Prep Questions
A 17 yo girl presents to the emergency department with complaints of malaise, fever, chills and "aching joints". On physical examination her temperature is 100.9 F. Her wrists and hands are not swollen but are clearly painful on ROM testing. Scattered about her palms and fingers are several painful 2-4mm necrotic lesions. There are also several petechial and pustular lesions present on the distal portion of the right forearm. Additional clinical findings include pain, warmth and erythema over the right shoulder without associated effusion. Which of the following findings is most likely to be identified upon further examination of this patient's skin lesions?
a) gram-negative intracellular diplococci
b) multinucleate giant cells
c) gram-positive diplococci in chains
d) budding yeast and pseudohyphae
e) gram negative cocco bacilli
A. The patient has symptoms of a disseminated gonococcal infection. Endocarditis, meningitis and osteomyelitis are rare complications.
Within a week of completing 6 wks of antimicrobial therapy for chronic osteomyelitis, a 7 yo boy presents with a 4 day history of frequent episodes of diarrhea. He is febrile and appears fatigued on exam, but the remainder of his vitals are age appropriate. A fecal PCR for c. diff is positive, a toxin assay is subsequently positive. Which of the following is currently considered the initial drug of choice for this patient?
a) amoxicillin
b) amoxicillin/clavulanate
c) trimethoprim/sulfamethoxazole
d) Metronidazole
e) cefixime
D. Metronidazole or PO vancomycin are recommended for initial treatment of children and adolescents with mild to derate disease. For severe disease with hypotension and severe abdominal pain, PO vancomycin is preferred +/- IV metronidazole
Most common causes of acute osteomyelitis & septic arthritis in children
Staph. aureus and group A strep. (and s. pneumoniae in <5 yrs)
A 1 day old infant with no history of prenatal care presents with fever and mottling. The mother delivered the infant at home. Which of the following presentations would be most likely for group B strep infection at this age?
a) septicemia
b) septic arthritis
c) meningitis
d) osteomyelitis
e) cellulitis
A. For infants up to 6 days old, the most common presentation for GBS is frank septicemia (45%) or pneumonia (40%). Meningitis occurs in <10% of infants at this age. Septic arthritis, osteomyelitis and cellulitis are more likely to occur with late onset GBS 7 days to 3 months.
A 3 yr old boy awakens from a nap complaining of L thigh and groin pain. He has difficulty walking and when encouraged to do so, walks with a noticeable limp. Transient synovitis is at the top of your list as the cause. Which on e of the following is most consistent with your working diagnosis?
a) Temperature of 39C
b) pain improves with activity
c) recent URI
d) recent gastrointestinal bacterial infection
e) history of sickle cell disease
C. As many as 50% of children presenting with transient synovitis have a history of a recent URI. Typically occurs between 3 & 8 yrs. Children are well-appearing and non-toxic. Recent GI illness supports reactive arthritis. Fever would support osteomyelitis.
A 6 yo girl presents with 3 days of low grade fever, abdominal cramping and diarrhea. Several of her classmates have similar symptoms. She is otherwise well and takes no daily medications. On physical examination, she has a temperature of 101.1 and her BP is 100/65. Her mucous membranes are moist. Capillary refill is <3 seconds. Her abdomen is moderately tender throughout. Bowel sounds are hyperactive. There is no evidence of rebound tenderness. A stool culture is obtained, which grows salmonella typhimurium.
Which is the most appropriate next step in tx?
a) oral amoxicillin
b) IM ceftriaxone
c) PO trimethoprim-sulfamethoxazole
d) symptomatic treatment only
e) oral erythomycin
D. Uncomplicated non-typhoidal salmonella is not recommended because it can prolong excretion of the organism in the feces. Invasive disease such as meningitis and osteomyelitis caused by salmonella may require up to 6 weeks of therapy with amoxicillin, or bacterium or 3rd gen cephalosporins.
Most common causes of osteomyelitis in neonates
S. aureus, GBS and gram negatives
A plain radiograph of a 17 yo boy reveals deep and superficial soft tissue swelling overlying a radiolucent lesion of the R calcaneus. He stepped on a nail 2 weeks ago, suffering a puncture wound to the R foot.
These radiographic findings are most likely caused by which of the following?
a) pseudomonas aeruginosa
b) strep pneumoniae
c) neisseria gonorrhoeae
d) E. coli
e) group A strep
A. pseudomonas is associated with nail puncture. Radiographic bone changes do not appear until 2-3 weeks after onset. Changes include periosteal elevation followed by focal bone lysis, sclerosis and new bone formation.
Which of the following is the most likely cause of this patient's findings?
a) treponema pallidum
b) toxoplasmosis
c) staph. aureus
d) cytomegalovirus
e) rubella virus
The patient has typical radiographic findings of congenital syphillis, which occurs when the spirochete treponema palladium is transmitted to the fetus during gestation. Bony abnormalities are painful and patients often refuse to move the involved extremity, termed pseudo paralysis of Parrot.
A 6 yo boy presents to the ED because of an infection that his parents believe is getting worse. He was seen 72 hours prior and was prescribed cephalexin for what appeared to be a secondarily infected insect bite. He has had an unmeasured fever now for 2 days and chills for 1 day. On exam, he is ill-appearing, his temp is 101.8, pulse 150, RR 28, BP 80/46 after a bolus of IVF. The bite on his upper thigh is erythemaotous, tense, warm, tender and draining pus. Based on the pictures his mom has on her phone from 24 hrs ago, the area is progressed significantly. Which of the following parenteral antibiotics is most appropriate for this patient?
a) vancomycin
b) clindamycin
c) nafcillin
d) ceftriaxone
e) ampicillin/sulbactam
A. Prulent infection which are almost always due to staphylococcus aureus (MRSA). In severe cases give IV vancomycin +/- nafcillin or cefazolin to vancomycin for more focused MSSA coverage when child is critically ill. Moderate infections, give PO clindamycin, doxycycline and timethroprim/sulfamethoxazole. Mild infections need I&D, no antibiotics.
A 16 yo girl presents with painful/erythematous R knee x2 days, fever 101, started menstruating 3 days ago. Aside from the most common organisms, which additional organism should be on your differential
a) Strep. pneumoniae
b) pseudomonas aeruginosa
c) non-type b haemophilus influenza
d) bartonella henselae
e) staphylococcus aureus
E. Strep pneumoniae is not as common a cause of disci tis, osteomyelitis or skin/soft tissue infection as s. aureus. However, it is a more common cause of respiratory infections.
A 4 yo boy has refused to walk since awakening from a nap. His parents are not aware of any recent injury. He has been less active and more irritable over the last several days, has had an intermittent low-grade fever and complained of back pain. On physical examination his temperature is 100.9, his mobility is restricted and he resists all attempts to encourage him to walk. There is localized tenderness over the T3-T4 area with associated paraspinal muscle spasm. Laboratory evaluation includes a WBC of 9000 and an ESR of 95.
Which of the following is the most likely to be identified upon further evaluation of this patient?
a) narrowing of the intervertebral disk space on MRI
b) positive blood culture for viridian's streptococci
c) bone scan showing decreased perfusion to the femoral head
d) a unilateral defect (separation) in the vertebral pars interarticularis
A. The patient has signs and symptoms consistent with disci tis.
A 16 yo girl presents to the ER because of fever, chills, myalgia, vomiting and severe L ankle pain. On exam, she is oriented, but lethargic. Her temperature is 103.2, BP is 95/45. A small area overlying the lateral malleolus and lateral portion of the foot is cellulitis, surrounding what appears to be a small razor nick. Despite aggressive fluid resuscitation, she remains hypotensive and is admitted to the PICU where she continues to require fluid and inotropic support. 2 days later, cultures from the wound grew group A strep. The patient has NKDA.
Following identification of the organism, which of the following is the most appropriate treatment?
a) Penicillin G plus clindamycin
b) metronidazole
c) vancomycin plus clindamycin
d) meropenem
e) penicillin g plus IVIG
A. The child has evidence of GAS toxic shock. Invasive infections with GAS are increasing in frequency. Clindamycin provides protein synthesis inhibitor, blocking new toxin production.
An 18 month old boy with pmhx of suspected stroke in infancy, recently immigrated from Nigeria presents to the ED with hip erythema, refusal to move his L leg for the past 36 hrs. Additionally he's having diarrhea with some blood in his stool. He's febrile to 102.1. At baseline he has very little motor function in his R arm thought to be secondary to his stroke. He also has delayed speech. You obtain aspirate from his L hip joint and gram stain reveals gram negative rods with flagella. Most likely organism?
Salmonella (in the setting of sickle cell)
A 2 yo girl, hospitalized for treatment of osteomyelitis, undergoes a colonoscopy following the development of fever, abdominal pain, profuse diarrhea and abdominal tenderness on exam. Findings reveal hyperemic, friable colonic mucosa associated with multiple 3-5 mm yellowish plaques. Which of the following is the most likely cause of this patient's clinical signs and symptoms?
a) ulcerative colitis
b) E. coli O157:H7
c) Chron's disease
d) shigella flexneri
e) clostridium difficile
E. C. diff colitis is associated with tx with penicillins, macrolides, clindamycing, cephalostonis and flouroquinolones.
A 16 yo girl presents with complaints of generalized malaise, fever and chills. She also complains of pain in her hands and fingers; over the last several days, the has made it difficult for her to button her shirt, write with a pen or type on her computer. On exam her temp is 101.6. She prefers not to move her fingers and wrists, wincing with pain on ROM testing. Several tender 3-4 mm pustular and petechial lesions some of which appear necrotic are noted on her palms, left forearm and plantar surfaces.
Which of the following organisms is the most likely cause of this patient's clinical signs and symptoms?
a) n. gonorrhoeae
b) Herpes simplex
c) bartonella henselae
d) borrelia burgdorferi
e) hepatitis B virus
A 12 yo girl presents with a draining lesion. Her mother reports she has had this lesion for 5-6 months and it has not responded to cephalexin, clindamycin or ciprofloxacin. She has no travel history. She spends the summer and winters at the local club indoor pool and remembers that she scraped her leg against a pool tile 6 months ago. Routine bacterial cultures have been negative except for MRSA which was sensitive to ciprofloxacin. Which of the following organisms is the most likely cause based on her history?
a) francisella tularensis
b) mycobacterium marinum
c) mycobacterium tuberculosis
d) corynebacterium pseudotuberculosis
e) listeria monocytogenes
B. Chronic draining lesions in combination with water exposure. Fansicella causes tularemia and would have history of exposure to animal hides. TB would have enlarged lymph nodes and history of exposure risks. Corynebacterium is associated with occupational exposure to infected sheep and requires surgical excision of lymph node. Listeria is acquired from ingestion of improperly processed meats or unpasteurized dairy products.
You are called by the ER who evaluated a 12 yo F patient of your about 24 hrs ago. The child has R tibial osteomyelitis due to MSSA and has been receiving IV cefazolin via a PICC for 14 days. She has been afebrile since the 5th day of tx but developed a fever of 102.1 on the 12th day of cefazolin therapy. She is otherwise well and has no complaints. In the ER her MSK exam is normal. Her CBC and CRP were wnl. The ER is concerned that the fear may be due to failure of the cefazolin to adequately treat the osteomyelitis, because a blood culture obtained from the PICC is now growing gram-positive cocci in clusters. What is appropriate for this patient?
a) Continue cefazolin bc the organism growing from ER was likely contaminant
b) Perform a bone scan to look for alternate sources of osteomyelitis
c) obtain a repeat blood cx, hospitalize and begin IV vancomycin for possible CLABI
d) Continue cefazolin until the organism growing in the blood cx is completed
e) begin daily IM therapy with ceftriaxone
C. Likely CONS. Not a contaminant because she has a central line.
A 14 yo girl presents with complaints of low back pain that has gradually increased in intensity over the last 4-6 wks. She does not have a history of trauma although she participates in gymnastics every afternoon after school. She has not had a fever or other systemic symptoms. On physical examination, she has moderate point tenderness over the lower lumbar region that worsens when asked to bend backwards. There is also evidence of moderate hamstring tightness. Examination of the spine reveals no evidence of scoliosis, kyphosis, or lordosis. Which of the following is most likely to be identified upon further evaluation of this patient?
a) radiographic evidence of vertebral collapse associated with acute lymphoblastic leukemia on bone marrow exam
b) spinal cord tumor on MRI
c) stress fracture of the pars interarticularis on bone scan
d) dis space narrowing and irregularities of the lower lumbar vertebral bodies on plain radiograph
e) marked forward slippage of L5-S1 on lateral radiograph
c. The condition described is spondylosis, due to overuse and repetitive stress. The absence of malaise, fever and other systemic symptoms make ALL or infection process unlikely.