Whooping cough

prolonged cough illness with significant morbidity and mortality especially in infants

caused by Berdetella pertusis

gram negative coccobacillus

respiratory droplets-up to 5 ft

humans are only reservoid

incubation 1-3wks, average 10 days

1. inhaled-adheres to coliated epithelium in nasopharynx

2. bacteria proliferation and dissemination through lower respiratory airways

3. rarely as far as pulmonary alveoli causing pneumonia

4. will not invade farther than epitherlium

produces several biologically active substances

and virulence factors that affect cell attachment, cause local tissue damage, interfere with host defense mechanisms

1. waning vaccine-induced immunity in adolescents and adults

2. inc. awareness among heath care providers, inc use of pcr for diagnosis, inc puplic reporting

-Infants less than 12 months (incomplete vaccine) MC <6mo old

-Adolescents and adults common reservoir

7-10 days

indistinguishable from viral URI

-gradually becomes more severe

1-6 wks up to 10 wks

inc cough for 1-2 wk then plateau 2-3, dec grad

bursts of coughs- numerous in one inspiration

-posttussive emesis and exhaustion

-purulent or non-purulent sputum

Convalescent phase of pertusis

paroxysms less common

cough resolves over 2-3 wks

can get recurrent cough from URI

prolonged persistent paroxysms of cough 36-48 days

post tussive vomiting more common than whoop

-prolonged respiratory illness and paroxysms cough with whoop

atypical common: short absent catarrhal pphase , gagging, feeding dificulties

1. bacterial pneumonia

2. paroxysms of cough

-limit food and fluid intake , feeding difficulties

-hypoxia

3. post tussive vomiting

uncommon

rib fracture

hernia

back pain

incontince

pneumonia-unusual

death-rate

subconjuctival hemmorhage

pneumothorax

inc WBC

absolute lymphocytosis >10,000 cells

degree of lymphocytosis parallels severity

Peribronchial cuffing

perihilar infiltrates

interstital edema

atelectasis

Clinical case definition

confirmational tests:

bacterial culture

PCR

serology

Cough illness> 2 wks

Plus one:

+paroxysms of cough

+inspiratory whoop

+post-tussive vomiting w/o other cause

bacterial culture:

Isoloation from nasopharyngeal secretion (swab post pharynx x 10 secs) or nasal aspirate

-100% specific

-sensitivity <3 wks approach 50-60%

for pertusis

-swab posterior phaynx

-100% specific

-Sensitivity much better than culture at 3-4 weeks (60%)

looking for antibodies

not practical clinically

IGG will increase with infection

Take initial IGG before vaccination (IGG will inc)

First Report disease!

initiate antibx with clinical suspicion (since labs take longer)- Z pack or clarithro (4-7days)

best to treat during catarrhal phase -when its most contageous to dec transmission and severity

Treat is symptoms <3-4 wks

healthcare workers (6-8wks)

-suggested for close contacts

-high risk for severe complications

-kids and adults in household, daybare and some school settings

-watch for those who were exposed for 20 days

No school, daycare, health care worker until 5 days of treatment or 21 days of symptoms

Avoid those at risk of complications until 5 days of treatment

Public health requirement for schools

cause an immune response w/o causing disease

triggers immune system to produce antibodies in absence of disease

live attenuated- weakend whole cell-never to pregnant women (measles, small pox)

Inactivated/killed-whole cell organism without toxin (tetanus, polio)

Acellular-just toxin no cell (flu, pertusis)

Subunit- fragement of microorganism (hepB, pneumococcus)

children 80-85% less likely to develop pertusis than unvaccinated

immunity lasts 5-10 years

Pertusis vacc at 2, 4,6 15-18, 4-6 mo

-important b/c immunity lot likely in breat milk

immunity dec in 4-12 years after primary series

-if its been more than 5 years assume patient doesenot have tDAP then go every 10 years TD

1. envelope glycoproteins

2. hemagluttinin binds to respiratory epithelium (H)

3. Neuraminidase liberates new virions for propagation of virus

1. susceptibility of population

2. intrinsic virulence of strain

-efficiency of transmission

-ability to cause symptomatic infection

major change can lead to epidemic and pandemic

reassortment of genes b/w human and animal influenza- virus that simultaneously infect host

-mainly affects extrenes of age

-virulent

-b/c of significant antigenic shift the population is susceptible

-sustained human to human transmission

Less extensive outbreaks

disease less severe

change in drift in H antigen

outbreak every 2-4 yrs

affects upper and lower respiratory tracts

signs if systemic illness

Not attributed to another cause

hyperemia

mild cervical LAD

Unremarkable chest

-lymphopenia (associated with shedding)

Fast onset-no prodome just abrupt sickness

usually seen 2 days after exposure

Large particle droplets (sneeze, cough, etc)

Shedding highest 1-2 days after onset. Peak=2nd day

Shedding longer in kids, and those with chronic disease

1.Pneumonia:

-primary viral-most severe

-secondary bacterial-most common

2. Rhabdomyolysis

3. myositis

4. CNS

5. Myocarditid

6. Pericarditis

screening limited by sensitivity, better specificity

++most common and easiest to do

Most sensitive and specific, can differentiate influenza types including swine and avian (within hours but usually a sendout)

exp: what type: H1N1? H1N3?

Not useful outpatient

(more for epidemiological basis)

antivirals could shorten duration of influenza symptoms by 1-3 days if given within 24-36 hours. greater than 48 hours little to no benefit.

Some evidence may reduce severity and incidence of complications of influeza

better to dec symp for one day, when it could inc resistance???

1. Neuraminidase inhibitors: potentially active against A and B (tamaflu=oseltamivir and zanamivir)

2. Adamantanes: Potentially active against influenza A only (high resistance, Amantadine and rimantadine, cns toxicity)

1. zanamivir

2. oseltamivir and amatadine/rimatidine

1. high risk <48 hours

2. close contact of those at high risk

3. those .48 hours if persistent moderate or severe illness

1.sidents in long term care facilities

2. high risk complications if not yet vaccinted

-give vacc and treat x 14 days

-new annually

-trivalent (3 strains)

-50-80% effective against a and b flu

-intramuscular (inactivated vaccine)

-intranasal live-attenuated

recommended for all persons 6 mo and older

-two doese

-tiered distribution

-influenza A H1N1

Concern for becoming pandemic

-MC in young people

-virulent

-antigenic drift-only thing that is limiting

-limited human-human transmission

Novel H1N1

most common complications: pneumonia and dehydration

concern for pandemic

-most common in young (30yo)

-human-human transmission

-human/avian/swine virus

sensitive to NA-I

Resistent to AT

treat:

-all hospital patients

-patients at high risk for complications

-<5 yo