Haemophilus

CASE 1

• A 20 month old girl from a remote village near Mampong is brought to the hospital with fever and lethargy. he was treated problems began one week ago when she began pulling her left ear and complaining of pain. She was treated with an herbal preparation, but the pain did not resolve. Two days earlier, she developed an intense fever and was treated for malaria with no apparent effect. Later that day, she became restless and irritable. He mother was unable to console her, and she stayed awake with bouts of crying throughout that night. The child was taken to the hospital the following morning. At that point, she had become lethargic, emitting occasional cries.

• The girl had three prior episodes of ear pain, one of which culminated in a perforated eardrum with drainage of pus (3 months earlier). She had a vaccine card, indicating that she had received polio, measles-mumps-rubella, and two injections of diphtheria-tetanus-pertussi vaccine.

• On admission, the child was responsive to a loud voice and physical stimuli but was otherwise lethargic and limp. There was some stiffness of the neck. The left tympanum was intensely red, dull, and bulging. There was a scar indicating a prior perforation. The rest of the examination was unremarkable.

• A lumbar puncture was performed and a Gram stain of the cerebrospinal fluid showed neutrophils that were too numerous to count. There were a few small, Gram-negative coccobacilli seen (below left).

• In spite of therapy with intravenous corticosteroids and ceftriaxone, the child died on the day of admission. A post-mortem examination was performed the following days and the base of the childs brain was coated with pus (see image below).

Questions:

1. What type of H. influenzae is likely to have caused this infection?
2. Is this pathogen encapsulated? What is the capsule composed of?
3. Are there also unencapsulated strains of H. influenzae? What part of this clinical scenario might have been caused by an unencapsulated strain?
4. How would you culture this organism from the CSF or the middle ear fluid? Are there any special culture requirements? What are they?
5. Is Chocolate agar made from chocolate?
6. Other organisms that cause meningitis (e.g., pneumococcus, meningococcus) are of similar virulence to the type of H. influenzae that this patient had. These infection are often cured. with treatment. So, what was the major factor involved in this child's death?
7. What other clinical manifestations of H. influenzae type b besides meningitis can occur in young children?
8. Is this disease preventable? How?

CASE 2

• A 55 year old man who smokes 10 cigarettes a day comes to the clinic with cough and fever. He is producing sputum that is thicker and more opaque than usual, and he has had a few chills and a persistent headache.

• His temperature is 38 degrees. There is no stiff neck. Examination of his chest reveals scattered rhonchi (sounds caused by mucous material in the large airways).

• A Gram stain of the patient's sputum reveals numerous neutrophils and small, Gram-negative coccobacilli identical to those shown in the Gram stain from Case 1. A culture grows Haemophilus influenzae.

Questions:

1. What difference would you expect in the H. influenzae isolate from this patient comparing it to the isolate from Case 1?
2. Why does this difference occur?
3. Could this purulent bronchitis (and possibly pneumonia) have been prevented if this patient had been immunized with current vaccines?
4. Which antibiotics are likely to help this patient? Which will not be helpful?

• A 24 year old male has 7 x 7 mm flat, purulent ulcer on the lateral aspect of his glans penis that started as a small papule about one week ago. The ulcer is not swollen or indurated , but it is extremely painful and tender to touch. He has no fever.

• The patient admits to having had unprotected sexual intercourse with prostitutes.

• A gram stain of a scraping from the ulcer shows Gram-negative coccobacilli, some linked together in winding chains.

Questions:

1. What relatively unusual sexually-transmitted disease does this man have?
2. What role do prostitutes play in the dissemination of this disease?
3. What complication may occur if he is no treated?
4. How should he be treated?