Acute Respiratory Infections in Children

Diseases of Respiratory System

Acute Respiratory Infections in Children
Introduction: Respiratory tract infections are described according to the areas of involvement. The upper respiratory tract or upper airway consists of primarily the nose & pharynx. The lower respiratory tract consists of bronchi & bronchioles.

Anatomy of the Respiratory system

Acute Respiratory Infections in Children
Etiology & characteristics: Viruses cause the largest number of respiratory infections. Other organisms that may be involved in primary or secondary invasion are group A beta- hemolytic streptococcus, haemophilus influenzae, & pneumococci.

Acute Upper Respiratory Tract Infections in Children:

Most URTIs are caused by viruses & are self-limited.

The Common Cold

The common cold is an acute viral infection of the upper respiratory tract in which the symptoms of rhinorrhea and nasal obstruction are prominent. Systemic symptoms and signs such as headache, myalgia, and fever are absent or mild. The common cold is frequently referred to as infectious rhinitis or rhinosinusitis.

ETIOLOGY:

Rhinoviruses are associated with more than 50% of colds. other viral etiologies of the common cold include respiratory syncytial virus, human metapneumovirus, parainfluenza viruses , and adenoviruses.

Epidemiology:

Pathogenesis:
Mode of spread of virusdirect hand contact (self-inoculation of one’s own nasal mucosa or conjunctivae after touching a contaminated person or object), inhalation of small-particle aerosols that are airborne from coughing,deposition of large-particle aerosols that are expelled during a sneeze.

Infections with rhinoviruses and adenoviruses result in the development of serotype-specific protective immunity. Repeated infections with these pathogens occur because there are a large number of distinct serotypes of each virus.


Viral shedding of most respiratory viruses peaks 3-5 days after inoculation,often coinciding with symptom onset. low levels of viral shedding may persist for up to 2 wk in the otherwise healthy host.

CLINICAL MANIFESTATIONS

Sore or scratchy throat is first symptome.and resolve quickly. nasal obstruction and rhinorrhea predominate in 2nd & 3rd day. Cough is associated with two-thirds of colds in children and usually begins after the onset of nasal symptoms. Cough may persist for 1-2 wk after resolution of other symptoms.

On Examination:

Increased nasal secretion. a change in the color or consistency of the secretions is common( accumulation of polymorphonuclear cells) Anterior cervical lymphadenopathy or conjunctival injection.


Differential diagnosis:
Allergic rhinitis Foreign body Sinusitis Congenital syphlis

TREATMENT

primarily supportive Care.

Antibacterial therapy is of no benefit. Maintaining adequate oral hydration. warm fluids may soothe mucosa, and loosen respiratory secretions. Topical nasal saline.

The first-generation antihistamines may reduce rhinorrhea and cough.Acetaminophen for sorethroat.NSAIDs used for headache & myalgiaAspirin should be avoided. Honey (5-10 mL in children ≥1 year old) has a modest effect on relieving nocturnal cough.

COMPLICATIONS:

Prevention:

cold

Flu (influenza)
Common cold is an upper respiratory infection that is caused by several families of viruses. It is one of the most common infectious diseases.
The flu is a respiratory infection which is caused by the influenza virus. The infection is very contagious.



Acute pharyngitis & Tonsillitis
Pharyngitis refers to inflammation of the pharynx, including erythema,edema, exudates, or an enanthem (ulcers, vesicles). Tonsillitis is a form of pharyngitis where the tonsils are primarily affected, often with a purulent exudate.

Etiology:

In addition to GAS, bacteria that cause pharyngitis include group C streptococci , Mycoplasma pneumoniae, and Corynebacterium diphtheriae

Streptococcal pharyngitis

The pharynx is red, the tonsils are enlarged and often covered with a white,or grayish exudates that may be blood tinged. petechiae on the soft palate and posterior pharynx. Enlarged and tender anterior cervical lymph nodes. Headache, vomiting, & abdominal pain.

Streptococcal pharyngitis

cough, coryza, ulcerations, and conjunctivitis are not associated with GAS pharyngitis and increase the likelihood of a viral etiology.

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Occasionally, group A streptococcal infection results in scarlet fever, which is most common in children aged 5–12 years. a typical appearance will include a ‘sandpaper-like’ maculopapular rash with flushed cheeks and perioral sparing.The tongue is often white and coated.


Scarlet fever is the only childhood exanthema caused by a bacterium, and requires treatment with antibiotics (penicillin V or erythromycin) to prevent acute glomerulonephritis or, very rarely , rheumatic fever.

diagnosis

Throat culture and rapid antigen-detection tests (RADTs) are the diagnostic tests for GAS.RADTs have very high specificity ≥95%, so when RADT is positive throat culture is unnecessary.if negative athroat culture is recommended

Treatment:

oral penicillin or amoxicillin therapy for 10 days. A single intramuscular dose of benzathine penicillin or a benzathine-procaine penicillin G combination. Rarely, in severe cases, children may require hospital admission for intravenous fluid administration and analgesia.

Patients allergic to penicillin can be treated with: a 10-day course of (first-generation) cephalosporin (cephalexin or cefadroxil). or 10 days with erythromycin, clarithromycin, clindamycin. or for 5 days with azithromycin.

Complications:

local suppurative complications, such as parapharyngeal abscess. nonsuppurative illnesses, such as ARF, APSGN, poststreptococcal reactive arthritis.

Chronic Group a Streptococcus Carriers

Streptococcal carriers are patients who continue to harbor GAS in the pharynx despite appropriate antibiotic therapy or when they are well. It can give false positive result during evaluation for pharyngitis which may be viral.

Erradication of chronic carriage:

outbreak of ARF or APSGN. personal or family history of ARF. outbreak of GAS pharyngitis in a closed community. repeated episodes of symptomatic GAS pharyngitis.

Drugs used for erradication:

Clindamycin for 10 days is effective therapy (20 mg/kg/day ). Amoxicillin-clavulanate (40mg amoxicillin/kg/day for 10 days), 4 days of oral rifampin (20 mg/kg/day divided in 2 doses) plus either intramuscular benzathine penicillin once or oral penicillin given for 10 days.

Tonsillectomy may lower the incidence of pharyngitis for 1-2 yr among children with frequent episodes of documented pharyngitis (≥7 episodes in the previous year or ≥5 in each of the preceding 2 yr, or ≥3 in each of the previous 3 yr).