Infectious Disease Part 3 Flashcards
Causes:
Sinusitis, mastoiditis, and otitis media, abscesses, emboli from congenital heart disease, AVM, pulmonary infection, skin infection, endocarditis, abdominal and pelvic infections
Brain abscess
Anaerobic cocci & gram-negative and gram-positive anaerobic bacilli
Common organisms for brain abscess
Staphylococcus aureus, Enterobacter, Streptococcus species
Anaerobic cocci & gram-negative and gram-positive anaerobic bacilli for brain abscess
In order of occurrence:
Headache-> mental status changes-> focal neurologic deficits-> fever-> seizures-> nausea and vomiting -> nuchal rigidity-> papilledema
Brain abscess
Facial weakness, headache, fever, vomiting, dysphagia, and hemiparesis
Brainstem lesion
Diagnostic evaluation for brain abscess
MRI/CT of the head
CBC with diff, blood culture, ESR, CRP, specific serology
Surgical aspiration or stereotactic CT for culture
Brain abscess treatment
Vancomycin, cefotaxime, metronidazole
Control of ICP
Surgical resection, aspiration, or drainage (esp if more than one area is involved)
Consult with neurosurgeon and ID specialists
Inflammation of membranes lining the brain and spinal cord
Meningitis
When is the peak incidence for meningitis?
3-12 months
When is the peak season for meningitis?
Late fall and early winter
Males > Females
Urban areas, crowded living conditions, poverty
Underlying chronic illness/immunosuppression, asplenia
Routes of CNS invasion
Congenital or acquired defects in skull or spinal cord
Risk factors for meningitis
Age-associated pathogens for meningitis
<1 mo
Group B streptococcus
E. coli
Listeria monocytogemes
Klebisella species
Age-associated pathogens for meningitis
1-2 mo
Group B strep E. coli Strep. pneumoniae H. infleunzae type B N. meningitidis
Age-associated pathogens for meningitis
2 mo - 5 yr
Strep. pneumoniae
H. influenza type B
N. meningitidis
Age-associated pathogens for meningitis
5 yr and up
N. meningitis
Strep. pneumoniae
WBC in CSF will be _____ for bacterial meningitis
Increased or Decreased or Normal
Increased
Protein in CSF will be _____ for bacterial meningitis
Increased or Decreased or Normal
Increased
Glucose in CSF will be _____ for bacterial meningitis
Increased or Decreased or Normal
Decreased
Pressure in CSF will be _____ for bacterial meningitis
Increased or Decreased or Normal
Increased
Lactate in CSF will be _____ for bacterial meningitis
Increased or Decreased or Normal
Increased
Fever/chills, anorexia/poor feeding, myalgias/arthralgias, URI symptoms, tachycardia/hypotension, petechiae, purpura, erythematous macular rash
Severe throbbing headache, photophobia
Nuchal rigidity
Kernig sign
Brudzinski sign
Bacterial Meningitis
Passive extension of the knee in supine position causing back pain and resistance
Kernig sign
Passive flexion of the neck resulting in involuntary flexion of knees and hips
Brudzinski sign
When there is a traumatic/bloody spinal tap, how do you calculate the predicted WBC count?
CSF RBC x (serum WBC/serum RBC)
What is the safest interpretation of traumatic spinal tap for WBC?
Count the total number of WBCs and disregard RBC count
If there are more than normal WBC for age, then treat
If a child is too unstable for lumbar puncture, should antibiotics be on hold or started prior to obtaining LP cultures?
Start
DO NOT WAIT TO OBTAIN CULTURES PRIOR TO STARTING ANTIBIOTIC THERAPY IF CHILD IS UNSTABLE
Treatment for basilar skull fracture antimicrobials
Vancomycin + 3rd generation cephalosporin (cefdinir, cefixime, cefotaxime, ceftazidime)
Antimicrobials for recent neurosurgery or ventricular shunt infection
Vancomycin + Cefepime
Vancomycin + Ceftazidime
Vancomycin + Meropenem
What is the mortality rate for bacterial meningitis?
5-15%
Long-term neurodevelopmental sequelae of bacterial meningitis
Hearing loss, neurologic impairment, seizures, visual impairment, delay in language acquisition, chronic residual hydrocephalus
Most common cause of meningitis in children
Viral meningitis
When is the peak incidence of viral meningitis?
Late summer/early fall
Glucose in CSF will be _____ for viral meningitis
Increased, Decreased, Normal
Normal or Slightly Decreased
Protein in CSF will be _____ for viral meningitis
Increased, Decreased, or Normal
Slightly Increased
WBC in CSF will be _____ for viral meningitis
Increased, Decreased, or Normal
Mildly increased with neutrophil predominance (early) and lymphocyte (later)
What is the gold standard for HSV meningitis diagnosis?
CSF PCR for HSV
Acute-onset fever/lethargy/irritability Increased ICP, autoregulation Anorexia/vomiting Hyper/hyporeflexia Bulging fontanel, increased ICP Seizures Skin rash (varicella, enteroviruses) Diarrhea (enteroviruses) URI (enteroviruses) Not as "toxic" appearing
Viral Meningitis
Treatment for viral meningitis
Usually self-limiting and resolves in 7-10 days
Control of seizures
Specific antiviral therapy if HSV suspected
Ataxia, focal neurologic signs, acute encephalopathy
High suspicion for viral meningitis
If HSV meningitis is suspected, which medication should be promptly initiated?
Acyclovir IV
Inflammatory process of brain parenchyma which usually is caused by infectious process or hyperimmune reaction
Encephalitis
Can occur with bacterial meningitis with organisms, such as Borrelia burgdorferi, Bartonella, and Treponema pallidum
Encephalitis
Caused by cryptococcus and others; concern for immunocompromised children
Fungal encephalitis
Rabies virus, herpes simplex virus, and other etiologies can trigger this
Viral encephalitis
Fever, altered consciousness, seizures, focal neurologic signs
Neonates/infants present with shock, lethargy, irritability, poor feeding, seizures, apnea
Encephalitis
CSF is usually ___ and ____ for LP of encephalitis
Clear and colorless
Opening pressures may be ____ or ______ for LP for encephalitis
Normal or elevated
What is the typical mononuclear pleocytosis in LP for encephalitis?
> 5 WBC/uL
Protein and Glucose are ____ in LP for encephalitis
Increased, Decreased, or Normal
Normal
What is a normal protein in a normal CSF?
15-45 mg/dL CSF
What is normal blood/RBC in normal CSF?
NONE
What is normal glucose in a normal CSF?
50-75 mg/dl CSF
What is normal WBC for neonates in normal CSF?
0-30 cells/uL
What is normal WBC for 1-5-year-old in normal CSF?
0-20 cells/uL
What is normal WBC in 6-18 year old in normal CSF?
0-10 cells/uL
What is normal WBC in an adult in normal CSF?
0-5 cells/uL
Temporary placement of a needle in the subarachnoid space of spinal column to obtain CSF
Lumbar Puncture
What does cloudy CSF appearance indicate?
Increased WBC or protein
What does red-tinged CSF appearance indicate?
Presence of blood
What do neutrophils mean in CSF?
Bacterial meningitis/cerebral abscess
What do mononuclear lymphocytes mean in CSF?
Viral meningitis/encepahlitis
What causes protein to be present in CSF?
meningitis, encephalitis, and myelitis
When does glucose decrease in CSF?
When bacteria, inflammatory, or tumor cells are present
If CSF blood glucose level is less than 60% of blood glucose level, what does that indicate?
Neoplasm or meningitis
What are contraindications for LP?
Increased ICP (herniation)
Patient receiving anticoagulation (epidural hematoma)
Patients with an infection near LP site
Mild: Fever; headache; muscle aches; eye pain; itchy rash on neck, body, arms, or legs; lymphadenopathy, weakness, anorexia, nausea and vomiting
West Nile Virus
Severe: High fever, body and muscle weakness; itchy rash on neck, body, arms, and legs; GI upset; CNS symptoms
West Nile Virus
IgM antibody capture enzyme-linked immunosorbent assay (MAC_ELISA) of serum or CSF within 8 days of onset
West Nile Virus diagnosis
West Nile Virus Prevention
Stay indoors during most active times (between dust and dawn)
Apply insect repellant
Remove standing water
Use screens on doors and windows
Report dead birds to local health department
Borrelia bugdorferi spirochete organism causes what?
Lyme Disease
Where is the prevalence highest for Lyme disease?
Northeast, mid-Atlantic, Wisconsin, Minnesota, Northern California
ELISA from blood sample
IgG and IgM Western blot if symptoms > 30 days
Lyme disease
What is treatment for uncomplicated lyme disease?
Doxycycline
What is the treatment for complicated lyme disease?
IV ceftriaxone or penicillin
Rickettsia rickettsii (obligate intracellular gram-negative) caused what?
Rocky Mountain Spotted Fever
Where is the prevalence for rocky mountain spotted fever?
Everywhere but Maine/Vermont
Fever, severe headache, myalgia, characteristic rash (starts on wrists, ankles, palms, and soles and then progresses to trunk), thrombocytopenia
rocky mountain spotted fever
RMSF serologic assay
diagnosis of rocky mountain spotted fever
Treatment for rocky mountain spotted fever
Doxycycline until afebrile for 72 hours
Should treatment be delayed for serologic testing for rocky mountain spotted fever?
NO
Where is dengue fever typically present?
Tropics and subtropics
Puerto Rico, Virgin Islands, and American Samoa
Acute phase–nonspecific febrile phase, retro-orbital headache pain, myalgias, maculopapular rash
Critical phase–defervescence within 2 to 7 days after onset; some progress to severe case (vomiting, mucosal bleeding, leukopenia, thrombocytopenia, elevated hematocrit, difficulty breathing, shock, DIC, pleural effusion, and ascites)
Dengue Fever
Leukopenia with thrombocytopenia and elevated hematocrit
Dengue Fever
ELSIA for anti-dengue IgM and IgG antibodies
Dengue Fever
What medications do patients with dengue fever avoid>
Aspiring and NSAIDs
Where is typhoid most common?
Tropics, subcontinental India, Southeast Asia, and southern Africa
How is typhoid fever acquired?
Ingestion
Fever, headache, lethargy, malaise, abdominal pain with diarrhea or constipation, hepatosplenomegaly, stupor, rose spots (blanching erythematous macules), confusion, delirium, convulsion, obtundation
Typhoid Fever
What is the most life-threatening complication of thyroid fever?
Intestinal perforation
What is the best source for culture for typhoid?
Bone marrow
Blood culture in large volumes (1-15 mL)
Normal-to-low WBC count, elevated LFTs
Typhoid
Treatment for typhoid
Ceftriaxone or ciprofloxacin
Ampicillin
How long can fevers persist with appropriate therapies with typhoid?
up to 7 days
Vi capsular polysaccharide (Typhim Vi) vaccine can be given to what age groups? How soon should be given prior to exposure?
Older than 2 years
At least 2 weeks prior to possible exposure
Ty21a (Vivotif) vaccine is what kind of vaccine?
Live-attenuated oral vaccine
How old can you be to receive Ty21a?
Older than 6 years
How many doses of ty21a?
4 doses; taken every other day
Where is Japanese encephalitis present?
Eastern Asia, subcontinental India, and western Pacific
Leading cause of vaccine-preventable encephalitis
Japanese encephalitis
Vast majority are asymptomatic
Incubation period of 5-15 days
headache, vomiting, fever, altered mental status, weakness, parkinsonism, seizures progressing to paralysis
mild leukocytosis, mild anemia, hyponatremia
Japanese encephalitis
Normal glucose, elevated protein, leukocytosis with lymphocyte predominance
CSF Japanese encephalitis
Anti-JEV IgM antibodies
Japanese encephalitis
Mosquito-transmitted Plasmodium parasitic infection
Malaria
What are the high-risk travel places?
Sub-Saharan Africa, Vanuatu, Papua New Guinea, Solomon Islands, Indian subcontinent
Paroxysmal fever, due to synchronicity of reproductive cycles, is characteristic sign
Chills, headache, malaise, cough
Anemia with thrombocytopenia
Proteinuria and hemoglobinuria in times of fever or presence of rapid hemolysis
Malaria
Hypotension, renal dysfunction, metabolic acidosis, hypoglycemia
Severe Malaria
Artesunate monotherapy or quinidine in combination with doxycycline, tetracycline, or clindamycin
Severe Malaria
Chloroquine or hydroxychloroquine
Mild Malaria
Avoid doxycycline and tetracycline in those ___ years of age
<8
