Infectious Flashcards
Caused by HHV6
Peak at 6-9m
95% of children have been infected by 2 mos
Saliva transmission from entry to oral nasal or conjunctivs
Supress cellular lineages in bone marrow
Fever in first 3-5 days and rash
Exanthem subitum
Roseola
Sixth disease
Most conmon type of roseola
Type B
Fever in 3-5d with fusiness 90%
Rash in 12-24 h of fever resolution
Asians: ulcer in uvulopalatoglossal junction called
Nagayama spot
Roseola
Where is the koplik spot best appreciated
Opposite lower molar
RNA virus from paramyxoviridae by droplet aerosol in prodromal period
Incubation 8-12 d
Period of comm is 4 days before and 4 days after onset of rash
Measles
Causes necrosis of respi epithelium
Small vessel vasculitis in skin and mucous membrane
Pathognomonic of
(multinucleated giant cells)
Measles
Warthin Finkeyldey giant cells
High grade fever with conjunctivitis and colds 3-5 d
Measles prodrome
Enanthem Grayish white dot with red border opposite lower molar 1-4d prior onset of rash
Rash at height of fever
Koplik spots
Rash fades downward in same seq which it appears
Rash: cephalocaudal with branny desquamation in 7-10d
Measles
Rash in Roseola
starts at trunk and then grows peripheral
Give to prevent complications in measles
Vitamin A: single 100,000 IU for 6-1 yr
200,000 IU for >1
OD x 2 d
<6 mos: 50,000 IU
If with vit A def, repeat after 1 month
Measles complication
Otitis media
Pneumonia
SSPE
Delayed chronic complication due to persistent infection with virus
SSPE
Ulcers in uveopalatoglossal junction
Nagayama spot
Sixth disease
Painful enlargement of parotid glands as usual presenting sign
by RNA virus of paramyxoviridae
Period of comm: 1-2 d before onset of parotid swelling till 5 days after onset of swelling
Respiratory droplet
Mumps
Pain and swelling of one or both parotids (1-3d)
Fills the space bet posterior border of mandible and mastoid
Pushes earlobe upward and outward and angle of mandible no longer seen
Swelling subsides in 7d
Edema of homolateral pharynx and soft palate displacing tonsil medially
Edema of larynx and manubrium
Mumps
Most freq complication of mumps
Meninggoencephalitis in 5 days
Others Orchitis and epididymitis (infertility rare) Oophoritis Dacryoadenitis Optic neuritis
3 day measles
Caused by RNA from Togaviridae
Spreads by oral droplet of transplacental to fetus
Risk for congenital defects and disease greatest with primary maternal infection during 1st tri
Period of comm: 5d before until 6d after onset of rash
Rubella
German measles
Most prominent Characteristic of rubella
Retroauricular
Posterior cervical
Postoccipital LAD (24h before rash till 1 week)
enanthem in Rubella
discrete rose spots on soft palate
Forscheimer spots
Rubella in older girls present with
Polyarthritis
No photophobia
Pertussis is causes by
Bordetella pertussis Gram neg
Secretion from RT of infected person
Transmission by close contact with large aerosol drops
Pertussis
Whooping cough
Most infectious stage of pertussis/whooping cough
Catarrhal stage
Stages of Pertussis
3 lasting 2 weeks each stage
Catarrhal
Paroxysmal -explosive outbursts of cough in 5-10 series in one expiration and ending in high pitched whoop associated with suffusion of face, popping out of eyes and vomiting
Convalescent
In between paroxysms of pertussis,
child may look well
conjunctival or petechial hemorrhage on upper body
Tx for pertussis
Erythromycin 40-50 mg/kg/day q6 PO or IV
Placed in respiratory isolation for at least 5 days after initiation of antibiotics
Beyond this nininfectious
Results in lifelong latent infection of sensory ganglion neuron
Primary Chickenpox
Caused by neurotropic human herpes virus
Transmission: oropharyngeal secretion by airborne spread and direct contact
Period of comm: 1-2d before onset of rash till 3-7d after rash until ALL has crusted
Varicella
Rash pattern in varicella
Starts on scalp, face or trunk with rapid progression
Simultaneous presence of lesions in various stages
Varicella complications
Secondary bacterial infection Meninggoencephalitis Pneumonia Reye syndrome GN
Fetus infected at 6-12w of gestation with max interruption with limb development (short and malformed) covered with:
which are skin lesions with zigzag scarring assoc eith atrophy of affected limb
Congenital varicella
cicatrix
If infected at 16-20w of gestation, varicella may induce
eye and brain involvement in fetus
Lifetime risk for herpes zoster
10-15% with 75% of cases occuring after 45yrs
Due to Parvovirus B19
Transmission by large droplet spread and blood
Rash and aplastic crisis in 5-15 y o
Erythema infectiosum
5th disease
Parvo B19 target
erythroid cell with arrest in development of RBCs
Erythema infectiosum hallmark sign
Slapped cheek: rash erythematous facial flushing
spreads rapidly to trunk prox extremities and diffuse macular edema
Lacy reticulated appearance of rash on extremities esp on extensor areas
Palms and soles spared
Rash resolves without desquamation waxes and wanes in 1-3 weeks
Not infectious at presentation bec rash and arthropathy are immune mediated
Erythema infectiosum
Virus replication from Flaviviridae carried by Aedes egypti
Viremua
Ag-ab complex
Complement cascade and Hagemab factor activation
Extravasation of fluid
Shock
Dengue
Dengue fever rash:
Transient macular generalized rash blanching under pressure seen during first 24-48h of fever
Generalized maculipapular rash appearing which spares the palms and soles and disappears in 1-5 days with desquamation
Hermann’s rash
Day 1-4 illness dx of dengue
Dengue NS1
End of acute phase dengue dx
Serology
IgM by day 5
IgG low titer at end of first week of illness even after several months
If secondary infection IgG first week to 10 mos
Dengue endemic area with fever + any 2 of ff: headache myalgia Arthralgia Retroorbital pain Body malaise Nausea and vomiting Anorexia diarrhea flushed skin And
CBC with leukopenia with or without thrombocytopenia
Probable dengue
Dengue endemic + fever lastinf 2-7d plus any one
Abdominal pain
Mucosal bleed
Persistent vomiting
Lethargy, restlessness
Liver enlargement
Dec or no urine output within 6h
Labs: inc in hct and dec platelet count
With no warning
But if with liver enlarge: with warning
Dengue endemic + fever in 2-7d + dengue with or without warning signs plus any one:
Shock Fluid accumulation with respiratory distress Liver AST or ALT >1000 CNS: seizure, impaired consciousness Heart: myocarditis Kidneys: renal failure
Severe Dengue
Fever Dehydration Normal Hct Normal platelet High viral load: NS1 (viremia)
Febrile phase
Afebrile Shock Bleeding Organ impairment DECREASED HCT DECREASED PLATELET COUNT
IgM +
Critical Dengue phase
Reabsorption
Fluid overload
Platelet
IgM/IgG
Recovery Dengue phase
Recovery phase in dengue is characterized by
Diuresis
Monitor UO
Caused by Corynebacterium
Transmission: direct contact via airborne respiratory droplet
Period of communicability: variable
Diptheria
Organism in superficial layers of skin Produce exotoxin Inhibits protein synthesis and causes necrosis Gray grown adherent pseudomembrane May cause paralysis of palate Bukl neck appearance Leather like adherent membrane
Diptheria
Diptheria vs strep
Lack of fever
Non exudative throat
Diptheria dx
Culture from nose and throat from beneath membrane including the membrane
Negative results do not rule out
Diptheria tx
Pen G IM/IV 100,000 - 150,000 U/kg/day q6 for 14 d
Erythromycin 40-50mg/kg/day if allergic also to eradicate nasopharyngeal microbe
Asymptomatic case contact of diptheria pxs
Benzathine Pen G
600,000 U IM for younger 6
1.2M IM for 6 yrs
Or Erythromycin 40-50mg/kg/day for 10d
Complication of diptheria:
Toxic cardiomyopathy
Toxic neuropathy
Most common complication of mumps
Meningoencephalitis
Most common complication of congenital rubella syndrome
sensorineural hearing loss
Most debillitating complication of shingles
neuropathic pain
Most common dermatome involved in shingles
Thoracic
Lumbar
DOC for neuropathic pain
pregabalin
gabapentin
Pregabalin and gabalin binds to
Alpha 2 delta subunit of voltage gated channel (a2d)
Only FDA approved for trigeminal neuralgia
Carbamazepine
FDA approved for DM neuropathy
duloxetene
Level A: Pregabalin
HLA in chinese that predilects risk for SJS
HLA B1502
Most common drugs causing SJS
Sulfonamide
Phenytoin, Phenobarb, CBZ
Allopurinol
Preferred tx for pertussis
Azithromycin
Infant <1
With pyloric stenosis: palpable olive
Hx of cardiac problem (QT)
Avoid
macrolide
Ingestion of food or water contaminated by S typhi
Period of comm: throughout excretion in feces
Typhoid fever
High grade fever Gen myalgia Abdominal pain Hepatosplenomegaly Rose spots in 25% lower chest and abdomen
Typhoid fever
Complications of typhoid
Intestinal hemorrhage
Intestinal perforation
Typhoid fever dx
Blood culture - 1st week of illness
Urine
Stool - after 1st week
Typhoid fever tx
Uncomplicated and sensitive: Chloramphenicol 50-75mg/kg/day
Amoxicillin x 14d
Excretion of S typhi for more than 3
mos
Chronic carrier
Aerobic nonspore forming
Coagulase +
Staph aureus
Staph coag neg
Epidermidis
Saprophyticus
Hemolyticus
Secondary to exfoliative toxin A&B
Rash preceded by malaise, fever, irritability, exquisite skin
Staph scalded skin syndrome
Secondary to enterotoxin
Severe nausea, vomiting, abd pain, watery diarrhea
Staph food poisoning
Necrotizing pneumonia
Pneumatocoele
Pleural effusion
Empyema
Staph pneumonia
Major cause of bacterial pharygitis
Petechisl mottling of soft palate
Group A Beta hemolytic strep
Dx of strep pharyngitis
throat culture
serology
DOC for strep pharygitis
Penicillin V
<60 lbs 250 2-3x/day
>60 lbs 500 2-3x/day
10 days, start before first 10 days of treatment
prevent RHF
Erythromycin 10d if allergic
Causes by pyrogenjc exotoxin or erythrogenic toxin
Fever, vomiting; toxicity
Scarlet fever
scarlet fever rash
gooseflesh or sandpaper rash
Erythematous indurated with advancing margins with raised firm borders
Erysipelas
Rheumatic fever
GN
both by GAS
Sudden OCD
Tic disorder
Autoimmune antibody in response to GAS crossreacting with brain tissue
PANDAS
In children most common valves affected in RHD are
Mitral valve
Aortic valve
Most common symptom in polyarthritis
responds to
Polyarthritis
ASA
Diagnosis of RF can be made without following guidelines if presence of the ff
Chorea
Indolent carditis
Recurrent RF
toxin for splitting of skin by SSS
exfoliatin a, b
toxin for pneumatocoele
panton valentin leukocidin
Responsible for golden yellow colonies or pigment of staph
Staphyloxanthin
Most severe form of SSS
Ritters disease
Parenchymal lung pattern of Pseudomonas
Fleur de lis pattern
Striking whitish necrotic center
Fleur de lis pattern of pseudomonas
Rash in scarlet fever
boiled lobster appearance
