Vector Borne Bacteria

Case One

• HPI: A fifteen year old boy was in his usual state of health in November when he developed a fever, which lasted several days. He's brought to you for evaluation by his parents.
• ROS: No acute S/S other than fever and fatigue. Vaccinations up to date. History of mild asthma, well-controlled on montelukast and prn albuterol. Otherwise healthy.
• FH/SH: Parents, two siblings A&W. Paternal GF died in MVA prior to birth; other grandparents still living, maternal GM s/p breast CA, dx at age 56. Lives in Madison, CT. Does well in school; runs on the cross-country team.
• MEDS: montelukast 10 mg daily; albuterol, 1 puff prn wheezing / SOB
• PEx: T 101.2F, P 80, BP 105/70, RR 15
• Thin, well-developed young man in NAD
• PEx negative except for rash (picture)
• Labs: normal CBC

Question one

What is the most likely diagnosis?

1. Rocky Mountain Spotted Fever
2. Anaplasomosis
3. Babesiosis
4. Lyme Disease

Question two

What do you do next?

1. Treat with oral doxycycline
2. Treat with IV ceftriaxone
3. Draw Lyme serologies; treat if positive
4. Treat only if the patient becomes symptomatic

Question three

A teammate of this patient develops fever and a polyarticular arthritis, and sees a Lyme specialist who diagnoses him with Lyme disease on the basis of a PCR test performed on blood by a specialty laboratory. He's been on IV ceftriaxone for six months with only modest improvement to symptoms when he comes to you (his Lyme doctor is on vacation) because he has become febrile and very ill. The skin around his indwelling catheter is red and warm, he has back pain and hematuria, and effusions in several joints. He is eventually diagnosed with an MRSA line infection, the indwelling catheter is removed and he's treated for the MRSA infection. You're about to discharge him from inpatient care, when the Lyme antibody test you ordered on admission comes back negative. What do you do?

1. Reassure him that he probably didn't have Lyme, complete treatment for the MRSA, and send him back to his prior provider for follow-up and continuation therapy.
2. Complete his MRSA treatment and initiate a diagnostic workup for his joint disease.
3. Complete his MRSA treatment and caution him not to return to the other provider.
4. Repeat the serology, it's likely a false-negative since the PCR was positive

Case Two

• HPI: A 10 year old girl from North Carolina presents in May with two days of sore throat, malaise, and a low-grade fever. She is initially seen by her pediatrician, who suspects a viral URI. She returns 2 days later with a history of a day of emesis, diarrhea, increased fever, and rash.
• ROS: Occasional tick exposures; plays outdoors, household has several dogs; tick removed 10d ago. Vaccinations up to date. No prior medical problems other than colds and such.
• FH/SH: Only child, parents A&W. Repeated 2nd grade; doing well since. Loves animals, has trained one of her dogs for local shows.
• MEDS: Tylenol used for fever in age-appropriate doses.
• PEx: T 103.3, P 104, BP 100/60, RR 24
• HEENT with injected conjunctivae and red spots on palate
• Skin with rash (see picture). These lesions are non-blanching, predominantly on the distal upper and lower extremities, but beginning to spread to the trunk. Extremities are cool, with weak pulses.
• Chest clear. Heart RRR, no m/r/g. Abdomen soft without tenderness, no masses.
• Labs: Chemistries include sodium 125 mmol/L, Co2 15, otherwise normal CBC WBC 14,900, differential includes 78% neutrophils, Hgb 8.8, plt 26,000, PT/PTT greatly prolonged.

Question Four

What is the most likely diagnosis?

1. Endemic typhus
2. Anaplasomosis
3. Rocky Mountain Spotted Fever
4. Babesiosis

Question Five

What do you do next?

1. Treat with doxycycline as an outpatient.
2. Admit the patient to the hospital and treat with doxycycline.
3. Admit the patient to the hospital and treat with ceftriaxone.
4. Perform a skin biopsy and send the sample to the lab for STAT RMSF studies, transfuse plasma and platelets to correct the coagulopathy, and treat with antibiotics if test is positive.

Case Three

• HPI: A 38 year old man from Guilford presents in September with a 4 day history of fever, chills, and malaise. His condition has gradually deteriorated, but because of a lack of health insurance he delayed seeking care. His girlfriend had difficulty awakening him, called an ambulance, and he presents to the ER.
• ROS: No significant health problems according to his girlfriend, but she doesn't know his history well.
• FH/SH: He is a professional gardener, divorced, with one child who doesn't live with him. No significant family history, girlfriend is well.
• MEDS: ibuprofen prn pain, perhaps 2x/week.
• PEx: T 102.2F P 108 BP 60/40 RR 16
• Labs: normal chemistries, a hematocrit of 42, WBC of 2.2K with 32 segs, 52 lymphs, 12 monos, 3 eos and 1 baso, and no other abnormalities noted on the smear. Platelet count is 32K. You get a call from the laboratory.

Question Six

If the laboratory calls to tell you there are inclusions in the patient's white cells, which is the most likely diagnosis?

1. Lyme disease
2. Ehrlichiosis
3. Anaplasomosis
4. Babesiosis

Question Seven

If the laboratory calls to tell you there are inclusions in the patient's red cells, which is the most likely diagnosis?

1. Rocky Mountain Spotted Fever
2. Anaplasomosis
3. Babesiosis
4. Ehrlichiosis

Question Eight

Which of the following patients is most at-risk for severe Babesia infection?

1. A 10 year old boy with severe sickle cell disease.
2. A 34 year old woman in the second trimester of her third pregnancy.
3. A 65 year old man with 15 years of type II diabetes and significant atherosclerotic disease.
4. A 40 year old man s/p severe motor vehicle accident with six weeks of hospitalization and multiple courses of antibiotics.

Question Nine

Which of the following pathogens is most likely to develop antibiotic resistance?

1. Borrelia burgdorferi
2. Rickettsia rickettsiae
3. Anaplasma phagocyotophila
4. Coxiella burnetti

Question Ten

Which of the following patients is most likely to present with a pustule on the hand with associated fever, headache, and axillary lymphadenopathy?

1. A 22 year old man hiking the Appalachian Trail in Georgia in August.
2. A 63 year old avid gardener in Hamden, CT.
3. A 32 year old abbatoir worker in Nebraska.
4. A 7-year old girl who got a new kitty a month ago.