Infectious Dz Flashcards
Meningitis
- what is this
- Most common causes of each etiology
- -bacterial
- -viral
- -fungal
- -noninfectious
What
-a CNS infection (affects the arachnoid, subarachnoid space, and CSF)
Etiologies
- Bacterial
- -Strep pneumo
- -neisseria meningitidis
- -H. Flu
- viral
- -enteroviruses, HSV, HIV, west nile, VZV, mumps
- Fungal
- -cryptococcus (MC)
- Noninfectious
- -tumor, trauma, brain abscess, subdural empyema, pharmacologic reaction
Meningitis
- Sx
- -classic triad
- -others
- -sx in pediatrics?
Sx
- Triad: Fever, nuchal rigidity, change in mental status
- abrupt onset
- intense HA
- photophobia
- lethargy, drowsiness
- nausea
- vomiting
- joint pain
- sz
- petechial rash associated with N. Meningitidis**
Pediatrics
- irritability
- poor feeding
- paradoxical irritability (crying worsens when being held)
Is the rash you see with N. Meningitidis meningitis blanching or non-blanching?
Its NON-BLANCHING!
Who needs a head CT prior to LP?
T/F, perform LP IMMEDIATELY in the absence of papilledema or focal neuro findings.
if the following are present:
- immunocompromised
- hx of sz within one week to presentation
- any of the following neurologic abnormalities
- -abnormal level of consciousness
- -hx of cns disease (mass lesion, stroke)
- -PAPILLEDEMA
- -abnormal level of consciousness
- -focal neurologic deficit
- mandatory in pts with possible focal infection
TRUE
Meningitis
- work up
- Tx
Work up
- blood cultures, CBC, C7
- CSF for cell count, gram stain, culture, glucose, and total protein
- -any positive gram stain is diagnostic
- -WBC in CSF greater than 1000 if PMNs make up 85% is diagnostic
- -CSF glucose less than 50% of serum glucose is suggestive
Tx
- 2G rocephin IV as soon as LP is completed
- hospital admission and rocephin is continued
CSF normal values
- pressure
- appearance
- CSF total protein
- CSF glucose
- CSF cell count
- Chloride
What might the CSF levels be in bacterial meningitis?
- pressure: 70-180 mmH2O
- appearance: clear, colorless
- CSF total protein:15-45mg/100ml
-CSF glucose:50-80mg/100ml (or greater than 2/3 of
blood sugar level)
- CSF cell count:0-5 EBC (all mononuclear) and no RBCs
- Chloride: 110-125 mEq/L
Bacterial: glucose is low, protein is high, WBC is high
Now would be a good time to look at slide 25 in this lecture.
There are 4 practice LPs, and the answers are at the end of the lecture.
Encephalitis
- what is this?
- MC cause
- sx
- sx in children
- work up
- Tx
What
-inflammatin of the brain
MC cause
- viral infections
- -HSV-1 and HSV-2 are rapidly progressing and LIFE THREATENING
Sx
- flu like sx
- Severe HA, fever, altered consciousness, confusion, agitation, personality changes, sz, loss of sensation, paralysis, muscle weakness, hallucinations, double vision, perception of foul smells, problems with speech or hearing, LOC
Sx in children
-bulging fontanels, n/v, body stiffness, inconsolable crying, paradoxical irritability, poor feeding
Work up
- CT/MRI of head
- CBC, CMP
- LP
- -usual cultures but also PCR for HSV1
- -If RBCs in CSF and nontraumatic tap, it is HSV until proven otherwise**
Tx
-Acyclovir ASAP
Septic Arthritis
- Progression
- signs and sx
- dx
- what organism is too small to show up on a gram stain?
- Tx
Progression
- MEDICAL EMERGENCY
- can destroy a joint in 12-24 hours
Signs and sx
- usually affects only one or a few asymmetrical joints
- usually large joints, esp knee
- acute or subacute onset of pain*
- erythema, swelling, limited ROM
- +/- systemic sx
Dx
- MUST do arthrocentesis, send for crystals, glucose, cell count, culture (and specify culture and sensitivity to rule out gonorrhea!)
- joint fluid analysis shows more than 40,000 WBCs
Gram stain will show the causative organism EXCEPT GONOCOCCAL arthritis, because its too small
Tx
-high dose IV abx (could start empirically with rocephin, check CDC)
Bacteremia
- sx
- source of infection
- tx
Sx
- fever
- +/- chills, rigors
- disorientation
- hypotension
- resp failure
- sepsis
- septic shock
- skin lesion
Source of infection
-resp tract, central venous catheters, urinary tract, GI tract, skin…
Tx
- ABX! (a lot of strong ones)
- if gram positive, start empiric therapy with vancomycin
Sepsis/Septicemia
- what is this
- definition
- tx
What
-dysregulated inflammatory response to an infection
Definition
- Infection PLUS:
- temp greater than 38.3 or less than 36
- HR greater than 90
- RR greater than 20
- AMS
- significant edema
- hyperglycemia without a hx of DM glucose greater than 140
- WBC greater than 12K or less than 4K
- hypotension
- poor urine output
- low platelets
- etc…
Tx
-supportive and treat most likely source of infection same as bacteremia
Cellulitis
- what condition would make this an emergency?
- Tx
Emergency if:
- infection around the face and hand
- cellulitis in the presence of DM or PVD
- local infection with presence of leukemia or HIV
Tx:
- ALL cellulitis, folliculitis, furunculosis is due to MRSA until proven otherwise
- DOC is BACTRIM
Endocarditis
- what is this
- risk factors
- sx
- characteristic cutaneous lesions
- dx
- tx
What
-infection of the endothelial surface of the heart, most often the valves
Risk Factors
- previous valve damage
- valve replacement
- hx of IV drug use
Sx
- anorexia, night sweats, weight loss
- cardiac failure, stroke due to septic emboli, cold extremity due to septic emboli
Characteristic cutaneous lesions
- conjunctival and palatal petechiae
- subungual hemorrhages
- osler nodes (tender erythematous nodules with opaque centers which appear on the pulp of fingers/toes)
- Janeway lesions (nontender red or maroon macules or nodules on the palms and soles)
- Roth spots (pale oval areas surrounded by hemorrhage near optic disc)
Dx
- Echocardiogram (shows valvular vegetation) (TEE is more sensitive than TTE)
- normocytic, normochromic anemia
- elevated ESR
- blood cultures
Tx
-start empiric abx based on latest CDC recommendation
Toxic Shock Syndrome
- Pathophys
- signs and sx
- dx
- tx
Pathophys
-results from the absorption of TOXIN from localized staph aureus colonization or infection
Signs and sx
- short prodrome: fever, myalgias, vomiting, diarrhea, pharyngitis
- rapidly develop fulminate shock (BP less than 80) and fever greater than 102.2 with multiple organ failure
- diffuse, blanching, macular erythema (rash fades in 2-3 days, desquamation of hands and feet in 5-12 days after rash disappears)
Dx
- leukocytosis and thrombocytopenia
- elevated BUN, creatinine (renal toxicity)
- elevated LFTs and Bili (liver toxicity)
- sterile pyuria
- elevated CPK (muscle damage)
- decreased serum albumin and total protein due to leaking caps
- blood cultures will be NEGATIVE (because this is toxin induced)
- culture of source will grow s. aureus
Tx
-max supportive care and treat to prevent additional toxin production
Rocky Mountain Spotted Fever
- organism
- sx
- dx
- tx
Organism
-Rickettsia rickettsi
Sx
- sudden onset fever, chills, malaise, myalgias, severe frontal HA
- on the 2-5th day of illness the rash appears
- -pink, macular 1-4 mm in diameter appears on the palms and soles*, hands, feets, wrists, ankles
- over the next 24-48 hours, rash becomes petechial, purpuric, and even gangrenous (black measles!)
- spreads centripetally
- diffuse edema
Dx
-all labs may be normal… clinical
Tx
- DOXY
- in children use chloramphenicol
