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Signs and Symptoms

Haemophilus influenzae, including Hib, disease causes different symptoms depending on which part of the body is affected. The most common severe types of H. influenzae disease are:

  • Pneumonia (lung infection)
  • Bacteremia (bloodstream infection)
  • Meningitis (infection of the covering of the brain and spinal cord)

Pneumonia occurs when the lungs become infected, causing inflammation (swelling). H. influenzae pneumonia is considered non-invasive if there’s not bacteremia or pleural fluid (fluid surrounding the lungs) infection occurring at the same time. When there is pneumonia with either bacteremia or pleural fluid infection occurring at the same time, it is considered invasive. Symptoms of pneumonia usually include:

  • Fever and chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Sweating
  • Chest pain
  • Headache
  • Muscle pain or aches
  • Excessive tiredness

Bacteremia is an infection of the blood. It can cause symptoms such as:

  • Fever and chills
  • Excessive tiredness
  • Pain in the belly
  • Nausea with or without vomiting
  • Diarrhea
  • Anxiety
  • Shortness of breath or difficulty breathing
  • Altered mental status (confusion)

Bacteremia from H. influenzae can occur with or without pneumonia.

Meningitis is an infection of the covering of the brain and spinal cord. Symptoms typically include sudden onset of:

  • Fever
  • Headache
  • Stiff neck
  • Nausea with or without vomiting
  • Increased sensitivity to light (photophobia)
  • Altered mental status (confusion)

Babies may appear to be lethargic (limp, loss of alertness) or irritable, or may not eat well. In young children, doctors may also test the child's reflexes, which can be abnormal with meningitis.

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