Whooping cough due to Bordetella pertussis/parapertussis. Flashcards
what’s the ETIOLOGIC OF WHOOPING COUGH ?
bordetella pertussis
what is the EPIDEMIOLOGY OF PERTUSIS ?
it is typically a childhood disease - however older patient are being increased affected
6mo-5yrs
highly communicable
cyclic outbreaks evert 3-5 years occurring in all months
what are the CHARACTERISTICS OF BORDETELLA PERTUSSIS?
a gram‑negative, obligate aerobic coccobacillus.
B. pertussis only grows on respiratory epithelium
has fimbrae for attachment
tracheal cytotoxin - causes resp epithelial damage
pertussis toxin - affects circulation of lymphocytes and serves as adhesion to resp epithelial cells
dermonecrotic toxin - resp mucosal damage
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TRANSMISSION OF BORDETELLA PERTUSSIS?
airborne droplet (through coughing); direct contact with oral or nasal secretions
PATHOGENESES BORDETELLA?
most contagious stage is the catarrhal stage
attachment of bordettella on ciliated resp epithelium
Proliferation of Bordetella pertussis on ciliated epithelial cells of the respiratory mucosa → production of virulence factors TRACHEAL CYTOTOXIN → paralysis of respiratory epithelium cilia and inflammation
→ secretion of inflammatory exudate into respiratory tract
Bordetella pertussis produces pertussis toxin →
Pertussis toxin is responsible for most of the systemic manifestations associated with whooping cough (e.g. hypoglycemia, lymphocytosis, modulation of host immune response).
adenylate cyclase toxin
INCUBATION PERIOD FIR BORDETELLA?
on average 7–10 days (range 4–21 days)
CLINICAL MANIFESTATION OF BORDETELLA PERTUSIS?
Catarrhal stage (1–2 weeks) Nonspecific symptoms similar to an upper respiratory infection - mild cough, watery nasal discharge, rarely low-grade fever) Possibly conjunctivitis
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Paroxysmal stage (2–6 weeks)
Intense paroxysmal coughing (often occurring at night)
mucous expelled at the end of an episode
Followed by a deep and loud inhalation or high-pitched whooping sound
Accompanied by tongue protrusion , gagging, and struggling for breath
whoop occurs upon rapid inspiration against a closed glottis at the end of a paroxysm
in infants whoops ae rare to observe - more gagging , gasping
in adults - whooping and post tussive vomiting vomiing ( (risk of dehydration))
Possibly accompanied by cyanosis neck vein distentions, bulging eyes,
Potential bleeding of the conjunctiva, petechiae, and venous congestion
Infants (< 6 months) may only develop apnea and not the characteristic cough
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convalescent phase
(1-3months)
coughing episodes less severe
DIAGNOSIS BORDETELLA PERTUSSIS ?
clinical diagnosis possible in patients with a cough lasting ≥ 2 weeks and at least one of the following symptoms: Coughing paroxysms Whooping on inspiration Vomiting following coughing attack Apnea (in infants) Inquire about immunization history
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Blood count:
lymphocyte-predominant leukocytosis corresponds with disease severity
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Pathogen detection (to confirm the diagnosis) Culture (gold standard) or PCR: samples from deep nasopharyngeal aspiration or posterior nasopharyngeal swab
Serology: unsuitable for early diagnosis because antibody detection (IgA, IgG, IgM) first occurs after a period of 2–4 weeks
dd of whooping cough?
Bordetella parapertussis infection
adenoviral resp infectionns
Respiratory syncytial virus bronchiolitis
Pneumonia, particularly due to
Chlamydia trachomatis or Mycoplasma pneumoniae
Croup (laryngotracheobronchitis)
what’s the TREATMENT OF WHOOPING COUGH?
early initiation of treatment, especially in high-risk patients (e.g., infants),
Hospitalization and monitoring: infants < 4 months;
Oxygen administration with humidification
Increased fluid intake and nutritional support
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Macrolides (e.g., azithromycin, clarithromycin, erythromycin)
In children > 1 month and adults:
If macrolides are not tolerated, use trimethroprim-sulfamethoxazole.
Infants < 1 month: azithromycin
for 14 days
Early administration may lessen symptoms
COUGH SUPPRESSANTS ARE NOT EFFECTIVE!
what are the COMPLICATIONS OF WHOOPING COUGH /?
pneumonia
in hospitalized patients and newborns (<1
month of age) either by B.pertussis itself,
by Respiratory syncytial
virus (RSV),
Streptococcus pneumoniae or Haemophilus influenzae
subconjuctival haemorrhages
abdominal and inguinal hernia
infections: otitis media, pneumonia
Respiratory: hemoptysis, atelectasis, pneumothorax
Neurologic: seizures, encephalopathy with possible permanent damage - thought to be caused by hypoxia and apnea secondary to coughing fits.
what are the PREVENTION TECHNIQUES ON BORDETELLA PERTUSIS ?
Children
Routine immunization: DTaP vaccine (diphtheria, tetanus, and pertussis)
at 2, 4, 6, and 15–18 months and at 4–6 years
Single-dose boost at 11–18 years of age, at least 10 years following the last dose
Whole-cell pertussis vaccines
,which may show CNS Adverse
effects - not likely to be used
Acellular pertussis vaccine
Booster vaccination: Tdap vaccine
Single dose at 7–10 years of age if immunization is incomplete
(Td is a booster vaccine for tetanus and diphtheria)
Neither vaccination nor actual infection confers complete or lifelong immunity.
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post exposure chemo prophylaxis
All household contacts of a pertussis case, regardless of their vaccination status
Regimen: choice of antibiotics is identical to treatment
Isolation
Required for 5 days after initiation of antibiotic therapy
Without antibiotic treatment: minimum of 3 weeks after the onset of first symptoms
what is the difference BETWEEN BORDETELLA PERTUSIS AND BORDETELLA PARAPERTUSSIS
similar clinical findings, although the course of disease is shorter and milder
almost identical at the DNA level
pathogenetically important difference between the two is that B parapertussis does not secrete pertussis toxin
immunity derived from B. pertussis does not protect against infection by B. parapertussis,
