Pertussis Syndrome By DR; RIADH ALOBAIDI

ETIOLOGY The pertussis is MOSTLY disease caused by Bordetella pertussis) a gram-negative pleomorphic bacillus (. Vaccine for this available DPT Bordetella parapertussis, which causes a similar but milder illness that is not affected by B. pertussis vaccination Adenoviruses have been associated with the pertussis syndrome.

EPIDEMIOLOGY The mean incubation period is7-10 days, range 4-21 days. pertussis is very common and important to know this illness.It is called one( month cough disease). Patients are most infectious during the catarrhal stage till after 3 weeks of coughing stage.Three stages each 2wks durations catarrhal,paroxysmal,convalescent

CLINICAL MANIFESTATIONS pertussis is the syndrome seen in most infants 1-month to school age. The progression of the disease is divided into: 1.The catarrhal stage is marked by nonspecific signs (upper respiratory tract infection as running nose, sneezing and low-grade fever) that last 1wk. 2.The paroxysmal stage :coughing stage; is the most distinctive classic stage of pertussis. Coughing occurs in paroxysms (episodes) during expiration, causing young children above 6 months to lose their breath and even apnea followed by high pitch inspiratory sound -whoop

Clinical feature con. The forceful i nhalation against a narrowed glottis that follows this paroxysm of cough produces the characteristic whoop. Post-tussive emesis should raise the suspicion of pertussis.Facial congestion and cyanosis may be seen in the attack. This stage lasts 2- weeks. Pertussis may produce anoxic brain damage and even encephalopathy. 3. The convalescent stage is marked by gradual resolution of symptoms over 1 to 2 weeks. Coughing becomes less severe, residual cough may persist for months

Infants below 3 months and neonates may get the illness due to lack of maternal immunity,may not give the classic pertussis syndrome; the first signs may be episodes of repetitive coughing and some may develops apnea.. Adolescents and adults with pertussis usually present with a prolonged cough without whoops many weeks to months. Physical examination is nonspecific

LABORATORY AND IMAGING STUDIES 1.Culture of nasopharyngeal swabs. 2.Direct fluorescent antibody staining of the swab from nasopharynx. 3.PCR is useful. 4.Leukocytosis (15,000–30,000 cells/mm 3 ) due to absolute lymphocytosis.

5. Radiological X-R ; not specific, It may show segmental lung atelectasis to develop during pertussis, especially during the paroxysmal stage. Perihilar infiltrates are common and are similar to what is seen in viral pneumonia. Secondary bacterial pneumonia may develop.

DIFFERENTIAL DIAGNOSIS 1. Respiratory viruses such as RSV, parainfluenza virus, and Chlamydia pneumoniae can produce bronchitic illnesses among infants. 2. In older children and young adults, Mycoplasma pneumoniae may produce a prolonged bronchitic illness that is not distinguished easily from pertussis in this age group.

TREATMENT Erythromycin,, or Azithromycin if given early in the course of illness it eradicates organisms within first 3 to 4 days in (catarrhal stage), and it abort and stop the course of infection. Treatment is indicated during the first 3 weeks of whooping cough stage illness to reduce the severity and infectivity, but it does not treat the the coughing. Antibiotics reduce the risk of infectivity to contacts when given for full 5 days course during the infectivity period (first 3 wks of coughing illness). It also should be given to contacts members regardless of their vaccination. When given to neonates pt. younger than 4 weeks old, clarythromycin or erythromycin may rarely been associated with pyloric stenosis, but treatment is still recommended because of the seriousness of pertussis in this age. Azithromycin has less such side effect and is drug of choice for neonates for 5 days.

COMPLICATIONS 1.Hypoxia 2.Apnoea specially in young infants. 3.Pneumonia : caused by B. pertussis itself or resulting from secondary bacterial infection 4.seizures, encephalopathy 5. failure to thrive. 6.Atelectasis may develop

7. The force of the paroxysm may rupture alveoli and produce pneumothorax, 8. epistaxis; and retinal and subconjunctival hemorrhages, hernia 9. Otitis media and sinusitis may occur. Infants <4 mo of age account for 90% of cases of fatal pertussis

PREVENTION Active immunity can be induced with acellular pertussis vaccine, given in combination with the toxoids of tetanus and diphtheria (DTaP). Pertussis vaccine has an efficacy of 70%.the efficacy declines if fewer vaccinations given. Compared with older, whole cell pertussis vaccines, acellular vaccines have fewer adverse effects and local reactions. Patient who have pertussis produce life long immunity.

Erythromycin is effective in preventing disease in contacts exposed to pertussis. Close contacts younger than 7 years old who have received four doses of vaccine should receive a booster dose of DTaP.They also should be given erythromycin. Close contacts older than age 7 should receive only prophylactic erythromycin 5 days, but not the vaccine.

Immune deficiency status Immunity depend on humoral antibodies produced by B-lymphocytes,and complements. While cellular immunity depends on T-lymphocytes, and neutrophils. Humoral antibodies is mainly to bacterial infection. Cellular T-CELL mainly to viral and fungal infection. May be primary due to genetic defects or inherited or may be secondary causes like AIDS or malignancy or drugs.

PRESENTATIONS OF IMMUNE DEFICIENCY Recurrent bacterial infections. Severe bscterial infections; like meningitis and sepsis. Infections with unexpected opportunistic m.o. Extensive candidiasis. Abscesses any where in the body skin or internal organs. Delayed separation of umbilical cord in newborn.

HIV infection AIDS Route of infection is mother to child by transplacental or during delivery or by breast feeding from infected mother. To children may be by blood products or unsterile needles.

Diagnostic tests Less than 18 months born to infected mother is by HIV DNA- PCR. For older than 18 m.is by antibodies and antigens of HIV.

Clinical features of AIDS May remain sublinical for 1yr in infants and for many months for children untill symptoms appears ; as prolonged fever PUO, faiure to thrive. chronic diarrhea, candidiasis TB, lymphadenitis,hepatosplenomegaly, serious infections.