Case Study Exercise 3

EXAMPLE:  Sarah, a 19-year-old female has a history of a urinary tract infection (UTI) 4 months prior to admission for which she was treated with oral ampicillin without complications.  Five days prior to this admission, she began to note nausea without vomiting. One day later she developed left flank pain, fevers and chills, and increased urinary frequency.  Sarah noted foul-smelling urine on the day prior to admission.  She presents with a temperature of 101.8o F, and physical examination shows left costovertebral angle tenderness.  Urinalysis of a clean-catch urine sample is notable for >50 white blood cells per high-power field, 3 to 10 erythrocytes per high-power field, and 3+ bacteria.  Urine culture is subsequently positive for >100,000 CFU of a Gram negative, lactose-fermenting rod per ml; this bacterium was indole positive.

            E1.  What do the urinalysis findings indicate?  Explain your answer.  The bacterium responsible for the infection is the most common cause of UTI’s:  What is the pathogen?

            E2.  How do the biochemical reactions help in the diagnosis?

            E3.  Why are urinary tract infections more common in women than in men?  Did this woman have cystitis or pyelonephritis?  Why is it important to differentiate?


A.  Sally underwent surgery for a block ureter 3 days ago and is now experiencing vaginal itching and has a milky white discharge, local inflammation and ulceration.  An ovoid yeast recovered from the discharge has white colonies on Blood Agar, reproduces by budding and shows germ tube production.

1.      What is causing Sally’s discomfort?  Give your reasons for this diagnosis.

2.      Is this organism life-threatening?

3.      How did Sally likely contract the infection?


B.  Bernice, a 24 year-old woman is referred to a public health clinic as the result of contact tracing from a gonorrhea case.  She recently had unprotected sex with her infected male partner who showed no symptoms.  A pelvic exam recovers a greenish discharge containing a protozoa with a “jerky” motility.  Bernice tests negative for gonorrhea and chlamydia.

4.      What is causing Bernice’s problems?

5.      How common is this infection?

6.      What symptoms does it produce in men?

7.      What symptoms does it produce in women?

8.      How would this disease be treated?


C.  Brett, an 18-month-old is brought to the pediatrician with fever and diffuse vesiculopustular lesions over her entire body.  Two days before, he had a rash on her scalp, face and trunk.  On examination, Brett  has mild fever and a rapid heart rate and is distressed because the lesions are “itchy.”  His doctor advises home care with ointments to relieve the symptoms.  He further advises that NO ASPIRIN be given to alleviate the discomfort.  The lesions heal but leave a tiny pit or scar.

9.      What is causing Brett’s discomfort?

10.  How can this disease be prevented?

11.  Why is aspirin not use not recommended?


D.  Cecil is admitted to the hospital with severe chest pain and diagnosed with an acute MI.  He is put in the CCU where invasive monitoring allows him to survive the episode. On the 13th day Cecil develops a significant fever.  A central venous catheter is removed and blood cultures taken.  Both aerobic and anaerobic blood cultures show catalase positive, coagulase positive cocci in clusters.

12.  What is causing Cecil’s septicemia?  Explain your reasoning.

13.  How was Cecil likely infected?

14.  What problems might be encountered with his treatment?


E.  Ted, a 9-year-old with a 2-day history of diarrhea presents to the ER with blood in his stools and increased stool volume.  He has vomited once.  Tedwent to a cook-out 5 days earlier and ate a hamburger that was still “pink” inside.  On examination, he is dehydrated but generally well.  A stool culture produces lactose-positive colonies on MacConkey agar, but non-fermenting colonies on sorbitol MacConkey agar.

15.  What is likely wrong with Ted…explain your thinking.

16.  How is this organism usually spread?

17.  What might happen to the patient?


F.  Nick, a 39-year-old was in good health until mid-July when he developed myalgias and fever.  These symptoms resolved.  Two weeks prior to the evaluation, he developed large, erythematous, annual rashes on his left forearm, right hip, and left knee.  Nick subsequently developed a left facial (cranial nerve VII) palsy.  His past history is notable only for travel to the northeast United Stated (Connecticut) prior to the onset of his symptoms.  On physical examination, Nick is afebrile with normal vital signs.  A skin examination demonstrates the three lesions previously noted which had, according to the patient, faded considerably.  A neurological examination demonstrates left facial nerve weakness.  Lab studies include a normal CBC.  A lumbar puncture is preformed.  His CSF contains 78 nucleated cells/mm3 with 88% lymphocytes and 12% monocytes.  Nick’s CSF glucose is 60 mg/dl, and the protein level is 55mg/dl.  The clinical diagnosis is confirmed serologically.

            18.  What is the etiologic agent of Nick’s infection?  Which signs and symptoms were important clues?

            19.  What is the significance of Nick’s travel history and the time of year he was infected?

            20.  How is this infection acquired (be specific!)?