Infectious Disease Board Review

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Infectious DiseaseBoard Review

• Jennifer Rogers
• 6/20/08

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Outline

• Meningitis
• Actinomyces
• Urinary Tract Infections
• Secondary syphilis
• Malignant otitis externa
• HIV questions

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Bacterial Meningitis

• Strep. Pneumoniae is most common cause of
  bacterial meningitis 47, associated w/ 19-26
  mortality
• May occur in conjunction with pna, otitis,
  mastoiditis, sinusitis, endocarditis, s/p head
  trauma
• Often presents with fever, headache, nuchal
  rigidity
• Neurologic complications including focal
  deficits, seizures, papilledema

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Meningococcemia

• Neisseria meningitidis is 2nd most common w/
  3-13 mortality
• Meningococcal disease can manifest as three
  syndromes often with varying presentations from
  febrile illness to fulminant disease and death
  w/in a few hours
• -Meningitis
• -Meningitis with accompanying meningococcemia
• -Meningococcemia without clinical evidence of
  meningitis.

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Meningococcemia

• Predisposed in pts w/ C5-C9 deficient pt and
  those with dysfunctional properdin
• Presents w/ acute onset headache, fevers, nausea,
  confusion, myalgias
• 50 pts presents with petechial rash
• Can progress to shock, DIC, purpura fulminans,
  death
• Focal neurological signs and seizures are less
  common compared to Strep pneumo.
• Cardiac involvement myocarditis, pulm edema,
  heart failure is common in roughly 50 cases

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Purpura Fulminans
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Meningitis

• Listeria monocytogenes GI portal of entry raw
  veggies, mild, cheese, meats. Associated w/
  extremes of age and immunosuppressed patients
• Group B strep neonates and immunosuppressed
• Gram Negative bacilli including Klebsiella,
  E.coli, Serratia, Pseudomonas following NSG
  procedures and as co-infection in pts w/
  disseminated strongyloidiasis hyperinfection
  syndrome.
• H. influenza type b- now rare given vaccination
• Staph aureus- post surgical or following head
  trauma

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Diagnosis

• Indication for CT scan prior to LP seizure,
  papilledema, AMS, focal neurological deficit, h/o
  CNS dz, immunocompromised
• CSF analysis

Bacterial Viral TB Crytpo
WBC count 1000-5000 50-1000 50-300 20-500
Diff PMN Lymph Lymph Lymph
Glu lt40 gt45 lt45 lt40
Pro 100-500 lt200 50-300 gt45
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Empiric Therapy

• If gram stain is negative or LP delayed, start
  empiric abx based on age and underlying condition
• If gram stain is positive, target abx
• Adjunctive dexamethasone should be considered in
  pts w/ acute bacterial meningitis, give before or
  with 1st dose of abx

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Empiric Abx
Age 2-50 S. pneumo, N. meningitidis Vanc 3rd gen cephalosporin
Age gt50 S. pneumo, N. men, Listeria, GN bacilli Vanc 3rd gen cephalosporin ampicillin
Basillar skull fracture S. pneumo, H.influ, group A strep Vanc 3rd gen cephalosporin
Post-NSG or trauma Staph, Gram negative Pseudomonas Vanc either ceftaz, cefepime, or meropenem
CSF shunt Staph aurues, CONS, GNR Vanc either ceftaz, cefepime, or meropenem
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• 1. A 45 yo woman who has a 3-day h/o progressive
  earache and fever is hospitalized after becoming
  unresponsive. Medical history is unremarkable
  she has no allergies and she takes no
  medications. On physical exam on admission,
  temperature is 40oC, pulse is 120/min,
  respiration rate is 32/min, and blood pressure is
  80/50 mm Hg. The patient is obtunded and had
  meningismus. The leukocyte count is 25,000 uL w/
  25 band forms, and the platelet count is
  20,000/uL. Lumbar puncture is performed CSF
  fluid exam shows Appearance cloudy, WBC
  2500, 99 PMNs, glucose 20mg/dL, protein
  240mg/dL. A gram stain of unspun CSF fluid shows
  
• Which empiric treatment regimen should be
  initiated?
• PCN dexamethasone
• Ceftriaxone dexamethasone
• Vanc dexamethasone
• Vanc ceftriaxone dexamethasone
• Vanc ceftriaxone

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• 2. A 24 yo woman is brought to the ED
  because of fever, photophobia, and a stiff neck.
  On physical exam, the patient is irritable. Temp
  is 40oC. There is nuchal rigidity and a purpuric
  rash is seen on dependent areas of the body.
  While in the ED, the patient develops respiratory
  distress and requires intubation. She is
  subsequently admitted to the ICU.
• During transfer, the patient is isolated
  with droplet precautions, and all health care
  workers wear masks and use the appropriate
  barriers. Lumbar puncture is done in the ICU,
  and CSF exam shows gram negative diplococci.
• Which of the following health care workers
  requires antibiotic prophylaxis?
• All staff who were present in the ED and ICU when
  the patient was in these areas.
• All staff who examined the patient in the ED and
  ICU.
• The resident who intubated the patient in the ED.
• Prophylaxis is not required for any staff.

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• A 26-yo man comes to the ED w/ 5 days of HA,
  stiff neck, fatigue, N/V, myalgias, and weakness.
  He has just returned from a vacation in Jamaica,
  where he spent most of the day on the beach and
  much of each evening socializing in bars. He did
  not have any sexual contact on the trip. Medical
  history is unremarkable.
• On PE, temp is 38oC, pulse 78/min, RR 18/min, BP
  118/72. There is marked pain on flexion of the
  neck and moderate nuchal rigidity.
  Cardiopulmonary and abd exam are nml. The
  extremities are nml. There is mod photophobia.
  The CN are intact. Motor strength appears
  unimpaired, but the pt develops muscle pain
  during strenuous activity. Reflexes are
  symmetric and slightly hyperactive.
• Labs Hg 15.1 g/dL, Hct 47, WBC 9800/uL w/ 72
  PMN, 11 lymph, 13 eos, 4 monos. Plt
  288,000/uL, BUN 14, CR 0.8, electrolytes nml,
  LFTs nml.
• LP is performed. Opening pressure is 240cm H20.
  CSF WBC is 290/uL w/ 70 lymphs, 21 eos, 9
  monos
• Which of the following is the most likely
  pathogen?
• Angiostrongylus cantonensis
• Trichinella spirilis
• Strongyloides stercoralis
• Entamoeba histolytica
• Treponema pallidum

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• A 35yo woman is hospitalized b/c of fever, HA,
  ataxia, confusion, and loose stools. The pt
  underwent cadaveric kidney transplant 12 mo ago
  for ESRD. Current meds are prednisone and
  azathioprine. She is allergic to penicillin,
  which causes anaphylactic shock. However, she
  has received cephalexin in the past w/o a
  reaction.
• On PE, temp is 39.4oC, pulse 100/min, RR is
  30/min, and BP 90/60. The pt is confused and is
  oriented to person but not to place or time. Her
  neck is supple. The plantar response is extensor
  bilaterally.
• The WBC count is 18,500/uL w/ 20 bands. LP is
  performed and CSF shows WBC 1500/ul w/ 50 PMN
  and 50 lymphs, glucose 30 mg/dl, protein
  300mg/dl, gram stain negative.
• In addition to vancomycin, which of the following
  antibiotics should be initiated?
• Ceftriaxone
• Ceftriaxone plus trimethoprim-sulfamethoxazole
• Ceftriaxone plus levofloxacin
• Ceftriaxone plus azithromycin

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• A 30 yo woman is hospitalized following the
  sudden onset of severe HA, stiff neck, and
  vomiting. Evaluation reveals a subarachnoid
  hemorrhage secondary to a leaking aneurysm. The
  aneurysm is repaired surgically and a
  ventriculostomy tube is placed to drain CSF.
• Four days postoperatively, the pt develops
  fever, worsening headache, and confusion. On PE,
  her temp is 39.4oC, pulse 100/min, RR is 24/min,
  BP is 120/70. The ventriculostomy tube is
  draining clear CSF. All surgical sites are clean.
  
• The leukocyte count is 15,000/uL w/o a left
  shift. U/A and CXR are nml. CSF analysis is WBC
  300/ul w/ 90 PMN, WBC 900/ul, glucose 30 mg/dl,
  protein 150mg/dL, gram stain negative, culture
  pending.
• Which of the following empiric antibiotics should
  be initiated?
• Vancomycin
• Vanc rifampin
• Vanc ceftriaxone
• Vanc cefepime
• No therapy is indicated

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Actinomycosis
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Actinomyces

• Subacute-to-chronic infection caused by
  filamentous, gram-positive, non-acid fast,
  anaerobic bacteria.
• Part of normal oral flora
• Infection is characterized by suppurative and
  granulomatous inflammation with abscess and sinus
  tract formation with sulfur granules
• Most often results in cervicofacial infection 50
  cases
• Presents in pts predisposed to facial infection
• - dential caries, gingivitis, tooth
  extractions
• -underlying DM, immunosuppression, oral
  malignancies or radiation

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Cervicofacial actinomyces

• Most common manifestation, 50-70 of cases
• Presents as slow growing, non-tender indurated
  mass
• Progresses to multiple abscess and fistula
  formation with pain, trismus, and yellow purulent
  discharge (sulfur granules)
• Usually involves the mandible, but can infect
  any structure including cheek, chin, submaxillary
  sinus

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Thoracic and Abdominal

• Thoracic actinomyces 20 of cases is usually due
  to aspiration.
• Also occurs via hematogenous spread or after
  esphageal perforation
• Presents as pulmonary mass or infiltrate on
  CXR,CT
• Abdominal actinomyces often presents as slow
  growing mass/tumor often in ileocecum following
  in pts w/ h/o bowel surgery or foreign body
  ingestion
• Pelvic infection can occur in women with
  long-standing IUCD

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Diagnosis and Treatment

• Culture, monoclonal antibody stain
• Treatment
• Mild infections treat w/ oral Penicillin V
  2-4g/day divided q6hrs for 2-6 months
• Serious infections Penicillin G IV 2-4g/day
  divided q6hrs x 4-6 weeks, followed by oral PCN V
• Surgical excision required for complicated
  abscesses and fistulas

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Urinary Tract Infections

• Asymptomatic UTI in pregnancy treat w/ 3-7 days
  of sulfisoxazole, amoxicillin, or nitrofurantoin
  or single dose of fosfomycin. Obtain f/u culture
• Symptomatic UTI in pregnancy treat w/ 7 days of
  amoxicillin, nitrofurantoin, or cephalexin
• Catheter associated UTI Treat if symptomatic
  based on culture results, replace catheter.
• Asymptomatic candiduria do not treat unless
  neutropenic or recent urinary tract surgery
• Symptomatic candiduria treat based on culture.
  Fluconazole, flucytosine, or IV amphotericin.
  Bladder irrigation not recommended.

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Recurrent UTIs

• Common infection representing re-infection, not
  relapse
• Risk factors include sexual intercourse,
  spermicides, diaphragm use, and postmenopausal
  women
• Treatment tailored for the individual patient
• Options include
• Daily low-dose antibiotic prophylaxis
• Postcoital prophylaxis
• Patient initated antibiotic treatment

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UTIs

• 4. A 32-year old sexually active woman w/ type 1
  DM is evaluated b/c of recurrent UTIs. She has
  had three episodes this year. The most recent
  episode occurred 2 weeks ago.
• Physical exam, including vital signs, is nml.
  U/A is nml except for the microscopic exam which
  sows 4bacteria.
• Which of the following management strategies is
  the most appropriate at this time?
• Patient-initiated empiric antibiotic therapy
• Continuous standard-dose antibiotics
• U/A and culture at the onset of dysuria
• Post-coital empiric antibiotic therapy

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Malignant Otitis Externa

• An invasive infection of the external auditory
  canal and skull base
• Often occurs in elderly patients with diabetes
  mellitus or immunodeficiency.
• Pseudomonas aeruginosa is the usual pathogen, but
  can also include staph aureus, proteus,
  klebsiella, and candida

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Malignant Otitis

• Clinically presents with otalgia and otorrhea
  that is not responsive to topical antibiotics
• Severe, often nocturnal pain
• Can progress to osteomyelitis of TM w/ CN palsies
• Diagnosis Obtain CT or MRI, culture, and
  consider biopsy to r/o malignancy

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Malignant Otitis Treatment

• Treatment directed at anti-pseudomonal
  antibiotics
• Ciprofloxacin 400mg IV q8hrs until clinical
  improvement then PO Cipro for 6-8 weeks
• No role for topical antibiotics
• If aspergillus, treat with liposomal amphotericin
  B for gt12 weeks.

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Primary Syphilis
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Syphilis

• Primary syphilis presents as a painless
  ulcerative chancre approx 3 weeks after exposure
  to Treponema pallidum
• Primary lesion usually resolves and progresses to
  secondary syphilis 2-8 weeks later
• Secondary syphilis is characterized by
  hematogenous dissemination in the skin, liver,
  lymph nodes usually resolves and progresses to
  latent, tertiary or neurosyphilis
• Latent syphilis is asymptomatic infection with
  positive serology
• Tertiary syphilis includes CNS, cardiovascular
  and gummatous disease involving skin, soft
  tissues, bones, and internal organs.
• Neurosyphilis now most often seen w/ HIV,
  involves CNS, meninges, vascular sxs w/
  meningitis, CN palsies, tabes dorsalis

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Secondary Syphilis
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Diagnosing Syphilis

• Darkfield microscopy
• Nonspecific tests rapid plasma reagin (RPR) and
  Veneral Disease Research Laboratory (VDRL) used
  as screening tests, reported as titer and
  followed for response to tx
• Specific treponemal tests fluorescent treponemal
  antibody absorption (FTA-ABS) assay and the
  microhemaglutination assay (MHA-TP) used as
  confirmatory tests
• False positive nonspecific and treponemal tests.
  FP treponemal tests SLE, HIV, ESLD, IVDU
• False negative occur prior to development of abs

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Treatment

• 1. Primary, secondary or early latent (less than
  1year)
• -Benzathine PCN G 2.4million units IM x1
• -PCN allergic, nonpregnant doxycycline 100mg
  bid x14 days
• -In pregnancy, PCN desensitization
• 2. Late latent, tertiary or unknown duration
• -Benz PCN G, 2.4 million units IM q week x3 weeks
• -PCN allergic doxycycline 100mg bid x4 weeks
• 3. Neurosyphilis
• -PCN G 3-4 million units IV q4hrs x10-14 days

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• A 24-yo woman who is 4 months pregnant has an
  abnormal rapid plasma reagin test for syphilis
  (titer of 1128) and a reactive fluorescent
  treponemal antibody absorption (FTA-ABS) assay.
  She is asymptomatic and has no h/o of STDs. Her
  pregnancy has been uncomplicated, and her only
  medication is a prenatal vitamin. Physical exam,
  including pelvic exam, is nml for her stage of
  pregnancy.
• The patient developed hives when taking
  amoxicillin 4 yrs ago. At that time, she had a
  sore throat, fatigue, and enlarged cervical lymph
  nodes. Symptoms lasted for more than 1 month and
  did not respond to the course of amox.
• Which of the following is the most appropriate at
  this time?
• Perform skin test for PCN allergy
• Begin PCN now
• Desensitize, then begin PCN
• Begin ceftriaxone now
• Begin doxycycline now

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• A 40yo man w/ AIDS has a 2 week h/o of headache
  and subtle mental status changes. General exam,
  including a detailed neurologic exam is
  unremarkable. A CT scan of the brain is nml. LP
  is performed CSF shows WBC 40/ul w/ 80
  lymphocytes, glucose nml, protein nml, VDRL
  positive.
• The patient had a documented episode of
  angioedema after a penicillin injection 1 year
  ago.
• Which of the following is the most appropriate
  management at this time?
• Obtain radioallergosorbent tests for the major
  penicillin determinant
• Hospitalize for desensitization in preparation
  for PCN therapy
• Begin doxycyline now
• Begin ceftriaxone now

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• A 35 yo woman w/ HIV comes to f/u office visit.
  HIV was diagnosed 2 yrs ago when she presented w/
  weight loss, Pneumocystis jiroveci pneumonia, a
  CD4 count of 92/uL, and HIV RNA viral load of
  105,000 copies/ml. The pna was treated
  successfully, and highly active antiretrovial
  therapy zidovudine, lamivudine, and efavirenz
  was begun. The pt adhered to her medication
  regimen and had an excellent response. Her CD4
  cell count increased to 323/uL and her plasma HIV
  RNA viral load became undetectable w/in 6 mo.
• Approximately 1 yr ago, she began missing
  appointments. At a follow-up 4 mo ago, her viral
  load increased to 878 copies/ml and at todays
  visit the viral load is 5375 copies/ml. Her CD4
  count remains stable at 300/uL and she continues
  to be asymptomatic. She now acknowledges
  occasionally missing medication doses.
• Which of the following is the appropriate
  management at this time?
• Continue the current regimen
• Substitute nevirapine for efavirenz
• Add nevirapine to the current regimen
• Ordern an HIV genotype reistance assay
• Recommend a drug holiday until she becomes
  symptomatic

35

• A 38yo nurse is evaluated b/c of an abnormal
  ELISA for HIV discovered when she attempted to
  donate blood. A follow-up western blot had an
  indeterminate result.
• The patient is asymptomatic. She has worked on a
  medical/surgical hospital floor for 12 years, has
  been married for 16 yrs, and has 3 children. Her
  husband and children are well. She and her
  husband have a monogamous sexual relationship and
  neither spouse has ever used ilicit drugs. The
  patient has never received a transfusion. She
  had a needle-stick injury 8 years ago from an HIV
  negative source and did not receive
  antiretroviral post-exposure prophylaxis.
• On PE, she appears anxious but well. Exam is
  nml. Her CD4 count is nml, but her plasma HIV RNA
  viral load is slightly elevated at 82 copies/ml
  (nml lt75)
• Which of the following is the most appropriate
  management?
• Recheck the plasma HIV RNA viral load now
• Recheck the HIV serologic study in 3 months and 6
  months
• Begin highly active antiretroviral therapy now
• Begin highly active antiretroviral therapy if her
  CD4 count decreases to less than 350/uL or she
  becomes symptomatic.

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• A 42yo man w/ HIV infection is evaluated b/c
  of a 5 week h/o of night sweats and weight loss
  of 2.2kg. He moved to NYC from his home in the
  Dominican Republic 3 mo ago, when he started
  HAART. His CD4 count before starting HAART was
  240/ul. Following treatment, his CD4 count rose
  to 350/ul and his HIV RNA VL fell from 500,000
  copies to an undetectable level. The pt takes no
  other medications.
• PE is nml except for an enlarged right
  cervical lymph node. A CXR is nml. A lymph node
  is subsequently excised and stains positive for
  acid-fast bacilli.
• Which of the following is the most likely
  diagnosis
• Mycobacterium avium complex
• Mycobacterium marinum infection
• Mycobacterium kansaii
• Mycobacterium tuberculosis
• Immune reconstitution inflammatory syndrome

37

• A 35yo man is evaluated b/c of a lesion on his
  right arm that he noticed 2 weeks ago. The pt has
  a 4yr h/o of HIV, most likely acquired after
  having sex w/ another man. He has been
  asymptomatic until now and has never received
  HAART. His lowest CD4 count was 382/uL and his
  plasma HIV RNA vl has ranged from 15,000 to
  20,000 copies.
• On PE, he appears well. Vitals are nml. There is
  a small, raised, nontender violaceous lesion on
  his right arm. Exam of the skin and mucous
  membranes is nml. There is no lymphadenopathy or
  peripheral edema. Abd and rectal exam are nml. A
  stool specimen is negative for blood.
• WBC nml, CD4 count 402, HIV RNA VL 14,000, LFTs
  nml, Cr nml, CXR nml. Path exam of the biopsy
  specimen shows spindle cells c/w Kaposis
  sarcoma.
• Which of the following is the most appropriate
  treatment?
• Begin HAART and systemic chemotherapy for
  Kaposis sarcoma
• Begin HAART, defer chemo until HIV infection is
  controlled
• Begin HAART, defer chemo unless visceral or
  extensive skin involvement develops
• Begin system chemotherapy, defer HART until after
  chemo is completed
• Defer both HAART and chemo until the pt becomes
  symptomatic

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• A 44yo man w/ HIV is hospitalized b/c of 1 week
  of progressive left lower extremity weakness and
  inability to walk. For the past 3 months, he has
  had rapid weight loss, night sweats, and
  low-grade fever. Although HIV infection was
  diagnosed 2 yrs ago, the pt never returned for
  f/u. His CD4 count at that time was 88.
• On PE, he appears cachectic and chronically ill.
  Temp is 38.1oC. He has oral thrush, mild
  splenomegaly, bilateral LE weakness and
  hyperreflexia.
• Labs Hg 11.8 g/dL, HCT 34, WBC 2800/ul, plt
  98,000/ul, LFTs nml.
• MRI of the brain
• LP is performed, CSF OP nml, WBC 21/ul 98
  lymph, 2 PMN, WBC 1/ul, protein 85, glu 66,
  india ink neg, crypto ag neg. PCR positive for
  polyomavirus JC and negative EBV.
• Which of the following is the most appropriate
  treatment?
• HAART
• IV cidofovir
• IV acyclovir
• IV dexamethasone and radiation therapy

39

• A 25yo woman, who is 8 wks pregnant, is referred
  by her OB for management of newly diagnosed HIV
  found during routine prenatal screening. This is
  her first pregnancy. She had never been tested
  for HIV before and does not know how long she has
  been infected.
• On PE, she appears well. Vitals and exam are nml
  except for thrush.
• Labs Hg 10.2, Hct 31, WBC 3900/ul, LFTs nml, Cr
  nml, CD4 72/ul, HIV RNA VL 39,900 copies/ml.
• Which of the following is the most appropriate
  for treatment of HIV infection?
• Begin zidovudine, lamivudine, and nelfinavir now
• Begin lamivudine, tenofovir, and efavirenz now
• Defer HAART until the end of her 1st trimester
• Defer HAART until the end of her 2nd trimester