Infectious Disease Flashcards
Neonatal Fever
Fever in neonate (up to 28 days) and in infant (up to 2 months) with rectal temperature > 38C.
- Most likely with UTI or occult bacteremia.
Management: Full sepsis workup indicated
- CBC-D, UA (cathed), UCx, BCx, LP, CXR (if URI symptoms).
- Manage ABCs
- Treat for 48-72 hours
Most Common Organisms Causing Systemic Bacterial Infection in Neonate
- Group B Streptococcus
- E. coli
- Listeria monocytogenes
- Staph aureus
- Enterococcus species
- Herpes Simplex Virus
- Varicella zoster Virus
- RSV
- Candida species
- CMV
Most Common Organisms Associated with Fever of Unknown Origin in Children
- Salmonella
- TB
- Rickettsial disease
- Syphillis
- Lyme Disease
- Cat-Scratch Disease
- Atypical prolonged common viral diseases
- Infectious Mononucleosis
- CMV
- Viral Hepatitis
- Coccidioidomycosis
- Histoplasmosis
- Malaria
- Toxoplasmosis
Sepsis/Septic Shock
Sepsis: SIRS with infection.
Septic Shock: with CV organ failure.
Toxins and superantigens associated with gram + bacteria activate the immune system to produce cytokines to initiate a cytokine cascade resulting in fever and vasodilation, hemodynamic instability.
Risk Factors:
- Prematurity, compromised immune status, musculoskeletal or neurologic disease, chromosomal or genetic disease, increased number of resistant microorganisms.
Causative Factors:
- Gram + bacteria, Gram - bacteria, Fungus.
S/S: Fever or subnormal temperature, irritability, lethargy, tachypnea with respiratory distress, tachycardia, gallop rhythm with myocarditis, poor perfusion, hypotension, hepatomegaly or JVD, warm or cold shock, oliguria, rash, MODS (multiple organ dysfunction syndrome - 2 or more systems involved).
Tx: Address symptoms, fluid resuscitation, ionotropic therapy if indicated, antibiotic therapy (broad spectrum coverage).
Systemic Inflammatory Response (SIRS)
Nonspecific inflammatory process that occurs in adults after trauma, infection, burns, pancreatitis, and other diseases.
SEE SEPSIS
Disseminated Intravascular Coagulation (DIC)
Alteration of the normal coagulation mechanism triggered by tissue injury such as in infection, trauma, malignancy, etc…
S/S: Bleeding is initial symptom with prolonged bleeding studies. Thrombosis with tissue ischemia is other component. Respiratory failure, abdominal and kidney failure, seizures.
Dx: Coag studies, d-dimer.
Tx: Remove or correct causative agent or event. Management of obvious concerns - shock, respiratory compromise, acidosis.
- Administer vit K
Meningococcemia
Acute fulminant bacterial illness.
- Usually follows viral process
- Children have general illness prodrome and then become critically ill within 24 hours
S/S: Fever, fatigue, lethargy, altered mental status, neck stiffness, purpura, irritability, ataxia and other gait abnormalities, nausea, vomiting progressing to decreased perfusion, tachycardia, hypotension, respiratory distress, blood cell dysfunction.
Dx: Isolation of meningococcal organism in blood, synovial fluid or CSF is definitive diagnosis.
- Labs: CBC, liver and renal function, LP.
Tx: Isolation of patient, immediate resuscitation with ABC, fluids, antibiotics, blood products, ventilation, broad spectrum antibiotics (such as 3rd generation cephalosporins - ceftriaxone or cefotaxime).
Fungal Infections
Common pathogens include histoplasmosis, candida species, Pneumocystis jirovechi (PCP).
- Common in immunocompromised hosts, neonates, and critically ill children on long-term antibiotics.
- Typical therapy consists of fluconazole, voriconazole, amphotericin B complex, TMP-SMX for PCP prophylaxis.
Travel Organisms: Parasites and Vector Borne Infections
- Malaria
- Dengue Fever
- Typhoid, West Nile Virus
- Lyme Disease
- Rocky Mountain Spotted Fever
- Tularemia
Bacterial Meningitis
Neonates:
- GBS, E. coli, Listeria monocytogenes, Strep pneumoniae
- Fever, lethargy, bulging fontanelle
Infants:
- Strep pneumoniae, Neisseria meningitis, Haemophilus influenzae
- Fever, headache, neck stiffness, nuchal rigidity, + kernig sign, + brudinski
1 Year-Old:
- Strep pneumoniae, Neisseria meningitis, Haemophilus influenzae
Adenovirus
Can be associated with many system based processes such as respiratory (common cold, pharyngitis, tonsillitis, bronchiolitis), ocular (keratoconjunctivitis should be followed by ophthalmology), gastrointestinal, skin (SJS), GU, cardiac (myocarditisor pericarditis), neuro (meningitis)
Cytomegalovirus (CMV)
Double-stranded DNA of the herpesvirus family, can be primary infection, stay latent and reactivate with immunodeficiency or HIV infection.
S/S: Most infections are asymptomatic or benign. Can be severe in immunocompromised patients and neonates with congenital infections - also associated with hearing loss.
- System-based presentation such as pneumonia, myocarditis, pericarditis, uveitis, etc…
Dx: Isolated by cell culture, cytologic studies, DNA PCR.
Tx: Treatment of immunocompromised patients is antiviral therapy for 2-3 weeks.
- Supportive care of other infected patients.
Epstein Barr Virus (EBV)
Double stranded DNA virus of the herpes virus family.
- Can be latent or active.
- Causative factor for infectious mononucleosis.
- Transmitted by close physical contact.
S/S: Prodrome of fever, sore throat, malaise, fatigue. Cervical lymphadenopathy common finding. System-based findings.
Dx: EBV Viral antigen, monospot or monotest.
Tx: Supportive care, prevention of splenic rupture if splenomegaly.
Enterovirus
RNA virus including poliovirus, echovirus, coxsackie virus.
S/S: Wide range of clinical presentations dependent on specific virus.
Dx: Cell culture isolation, PCR.
Tx: Mostly supportive care.
Herpes Simplex Virus (HSV)
Double stranded DNA virus.
- Invades skin through mucous membranes.
- Can be latent or active.
S/S: Most common presentation is gingivostomatitis, also as genital herpes. Most concerning system based illness is encephalitis, which can be congenitally acquired.
Dx: Cell culture, antibody detection.
Tx: Preventive therapy and antiviral agents such as acyclovir.
