Module 3 Complex ID and Immune Response Flashcards
Redness that does NOT blanch, swelling, warmth, TENDERNESS, may be purulent, lymphangitis → appears like lymph streaking (advanced cases), may be raised in abscess formation or erysipelas (superficial skin infection), can also have constitutional sx
Typically a larger affected area
Classic Cellulitis
Redness that does NOT blanch, swelling, warmth, TENDERNESS
Classic Cellulitis
Skin discoloration from excess Ca; more brown like venous stasis
Calciphylaxis
Skin redness from venous stasis
Stasis Dermatitis
Where is DVT typically seen?
calf
ecchymosis, palpable hematoma, hx trauma
Hematoma
central erythema, not tender or warm, hx tick bite?
Erythema migrans
erythematous, edematous JOINT that is painful, circumferential erythema typical
Septic Knee
point tenderness, over MTP, erythema (can be hard to differentiate)
Gout
fluctuant mass where bursa is filled with fluid; NOT tender or warm; should have good ROM of elbow
Olecranon Bursitis
Tx for mild non-purulent cellulitis
Oral abx: Cephalexin, Dicloxacillin, Penicillin VK, Amoxi/Clav.
if true pcn allergy= clindamycin
Tx for moderate non-purulent cellulitis : SIRS 1
Oral abx: Cephalexin, Dicloxacillin, Penicillin VK, Amoxi/Clav.
if true pcn allergy= clindamycin
SIRS criteria for cellulitis
temp >38C (100.4), HR >90, RR >20, WBC >12
Tx for moderate non-purulent cellulitis : SIRS > or = 2 (treatment failure)
IV antibiotics: Cefazolin, Ceftriaxone, penicillin G,
If PCN allergy= Clindamycin
Tx for severe non-purulent cellulitis: SIRS > or + 2 (w/ hypotension, immune compromise, or rapid disease progression)
Broad coverage IV antibiotics
- Vanc + piperacillin/ tazobactam, imipenem, or meropenem
consider surgical assessment
Tx for severe non-purulent cellulitis: probable S pyogenes infection and/ or suspected MSSA
Iv:
Cefazolin, Cefotaxime, Cefriaxone, PCN G,
If allergy- Clindamycin
Tx for severe non-purulent cellulitis: suspected or known MRSA (previous tx failure)
IV: Vanc, CLina, Linexolia, daptomycin, ceftaroline…
Tx for severe non-purulent cellulitis: suspected or known MRSA (previous tx failure)
IV: Vanc, CLina, Linexolia, daptomycin, ceftaroline…
what are most likely pathogens for cellulitis
Group A Strep and Staph Aureus
I&D indications for purulent cellulitis
fluctuance, drainage, tx failure
Abscess I&D 1st line tx
Consult surgery based on site and severity
small abscesses <1cm can be observed and tx with abx and warm compresses
treating purulent MSSA
Cephalexin, Dicloxacillin, PCN, Aug; PCN allergy- clindamycin
treating purulent MRSA
Bactrim, doxycycline, minocycline
When to refer cellulitis to ED/Hospitalization
Predictors of outpt tx failure
fever , chronic ulcers, chronic edema/lymphedema, prior cellulitis of same site, cellulitis at wound site
Greater than or equal to 2 SIRS criteria, immunocompromised, rapid dx progression
Life-threatening (drug related or mycoplasma pneumonia) detachment of the epidermis from the dermis that manifests on the skin as blisters and erosions
develops w/in 8 weeks of drug initiation. Fever, oral and ocular symptoms often precede cutaneous reaction by several days. Malaise, sore throat, arthralgias, and stinging eyes.
SJS/TEN
Central and facial dermatitis begins and spreads peripherally
SJS/TEN
Skin tender to touch and shears easily
(Nikolsky sign)
SJS/TEN
Dx and Tx of SJS/TEN
clinical presentation. Skin punch biopsy shows dermal inflammation and epidermal necrosis
Tx: admission to burn unit for skin care and hemodynamic support
DRESS
drug reaction with eosinophilia and systemic symptoms
Dermatologic and systemic manifestations develop 2-8 weeks after drug exposure. a/w reactivation of herpes virus-6
Anticonvulsants, allopurinol, dapsone, and sulfonamides
-Facial edema** , fever, malaise, lymphadenopathy, and arthralgia. Eosinophilia and leukocytosis.
DRESS (drug reaction with eosinophilia and systemic symptoms)
TX for DRESS (drug reaction with eosinophilia and systemic symptoms)
hospitalization, topical and systemic corticosteroids. Relapse may occur without reexposure which makes identifying offending medication difficult.
dark colored urine and clay-colored stools may precede presentation of jaundice by 1-5 days. Hepatomegaly and splenomegaly. ½ pts are asymptomatic
Hepatitis
Hepatitis diagnostics labs
CBC LFTs (↑AST & ALT are often first sign) total bilirubin prolonged PT if severe (marker of prognosis) low PLT and albumin if cirrhosis
fecal-oral route, blood, person-person contact, ingestion of contaminated food (shellfish) and water. Can survive for months in fresh or salt water
Most infectious in the late incubation period. Contagious when asymptomatic and until 1 week after jaundice occurs. Newborns are infectious for months.
Hep A
Incubation, Vaccination and Inactivation of Hep A
Incubation: 2-6 weeks. Viral load peaks at 2 weeks. Vaccination: 2 injections 6-12 months apart; provides immunity for 20 years
Inactivated by: boiling for 1 minute, exposure to formaldehyde, chlorine, or UV rays
sexual contact and IV drug use
Blood, tears, CSF, breast milk, saliva, vaginal secretions, and seminal fluid
Asia and Africa: vertical transmission from mother during birth
Viral load peaks at 7-8 weeks
asymptomatic or liver failure. Ongoing replication leads to cirrhosis, HCC, or both.
Hep B
Vaccinations for Hep B
at birth, then in 1-2 months, then 12 months (3-dose series)
HBsAg-positive, anti-HBc-positive IgM, anti-Hbc negative, and anti-HBS-negative
Chronic Hep B
causes cirrhosis, hepatocellular carcinoma, and liver transplantation. USPSTF: 1 time screening for all adults born b/t 1945-1965
: blood-borne (IV drug use)
High rate of replication and mutation. Difficult to treat and leads to chronic disease.
RF: blood transfusion received before July 1992, chronic hemodialysis, IV drug use, tattoos, manicures/pedicures, body piercings.
Hep C
Dx and Tx Hep C?
Diag: if HCV Ab present, test using PCR
Tx: specialist if chronic. Tx often cost prohibitive
Stop drinking, vax (A and B), adherence to tx regimen
Vasculitis occurring in children 6 wks - 12yrs; peak at 1-2 y/o; etiology unclear
If untreated → coronary artery abnormalities
Kawasaki Disease (KD)
Kawasaki Disease dx criteria
- complete and incomplete
Complete
Fever + CREAM
(Conjunctivitis, rash, erythema palms and soles, adenopathy (cervical), mucous membrane)
Incomplete: Fever + 2-3 criteria and characteristic lab findings (including ESR and CRP, anemia, leukocytosis)
Fever >100.4 for at least 8 days with no identifiable source on initial eval
Rectal temp gold standard peds
Many are undiagnosed
Pediatric Fever of Unknown Origin (FUO)
resemble severe burn lesions and typically have skin detachment; mucosal erosions of lips, oral cavity, upper airway, conjunctiva, genitals, ocular area
SJS
widespread epidermal necrosis; rash accompanied by fever, severe pain and asthenia (weakness/lack of energy)
NASIDs, allopurinol, anticonvulsants
TEN
Under SJS/TEN umbrella → least severe
Hybrid of urticaria and vasculitis
bullseye lesions with deep red centers and pink urticarial rings (palms, hands, soles of feet)
Starts extremities → trunk with mucosal involvement
Erythema Multiforme
What cuases Erythema Multiforme
How to tx?
Virus (Herpes Simplex) or drug reaction
PO acyclovir or discontinuation of drug
Light combined with certain drugs can lead to reaction that mimics sunburn; can be severe
ex.
Photosensitivity reactions
Tetracyclines, sulfa drugs, NSAIDs, fluoroquinolones
Infectious disease that originated with animals.
Helminthic Zoonoses
IgM anti-HAV if acute (igM= iMmediate); IgG anti-HAV elevated indefinitely
Hep A Dx
How to tx Hep A?
self-limiting, usually undetectable by 6-8weeks after exposure. Supportive care.
Monitor LFT every 2 weeks
Immunity occurs after illness and is measured by serum IgG (IgM during acute, then IgG rises and persists indefinitely)
Prophylaxis w/in 2 weeks of exposure
Hep ____ Ig if traveling to endemic area >6 mo
Hep A
HbsAg-positive
IgM anti-HBc-positive
anti HBc-positive
anti IGM Hbs negative
Acute hep B
HBsAg-negative, HBsAb-positive
Hep B immunity
Tx of Hep B
Acute sx and supportive care
Chronic: Interferon alpha preps and nucleoside analogues (-vir)
Prophylaxis for Hep B
Hep B Ig within 14 days of exposure with simultaneous vaccination, second and third injections at 1 and 6 months.
HCC surveillance every 3-6 months (can progress to HCC without cirrhosis/sx)
Screen in Ages 15-65
Testing = P24
confirm type with NAT Test
HIV
Tests to order upon referral of HIV
CD4
Viral Load
CBC with diff/ plates
CMP, Liver
HIV Type, CMV, Syphilis, pap smear/ trich test
**combo testing new gold standard over ALISA
Pre-exposure prophylaxis of HIV
Recommended in women and men with sex with HIV + men, risky behaviors…
Prior to prescribing: pregnancy, HIV -,
Ongoing monitoring: Creatinine clearance, HIV, pregnancy Q 3 months
Post-exposure HIV prophylaxis:
Depends on timing ….must be started ASAP always with 72 hours of possible exposure and continued for 4 weeks
Dx of KD?
KD is a clinical diagnosis → labs are more helpful to assist in diagnosis of incomplete and are considered supplemental characteristics
- CBC: leukocytosis, neutrophilia, normocytic normochromic anemia, thrombocytosis
- CMP: mild transaminitis (incl AST/ALT), mild hypobili (severe), mild hyponatremia (severe)
- ESR: elevated, >40
- CRP: elevated, >3 (often used to track tx response)
- UA: sterile pyuria (increased WBC count)
Managing KD?
Urgent referral by a KD specialist (infectious dx) → ED transfer
Tx: high dose ASA, IVIG +/- steroids
ECHO at intervals with cardiology following (baseline at diagnosis, 1-2 wks, 6 wks post d/c, 1 yr post diagnosis)
Follow up things to remember for KD?
Know ASA plan and cardiac surveillance
No MMR or varicella for 11 mos AFTER IVIG
Annual flu vax (esp persistent CAL on ASA)
lymph nodes that have enlarged or changed in consistency.
Lymphadenopathy
Fever >100.4 x 3 wks @ 2 or more outpt visits or 1 wk inpatient
ADULT FUO
ANC <1.5 (normal: >15000; 1.5)
Cause: rapid neutrophil use vs myelosuppression, in a previously healthy child with a new/recent febrile illness.
Lymphoma, meds (typically adults), autoimmune
Infections most commonly associated (usually viral)
Post-infectious neutropenia
Likely to resolve on own BUT you CANNOT miss a possible concurrent serious diagnosis of malignancy or immunodeficiency!
Post-infectious neutropenia
Risk for serious infection with Post-infectious neutropenia
ANC <800, hypotension, fluid resuscitation, hx of leukemia
Dx for Post-infectious neutropenia
Initial: verify finding with repeat CBC and manual diff + peripheral smear, ESR
Follow up: repeat CBC w/ diff in 4 weeks in setting of no red flags
Transient postinfectious neutropenia appears in first 24-48h and resolves up to 2 months
When to refer Post-infectious neutropenia
s/s of sepsis/severe bacterial infection → ED
Pancytopenia (more than once cell line affected; WBC, plt, etc)→ heme/onc vs ED for BM bx
Hx suggestive of chronic neutropenia OR persistent neutropenia on recheck → heme/onc
acid fast bacilli (AFB); transmitted through air particles (droplet)
Common sites: brian, larynx, LN, pleura, lung, bone, spine, kidney
Mycobacterium TB
RF to move from latent to ACTIVE TB
Those infected within past 2 years, infants and children <4, hx of fibrotic lesions on CXR, hx of untreated/inadequately treated TB. active substance abusers, immunocompromised (chronic lung dx, COPD, DM, HIV, etc), underlying chronic medical illness,
Asx (can’t transmit, no need for isolation- evidence immune response by Mantoux test or IGRA), no radiographic evidence
LT TB
Dx TB
Abnormal skin test + abnormal CXR does not diagnose,
NEED sputum cultures to confirm!! → gold standard diagnostic (3 in 8-24 hour intervals with at least ONE in morning)
Skin test: Mantoux tuberculin skin test (TST, aka PPD)- create wheal 6-10 mm
Read in 48-72 hours
Blood test: interferon-gamma release assays (IGRAs), quantiFERON-TB gold in tub (QFT-GIT), T-SPOT
TST interpretation guidelines- detectable in 2-8 weeks after infection
+ PPD and asymptomatic … get CXR
CXR: infiltrates; if poorly differentiated may consider CT
Managing Active TB
health department manage tx unless inpatient; guided by CDC
Typically 8 weeks of 4 drug therapy, then decrease to 2 drug for 4-7 months
INH and rifampin are preferred drugs if TB is susceptible to them
Considered infectious until 3 negative sputum cx consecutively
Managing LTBI
Tx of LTBI essential for eliminating TB dx; reduces risk of progression
Tx
Isoniazid: 9 months → periph neuropathy common SE (vit B6 can help); hepatotoxic drug and must montor ALT/AST at beginning and then by targeted questions;
Rifampin: 9 months → need routine liver function screening
NO alcohol for duration of tx on both drugs!!
1x/wk DOT tx for 12 weeks (no HIV pt) → alternative to 9 month tx
Pregnancy considerations with LTBI
Preg: delay 2-3 months PP unless high risk to progress to TB
NO BF taking INH
Supplement Pyridozine (vit b6) for nursing
TB- Therapy ASAP, tx to fetus - INH, rifampin, ethambutol ( cross placenta but no terat effects)
Neonate/ Infant Meningitis
Highest incidence bacterial <2 mos
Red flags: fever under 3 mos, poor feeding, irritability/inconsolable, mental status changes/lethargy, seizure, dusky color, apnea or resp difficulty, unlikely to see nuchal rigidity
Hx may include maternal hx group b strep (GBS) → 50% of bacterial meningitis, preterm delivery
PE: appear apathetic to surroundings, inconsolable, poor tone
Children with meningitis
96% aseptic meningitis (viral)
Red flags: fever, HA, photophobia, nuchal rigidity (assess w/ Kernig and Brudzinski signs; not definitive), irritability, lethargy, petechial rash (does NOT blanch; hallmark meningococcal meningitis), mental status and neuro changes (diff with speech, altered gait)
Will appear like rapid onset flu-like illness (myalgia, n/v, fever, HA) but with the concerning features for neuro involvement
Hx RF: day care, recent URI, travel to high risk area, immunocompromised, trauma, under/unimmunized, known exposure
Adults with meningitis
More likely aseptic than bacterial in community acquired; >25% of bacterial originate from preceding sinusitis/URI
2 of these sx occur in 95% of pts: fever, HA, nuchal rigidity, mental status changes
Older adults: fever, mental status change, more likely to have seizure and hemiparesis, less likely to have HA
a new HA in any pt could be concerning and warrants a detailed neuro exam
Management of Meningitis
Suspected → refer to ED for eval (call to give report); CSF analysis is gold standard LP
Start abx RIGHT AWAY before results of testing are back!
Mask pt to prevent spread (droplet precautions), make sure you discuss possible ED outcomes with pt (imaging, LP, labs, etc)
Meningitis Postexposure prophylaxis
Recommended for close contacts
Admin as soon as case confirmed; limited benefit >14 days postexposure
Hib dx: rifampin all household contacts if more than 1 person in house is < 4 y/o and either unimmunized or incompletely vaxxed)
Meningococcal: rifampin, ceftriaxone, ciprofloxacin, azithro (cipro/azithro typical in adults)
prevention of meningitis
IMMUNIZE!
Routine childhood immunization (Hib, PCV 13, meningococcal)
Special attn high risk (sickle cell, asplenia, college freshmen, complement deficiencies), travel to endemic areas (sub-Saharan Africa)
inflammation of the brain and caused by a variety of pathologic organisms (primarily herpesvirus, arboviruses (from insects) and enteroviruses. Viruses cause CNS infections by direct spread to the cranial nerve, reactivating viruses within the CNS and spread across BBB.
Encephalitis
(similar to those with meningitis but more prevalent alterations in consciousness, neurologic signs, seizures, and autonomic and hypothalamic disturbances )
Fever, HA, consciousness, seizures , N/V, photophobia
Older adults: may lack fever or meningismus (stiff neck), confused
Encephalitis
Dx Encephalitis?
Two sets Bcx, CBC, E-, Coag studies, BS, ESR, CRP
CT before LP if signs of AMS, papilledema, immunocompromised LP
LP-patients with suspected meningitis and encephalitis , check opening pressures during LP
CSP protein, glucose, cell count and diff, gram stain, and culture)
Encephalitis (#1) neuroimaging: MRI- shows edema an temporal and orbital frontal lobes
Mgmt of encephalitis?
ARLY TREATMENT- ER
Viral encephalitis is supportive treatment- fluid and e-, Sx treatment for HA, fever, nausea, airway protection, mgmt of ICP, and seizures
preventing encephalitis
Prevention- vaccines (Hib/ PCV 13/23, MCV4)
Vector borne encephalitis- public health departments needed for education about mosquito control and bites
Plasmodium falciparum and Plasmodium vivax
Africa
Incubation period:
7-30 days (when travelers take antimalarial drugs while traveling it may delay appearance of sx by weeks/ months.
Malaria - Mosquito
Prophylaxis malaria treatment for travel:
chloroquine or hydroxychloroquine: 1 to 2 weeks prior to travel, weekly (same day each week) during travel, and for 4 weeks after leaving the endemic area atovaquone/proguanil: 1 to 2 days prior to travel, daily during travel, and for 7 days after leaving the endemic area
most common symptoms of malaria
fever, chills, headache, nausea with vomiting, and myalgia. In severe forms, malaria can cause hemolysis, multiple organ failure, and death.
Dx Malaria
traditional diagnosis involves use of thick and thin blood smears, consider the use of the rapid diagnostic test (RDT), which quickly establishes the diagnosis of malaria infection by detecting specific malaria antigens in a person’s blood. All positive RDTs should be followed by microscopy for species confirmation and to measure the degree of parasitemia.
Tx of malaria
Send to ED- should always be managed in conjunction with ID specialist
First line: Chloroquine
If in area that is resistant to Chloroquine- start on artemether/lumefantrine
Follow up:
Daily blood films should be performed until parasites are undetectable by microscopy.
Reported all over US, africa, europe, asia
Vector: mosquitoes
Reservoir host: birds
Late Summer and early fall
*humans must be bitten by a mosquito infected by a bird
Serologic testing most effective at 6-8 days post exposure
West Nile- mosquito
s/s: acute febrile illness and central nervous system infections, encephalitis, and aseptic meningitis Invade muscles, joints, and liver causing myositis, arthritis, and hepatitis 80% of cases are asymptomatic Incubation period: 3-14 days Dx ELISA 6-8 days post-exposure Treatment: Supportive care Hospitalized for severe cases
West Nile- mosquito
Vector: mosquitoes Reservoir host: humans ecology : rural, urban Geography: asia, africa, americas Incubation: 3-14 days causes : hepatitis or encephalitis S/S: Maculopapular rash or erythroderma Headache (retroorbital) or ocular pain Symptomatic dengue fever: marked by arthralgia and myalgia (BREAK BONE FEVER) Dengue hemorrhagic fever (DHF) due to endovascular immune activation and hemorrhage
Dengue- mosquito
Warning Signs for Dengue Hemorrhagic Fever
- Petechiae, ecchymosis, purpura
- Bleeding from gingiva, injection sites, gastrointestinal tract
- Vomiting or abdominal pain
- Hemoconcentration and/or thrombocytopenia
- A positive tourniquet test: petechiae in the arm after applying a tourniquet for 5 minutes.
A neurotropic flavivirus, transmitted by Aedes mosquitoes, and known for outbreaks. Most infection is asymptomatic, but 20% develop clinical disease.
The incubation period is 2 to 14 days.
Zika - mosquito
acute low-grade fever, pruritic rash (diffuse macules and papules), arthralgia of small joints, fatigue, and retro-orbital pain. Congenital microcephaly, neurologic sequelae, and fetal losses are seen with intrauterine exposure, but infants who acquire the virus by mosquito bite develop normally.
Adults may develop varying degrees of GBS, encephalitis, myelitis and cognitive symptoms Red flags: Distal weakness and sensory loss (GBS) Hemorrhage or shock (DHF or DHS) Signs of meningoencephalitis
Zika - mosquito
Dx and Tx Zika?
Diagnosis is by RT-PCR (serum, urine, or whole blood) in the first 14 days, but negative PCR does not exclude the diagnosis; if negative, reflex serology for IgM and plaque reduction neutralization test (PRNT) is performed.
Tx:
Supportive therapy, tylenol, rest, fluids
Semen may carry the virus for 6 to 9 months after infection.
Men should use condoms during this period.
Vector: mosquitos
Reservoir: humans, monkeys, marsupials
Geography: historically worldwide, brazil
Incubation: 3-14 days
Vaccines at certified clinics
Causes: acute hepatitis, hemorrhage and shock, rarely inflammatory encephalitis
S/S: erythroderma, conjunctival and gingival erythema, and liver tenderness Bradycardia with fever (faget signs) Red flags: Relapse of fever following defervescence SIRS symptoms AST twice ALT Acute renal failure (ATN)
TX: There is no antiviral therapy. Supportive care and fluid resuscitation are effective, but mortality is 50% in severe disease
Yellow Fever
Reservoir: Bat
Human to human transmission- contact
Incubation: 11 days
CM
fever, fatigue, diarrhea, vomiting, headache, and anorexia.
Tx:
fluid resuscitation (oral and intravenous), oxygen, and antibiotics (cephalosporins or fluoroquinolones)
Ebola
