Infectious Disease Flashcards
Rabies
Reservoir?
Name the two presentations
- AMS, agitation, hydrophobia, aerophobia, pharyngeal spasms
- ascending flaccid paralysis
Rabies
- -neurotropic virus
- -transmitted via saliva (eg, from bite)
- -raccoon, bats
- Encephalitic
- -AMS, agitation, hydrophobia, aerophobia, pharyngeal spasms
- Paralytic
- -ascending flaccid paralysis
Tx
–PEP: rabies IG and vaccine
Childhood Infections with Exanthems
–name the disease and etiology
- cough, coryza, conjunctivitis, high fever, Koplik spots on buccal mucosa; rash begins at hairline, face, neck and spreads to trunk and extremities
- low fever and other constitutional symptoms; Forscheimer spots (patchy erythema or red petechiae) on soft palate; rash begins on face and spreads to trunk and extremities, lasts 3d; non-exudative conjunctivitis; posterior cervical and auricular lymphadenopathy
- h/a, fever, malaise, muscle pain; swollen parotid and submandibular glands
- low fever, malaise, URI s/s; crops of crusting papules and vesicles that spread central to peripheral
- mild URI s/s; slapped cheek rash that spreads to trunk; central clearing and lacy
- URI s/s, abrupt onset of high fever that breaks; then fine macular rash on trunk that spreads to face and extremities
- sore throat, exudative pharyngitis, strawberry tongue; circumoral pallor; maculopapular rah that feels like sand paper in antecubitus and inguinal areas; pastia lines (creases become brighter red)
Childhood Infections with Exanthems
- Measles (Rubeola)
- -paramyxovirus - Rubella
- -togavirus - Mumps
- -paramyxovirus - Varicella
- -varicella zoster virus - Fifth Disease (Erythema Infectiosum)
- -Parvovirus B19 - Roseola
- -HHV6 - Scarlet Fever
- -Group A strep
Complications associated with childhood infections with exanthems
–name the disease and etiology
- subacute sclerosing panencephalitis
- encephalitis, orchitis, pancreatitis
- aplastic anemia
- febrile seizures
- acute rheumatic fever, glomerulonephritis
- Measles
- -paramyxovirus
- -subacute sclerosing panencephalitis
NB: another complication is leukopenia
*tx: Vitamin A
- Mumps
- -paramyxovirus
- -encephalitis, orchitis, pancreatitis - Fifth Disease (Erythema Infectiosum)
- -Parvovirus B19
- -aplastic anemia - Roseola
- -HHV6
- -febrile seizures - Scarlet Fever
- -Group A strep
- -acute rheumatic fever, glomerulonephritis
Bacterial Meningitis
- -fever, lethargy, irritability, anorexia, n/v, photophobia, neck pain and rigidity
- -petechial rash at axilla, wrists, flanks, ankles
- Most common etiologies during age 0-2m (3)
- Most common etiologies during age 2m-12y (3)
- Initial empiric abx?
- Steroid to prevent 8th CN damage?
Bacterial Meningitis
Ages 0-2m
–GBS, E.coli, Listeria
(maternal vaginal flora)
Ages 2m-12y
–S. pneumo, N. meningitidis, HiB (haemophilus influenza bacteria, rare)
Empiric Abx: vancomycin plus cefotaxime OR ceftriaxone
IV dexamethasone to prevent CN8 damage
Viral (Aseptic) Meningitis
- -fever, n/v, photophobia, neck, back and leg pain
- older children: h/a, hyperesthesia
- infants: irritability, lethargy
Cytology differences between bacterial and viral?
- Most common etiology?
- Etiology re: temporal lobe involvement (focal seizures or imaging evidence)
- Etiology for cerebellar ataxia and acute encephalitis
- Etiology re: disseminated disease in immunocompromised host
- Etiology re: mild s/s, but with CN8 damage
Viral (Aseptic) Meningitis
Bacterial: PMNs
Viral: mostly lymphocytes
Etiologies:
–enteroviruses (most common)
–arboviruses (mosquitoes, ticks)
- -herpes simplex (temporal lobe involvement)
- can be lethal
–varicella zoster (cerebellar ataxia, acute encephalitis)
–CMV (disseminated dz in immunocompromised)
–EBV or mumps: mild, but with CN8 damage
Pertussis
(Bordetella pertussis)
Catarrhal phase: coldlike s/s
Paroxysmal phase: severe coughing paroxysms; inspiratory “whoop”, facial petechiae; subconjunctival hemorrhages, post-tussive emesis
Convalescent phase: gradual resolution of cough
Labs: what type of cell predominates the leukocytosis?
Tx: what antibiotic for 14d?
–treat all close contacts
Pertussis
(Bordetella pertussis)
Catarrhal phase: coldlike s/s
–2 wks
Paroxysmal phase: severe coughing paroxysms; inspiratory “whoop”, facial petechiae; post-tussive emesis
–2-5 weeks
Convalescent phase: gradual resolution of cough
–2+ wks
Labs: lymphocyte-predominant leukocytosis
Tx: erythromycin for 14d
- -treat all close contacts
- tx only decreases infectious period!
DDx: neonatal conjunctivitis
- less than 24 hrs; conjunctival irritation, injection and swelling after chemoprophylaxis with topical silver nitrate
- age 2-5d; marked eyelid swelling, profuse purulent discharge, corneal edema and abrasion;
- age 5-14d; eyelid swelling, chemosis, and watery, bloody, or mucopurulent discharge
Etiology?
Tx?
DDx: neonatal conjunctivitis
- Chemical
- -eye lubricant - Gonococcal
–cefotaxime or ceftriaxone
NB: don’t use ceftriaxone in infants with hyperbilirubinemia; it displaces bilirubin from albumin thus increasing kernicterus risk - Chlamydial
- -oral eyrthromycin
NB: topical erythromycin at birth can prevent gonococcal conjunctivitis; it does NOT prevent or cure chlamydia
Meningitis: CSF Analysis
Compare: WBC count, glucose, protein
Viral Meningitis
Bacterial Meningitis
Tuberculous Meningitis
Meningitis: CSF Analysis
Viral Meningitis
- -Coxsackie, Echovirus, Rhino/Entero
- -pleocytosis, lymphocyte predominance
- -normal glucose (40-70)
- -normal to slightly high protein (less than 100)
Bacterial Meningitis
- -S. pneumo, N. meningitidis
- -pleocytosis, neutrophil predominance
- -low glucose (less than 40)
- -high protein (greater than 250)
Tuberculous Meningitis
- -pleocytosis, lymphocyte predominance
- -low glucose (less than 10)
- -high protein (greater than 250)
pharyngitis; circumoral pallor; red papular “sandpaper” rash; erythematous lines in skin creases (Pastia’s lines)
Dx?
Etiology?
First dx test?
Tx?
Scarlet Fever
Group A Strep
Rapid strep test
- -no need to culture if positive
- -if negative, culture if clinical suspicion is high
Penicillin
–if allergy, use erythromycin
DDx: infectious diarrhea
- bloody diarrhea; HUS
- associated with poultry and eggs; diarrhea may last wks; erythematous rash of “rose colored” spots on abdomen
- food poisoning; begins 12h post-ingestion
- watery diarrhea and vomiting; fever
- bloody diarrhea; liver abscess
- “rice water” diarrhea; severe dehydration; epidemics; seafood
- “traveler’s diarrhea”
- bloody diarrhea; comma- or S-shaped
DDx: infectious diarrhea
- EHEC O157:H7
- Salmonella
- S. aureus
- Rotavirus
- E. histolytica
- V. cholerae
- ETEC
- Campylobacter
What is the classic triad of HUS?
HUS
- -hemolytic anemia
- -thrombocytopenia
- -uremia
Tx for Lyme, RMSF
- Lyme Disease
- -tx for ages greater than 8
- -tx for age less than 8; pregnant women
- -tx for meningitis, carditis in disseminated disease? - RMSF
- -tx (2)
Tx for Lyme, RMSF
- Lyme Disease
- -Doxycyline for ages greater than 8
- -Amoxicillin for ages less than 8; pregnant women
- -Ceftriaxone for meningitis, carditis - RMSF
- -Doxycycline or Tetracycline
Croup – viral etiology?
–URI followed by barking cough, hoarseness, inspiratory stridor
Epiglottitis
- -acute onset, high fever, extremely sore throat, drooling, cannot swallow, sniffing or tripod position
- -formerly HiB (vaccine success)
- -now S. pyogenes, S. aureus, Strep pneumo, Mycoplasma
Peritonsillar Abscess
- -adolescent with recurrent hx of acute pharyngotonsillitis
- -asymmetric tonsillar bulge; displacement of uvula away from affected side
Croup
- -parainfluenza (types 1, 2, 3)
- -URI followed by barking cough, hoarseness, inspiratory stridor
- -tx; racemic epinephrine
Epiglottitis
- -acute onset, high fever, extremely sore throat, drooling, cannot swallow, sniffing or tripod position
- -formerly HiB
- -now S. pyogenes, S. aureus, Strep pneumo, Mycoplasma
Peritonsillar Abscess
- -adolescent w recurrent hx of acute pharyngotonsillitis
- -asymmetric tonsillar bulge; uvula displaced away from affected side
Neonatal Sepsis
- -temperature instability (high or low), poor feeding, lethargy or irritability
- -workup: blood cx, urine cx, CSF cx
- Three most common etiologies?
- Other common etiology if age greater than 7d?
- Abx for sepsis with no meningitis?
- Abx for sepsis with suspected meningitis?
Neonatal Sepsis
- GBS, E. coli, Listeria
- S. aureus
- Ampicillin, Gentamycin
- Ampicillin, Gentamycin, Cefotaxime
- do NOT use ceftriaxone in jaundiced neonates!
- -ceftriaxone displaces bilirubin from albumin
Viral versus Bacterial Pneumonia
- Compare viral v bacterial re:
- -temp
- -URI
- -toxicity
- -location of rales - Most common viral etiology of bronchiolitis?
- Etiology of pneumonia associated with eosinophilia?
- Type of pneumonia associated with CXR showing “hyperinflation, bilateral interstitial infiltrates and peribronchial cuffing”?
- Which two types of pneumonia look worse on CXR than their clinical presentation?
Viral versus Bacterial Pneumonia
- Viral v Bacterial
- -bacterial has higher fever
- -viral assoc w several days of URI
- -bacterial causes more toxic appearance
- -rales: viral - scattered; bacterial - localized - RSV
- -most common viral etiology - Chlamydia trachomatis pneumonia
- -eosinophilia - Viral pneumonia
- -CXR: hyperinflation, bilateral interstitial infiltrates, peribronchial cuffing - Mycoplasma, Chlamydia
- -look worse on CXR
Epstein-Barr Virus
- -transmitted via oral secretions
- -patient age 15-24
- -may present with rash after having been treated with ampicillin or amoxicillin for URI s/s
- -heterophile Ab test
- -splenomegaly (no contact sports!)
- Infectious mononucleosis triad?
- Three associated malignancies?
Epstein-Barr Virus
Triad: fever, exudative pharyngitis, posterior or diffuse cervical lymphadenopathy
Malignancies: nasopharyngeal carcinoma, Burkitt lymphoma, Hodgkin disease
Osteomyelitis
- Most common etiology?
Other Etiologies:
- -sickle cell
- -diabetics or IVDU
- -sexually active young adult
- -children age less than 1y
Osteomyelitis
- -S. aureus (most common)
- -Salmonella (sickle-cell)
- -Pseudomonas (diabetics, IVDU)
- -N. gonorrhoeae (sexually active young adult)
- -GBS (children age less than 1yr)
Cat bites in children may lead to infection with Pasteurella multiocida.
Tx?
Cat bite –> Pasteurella multiocida
Tx: Amoxicillin/Clavulanate (Augmentin)
Which virus can cause the following presentations?
- Herpangina
- -high fever, sore throat, vesicular oral ulcers - Hand-Foot-Mouth Disease
- -high fever, sore throat, vesicular ulcers at mouth, palms, soles
Which virus?
3. viral myocarditis
Tx: supportive care
Coxsackievirus A
Herpangina
- -high fever, sore throat
- -vesicular oral ulcers
Hand-Foot-Mouth Disease
- -vesicular ulcers in oral mucosa, palms, soles
- -“hand-foot-mouth” disease
Coxsackievirus B
–viral myocarditis
Viral Exanthems
- reddish-brown macular rash that starts at nape of neck and behind ears and spreads to trunk and extremities
- differentiate from above by shorter duration (3d) and more pinkish color of rash and presence of patchy erythema on palate before onset of rash
- after breaking of high fever, a rose-colored papular rash on trunk that spreads to extremities, neck, face
- swollen parotid and submandibular glands
- pruritic rash with crops of lesions in various stages of macules, papules, vesicles, open vesicles, and crusting; begins centrally and spreads to extremities
- slapped cheeks; lacy reticular rash over trunk and extremities
Viral Exanthems
Measles
- -macular rash that starts at nape of neck and behind ears, spreads caudally
- -Paramyxovirus
Rubella
- -similar rash as Measles
- -Forscheimer spots may precede rash
Roseola
- -after breaking of high fever, a rose colored papular rash on trunk that spreads to extremities, neck, face
- -HHV-6
Mumps
- -swollen parotid and submandibular glands
- -Paramyxovirus
Varicella
- -pruritic rash with crops of lesions (macules, papules, vesicles, crusting)
- -begins centrally, spreads peripherally
- -VZV
Erythema Infectiosum
- -slapped cheeks; lacy reticular rash over trunk and extremities
- -Parvovirus B19
Acute Rheumatic Fever
Diagnosis
- recent group A strep infxn
- JONES criteria
- -name the major criteria
Labs
- -elevated ESR, CRP
- -high antistreptolysin (ASO) titers
Tx: penicillin
- -carditis?
- -chorea?
Major complication?
Prophylaxis
–what type of penicillin?
Acute Rheumatic Fever
Diagnosis
- recent group A strep infxn
- JONES Criteria: two major; or one major and two minor
J - joints (migratory polyarthritis) O - carditis N - nodules (subcutaneous) E - erythema marginatum (pink rash with sharp edges) S - Sydenham chorea
Minor criteria: fever, arthralgia, inflammatory markers, prolonged PR interval
Tx: penicillin
- -carditis w CHF –> prednisone
- -chorea –> phenobarbital
Complication: valvular disease
Prophylaxis
–IM benzathine penicillin G
DDx: TORCH infxns
- skin vesicles, keratoconjunctivitis, acute meningoencephalitis
- hydrocephalus, intracranial calcifications, chorioretinitis
- osteochrondritis, periostitis, desquamating skin rash involves palms and soles, snuffles (mucopurulent rhinitis)
- cataracts, deafness, and heart defects
- microcephaly, periventricular calcifications, petechiae with thrombocytopenia
DDx: TORCH infxns
Toxoplasmosis
–hydrocephalus, intracranial calcifications, chorioretinitis
Other (Syphillis)
–osteochrondritis, periostitis, desquamating skin rash involving palms and soles, snuffles
Rubella
–cataracts, deafness, heart defects
Cytomegalovirus
–microcephaly, periventricular calcifications, petechiae with thrombocytopenia
Herpes Simplex
–skin vesicles, keratoconjunctivitis, acute meningoencephalitis
Infant; meningococcemia; sudden vasomotor collapse; petechial and purpuric lesions on flanks
Dx?
Waterhouse-Friderichsen Syndrome
–adrenal hemorrhage
DDx: oropharyngeal lesions in children
- recurrent ulcers on anterior oral mucosa; no fever or systemic s/s
- gray vesicles and ulcers on posterior oropharynx; fever
- clusters of vesicles on anterior oral mucosa and around mouth; fever
- fever; exudative pharyngitis; anterior cervical lymphadenopathy
- fever; exudative pharyngitis; posterior or diffuse cervical lymphadenopathy
DDx: oropharyngeal lesions in children
- Apthous stomatitis (canker sore)
- Herpangina
- -Coxsackie A - Herpes gingivostomatitis
- -HSV-1 - GAS (strep throat)
- EBV (infectious mononucleosis)
* hepatosplenomegaly
* maculopapular rash after amoxicillin/ampicillin
