Infectious Disease High Yield Flashcards
0-1 month Bacterial Meningitis
GBS, E. coli, Listeria
Ampicillin + Gentamicin or Cefotaxime
1-3 months Bacterial Meningitis
GBS, Strep pneumoniae, Listeria
Ampicillin + Cefotaxime (or + Vancomycin if suspect bacterial
meningitis)
3 months-3 years
Strep pneumoniae, HIB, Neisseria meningitidis
Cefotaxime (or + Vancomycin if suspect bacterial meningitis)
3 years to adult
Strep pneumoniae, Neisseria meningitidis
Ceftoxamine (or + Vancomycin if suspect bacterial meningitis)
Listeria
o Neonates are prone, especially those w/ T Cell defects
o Gram+Rod
o Can be maternally acquired from unpasteurized dairy, soft cheeses
Mom may just have flu-like illness
Has predilection for causing amnionitis
Brown, murky fluid
Can result abortion, stillbirth, neonatal sepsis
o Neonatal distress: Respiratory distress, temperature instability, poor feeding, lethargy/irritability
o Severeform
Gramulomatosis Infantiseptica
Pathognomic for Listeriosis
Granuloma formation and tissue destruction
o Skin (popular or ulcerative necrosis), liver, adrenals, lymphatics, lung, & brain
Neisseria Meningitidis
o Children ≤2 y/o at greatest risk o Will have petechial rash prominent on ankles, wrist, axilla, flanks o Complication Waterhouse-Friderichsen Fulminant Meningococcemia Vasomotor collapse o Severe HoTN Large purpura and petechiae on flanks from Adrenal hemorrhage
Complications of Meningitis
Hearing loss (most common, 25%) (prevent with corticosteroids)
Global Brain Injury (5-10%)
SIADH, seizures, hydrocephalus, brain abscess, CN palsy
Can have developmental regression
o Ex. Forgetting how to copy shapes
Aseptic Meningitis
Definition
Inflammation of the meniges w/ CSF lymphocytic pleocytosis
And if caused by a virus
o Normal Glc, normal to minimally ↑ protein
Causes
Viral most common
o If involves the brain also, then meningoencephalitis
o Enteroviruses
Most common in US Summer & Fall
o Mumps,HerpesViruses
o Viruses that cause encephalitis
Arboviruses (St. Louis, Western equine, Eastern equine, West Nile), influenza, Herpes viruses
Bacterial (some can cause aseptic presentation)
o TB(Children<5y/o)
o Borrelia burgorferi(Lyme)
o Treponema pallidum (Syphilis)
Fungal
o Coccidioides immitis, Cryptococcus neoformans, Histoplasmosis capsulatum
Parasitic
o Taenia solum (cysticerosis)
o Toxoplasma gondii (immunocompromised pt.)
Simple URI (Common Cold)
Rhinovirus, parainfluenza, coronavirus, RSV S/Sx
Low grade fever, rhinorrhea, cough, sore throat
o Resolves in 7-10d
Color of nasal discharge alone doesn’t predict the presence of concurrent sinusitis
o Purulent nasal discharge may occur early in course of URI
Persistent Sx (>10d) or fever, suspect bacterial superinfection (sinusitis,
otitis media)
Sinusitis
Clinical Diagnosis
Persistent Sx, ≥10d w/out improvement
Or Severe Sx (Fever ≥102°F, purulent nasal discharge, face pain ≥3d)
Or Worsening Sx ≥5d after initial improvement of Viral URI
Pus drainage from the meatus Formation
Ethmoid & Maxillary: present at birth
Sphenoid: Develop between 3 to 5 y/o
Frontal: 7 to 10 y/o
Complications
Cerebral Abscess
o Visualized by CT or MRI
Tx
Antibiotics
o OralAmoxicillin-ClavulanicAcid(Augmentin)
Covers the most common (S. pneumoniae &
nontypeable Haemophilus influenzae)
Pharyngitis
Viral o Coxsackievirus, EBV, CMV Bacterial o Strep pyogenes (GA β hemolytic Strep [GABHS] aka “Strep Throat”) o Arcanobacterium hemolyticum, Corynebacterium diphtheria (diphtheria) S/Sx Viral and GABHS overlap Viral o Simple URI Sx o Can have tonsillar exudates o EBV Pharyngitis Enlarged posterior cervical lymph nodes, malaise, & hepatosplenomegaly o Coxsackievirus Pharyngitis Painful vesicles/ulcers on P. Pharynx Soft palate (herpangina) (not herpes) Blisters on palms/soles (hand-foot-mouth disease)
GABHS pharyngitis
o Typically school age (5-15 y/o), winter & spring o Lack of other URI Sx (rhinorrhea, cough)
o S/Sx
Sore throat
Exudates on the tonsils, Petechiae on soft palate,
Strawberry Tongue, enlarged tender A. Cervical LN
Fever
Scarlatiniform rash (also in Scarlet fever)
Sandpaper rash
o Dx
Rapid Strep
o Tx
Amoxicillin
Erythromycin for penicillin allergic
o Complications
PSGN (ABx don’t prevent) and Rheumatic Fever (ABx prevent)
Peritonsillar Abscess
Asymmetric tonsilar bulge
o Displaces uvula to side
Acute Otitis Media
Otitis media w/ effusion (OME): fluid w/ middle ear without Sx of infection Can have a retracted TM
If >3m then conduct audiometry testing to assess hearing loss If normal hearing then give ABx or can observe
o Causes
Bacterial
S. pneumoniae (most common), non-typeable H. influenzae, Moraxella catarrhalis
Viruses o S/Sx of AOM
AOM usually develops after simple URI
Fever, ear pain, ↓ hearing, pulling at ear
If TM perforates, may have drainage from ear
o Dx
Dx of AOM: fluid in middle ear (bulging TM, absent motility, otorrhea) & Sx of
Infection (erythema of TM)
Pneumatic Otoscopy identifies abnormal movement of TM
o From fluid
o Most reliable way of detecting middle ear fluid o BulgingTM
o Complications
Cerebral Abscess
Visualized by CT or MRI S/Sx
o Persistent fever, neurologic deficits,headache,seizures
o ↑ ICP
From accompanying edema from abscess
Mastoiditis
Erythematous, swollen, tender, skin overlying mastoid
Conductive hearing loss
Can spread to the meninges
o Tx
Don’t have to treat if ≥2 y/o and nonsevere
Treat if worsen w/in 48-72h ABx if used
Amoxicillin (80 mg/kg/day BID) initially o Higher dose than for Strep throat
If attended daycare w/in previous 2 months, then increased likelihood of penicillin resistant S. pneumoniae
o High dose amoxicillin, amoxicillin-clavulanic acid, or a cephalosporin
Macrolide (Erythromycin) if penicillin allergic No ABx for OME
Tube placement only if >3 infections in 6m or >4 infections in one year
Otitis Externa (OE)
o Infection of the external auditory canal (EAC)
o Predisposition
Cerumen removal, trauma, maceration of skin from swimming, excess moisture
o Causes
Pseudomonas aeruginosa, S. aureus, or C. albicans
2° to perforated TM from AOE
o S/Sx
Pain, itching, and drainage
o Dx
Erythema/edema of EAC
Sometimes purulent white discharge
o Tx
Restore EAC to natural acidic state
Mild (minimal pain/discharge): acetic acid
Severe: Topical ABx/Corticosteroids
Perforated AOM w/ OE: Both oral & topical ABx
Cervical Lymphadenitis
o Enlarged, inflamed tender lymph nodes o Causes
Localized Bacterial Infection
S. aureus, most common
o Fever &Tender
S. pyogenes, common
Mycobacterium: TB and MAC (atypical mycobacteriums)
Francisella tularensis
o Ulcerative lesion at inoculation site
o Regional extremely tender lymphadenopathy
B. henselae (cat scratch disease)
o May have Hx of cat exposure
o Papules develop at scratch site
o Nontender local lymphadenopathy: Cervical, inguinal, axial
o Nonspecific Sx: low-grade fever, malaise, fatigue
o Gram–bacilli on Warthin-Starry Stain
o Tx
Typically self limited, but can give Azithromycin
Non-bacterial Cervical Lymphadenitis
Viral
Reactive lymphadenitis: EBV (tender generalized lymphadenopathy),
CMV, HIV
o Kawaskai
Unilateral cervical lymphadenitis
o T. gondii
Mono like illness w/ cervical lymphaenopathy
o Bilateral, symmetric, tender or nontender cervical adenopathy
Parotitis
o Inflammation of the parotid salivary glands
o Causes
Mumps and other Viruses (CMV, EBV, HIV) Bilateral
Before vaccination, mumps was #1 cause Bacterial parotitis (acute suppurative parotitis)
Unilateral
S. pyogenes & TB
o S/Sx
Fever
Neck Swelling centered above the angle of the jaw & fever
Pus in oropharynx
Can be expressed from Stensen’s Duct
o Complications
Mumps: meningoencephalitis (also complication of bacterial), orchitis (most common complications, esp. for post puberty), & epididymitis, pancreatitis
Staphylococcal Scaled Skin Syndrome(SSSS)
S. aureus exfoliative toxin
Scarlatiniform erythema
More erythematous in skin flexures and periorally
Fever, tender skin, bullae
Intact bullae are sterile (unlike impetigo bullae)
Nikolsky Sign
Extension of bullae when pressure applied
Skin Sloughs off
Extensive fluid and electrolyte loss
Tx
Clean and moisten skin w/ isotonic or burrow solution
IV Oxacillin or Naficillin (penicillinase resistant)
Scarlet Fever
GABHS that produce erythogenic toxin S/Sx
Exanthem may develop during any GABHS infection o Begins on trunk
Moves peripherally
o Skin is erythematous w/ skin colored papules (scarlatiniform
appearance)
Sandpaper Rash texture
o Pastia’s Lines
Petechiae w/in skin crease
o Desquamation of dry skin as infection resolves
William Martin MD MBA 2016 TTUHSC SOM OC USN
2.23.2015
Fever
White exudates on inflamed tonsils, pharyngitis
Strawberry tongue w/ circumoral pallor
Dx
+ Culture/Throat Swab
Tx
Goal is to prevent Rheumatic Fever
Oral Penicillin VK, IM Benzathine Penicillin, or for penicillin allergic
erythromycin or Macrolide
Complications of Strep Pharyngitis
PSGN (ABx doesn’t prevent), rheumatic fever (ABx prevent), Post Strep Arthritis (ABx doesn’t prevent)
Pediatric autoimmune neuropsychiatric disorder associated w/ streptococcal infection (PANDAS)
o Acute OCD or Tic DO after Strep Infection
o ABx prevents
Toxic Shock Syndrome
Toxin Mediated
Fever, shock, desquamating skin rash, multiorgan dysfunction Causes
S. aureus #1, GABHS also
Tampons
Dx: 5 of 6 probable, 6 of 6 confirmed
Fever > 101
HoTN (SBP <90)
Diffuse macular erythroderma (looks like sunburn)
Desquamation (10-14d after illness)
Multisystem Involvement
o GI, Myalgias (↑CPK), Hyperemia of mucous membranes (pharyngitis, vaginits), pyuria, thrombocytopenia, CNS (∆MS)
- cultures other than S. aureus (CSF, blood, pharynx) Tx
Reverse shock, ABx, IVIG
Diarrhea
o Viral
Rota and Norwalk
Rotavirus
Most common infectious cause of gastroenteritis
o Winter Months
Incubation is 1-3d
Vomiting, watery osmotic diarrhea, dehydration
o Self limited for 4-7d
Supportive Tx
Norwalk Virus
Outbreak of gastroenteritis in all age groups
o Esp. closed populations (day care, cruise ships)
Same Sx as Rotavirus, just more prominent vomiting
o Shorter duration, 2-3d
o Evaluation
Recent ABx
C. difficile
Unusual pets (e.g. turtles)
Salmonella
ELISA
Rotavirus, Giardia lamblia, C. difficile If WBCs absent, culture is of limited use
o Non-anion gap Hyperchloremic Metabolic Acidosis Result of bicarb loss in stools
o Tx
Fluids
HIV and AIDS
o S/Sx
Infants typically asymptomatic for the first few years
Early Sx of HIV infection
FTT, Thrombocytopenia, Recurrent Infections (otitis media, pneumonia, sinusitis) Generalized Lymphadenopathy, Parotitis, Recurrent Thrush, loss of developmental milestones, Severe VZV, diarrhea
Older children may present w/ weight loss (FTT), AIDS defining illnesses (e.g. oral lesions), lymphadenopathy
o Dx
Infants
All infants born to HIV infected mothers have maternal Ab that may last 18-24m
o HIV specific DNA PCR is the test <18m (bc maternal Ab will interfere)
HIV specific DNA PCR is performed at birth & monthly until 4m to detect those infected perinatally
Negative HIV specific DNA PCR @ 4m consistent w/ non infected
o Followed till 18-24m when lose maternal Ab Older Children
ELISA, confirm Western Blot
o Tx
Infants born to HIV mothers
Zidovuidine for 6w postexposure prophylaxis after birth o Also for mother starting @ second trimester
TMP/SMX for PCP prophylaxis at 6 weeks old until HIV DNA PCR - @4m
No breastfeeding
Urine CMV Culture to detect CMV/HIV co infection (5%)
Infectious Mononucleosis
o EBV #1 cause
Toxoplasmosis, CMV, and HIV can cause a similar clinical syndrome o S/Sx
Young children may be asymptomatic Older children: typical S/Sx
Fever, up to 2w
Malaise & Fatigue
Pharyngitis (typically exudative, resembling GABHS)
Posterior cervical lymphadenopathy
Hepatosplenomegaly
Takes weeks to months to resolve
o Complications
Post infectious Bell’s Palsy
o Dx
CBC shows atypical lymphocytes
May also have neutropenia, thrombocytopenia, & ↑LFT Monospot (first line)
Measures heterophile Ab
Less sensitive for children <4 y/o
o InsteadhaveEBVAbTiters
Viral Capsid Antigen (VCA) & EB Nuclear Antigen (EBNA)
Acute infection: ↑ IgM-VCA and absent EBNA Ab
CMV causes the majority of monospot negative mononucleosis Tx: supportive, corticosteroids for severe pharyngitis
Complications
Neurological, CN palsy and encephalitis
Severe pharyngitis can cause obstruction
Amoxicillin-Associated Rash
o EBV infected pts. who are misdiagnosed w/ GABHS and prescribed amoxicillin develop a diffuse pruritic maculopapular rash 1 week after
Splenic rupture
Malignancy: Burkitt’s lymphoma and nasopharyngeal carcinoma
Measles
o Highly infectious
o S/Sx
Appear 8 to 10d after incubation
Classic prodrome followed by a transient enanthem (rash on mucous
membranes) and exanthem (skin rash)
Classic prodrome, The Three C’s (Cough, Conjunctivitis, & Coryza)
Other early Sx: Photophobia & fever
Enanthem: Koplik spots (small gray papules on an erythematous base on the
buccocal mucosa)
Pathogonomic and present before the generalized exanthem
Exanthem: erythematous maculopapular eruption, begins around neck & ears, spreads down the chest and upper extremities during 24h
Covers the LE by 2nd day and becomes confluent by the third day Fever
o Complications
Bacterial Pneumonia
Otitis media, laryngotracheitis, encephalomyelitis (inflammation of brain and spinal cord), subacute sclerosing panencephalitis
o Tx
Supportive, Vitamin A
IVIG for immunocompromised postexposure prophylaxis
Rubella
o Unlike measles, typically mild or asymptomatic, incubation 14-21d o S/Sx
Prodrome: Mild URI w/ low grade fever (<101oF) Painful lymphadenopathy
Suboccipital, posterior auricular, and cervical nodes Exanthem follows the adenopathy
Nonpruritic, maculopapular, and eventually confluent
Begins on Face and spreads to trunk/extremities
o Complications
Meningoencephalitis Polyarthritis
Teenage girls/young women Congenital Rubella Syndrome
First trimester infection
Thrombocytopenia, Hepatosplenomegaly, jaundice, purpura (blueberry muffin baby), MR
XR
o Longitudinal striations in metaphysis (osteochondritis or
periostitis = congenital syphilis)
Triad
o Cataracts, PDA, Sensorineural Hearing Loss
Pregnancy test priority if woman is infected of childbearing age
