Haemophilus influenza type B is a bacterium that inhabits the upper respiratory tract of humans. It is spread by person-to-person contact of respiratory secretions. Widespread vaccination against this bacterium has reduced the incidence of disease, but neonates and people with weakened immune systems can still be effected.
Respiratory Symptoms
Haemophilus influenza type B causes several respiratory infections. It can cause ear infections, which is manifested by ear pain and fever. Another common respiratory infection is pneumonia. Patients with pneumonia due to Haemophilus type B have frequent coughing with phlegm production, fever, difficulty breathing with rapid respiratory rate and retractions (pulling-in of abdominal and chest muscles to aid breathing). Haemophilus can cause another respiratory infection called epiglottitis. This is a dangerous inflammation of the epiglottis, the cartilage that covers the trachea. During epiglottitis, patients have high fever, sore throat and eventually develop severe upper airway narrowing and respiratory difficulty. Patients can have stridor (a high-pitched noise on inspiration) and cyanosis (bluish tinge around the lips as a result of decreased oxygen availability). Patients with epiglottitis adopt a "sniffing dog" position, in which they extend their neck to try to maximize the opening of the airway. Untreated, this can result in death by asphyxia.
Neurological Symptoms
Haemophilus type B can cause meningitis, which is an inflammation of the tissue covering the brain. Symptoms include severe headache, neck stiffness, photophobia (eye pain with bright lights), irritability and change in mental status. Occasionally, patients can pass out or have seizures. This is a potentially devastating condition especially on newborns.
Other Symptoms
Haemophilus can cause other invasive conditions and its symptoms depend on the effected body part. This bacterium can cause septic arthritis, in which the effected joint becomes swollen and painful to move. It can cause skin infections like cellulitis and abscesses, in which the skin becomes red and tense to the touch. Also Haemophilus type B can cause bacteremia, a blood-borne infection that manifests itself as unremitting fevers. From there the bacterium can infect bones causing osteomyelitis, in which the bone becomes tender to the touch.
