Pertussis toxin causes lymphocytosis by an unknown mechanism. The elevated number of white blood cells leads to pulmonary hypertension, a major cause of death by pertussis. In infants who develop encephalopathy, cerebral hemorrhage and cortical atrophy occur, likely due to hypoxia. Diagnosis
Based on symptoms
A physicians overall impression is most effective in initially making the diagnosis. Single factors are much less useful. In adults with a cough of less than 8 weeks, vomiting after coughing or a "whoop" is supportive. If there are no bouts of coughing or there is a fever the diagnosis is unlikely. In children who have a cough of less than 4 weeks vomiting after coughing is somewhat supportive but not definitive. Lab tests
Methods used in laboratory diagnosis include culturing of nasopharyngeal swabs on a nutrient medium (Bordet–Gengou medium), polymerase chain reaction (PCR), direct fluorescent antibody (DFA), and serological methods (e.g. complement fixation test). The bacteria can be recovered from the person only during the first three weeks of illness, rendering culturing and DFA useless after this period, although PCR may have some limited usefulness for an additional three weeks. Serology may be used for adults and adolescents who have already been infected for several weeks to determine whether antibody against pertussis toxin or another virulence factor of B. pertussis is present at high levels in the blood of the person. Differential diagnosis
A similar, milder disease is caused by B. parapertussis. Prevention
The primary method of prevention for pertussis is vaccination.
Retropharyngeal abscess (RPA) is an abscess located in the tissues in the back of the throat behind the posterior pharyngeal wall (the retropharyngeal space). Because RPAs typically occur in deep tissue, they are difficult to diagnose by physical examination alone. RPA is a relatively uncommon illness, and therefore may not receive early diagnosis in children presenting with stiff neck, malaise, difficulty swallowing, or other symptoms listed below. Early diagnosis is key, while a delay in diagnosis and treatment may lead to death. Parapharyngeal space communicates with retropharyngeal space and an infection of retropharyngeal space can pass down behind the esophagus into the mediastinum. RPAs can also occur in adults of any age. RPA can lead to airway obstruction or sepsis – both life-threatening emergencies. Fatalities normally occur from patients not receiving treatment immediately and suffocating prior to knowing that anything serious was wrong. Signs and symptoms
Signs and symptoms may include the following stiff neck (limited neck mobility or torticollis), some form of palpable neck pain (may be in "front of the neck" or around the Adams Apple), malaise, difficulty swallowing, fever, stridor, drooling, croup-like cough or enlarged cervical lymph nodes. Any combination of these symptoms should arouse suspicion of RPA. Causes
RPA is usually caused by a bacterial infection originating from the nasopharynx, tonsils, sinuses, adenoids, molar teeth or middle ear. Any upper respiratory infection (URI) can be a cause. RPA can also result from a direct infection due to penetrating injury or a foreign body.