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B. PO cephalexin


This patient has cellulitis and should be managed according to the 2014 Infectious Diseases Society of America guidelines for the treatment of skin and soft tissue infections. Cellulitis should be divided into purulent vs. non-purulent, this case representing the latter given the absence of pus. Next, the severity should be determined. Patients who are septic and/or have evidence of penetrating trauma, immunocompromise and/or necrotizing fasciitis are classified as severe and require surgical intervention and empiric vancomycin and piperacillin-tazobactam. Cases with systemic signs but not meeting the criteria for severe disease are classified as moderate severity and should receive IV therapy with antibiotics directed at Streptococcus pyogenes such as penicillin, cefazolin, ceftriaxone, or clindamycin. Patients with no systemic signs and no criteria for severe disease (this patient) are considered mild and should receive oral therapy with an antibiotic predictively active against S. pyogenes such as penicillin, cephalexin, dicloxacillin, or clindamycin.

Purulent cellulitis should be drained (sufficient therapy for mild cases), and receive oral therapy directed at methicillin-resistant Staphylococcus aureus (trimethoprim-sulfamethoxazole or doxycycline) if there are systemic signs (moderate severity) or IV therapy (vancomycin, daptomycin, linezolid, televancin, or ceftaroline) if there is sepsis, failure of prior therapy, or immunocompromise (severe disease).

Conjugated meningococcal vaccine (Menactra®, Menveo®) is recommended for all adolescents today but particularly for military recruits, college students living in dormitories, and travelers to endemic areas of meningococcal disease.
A 30-year-old man comes to the emergency department with increasing inability to walk without holding on to something. He denies any other complaints.

Works as a bellhop in a local hotel
Admits to having multiple sexual partners (both male and female)
Smokes 2 packs/day of cigarettes
Drinks a 6-pack of beer daily
FAMILY HISTORY: Noncontributory
BP 130/70, P 90, Temp 99° F, RR 18
TMs clear
Throat clear
Neck: Supple; no meningismus
Heart: RRR without murmurs, rubs, or gallops
Lungs: CTA
Abdomen: Bowel sounds present, no hepatosplenomegaly
Extremities: Benign
GU: No lesions
Neurologic: Romberg sign is present; possible decreased position sense in lower extremities
MRI of head: Normal
WBC: 2500/cu mm; 60% polys, 30% lymphs
CD4: 160/cu mm
HIV ELISA: Pending
Electrolytes: Normal
Renal panel including creatinine and BUN: Normal
Serum VDRL: Positive at 1:32
Serum fluorescent treponemal antibody test (FTA-ABS): Positive
LP Results are below:
CSF WBC: 50 WBCs/cu mm; 65% lymphocytes
CSF Protein: 150 mg/dL
CSF Glucose: 60 mg/dL (plasma glucose 90 mg/dL)
CSF VDRL: Negative

Based on your findings, which of the following is the appropriate treatment?
A) Benzathine penicillin G, 2.4 million units IM, single dose
B) Penicillin G, 1 million units intravenously q 6 hours
C) Vancomycin, 1 gram intravenously q 12 hours and ceftriaxone, 2 grams IV q 24 hours
D) Penicillin G, 3 million units intravenously q 4 hours
E) Benzathine penicillin G, 2.4 million units IM, q week x 3 weeks
A 60-year-old man is evaluated because of a 1-week history of lower extremity weakness, new onset of difficulty speaking, and decreased attention span. He has had occasional diarrhea and abdominal pain in the last year. Of significance is that he has lost about 25 lbs during the past year. He complains of joint pains, particularly in his knees. He has had low-grade fever but no chills during the last year. He reports occasional night sweats. He has noted no other neurologic findings like seizures. His wife reports that areas of his skin are becoming darker—particularly those exposed to light.

PAST MEDICAL HISTORY: Healthy before this episode
SOCIAL HISTORY: Lives in Michigan
Works in the auto industry
REVIEW OF SYSTEMS: Pretty much covered in the HPI
BP 130/80, T 99.9° F, P 84, RR 18
General: Alert, but oriented only to person and place
Mild right-sided facial droop
Throat clear
Neck: Scattered lymphadenopathy in the anterior and posterior cervical chains; most nodes are 1 x 1 cm, but a few are 2 x 1 cm
Heart: RRR without murmurs, rubs, or gallops
Lungs: CTA
Abdomen: Spleen tip palpated; no hepatomegaly
A questionable abdominal mass discerned with deep palpation
Extremities: No cyanosis, clubbing, or edema
Neuro: Right lower extremity with increased tone and 4/5 muscle strength
Sensation is normal
Deep tendon reflexes are symmetrical
Hemoglobin: 15.2 gm/dL
Hematocrit: 50%
WBC: 30,000/cu mm; 65% neutrophils, 28% lymphs
ESR: 13 mm/hr
Glucose: 200 mg/dL
Albumin: 3.5 g/dL
ALT: 30 U/L
AST: 25 U/L
CT of the head shows a hypodense left frontal lobe lesion. A stereotactic brain biopsy is taken and shows acute inflammation and necrosis with no malignant cells. Gram stain shows 1+ WBCs but no organisms. However, a specimen stained with periodic acid-Schiff (PAS) shows multiple PAS-positive foamy macrophages.

Which of the following organisms is likely responsible for his condition?
A) Coxiella burnetii
B) Trophermyma whipplei
C) Mycobacterium tuberculosis
D) Nocardia asteroides
E) Actinomyces israelii
A 32-year-old, otherwise healthy man is brought by ambulance to the emergency department for confusion and hypoxia. His wife called EMS after returning from work and found him febrile and confused, lying in the bed. During the morning, he reported feeling unwell and decided not to go to work, but he was not confused and looked well. At lunch, when his wife called, he was also fairly well but reported having developed a fever. He has no medical history and takes no medications. For the past 3 days, he had been keeping a bedside vigil for his brother who accompanied him on the hunting trip and succumbed to a case of "severe pneumonia" yesterday.

He works as a postal worker in New Mexico, and his wife reports that he handles "suspicious packages all the time." He is an avid hunter and returned 4 days ago from a 7-day deer hunt in northern New Mexico, where they stayed in a cabin. He and his brother both killed a deer; his wife does not know whether he wears gloves while field dressing the animals. She reports he sustained several tick bites, and several rodents were noted in the cabin. He does not smoke or use drugs.

Physical examination: T 103.8° F, HR 125, RR 32, BP 95/60, Pulse oximetry on room air: 85%

He is cyanotic, confused, and somnolent.

Nuchal rigidity is absent. Head and neck examination is normal.

He is tachypneic with shallow respirations and coughing profusely with blood-tinged sputum. Coarse crackles are audible throughout.

Heart rate is tachycardic but regular.

Abdomen and skin exam is normal.

He moves all his extremities; cranial nerves appear normal.

Chest radiograph reveals diffuse, bilateral consolidations.

Assuming the patient acquired his infection from his brother, which of the following is the most likely pathogen?
A) Bacillus anthrax
B) Clostridium botulinum
C) Salmonella typhi
D) Francisella tularensis
E) Yersinia pestis
A 28-year-old man is referred to you because he is found to be seropositive for Epstein-Barr virus. For a year he has had difficulty falling asleep, as well as frequent awakening during the night. He has had increasing problems with daytime fatigue and reports that he can't concentrate as well. He has lost interest in his hobbies; he used to enjoy playing basketball avidly. He has gained 20 lbs in the last year and says that he "just doesn't feel like exercising."

PAST MEDICAL HISTORY: Negative; started coming to the local physician about 1 year ago with sleep disturbances
SOCIAL HISTORY: Divorced about 2 years ago
Has 2 children; wife has custody
"Recovered alcoholic"; hasn't had a drink in 5 years
Smokes 1 pack of cigarettes daily
No illicit drug use
FAMILY HISTORY: Mother age 60; history of depression
Father age 60; hypertension
No fever
No chills
No sore throat
No lymph node enlargement noted
No diaphoresis
No cough
No palpitations
No constipation
No diarrhea
No risk factors for HIV
BP 120/70, P 90, RR 18, Temp: 99° F
Ht. 5'10" Wt. 190 lbs (moderate truncal obesity)
TMs clear
Throat clear; no erythema; no obvious dental caries noted
Neck: Supple
Heart: RRR without murmurs, rubs, or gallops
Abdomen: Bowel sounds present; liver span 6 cm; no spleen palpated
Extremities: No cyanosis, clubbing, or edema
Electrolytes: Normal
Liver enzymes and panel: Normal
EBV titers: Only positive is EBV viral capsid (VCA) specific IgG antibody titer at 1:160

Based on your findings, which of the following do you think he needs?
A) CMV testing.
B) Referral to an infectious disease specialist for evaluation of chronic EBV syndrome.
C) Check EBV DNA viral load.
D) Measurement of T-lymphocytes.
E) No further infectious workup is indicated.

A. Several cutaneous papules


Bartonella henselae , a curved, pleomorphic, gram-negative bacillus, is responsible for cat-scratch disease. This disease is characterized by tender regional lymphadenopathy and erythematous tender papules following a kitten or, less often, a cat scratch. Following an incubation period of 3-14 days, one or several cutaneous papules or pustules develop at the inoculation site. The lesions persist for 1-3 weeks but often go unnoticed. As they resolve, regional lymphadenopathy develops proximal to the inoculation site. Painful and often suppurative lymphadenopathy most often involves the axillary nodes, followed in frequency by the cervical, and then the inguinal lymph nodes. Constitutional symptoms are more often than not mild and may include generalized malaise, low-grade fever, anorexia, nausea, headache, and fatigue. Complications may include encephalitis, osteomyelitis, neuroretinitis, pneumonitis, transverse myelitis, and arthralgia/arthritis. Antibiotics are not required in the majority of cases. Although aspiration of fluctuant nodes will relieve pain, incision and drainage does not hasten recovery and should be avoided because of residual scaring and draining fistulae. Thickened yellow nail plates describes onychomycosis; retinal hemorrhages with whitish-pale center describes Roth spots; nontender erythematous lesions on the palms and soles describes Janeway lesions; and painful lesions on the palms and soles describes Osler nodes. These latter 3 findings are all associated with bacterial endocarditis.

D. Epstein-Barr virus


She has clinical signs and symptoms often associated with infectious mononucleosis, caused by Epstein-Barr virus. Periorbital and eyelid edema is an early clinical finding in up to 50% of patients with this disorder. Although a rash develops in a large proportion of patients with mononucleosis treated with ampicillin or amoxicillin (usually for presumed streptococcal infection), up to 10-15% of patients will develop a morbilliform-like rash as described in the vignette in the absence of any antimicrobial treatment. An enanthem, characterized by petechial lesions at the junction of the soft and hard palates, may also be seen in up to 25-30% of patients. Additional clinical findings may include severe membranous tonsillitis, anterior and posterior cervical lymphadenopathy, splenomegaly, hepatomegaly and jaundice secondary to icteric hepatitis. Large basophilic-staining lymphocytes containing a "foamy-like" cytoplasm (atypical lymphocytes) are often identified on peripheral smear. Rapid diagnosis is made by the rapid Monospot test which identifies heterophil antibodies produced in infectious mononucleosis. However, the rapid test may be negative early in the course of the disease. In general, treatment is symptomatic only, with avoidance of contact sports and other activities which could lead to increased risk of splenic rupture, following abdominal trauma, for 4-6 weeks. Corticosteroids should be avoided unless there is concern about significant upper airway obstruction.
A 22-year-old pop singer has been ill with diarrhea for the past 2 weeks. She says that she noted this while she was performing in Latin America. You are the physician for the cruise line that she is performing for now.

She tells you that she has had some low-grade temperatures since returning from her tour. She did not eat any fresh vegetables (unless you call French fries a fresh vegetable). She likes to eat beef jerky and prefers the "extra salty" version. She drank only bottled water and a soft drink for which she is a national spokesperson. She did drink these beverages poured over ice, but she thought that the "frozen stuff would kill the cooties."

She has not noted any blood in her stool. She has lost about 2 pounds in the last week.

Past Medical History:
Cosmetic surgery at age 16
Depression since age 14, on no medications at the moment

Social History:
Sexually active with multiple partners
Smokes 1 pack/day for the past 3 years
Denies illicit drug use
Denies use of alcohol

Family History:
She and her mother are estranged at the moment.
Father left when she was 12 years of age
Sister healthy
Recently was married in Las Vegas; marriage was annulled after 24 hours—"I don't know what I was thinking."

Review of Systems:
Diarrhea is intermittent, and she has crampy abdominal pain on occasion.
No rash
No burning on urination
No chills
Diminished appetite

Physical Examination:
General: Pink hair with numerous piercings
VS: Temp 100.0° F, BP 110/70, Pulse 95, RR 16
Throat: Clear
Heart: RRR with no murmurs, rubs, or gallops
Lungs: CTA
Abd: Hyperactive bowel sounds, non-tender examination; no hepatosplenomegaly
GU: Normal female genitalia; no tenderness on bi manual palpation; no discharge noted
Extremities: No cyanosis, clubbing, or edema
Rectal: Heme positive (slight)

Check for stool leukocytes: Positive
Giardia specific antigen: Negative
Stool culture: Salmonella enteritidis beta-lactamase producing

Based on this information, which of the following is the best treatment?
A) Ciprofloxacin 500 mg bid for 10 days
B) Erythromycin 500 mg bid for 5 days
C) Tetracycline 500 mg qid for 10 days
D) Amoxicillin 500 mg tid for 10 days
E) No antibiotic therapy
A 25-year-old man comes to the emergency department complaining of weakness in both legs. He reports that he started to have a tingling sensation in his toes about a day ago along with a slight bilateral foot-drop sensation. On awakening this morning, he had problems grasping objects and noted some weakness in his upper legs. He has had no fever, diplopia, dysphagia, or dyspnea. He had a "cold" 1 week prior to his current symptoms. He removed a tick from his waist about a week and a half ago. He eats homegrown vegetables and fruits that his mother cans for him back in West Virginia.

Immunizations up to date
SOCIAL HISTORY: Works as a truck driver in the Washington, DC area
Smokes 2 packs/day of cigarettes
Doesn't drink alcohol
BP 120/76, RR 18, Temp 97.9° F, P 86
Discs sharp
TMs clear
Throat clear
Neck: Supple
Heart: RRR with I/VI systolic flow murmur
Lungs: CTA
Abdomen: Bowel sounds present; no hepatosplenomegaly
Extremities: No cyanosis, clubbing, or edema
Neuro: Symmetrical weakness of lower extremities—distal muscles more affected than proximal muscles
Bilateral foot drop
Weakness of both hands noted
Cranial nerves II-XII tested and intact
Sensory perception is slightly decreased in the distal lower legs
Patellar and Achilles reflexes are absent bilaterally

Which of the following is the most likely diagnosis?
A) Rabies
B) Guillain-Barré syndrome
C) Poliomyelitis
D) Botulism (foodborne)
E) Tick paralysis

A. Counsel that valacyclovir or famciclovir started in the first 48 hours of a zoster flare can reduce the duration of post-herpetic neuralgia.


Varicella zoster is responsible for chicken pox (varicella) in children, herpes zoster in adults, and infrequently, primary varicella infections in adults. Adults who experience a primary infection with varicella tend to have a much more serious course, with increased morbidity and mortality. Primary infection in adults does not present as shingles, but rather, presents as a very serious case of chicken pox with possible pneumonia and/or encephalitis. Children can contract varicella from an adult with shingles, but an adult does not contract shingles from a child with chicken pox. Shingles only results after the virus, through primary infection, establishes itself in the nerve roots, then reactivates at a later date. Dermatomal flares are consistent with reactivation of dormant varicella virus in adults who experienced the initial infection during childhood. Vaccination for susceptible patients older than 12 years of age requires two injections at least one month apart to achieve reasonable levels of immunity. With this vaccine, you are preventing primary infection with chicken pox; and, the reason to vaccinate is to prevent the serious morbidity from adult chicken pox. Valacyclovir or famciclovir started early in the course of a zoster flare can reduce the duration of post-herpetic neuralgia. These 2 agents have been shown to be superior to acyclovir. The grandchildren should be immunized against varicella and if so, they are of no risk to the grandmother. If for some reason they were not immunized, as long as her lesions can be kept covered (by a blouse for truncal lesions), then the risk is very low as well to the unimmunized grandchildren.

A. Oral trimethoprim/sulfamethoxazole


Community-acquired methicillin-resistant S. aureus (MRSA) is an emerging challenge for infection control. These strains are often associated with skin and soft tissue infections, but may also cause sepsis, pneumonia, and necrotizing pathology. Clindamycin, trimethoprim/sulfamethoxazole, and quinolones are outpatient options for oral treatment. Unfortunately, community-acquired MRSA has a significant tendency to develop inducible resistance to both clindamycin and the quinolones. The erythromycin-clindamycin D-zone test evaluates a MRSA isolate for its capacity to express inducible resistance genes in the presence of clindamycin. A positive D-zone test indicates that even though an isolate appears susceptible to clindamycin in vitro , the organisms can express their resistance genes after being in the presence of clindamycin after some time. Thus, clindamycin is inappropriate in the setting of a positive D-zone test.

Unfortunately, we have no such test for the quinolone drugs. Should you choose to treat a MRSA skin infection with a quinolone, you must be vigilant in observing the clinical response to ensure treatment failure does not occur. Amoxicillin-clavulanate does not cover MRSA. Vancomycin requires intravenous administration and is unnecessary for skin and soft tissue infections only (in the absence of osteomyelitis); oral vancomycin is only used for moderate-to-severe C. difficile infection. MRSA is resistant to dicloxacillin.
A previously healthy 45-year-old man comes to the emergency department with a history of headache and fever, which he has had for about a day and a half. His wife reports that he has been confused and, at times, she is not able to understand what he is saying. This has progressively gotten worse in the past few hours. They are "outdoorsy" people and camp quite a bit in the Ozark Mountains in Missouri and Arkansas.

SOCIAL HISTORY: Airline pilot; no travel outside of U.S.
FAMILY HISTORY: Father with Alzheimer's at age 60
Mother healthy
BP 110/70, P 100, RR 18, Temp 102° F
Oriented only to person; does not know where he is or the current year
TMs clear
Throat clear
Neck: Stiff with meningismus
Heart: RRR without murmur, rubs, or gallops
Lungs: CTA
Abdomen: Bowel sounds present; no hepatosplenomegaly
Extremities: No cyanosis, clubbing, or edema
Skin: No rash
Neuro: Normal other than mental status testing
LABORATORY: CT without contrast preliminary results: no infarct; ventricles normal
EEG shows abnormalities in the right temporal lobe area
Lumbar puncture results below:
WBC: 220 WBC/cu mm (30% polys; 70% lymphs)
RBC: 400 RBC in tube 1
RBC: 300 RBC in tube 4
Protein: 65 mg/dL (normal)
Glucose: 80 mg/dL with serum of 120 mg/dL
Gram stain of CSF: No organisms seen
Acid-fast stain: No organisms seen
Cryptococcal antigen assay on CSF: Negative

Which of the following is the most likely cause of his illness?
A) Streptococcus pneumoniae
B) Herpes simplex virus
C) Listeria monocytogenes
D) Francisella tularensis
E) Borrelia burgdorferi

B. Staphylococcus aureus


She has clinical evidence of toxic shock syndrome (TSS), often caused by extracellular toxins produced by Staphylococcus aureus , which cause intravascular fluid loss leading to multi-system disease. TSS may also be caused by certain types of group A β-hemolytic streptococci containing specific M proteins. Clinical signs and symptoms follow systemic absorption of toxin and include fever, hypotension, and an intensely erythematous generalized rash (erythroderma) often involving the mucous membranes. The rash may be preceded by a 2-3 day prodrome of nausea, vomiting, diarrhea, malaise, and myalgia. In addition, documentation of dysfunction in at least 2 other organ systems is required for the diagnosis: elevated serum transaminases, coagulopathy, elevated renal functions, elevated serum creatinine kinase, or altered mental status. Potential sources of toxin-producing Staphylococcus aureus include burns, abrasions, surgical wounds, tampons, indwelling catheters, and nasal packings. Recovery may be complicated by adult respiratory distress syndrome, disseminated intravascular coagulation, renal failure, and cardiogenic shock. Aggressive fluid and hemodynamic resuscitation to reverse hypotension is required. Antimicrobial therapy is recommended to eradicate the offending organisms from the site of infection. Empiric treatment with clindamycin, to suppress toxin synthesis, and nafcillin/vancomycin is recommended prior to positive identification of the offending organism. During recovery, desquamation, especially of the palms and soles, is common. IVIG has also been used in some studies as an adjunctive therapy.
A 26-year-old man presents to the emergency department with fever and new-onset seizures. He has been acting erratically; and this morning, he thought he was the King of Nigeria. Prior to arrival, he had 2 episodes of tonic-clonic seizures, and upon arrival to the emergency department, he seized a third time. He was given lorazepam and a loading dose of phenytoin.

On physical examination, he appears agitated and confused.

Temperature 100.3° F (37.9° C), BP 120/65 mmHg, P 120 bpm, and oxygen saturation 97% on room air.

Blood glucose level at bedside = 98 mg/dL.

No papilledema
No lacerations or bruising
No meningismus
Regular rate without murmurs, rubs, or gallops
Symmetric excursions, resonant to percussion, vesicular breath sounds throughout
Normal bowel sounds, no hepatosplenomegaly
No cyanosis, clubbing, or edema
Sedated and unable to follow commands
No gross facial asymmetry noted
Gag reflex intact
Appropriate responses to
noxious stimuli
Well-developed musculature
No rigidity noted
Reflexes were equal and symmetrical bilaterally
Initial Laboratory:

13.0 g/dL
134 mEq/L
3.7 mEq/L
92 mEq/L
Carbon dioxide:
26 mmol/L
10 mg/dL
1.1 mg/dL
Drug screen:
CT of Brain:
No mass lesions; no hemorrhages
Opening pressure: 18 cm H2O
176 WBC/µL (90% lymphocytes)
760 RBC/µL
70 mg/dL glucose
95 mg/dL protein
Gram stain, acid-fast smear, and
cryptococcal antigen negative
Serum RPR:

Which of the following tests is the most sensitive for discerning HSV as a cause of meningoencephalitis?
A) CT of the head
C) Polymerase chain reaction (PCR) testing of CSF
D) Virus culture of cerebrospinal fluid (CSF)
E) MRI of the head
A 32-year-old Peace Corps volunteer presents to your office 3 weeks after returning from central Africa, complaining of fever, malaise, headache, and mild diarrhea. He spent his last 3 months providing medical care to a small village. He has no previous medical illnesses. He does not drink alcohol and smokes half a pack of cigarettes per day. He received yellow fever and hepatitis A vaccines before the trip. He was given mefloquine for the trip to Africa, which he took weekly during his stay there. He is currently taking only acetaminophen, as needed for the fever and headache. He denies having any sexual contacts during his stay in Africa.

On physical exam, he appears ill and fatigued. His blood pressure is 112/70 mmHg, pulse 88 bpm, respirations 14/min, and temperature 102.4° F (39.1° C).

There is no jaundice, but scleral icterus is present. ENT exam is normal. There is no lymphadenopathy. Heart is regular with no murmur; lungs are clear; and abdominal exam is normal with no hepatosplenomegaly. There is no peripheral edema. He is lethargic, but his neurologic exam is nonfocal. There is no rash.

Laboratory results:

10.7 cells/mm3
12.2 mg/dL
81,000 cells/mm3
92 mg/dL
30 mg/dL
1.2 mg/dL
20 U/L
22 U/L
Alk Phos:
100 U/L
Total Bili:
3.6 mg/dL
Direct Bili:
0.9 mg/dL
Several peripheral smears are done and show ring-shaped organisms within erythrocytes, with some of the RBCs infected with multiple organisms. One of the peripheral smears shows the following:

Which of the following is the most appropriate initial step in patient care?
A) Artemether-lumefantrine
B) Doxycycline alone
C) Chloroquine followed by two weeks of primaquine
D) Exchange transfusion
E) High-dose chloroquine alone

B. Gentamicin


She has clinical signs and symptoms most consistent with tularemia, caused by the gram-negative bacteria Francisella tularensis . It is most common among residents of Arkansas, Oklahoma, and Missouri. The organism, which can penetrate intact skin and mucous membranes, is transmitted following contact with an infected animal or by a tick vector. Tularemia most often presents with ulceroglandular or isolated glandular disease. The ulcer is often associated with eschar formation followed by regional lymphadenopathy. Physical findings may also include hepatosplenomegaly and a variety of cutaneous lesions including a generalized maculopapular rash, erythema multiforme, or erythema nodosum. Pneumonia may follow inhalation of the organisms, and conjunctivitis may result from direct inoculation by contaminated fingers or debris. The diagnosis may be confirmed by serum agglutination tests with titers of ≥ 1:160. The treatment of choice is gentamicin in more severe cases or doxycycline in those that are less severe; streptomycin is an alternative to gentamicin, but most prefer gentamicin because of the ability to use IV instead of IM injections. The Boards will not make you choose between appropriate antibiotic choices because it is a clinical decision, and there won't be a "right answer" unless the patient is deathly ill. Relapses are more common in patients treated with tetracyclines, but it is reasonable to try if the patient is not that ill. The organism is not susceptible to third-generation cephalosporins. Prevention is best accomplished by taking appropriate precautions in tick-infested areas and in handling injured animals.
A 19-year-old female presents to the emergency department with a one-day history of septic symptoms. She reports a significant toothache over the last three days; and, on the morning of presentation, she developed vomiting, diffuse muscle pain, fever, some confusion, and a diffuse erythematous, macular rash with nondescript borders. She has no medical history and is taking no medications. Her last menstrual cycle was 10 days previously and was normal.

On exam, she is in moderate distress. Her temperature is 38.9° C (102.0° F); heart rate is 136/min with weak peripheral pulses; blood pressure is 84/54 mmHg; and respiratory rate is 18/min. She has significant orthostatic changes. There is bilateral conjunctival erythema and significant swelling over the left maxillary area with an apparent complicated tooth abscess. There is significant hyperemia of the mucous membranes. Lungs demonstrate good air movement with clear auscultation. Cardiac exam reveals a rapid rate and no murmurs. Abdomen is unremarkable. Skin is erythematous and generally warm to the touch; no desquamation, blistering, or tenderness is noted.

Patient is started on aggressive intravenous hydration; blood and urine cultures are obtained; and she undergoes drainage of the dental abscess. She is also started on a broad-spectrum antibiotic.

Blood and urine cultures showed no growth, and cultures obtained during abscess drainage revealed Gram (+) cocci in clusters. Staphylococcus aureus grows in culture of the abscess.

Which of the following is the most likely explanation for these findings?
A) Staphylococcal scalded skin syndrome (SSSS)
B) Stevens-Johnson syndrome
C) Toxic epidermal necrolysis
D) Erysipelas
E) Toxic shock syndrome

E. Toxic shock syndrome


Toxic shock syndrome is a toxin-mediated process resulting from infection with either a toxin-producing Staphylococcus aureus or Streptococcus pyogenes . Although initially associated with tampon usage, current presentations can arise from any infection due to staph or strep organisms. Absence of host antibodies to the circulating toxin appears to be a primary risk for developing a toxic shock presentation. Treatment requires prompt intravenous fluid support, identification of the primary infection locus, and aggressive treatment of the underlying infection, including drainage of any localized purulence. Pending cultures, treatment is optimized with a β-lactamase-resistant, anti-staphylococcal antibiotic in combination with clindamycin. Clindamycin inhibits protein synthesis, which reduces the production of toxins and cytokines contributing to the systemic findings. Bacteria in deep-tissue abscesses are often in a stationary phase of growth, and very few organisms are replicating; hence, beta-lactam drugs that act on the cell wall during logarithmic growth are not the most effective drugs. Adding clindamycin helps to kill these organisms in stationary phase.

Desquamation, which is common in this disease process, is often delayed by 10-14 days from the original presentation.

Both Stevens-Johnson syndrome and toxic epidermal necrolysis are often caused by severe drug reactions that affect epidermal integrity resulting in varying degrees of epidermal detachment. Both can affect internal organs as well, resulting in a poor prognosis. This rash was present before the onset of medications and is not consistent with either of these diagnoses.

Staphylococcal scalded skin syndrome (SSSS) is mediated by two types of toxin—exfoliative toxin A and exfoliative toxin B. It is more common in younger children and displays blister formation—and often severe exfoliation. The skin is often tender to palpation, and the mucous membranes are usually spared.

Erysipelas is an infection typically caused by beta-hemolytic streptococci. The presence of the rash is typically concurrent with systemic symptoms, if these are present. Erysipelas is generally well-demarcated with raised edges, brightly erythematous, and tender to the touch. Rarely are systemic symptoms associated.

C. Do resistance testing, then, if okay per resistance testing, treat her with tenofovir, emtricitabine, and efavirenz. Also give her TMP/SMX.


Current guidelines now recommend:

1) Resistance testing for all treatment-naïve patients immediately before initiating treatment.

2) Start combination anti-retroviral therapy (ART) on all patients with HIV infection to reduce disease progression and help prevent transmission of HIV.

Preferred initial regimens for antiretroviral-naïve patients (after resistance testing):
*Tenofovir/emtricitabine/efavirenz (TDF / FTC / EFV) [Remember: EFV is absolutely contraindicated in pregnancy.]
*Tenofovir/emtricitabine/ritonavir-boosted atazanavir (TDF / FTC / ATV/r)
*Tenofovir/emtricitabine/ritonavir-boosted darunavir (TDF / FTC / DRV/r)
*Tenofovir/emtricitabine/raltegravir (TDF / FTC / RAL)

Note that TDF and FTC are included in all of the above combinations!

The TMP/SMX is for primary PJP prophylaxis based on her CD4 count < 200.

The other question answer choices are wrong—in some cases for multiple reasons. If resistance testing before treatment is not done, or if combination ART is not used, that answer choice is automatically wrong. Other points: It is inappropriate to send her away without offering therapy and not scheduling her follow-up for 6 months. The ZDV/d4T and efavirenz regimen is wrong because the ZDV/d4T combo is antagonistic. Using ZDV/d4T and ddC would also be wrong because of the ZDV/d4T antagonism as well as the inferiority of a 3-nucleoside regimen with the inferior ddC (never pick ddC). Again, never choose single-drug therapy such as ZDV alone as therapy for anyone.
A 52-year-old man is being evaluated because of a one-week history of lower extremity weakness, new onset of difficulty speaking, and decreased attention span (no jokes from the women out there about, "How would a man know if he had a decreased attention span?"). He has had occasional diarrhea and abdominal pain in the last year. Of significance is that he has lost about 25 lbs during the past year. He complains of joint pains, particularly in his knees. He has had low-grade fever but no chills during the last year. He reports occasional night sweats. He has noted no other neurologic findings like seizures. His wife reports that areas of his skin are becoming darker—particularly those exposed to light.

Past Medical History: Healthy before this

Social History:
Lives in Florida
Works as a bouncer for a teen-club

Family History: Negative

Physical Examination:
BP 130/80; T 99.9; P 84; RR 18
General: Alert, but oriented only to person and place
Mild facial droop
Throat: Clear
Neck: Scattered lymphadenopathy in the anterior and posterior cervical chains; most nodes are 1x1 cm but a few are 2x1 cm
Heart: RRR without murmurs, rubs, and gallops
Lungs: CTA
Abdomen: Spleen tip palpated; no hepatomegaly; a questionable abdominal mass discerned with deep palpation
Extremities: No cyanosis, clubbing, or edema
Neuro: Right lower extremity with increased tone and 4/5 muscle strength
Sensation is normal
Deep tendon reflexes are symmetrical

Hemoglobin: 16.0 g/dL; Hematocrit: 52%
WBC: 29,000/mm3; 65% neutrophils, 28% lymphs
ESR: 13 mm/hr
Glucose 200 mg/dL
Albumin 3.7 g/dL
ALT 32 U/L; AST 23 U/L

CT of the head shows a hypodense left frontal lobe lesion. A stereotactic brain biopsy is taken and shows acute inflammation and necrosis with no malignant cells. Gram stain shows 1+ WBCs and no organisms. Periodic acid-Schiff (PAS) staining shows multiple PAS-positive foamy macrophages.

Which of the following organisms is likely responsible for his condition?
A) Coxiella burnetii
B) Mycobacterium tuberculosis
C) Nocardia asteroides
D) Trophermyma whippleii
E) Actinomyces israelii
A 25-year-old man with a history of IV drug abuse is admitted with fever, malaise, headache, and weakness. He denies other symptoms at this time. He has not been in the hospital before.

PAST MEDICAL HISTORY: Negative; admits to using IV drugs for 5 years and currently still using
SOCIAL HISTORY: Works at a local restaurant as a cook
Drinks two 6-packs of beer on the weekends
Smokes 1 pack of cigarettes daily
Father 50 and healthy
Mother 50 and healthy
REVIEW OF SYSTEMS: Weight loss of 10 lbs noted for the past 2 months
Chronic "smoker" morning cough
Occasional night sweats
BP 98/70, RR 30, Temp 102° F, P 110
TMs clear
Throat slightly erythematous
Neck: Supple; no lymphadenopathy noted
Heart: RRR without murmurs, rubs, or gallops
Lungs: Coarse breath sounds; clear with cough
Abdomen: Bowel sounds present; no hepatosplenomegaly
Extremities: No cyanosis, clubbing, or edema
LABORATORY: Blood cultures grow Salmonella enterica, serotype typhimurium
You start him on intravenous ceftriaxone initially and then change him to oral ciprofloxacin 750 mg twice daily to complete a 2-week course. He follows up as an outpatient at the end of therapy and is doing well. However, 4 weeks later, he returns with the same symptoms, and blood cultures grow Salmonella enterica, serotype typhimurium again.

Which of the following diagnostic tests should you order at this time?
A) Bone marrow biopsy
B) Intravenous urography
C) Quantitative serum immunoglobulins
D) CT scan of the head

C. Viridans streptococci


She has clinical signs and symptoms consistent with subacute bacterial endocarditis (SBE). This disorder is caused most often by Staphylococcus aureus (~ 30%), viridans streptococci (~ 20%), enterococci (~ 10%), coagulase-negative staphylococci (~ 10%), Streptococcus bovis (~ 5%), and other streptococci (~ 5%). In suspected cases of SBE, the blood should be cultured for at least 7 days in order to detect fastidious bacteria or fungi. At least 3 cultures should be obtained in any patient undergoing evaluation for SBE. The yield on blood culture is relatively consistent and not related to the intensity of the patient's symptoms or presence or absence of fever. Pretreatment will decrease the yield of a positive blood culture to 50-60%. As with the case described, the majority with SBE has a preexisting structural cardiac abnormality (e.g., bicuspid aortic valves, septal defects, coarctation of the aorta, tetralogy of Fallot, a prosthetic valve) and present with a new or worsening murmur. Petechiae are common in SBE and are most often located on the mucous membranes and extremities. Other cutaneous findings may include splinter hemorrhages: nonblanching, linear reddish-brown lesions beneath the nail beds; Janeway lesions: macular, blanching, painless, erythematous lesions on the palms and soles; and Osler nodes: painful, violaceous nodules located on the pulp of the fingers and toes. Some patients will also have evidence of Roth spots, characteristic findings on eye exam that appear as exudative, edematous hemorrhagic lesions within the retina.
A 55-year-old man has fever and cough. He has AIDS and a history of disseminated histoplasmosis 2 years ago. He was treated initially with amphotericin B and had been maintained on itraconazole since. Last month, he started having fever and chills. Histoplasmosis was suspected again, and amphotericin B was restarted. Blood cultures, however, grew Mycobacterium intracellulare, and he was started on appropriate medications for that. He was restarted on his itraconazole maintenance therapy last month. Today, he comes in with recurrence of his fever and chills.

MEDICATIONS: Combivir and efavirenz for 6 months
Rifabutin 600 mg daily for 1 month
Azithromycin 500 mg daily for 1 month
Ethambutol 1200 mg daily for 1 month
Itraconazole 200 mg daily for 2 weeks
Ranitidine 150 mg bid for 2 weeks for gastric reflux symptoms
Trimethoprim/sulfamethoxazole DS 1 daily
Temp 103° F, BP 120/70, RR 24, P 100
TMs clear
Throat: clear
Neck: Supple
Heart: RRR without murmurs, rubs, or gallops
Lungs: Diminished breath sounds at left base
Abdomen: Liver span 14 cm
Spleen tip palpable
Extremities: No lesions noted
WBC: 1,200 cells/cu mm
Hgb: 10 g/dL
Platelets: 100,000
Peripheral smear: Yeast forms seen

Which of the following is most likely correct?
A) The yeast forms are likely contaminants.
B) The patient has itraconazole-resistant Histoplasma.
C) A serum cryptococcal antigen will be positive.
D) Blood cultures will grow Candida krusei.
E) Itraconazole and its metabolites are below therapeutic levels.