Infectious diseases Flashcards
high-risk conditions that increase risk of bacteremia
sickle cell, asplenia, malignancy, chemo, HIV, renal disease, prolonged steroid use, central lines/ indwelling catheters, VP shunts
Risk factors for UTI
febrile, white girls < 2 years old, and uncircumcised boys before toilet training. Previous UTI
Toxicologic causes of fever
serotonin syndrome, neuroleptic malignant syndrome, ASA, anticholinergics, sympathomimetics
Low risk criteria for fever in 1-2 month old infants
full term (> 37 weeks) no prolonged NICU stay no chronic medical problems no recent Abx in last 3 days well-appearing no focus on exam, WBC 5-15, Band/neut ratio < 0.2; Urine < 10 WBC/hpf, CXR no infiltrate (if done for resp symptoms)
Antibiotic choices for sepsis in < 1 month old
ampicillin and gentamycin (cefotaxime if meningitis)
Antibiotic choices for fever in 30-90 days
cefotaxime, vancomycin +/- ampicillin
Cervical lymphadenopathy - acute bilateral causes
resp viruses, enterovirus, adenovirus, EMV, CMV
Cervical lymphadenopathy - acute unilateral causes
S. aureus, S. pyogenes
Cervical LN - chronic unilateral causes
atypical mycobacteria, TB, bartonella Henselae
Risk factors for toxic shock syndrome
recent tampon use (prolonged/ high absorbency), recent surgery, and recent infection (involving skin or soft tissue or other site). Burns, steroids, malignancy, DM2, immunocompromised, IVDU
Treatment of Toxic shock syndrome
Cloxacillin + clindamycin
IVIG for GAS TSS
Classic triad of RMSF?
Fever, rash and headache
Treatment of RMSF?
doxycycline
When to do a CT scan before LP in meningitis?
focal neuro deficit, papilledema, history focal neuro disease, immunocompromised, signs cerebral herniation
3 types of neonatal HSV
- Skin, eye, mouth
- CNS
- Disseminated
Organisms that cause sinusitis
Same as AOM: pneumococcus, H. influenza, Moraxella, GAS
Complications of sinusitis
orbital cellulitis, facial cellulitis or abscess, intracranial abscess, meningitis, orbital subperiosteal abscess, cavernous sinus thrombosis, OM frontal bone with subperiosteal abscess (Pott’s puffy tumor), sinus mucocele
Clinical criteria for the diagnosis of sinusitis?
- Persistent > 10 days
- Worsening course
- Purulent nasal drainage (3 days) and fever
Complications of mastoiditis?
intracranial spread (abscess), bacteremia, facial nerve damage, labyrinthitis, osteomyelitis
Pathophysiology of tetanus?
bacteria enters wound and produces tetanus toxin that travels to the brainstem and spinal cord –> disrupts synaptic transmission by preventing release of neurotransmitters
o loss of inhibition (ie, disinhibition) of anterior horn cells and autonomic neurons results in increased muscle tone, painful spasms, and widespread autonomic instability
o may lead to life-threatening respiratory failure and autonomic dysregulation in severe cases
Incubation period of tetanus?
3-21 days
4 forms of tetanus?
o Generalized tetanus
o Local tetanus: tonic and spastic muscle contraction in one body extremity
o Cephalic tetanus: cranial nerve involvement (facial nerve)
o Neonatal tetanus: refusal to feed and difficulty opening mouth, facial muscle spasm, tonic contraction
Treatment of botulism?
Supportive, intubation if needed
o For infants: baby botulism immunoglobulin (BabyBIG), no antibiotics
o For children: botulinum antitoxin, and pencillin or flagyl
Treatment of tetanus?
Tetanus immunoglobulin (TIG) with some infiltrated into the wound and the rest IM; flagyl or penicillin 10-14 days
o Intubate + large doses of sedatives to reduce spasms/ laryngospasm
o Large doses of benzos
Etiology of pneumonia?
- Viral causes are most common
- Bacterial: pneumococcus, S. aureus, GAS
Indications for hospital admission for pneumonia?
< 3-6 months old, immunocompromised, no response to PO abx after 1-2 days, dehydration, suspected staph pneumonia (empyema, pneumatocele), O2 need, unstable vitals
What is Light’s criteria for exudative pleural effusion?
pleural fluid:serum protein ratio > 0.5
pleural fluid:serum lactate dehydrogenase (LDH) ratio > 0.6
pleural LDH concentration > 2/3 the normal upper limit for serum
Transudative pleural effusion causes (list 4)
CHF, Cirrhosis, Nephrotic syndrome, Malnutrition causing low protein state, IBD, Peritoneal dialysis, Sarcoidosis, SLE, Pulmonary embolism
Stages of pertussis?
- First stage = catarrhal phase: 1-2 weeks; similar to URTI; mild cough, conjunctivitis, coryza
- Second stage = paroxysmal stage = 2-4 weeks; prolonged spasm of coughing and characteristic whoop cough from inflow of air; posttussive emesis common; may become cyanotic, anxious
- Third stage (convalescent): intensity of cough wanes
Complications of pertussis?
complete airway obstruction from mucous plug leading to respiratory arrest, bacterial pneumonia, apnea, seizure, encephalitis, intracranial hemorrhage, rectal prolapse, rupture diaphragm
Infectious DDx of Kawasaki?
viral (adenovirus, EBV, CMV), scarlet fever, Staph scalded skin, TSS, ricketsiall disease (RMSF), leptospirosis.
Treatment of pertussis?
Azithromycin x 5 days
Chemoprophylaxis for household contacts (azithromycin or erythromycin), booster if not fully immunized
Which organisms cause endocarditis
S. aureus, S. viridans, HACEK organisms (haemophilus, actinobaccilus, cardiobacterium hominis, Eikenella, Kingella)
5 bacterial causes of gastroenteritis?
Salmonella, Shigella, Yersinia, Campylobacter, E. coli
Organisms that cause HUS?
E. Coli O157:H7 (and Shigella, pneumococcus, and campylobacter)
Treatment of HUS?
NO antibiotics, supportive care, IV fluids, platelets if life-threatening bleeding, nephrology and ICU – may need dialysis.
Complications of C. Diff?
toxic megacolon, perforation, peritonitis
Treatment of C. Diff?
Mild - stop offending abx
Mod/ mild but not-resolving = flagyl PO
Severe = vancomycin PO
Severe, complicated = flagyl IV + vanco PO
Predisposing factors for bacteremia with salmonella NON-typhi
< 4 yo, elderly, sickle cell, asplenia, HIV, immunosuppressed/ immunocompromised
Causes of ellulitis after animal bite
pasteurella multocida, staph, GAS, capnocytophaga canimorsus (sickle cell)
Causes of cellulitis after stepping on nail with running shoe?
Staph aureus, Pseudomonas, GAS
Risk factors for community-acquired MRSA
o close skin-to-skin contact
o openings in the skin such as cuts or abrasions
o contaminated items and surfaces
o crowded living conditions
o poor hygiene. Clusters or increased rates have been reported in Aboriginal populations, athletes, daycare attendees, military recruits, intravenous drug users, men who have sex with men, and prisoners, but many infected children have no risk factors.
Most common bacterial cause of septic arthritis
S. aureus
Other organisms: GBS, S.pneumo, GAS, Kingella, salmonella
Synovial fluid description in septic arthritis
synovial fluid WBC > 50,000-100,000 cell/mm3 with neutrophil predominance
Kocher criteria for septic arthritis?
non weight bearing, ESR > 40, fever, WBC > 12,000 (all four met =99%; 2/4 = 40%)
Treatment of nec fasc?
ABC, IV access, bolus fluids and consider vasopressor/inotropes, IV antibiotics (penicillin/ cloxacillin + clindamycin =/- vancomycin ), urgent plastic surgery consult for debridement; severe GAS consider IVIG
Neurologic complications of varicella?
- Acute cerebellar ataxia (after primary varicella)
- Encephalitis (diffuse cerebritis)
- Reye syndrome - associated with ASA administration
- Aseptic meningitis
- Peripheral motor neuropathy (herpes zoster)
- Transverse myelitis
- Guillain-Barre syndrome (herpes zoster)
- Bacterial meningitis (according to flieshers)
- Stroke like symptoms (secondary to infection of cerebral arteries)
- *seizures (secondary to encephalitis)
- *coma (secondary to encephalitis or reye’s)
Ophtho complications of varicella?
- Herpes zoster ophthalmicus (HZO) - *reactivation!
- hyperemic conjunctivitis
- episcleritis
- iritis
- corneal involvement (keratitis) [results from a necrotic ganglionitis]
- lid droop
- other: acute retinal necrosis (ARN)
What is Ramsay Hunt syndrome?
major otologic complication of VZV reactivation, which typically includes the triad of ipsilateral facial paralysis, ear pain, and vesicles in the auditory canal and auricle
Which form of malaria has the highest mortality?
Plasmodium falciparum
Criteria of severe malaria?
shock, acidosis, hypoglycemia, end-organ involvement (CNS, renal), > 5% parasitemia, severe anemia/ thrombocytopenia
Testing for malaria?
o Thin and thick smears x 2 (12-24 hours later)
o CBC/diff (thrombocytopenia is common), cultures
o R/O hypoglycemia, renal/liver dysfunction, cerebral malaria
Clinical criteria of dengue fever?
fever, vomiting, joint pain, “break-bone” fever, maculopapular rash, positive tourniquet test (petechiae)
Most common cause of traveler’s diarrhea?
Traveler’s diarrhea is usually bacterial (80%) of cases.
Most common cause is ETEC (enterotoxigenic E. Coli)
What does Dukoral protect against?
Dukoral, a killed whole-cell oral vaccine with the nontoxic B subunit of cholera toxin, also provides limited (<50 percent) protection against infection with enterotoxigenic Escherichia coli.
What animals carry rabies?
Bats and wild carnivores (raccoon, skunk, coyote, foxes)
When to treat for rabies?
contact with bats, wild carnivores, bat found in room with sleeping/ non-verbal child, potential unprovoked dog bite if unavailable for observation for 10 days *contact public health
When to perform primary closure of a bite?
- cosmetically needed, joint/tendon/bone involvement
- NOT for cat wounds (except face), old wounds, immunocompromised
When to treat a bite wound with prophylactic antiobiotics? Which abx to give?
crush wound, puncture wound, face, hands, feet, genitalia, immunocompromised, obvious signs of infection, ALL human bites, cat bites. Dog bites if primary closure
Use amox-clav x 5 days
Which organisms are involved in bite wounds?
o Human: Eikenella corrodens
o Dog/ cat: staph aureus and Pasteurella multocida
Complications of measles
pneumonitis, otitis media, meningoencephalitis, late: subacute sclerosing pancencephalitis
Lab diagnosis of measles (what to send for testing)?
o Measles IgM and IgG
o NP/throat swab for measles PCR
o Urine for measles PCR
Complications of mumps?
Parotitis, epididymitis, orchitis, mastitis, myocarditis, hepatitis, pancreatitis, arthritis
What is trachoma?
chronic chlamydia eye infection that can results in corneal neovascularization and blindness
What are signs of HIV infection?
recurrent fever, developmental delay, FTT, chronic/ recurrent diarrhea, parotitis, oral thrush, lymphadenopathy, HSM, acquired microcephaly, bacteremia
What are some features of congenital syphilis?
Condylomata lata, snuffles, bony changes (saddle nose, saber shins, osteochondritis, perichondritis), HSM, lymphadenopathy, meningitis, chorioretinitis, dental changes (Hutchinson teeth, Mulberry molars)
What are the treponemal and non-treponemal tests?
- Non-treponemal tests = non-specific, IgG (RPR for serum, VDRL for CSF). False positives and false negatives are common
- Treponemal tests = specific/ confirmatory (FTA-ABS, TP-PA, MHA-TP)
Which labs to send for a needlestick injury?
Labs at baseline, 6 weeks, 3 months, 6 months:
o HBsAG, HBsAb, HBcAb; HIV and HCV serology
What are the management principles of daycare bite wounds?
- Local wound care – clean well with soap and water
- Tetanus immunization
- Prophylactic abx if:
o Moderate or severe tissue damage
o Deep puncture wounds
o Affecting face, hand, foot, genitalia
- HIV prophylaxis only if one of the children is known HIV+, exchange of blood
- Hep B vaccine if unknown status
Which bacteria can cause PID?
Nisseria gonorrhea, Chlamycdia trachomatis, HSV, Trichomonas vaginals; Mycoplasma genitalium, Bacteroides, E.coli. H.influenza. Gardnerella vaginalis, GBS (non-STI bugs)
Risk factors for the development of PID?
young age, multiple partners, non barrier contraception, cigarette smoking, recent douching, BV, previous gynecological surgery, HIV, 3 weeks post IUD
Complications of PID?
tuboovarian abscess, infertility, chronic pelvic pain, ectopic pregnancy, perihepatitis (Fitz-Hugh Curtis syndrome), dyspareunia
Minimum criteria for the diagnosis of PID?
sexually active patient with pelvic or lower abdominal pain, no cause other than PID identified and one of the following: adnexal tenderness, uterine tenderness, cervical motion tenderness
Definitive/ specific criteria for the diagnosis of PID?
endometrial biopsy showing endometritis, laparoscopy showing abnormalities consistent with PID, transvaginal US showing thickened, fluid filled tubes or tuboovarian complex
What are the Jones criteria for the diagnosis of Acute rheumatic fever?
Need 2 major, or 1 major and 2 minor
- Evidence of recent GAS infection (ASOT positive, rapid strep positive, culture positive) AND
- 5 major: carditis, polyarthritis (migratory and large joints), syndenham chorea, subcutaneous nodules, erythema marginatum (mnemonic: JONES)
- 4 minor: fever (>38.5), arthralgia, elevated CRP/ESR (>60), prolonged PR
Which organism is associated with nec fasc in varicella?
Group A strep
List 5 clinical features that help you distinguish neonatal mastitis from hormone-stimulated breast bud in a neonate.
- fever
- erythema
- warmth
- purulent discharge
- unwell
- may have fluctuance if asbcess present
What is the most probable cause of an infection arising from an animal bite that develops in
< 24 hours?
> 48 hours?
< 24 hours: Pasteurella multocida
> 48 hours: S.aureus, S.viridans
When to give tetanus prophylaxis/ Ig?
If received childhood immunization (>=3 doses) and clean wound: none
If dirty wound and last vaccine was > 5 years ago, Tdap only
If received < 3 doses of vaccine and clean: Tdap only, if dirty Tdap and Ig
Which bacteria causes Guillain-Barre syndrome?
Campylobacter jejuni
What is the treatment for tinea capitis/ kerion?
terbinafine for 4 weeks
Criteria for watchful waiting in AOM (4)?
- The child is >6 months of age.
- The child does not have immunodeficiency, chronic cardiac or pulmonary disease, anatomical abnormalities of the head or neck, or a history of complicated otitis media (otitis media accompanied by suppurative complications or chronic perforation), or Down syndrome
- The illness is not severe - otalgia appears to be mild and fever < 39°C in the absence of antipyretics
- Parents are capable of recognizing signs of worsening illness and can readily access medical care if the child does not improve
2 modifiable risk factors for AOM?
- Daycare attendance
- household crowding
- exposure to cigarette smoke
- not being breastfed
- Bottle propping
2 non-modifiable risk factors for AOM?
- young age
- orofacial abnormalities (such as cleft palate)
- premature birth
- immunodeficiency
- family history of otitis media
What is a felon? Treatment?
Deep infection of the distal pulp space of a fingertip. ‘minicompartment syndrome’
Treatment = incision, blunt dissection, and drainage. A longitudinal incision over the area of maximal tension or fluctuance is the procedure of choice.
What is paronychia?
Pus collecting in a single thin-walled pocket under the cuticle
Alternative treatment for pertussis if allergic to macrolides (azithromycin)?
Septra
Suspected herpes encephalitis – 1 EEG finding, one MRI head finding
EEG – focal slowing or epileptiform discharges localized to the temporal lobes
MRI or CT– focal parenchymal involvement or edema of the temporal lobes
Treatment for gonorrhea/ chlamydia
ceftriaxone 250 mg IM + azithromycin 1g PO x1
child immigrated from Ethiopia with HSM. 4 infectious causes
EBV HIV Yellow fever Leishmaniasis Malaria
List 4 infections that may present with vaginal discharge in a sexually active adolescent
- Trichomonas vaginalis
- Chlamydia trachomatis
- Neisseria gonorrhoeae
- Bacterial vaginosis / Gardnerella vaginalis - not STI but inc risk with inc partners
How many days after measles vaccine could a fever and rash be expected to develop?
Faint rash and mild febrile illness may occur 7-10 days after immunization with the live attenuated vaccine
List 3 common protozoa that can cause diarrhea.
- Giardia Lambia
- Entamoeba histolytica
- Cryptospiridia
List 3 tick borne illnesses
- Lyme (erythema migrans)
- Tularemia (ulcer)
- Rocky Mountain Spotted Fever
- Ehrlichiosis (macpap rash)
- Babesiosis
