Step Up: infectious diseases II

  1. Symptoms of primary HIV infection
    • Fever, night sweats, weight loss
    • Lethargy, headache, myalgias
    • Diarrhea
    • Sore throat
    • Lymphadenopathy
    • Maculopapular rash on the trunk
  2. HAART
    • Two nucleoside reverse transcriptase inhibitors, plus-
    • Either a non-nucleoside reverse transcriptase inhibitor or a protease inhibitor
    • Test viral load to monitor response to treatment
  3. Toxoplasmosis
    • Seen in AIDS, or other IC patients
    • Presents with signs of a mass lesion (headache, focal deficits) plus signs of encephalitis (fever, altered mental status)
    • CT scan shows at least 3 contrast-enhanced lesions in the basal ganglia and subcortical white matter
  4. When should an HIV patient be started on Bactrim for PCP prophylaxis?
    When the CD4 count drops below 200 or if the patient has a history of oropharyngeal candidiasis`
  5. Virus associated with Bell's palsy
  6. Herpetic whitlow
    • HSV infection of the finger, caused by direct inoculation into open skin surface
    • More common in health care workers
    • Manifests with painful, vesicular lesions at the fingertip, plus fever and axillary lymphadenopathy
    • Treat with acyclovir, NOT incision and drainage
  7. Secondary syphilis
    • Maculopapular rash, 4-8 weeks after chancre heals
    • May also involve flu-like illness, aseptic meningitis, and hepatitis
  8. When are the RPR or VDRL tests for syphilis falsely positive?
    In SLE patients
  9. Painful genital ulcers with tender lymphadenopathy
    Chancroid, H. ducreyi
  10. Why does cellulitis tend to recur in the same area?
    Damage to lymphatics
  11. Most common causes of cellulitis
    • Group A strep
    • Staph aureus
  12. Conditions associated with cellulitis
    • Venous stasis
    • Lymphedema
    • Diabetic ulcer
  13. Erysipelas
    • Cellulitis confined to the dermis and lymphatics, usually caused by group A strep (e.g. strep pyogenes)
    • Manifests with red, painful, well-demarcated lesions on the legs and face
    • May involve chills and fever
  14. Most common causes of necrotizing fasciitis
    • Strep pyogenes
    • Clostridium perfringens
  15. Clostridium tetani
    • Gram positive anaerobic bacillus
    • Produces an exotoxin that blocks inhibitory NTs at the NMJ
    • A classic early symptom is trismus (contraction of the masseter, lockjaw)
  16. Management of a patient with tetanus
    • Respiratory support, diazepam for tetany
    • IM tetanus Ig to neutralize free toxin
    • Tetanus/diphtheria toxoid
    • Metronidazole or penicillin G
  17. Cause of osteomyelitis in IV drug users or neutropenic patients
    Pseudomonas or fungi
  18. Cause of osteomyelitis in sickle cell patients
  19. Most common causes of osteomyelitis
    • Staph aureus
    • Staph epidermidis
  20. Pott's disease
    • Osteomyelitis of the vertebral bodies
    • Caused by TB
  21. Why bother to measure ESR and CRP in a patient with osteomyelitis
    Used to monitor response to therapy
  22. How is osteomyelitis diagnosed?
    • Needle aspiration or bone biopsy (X-ray isn't enough because changes aren't visible until about 10 days)
    • MRI
  23. Causes of infectious arthritis
    • Staph aureus
    • N. gonorrhea
    • P. aeruginosa or salmonella in IVDA, sickle cell, or immunodeficiency
  24. Clinical indications of septic arthritis
    • Swelling, heat, and pain in the affected joint
    • Severely limited range of motion
    • Systemic symptoms such as fever and chills
  25. Large, painless, well-demarcated, target shaped lesion on thigh, groin, or axilla
    • Erythema migrans, Lyme disease
    • Multiple lesions indicate hematogenous spread
  26. Progression of Lyme disease in the early disseminated stage
    • Flu-like symptoms, headache, fever, neck stiffness, etc
    • After several weeks, 15% of patients develop-
    • Meningitis (with negative Brudzinski's and Kernig's signs)
    • Encephalitis
    • Cranial neuritis (bilateral Bell's palsy)
    • Peripheral radiculoneuropathy
    • Some patients develop cardiac manifestations (AV block, pericarditis)
  27. Symptoms of Rocky Mountain spotted fever
    • Sudden onset of fever, chills, nausea/vomiting, photophobia
    • Papular rash after 4-5 days of fever that begins peripherally, spreads centrally, and includes the palms and soles
    • Interstitial pneumonitis is a possible manifestation
  28. Fever patterns in malaria
    • Constant fever--falciparum
    • Fever spikes ever 48 hours--vivax or ovale
    • Fever spikes every 72 hours--malariae
  29. Treatment for malaria
    • Chloroquine or quinine and tetracycline if chloroquine resistance is suspected
    • Two weeks of primaquine if infection is vivax or ovale, which have dormant hypnozoites in the liver
  30. Treatment for systemic candidiasis
    Amphotericin B or fluconazole
  31. Allergic bronchopulmonary aspergillosis
    • A type I hypersensitivity reaction to to aspergillus
    • Presents with asthma and eosinophilia
    • Recurrent exacerbations are common
  32. Pulmonary aspergilloma
    • Caused by inhalation of spores into the lung
    • Presents with chronic cough and possibly hemoptysis
    • Increased risk with sarcoidosis, histo, TB, and bronchiectasis
  33. Invasive aspergillosis
    • Occurs when fungal hyphae invade lung vasculature
    • Causes thrombosis and infarction
    • Presents with acute onset of cough, fever, and diffuse bilateral pulmonary infiltrates
    • Seen in IC patients (leukemia, transplant recipients, AIDS)
  34. Diagnosis of invasive aspergillosis
    • Definitive diagnosis with tissue biopsy, but positive sputum sample in a patient with symptoms is good enough
    • Blood cultures are not useful because they are rarely positive
  35. Treatment of invasive aspergillosis
    IV amphotericin B, voriconazole, or caspofungin
  36. Where is histoplasma capsulatum found?
    Ohio and Mississippi river valleys
  37. Cryptosporidiosis
    • Severe, watery diarrhea in an IC host
    • Diagnose by oocytes on stool sample
  38. Entamoeba histolytica
    • Fecal-oral route
    • Bloody diarrhea with tenesmus, abdo pain, and maybe liver abscess
    • Diagnose by trophozoites on stool sample
    • Treat with indoquinol or paromomycin (metronidazole for liver abscess)
  39. Giardiasis
    • Chronic, water diarrhea
    • Seen in daycare children or campers
  40. S. haematobium
    • Trematode, causes urinary tract granulomas
    • Bladder polyps, dibrosis, and dysuria
  41. Definition of FUO
    Fever over 38.3 for at least 3 weeks with no working diagnosis, despite at least 1 week of inpatient workup/three outpatient visits
  42. Causes of FUO
    • Infectious (most common--TB, abscess, UTI, endocarditis, sinusitis, HIV, viral, malaria)
    • Neoplastic (especially Hodgkin's)
    • Collagen vascular disease
    • Sarcoidosis, Crohn's
    • Drugs PE
    • Hemolytic anemia
    • FMF
    • Gout
    • Subacute thyroiditis
  43. Drugs that can cause FUO
    • Sulfonamides
    • Penicillin
    • Quinidine
    • Barbiturates
    • diet pills with phenolophthalein
  44. Difference between chills and rigors
    • Chills--sensation of cold, often with shivering
    • Rigors--severe form of chills with pronounced shivering and teeth chatterin
  45. Tests indicated for a patient with FUO
    • CBC
    • Urinalysis
    • Cultures (blood, sputum, urine, CSF, stool)
    • Complement assay
    • PPD (if TB is on the DD)
    • LFTs, ESR, ANA, rheumatoid factor, TSH
    • Imaging
  46. What causes toxic shock syndrome?
    Staph aureus enterotoxin or group A strep exotoxin
  47. Caueses of neutropenic fever
    Drugs, toxins, hematologic malignancy/bone mets, hypersplenism, SLE, AIDS
  48. Most common infections seen in a neutropenic patient
    • Septicemia
    • Pneumonia
    • Cellulitis
  49. Which lymph nodes are commonly enlarged in infectious mono?
    Posterior cervical
  50. Signs of infectious mono on blood smear
    Lymphocytic leukocytosis with atypical lymphocytes
  51. Why should a throat culture be performed on a patient with mono?
    To rule out secondary infection with beta-hemolytic streptococci
  52. Which type of mono does not have heterophile antibodies (monospot test)
    CMV (EBV mono does have a positive monospot test)
  53. Complications of infectious mono
    • Hepatitis
    • Neuro complications (Guillain-Barre, meningoencephalitis, Bell's palsy)
    • Splenic rupture (avoid contact sports)
    • Thrombocytopenia/hemolytic anemia
    • Upper airway obstruction, due to lymphadenopathy
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Step Up: infectious diseases II
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