A mother takes her 18-month-old child to the pediatrician after the toddler develops a low-grade fever overnight.The little boy also has a runny nose...

A mother takes her 18-month-old child to the pediatrician after the toddler develops a low-grade fever overnight.  The little boy also has a runny nose and a harsh barking cough. Upon examination, the child has inspiratory stridor, mild retractions, and is sitting quietly on his mother's lap. The pediatrician suspects croup, which is primarily caused by: 

1. Retropharyngeal edema
2. Subglottic edema
3. Angioedema
4. Tonsillar edema

Briefly explain the pathophysiology for each one of the diagnosis and rationale to your answer.

2. The child is sent home with a prescription for both oral and nebulized glucocorticoid medications. Nurses instruct the mother to call in case the child's condition does not improve or worsens. The next morning when the mother goes to get the child up, she notes that the child continues with a harsh cough and fever. Instead of going back to the pediatrician's office, she drives to the emergency department at a nearby hospital. The physician suspects a more serious illness and is fearful that further examination may upset the child and further increase the boy's respiratory distress or cause complete obstruction. A lateral neck image is taken with the child on the mother's lap. The image shows no swelling in the cervical area and no foreign object. Consequently, the emergency department physician suspects that the child may have:

1. Peritonsillar abscess
2. Bacterial tracheitis
3. Bronchopulmonary dysplasia
4. Tracheomalacia

Briefly explain the Pathophysiology for each one of the diagnosis and rationale for your answer.