azithromycin: tetracycline: an alternative to erythromycin for the treatment of chlamydial and mycoplasma infections Treatment period is for a minimum of 10-14 days.