Infectious Disease Flashcards
3 Criteria for Virulence of Infection
- inflict serious harm
- go unrecognized my immune system
- spread efficiently
Diagnostic Aids for Infection
- CBC
- Platelet count
- C-reactive protein
- Procalcitonin
- Erythrocyte sedimentation rate
- Cultures and stains
- DNA/RNA
- Immunoserology
- Imaging (MRI)
What can a CBC tell you about infection?
- Leukocytosis: bacterial
- Leukopenia: viral
- Differential further focuses diagnosis
What can a C-reactive protein tell you about infection?
- Acute-phase reactant
- Increases in presence of acute inflammation
- Nonspecific
What can a platelet count tell you about infection?
Thrombocytosis in active phase of infection
What can procalcitonin tell you about infection?
- Biomarker for differentiating some viral from serious bacterial infections
- Increased in bacteremia/ can reflect severity
What can Sed-Rate tell you about infection?
- Acute-phase reactant; nonspecific
- Useful to evaluate therapy when antibiotics used
Typical Infections in Child Care Setting
- Hand foot mouth
- Erythema infectiosum
Physical Examination of Hand Foot Mouth Disease
- Skin: macular-papular; urticarial, vesicular, petechial
- Vesicles
- Febrile more than 3 days
- Mild URI
Physical Examination of Erythema Infectosium
- Prodrome: mild fever, myalgia, HA, malaise, URI symptoms
- Rash: 7-10 days after prodrome
- “slapped cheek” with circumoral pallor
- lacy, maculopapular rash (may last a month)
Clinical Findings for West Nile Virus
- Mimics influenza, GI infection
- Mild symptoms will resolve in 1 week
- Severe - neuroinvasive involvement
Diagnostics for West Nile Virus
MAC - ELISA
Tick-Bourne Diseases
- Lyme Disease
- Rocky Mountain Spotted Fever
Stage 1 of Lyme Disease
- erythema migrans (bulls eye rash)
- may resemble nummular eczema
- some may have flu like symptoms
Stage 2 of Lyme Disease
- early disseminated disease
- secondary annular lesions
- neurologic signs
- cardiac signs
- generalized manifestations (may last 2 weeks to 2 years)
Stage 3 of Lyme Disease
- Late disease
- Pauciarticular arthritis weeks to months after bite
Diagnostics Studies for Lyme Disease
- No other tests are needed if erythema migrans is present
- IgM antibodies not positive for 2-4 weeks
- IgG antibodies not positive for 4-6 weeks
- High rate of false positives
- CDC: ELISA - if neg then no more tests; IgG and IgM Western blot if having symptoms over 30 days
Management of Lyme Disease
- Prophylactic doxycycline/amoxicillin
- Amoxicillin or doxycycline in early localized disease
- Early or late disseminated disease - consult ID
Clinical Findings for Rocky Mountain Spotted Fever
- Fever, chills, myalgia, GI symptoms, photophobia, AMS
- Focal neurologic deficits with disease progression
- Maculopapular rash: wrists, forearms, ankles –> spreads to trunck
Diagnostics Studies for Rocky Mountain Spotted Fever
- PCR testing or IFA
- Thrombocytopenia, hyponatremia, leukocytosis, anemia
Management of Rocky Mountain Spotted Fever
- Antibiotics prior to onset of rash
- Disease may progress rapidly
- Doxycycline for 7-10 days for all ages
Complications of Rocky Mountain Spotted Fever
- Neurologic deficits
- 20% fatality if untreated
- Prevention: tick precautions
Bacterial Infections in Children
- Community-Acquired MRSA
- Cat Scratch Disease
- Meningococcal Disease
- Group A Strep (GAS)
Clinical Clues for Community-Acquired MRSA
- Boil, abscess without pus; rapid onset
- Other family members have similar infections
- Neonate with skin/soft tissue infection
- Hx of recurrent small, non-tender, maculopapular lesions; multiple lesions
- Ethnic minority or lower socioeconomic status
- Hx of hospitalization in past year
- Attends day care; is less than 2 years old
Management of Community-Acquired MRSA
- Superficial skin lesions - topical antibiotic
- Widespread impetigo - oral/IV antibiotics
- Warm compresses to localize pus in nonfluctuant
- Cultures for non-draining fluctuant abscess
**Refer immunocompromised patients to ID specialist
Clinical Findings for Cat-Scratch Disease
- 3-5 mm erythematous papules which heal; lymphandenopathy in 1-4 weeks; persists up to 1 year
- Parinaud oculograndular syndrome - painful non-supportive conjunctivitis/preauricular lymphadenopathy in small percentage
- In immunocompromised patients - recurrent fevers, bacteremia, weight loss
Diagnostic Studies for Cat Scratch Disease
- IFA for serum antibodies
- CBC - mild leukocytosis
- ESR/CRP elevated early
Management of Cat Scratch Disease
- Most resolves spontaneously
- Antibiotics only if concerns for systemic CSD
- Treatment for immunocompromised patients: oral agents and parenteral gentamycin
Complications of Cat-Scratch Disease
- Small percentage have systemic illness with high fever, malaise, fatigue, anorexia
- Enlarged mediastinal nodes - pleurisy, obstruction
- Splenic/hepatic abscesses
Clinical Findings for Meningococcal Disease
- Occult bacteremia - febrile URI or GI infection; may resolve without intervention
- Meningococcemia - rapid progression over several hours: fever, septic shock, petechiae to purpura fulminans, hypotension, DIC, adrenal hemorrhage, organ failure, coma: death in 12 hours
- Meningococcal meningitis - fever, HA, stiff neck
Diagnostic Studies for Meningococcal Disease
- Positive culture/Gram stain from CSF, blood, or synovial fluid
- PCR assays useful if antibiotics given
Management of Meningococcal Disease
- hospital is mandatory
- IV antibiotics pending cultures
- chemoprophylaxis within 24 hours of index case regardless of immunization status
- Prophylaxis during outbreak: vaccination and chemoprophylaxis
Clinical Findings of Group A Streptococcus (GAS)
- Respiratory tract infection - peritonsilar abscess, cervical lymphadenitis, GABHS
- Scarlet fever
- Bacteremia
- Vaginitis and TSS
- Perianal streptococcal cellulitis
- Skin infections
- Rheumatic fever
- Necrotizing fasciitis
Clinical Findings Scarlet Fever
- erythogenic toxin
- abrupt illness with sore throat
- fever
- vomiting
- HA
- chills
- malaise
- erythematous tonsils/exudate
- strawberry tongue
- sandpaper rash
Management of GAS
Antibiotics
Complications of GAS
Pediatric autoimmune neuropsychiatric disorders
1. OCD
2. Tic disorders
3. Tourettes
