Pertussis - what is it? plus Aetiology

Pertussis, also known as whooping cough, is a highly contagious disease caused by the bacterium Bordetella pertussis; it derived its name from the characteristic severe hacking cough followed by intake of breath that sounds like 'whoop'; a similar, milder disease is caused by B. parapertussis. Although many medical sources describe the whoop as "high-pitched," this is generally the case with infected babies and children only, not adults.

Characterization

After a two day incubation period, pertussis in infants and young children is characterized initially by mild respiratory infection symptoms such as cough, sneezing, and runny nose (catarrhal stage). After one to two weeks, the cough changes character, with an increase of coughing followed by an inspiratory "whooping" sound (paroxysmal stage). Coughing fits may be followed by vomiting due to the sheer violence of the fit. In severe cases, the vomiting induced by coughing fits can lead to malnutrition and dehydration. The fits that do occur on their own can also be triggered by yawning, stretching, laughing, or yelling. Coughing fits gradually diminish over one to two months during the convalescent stage. Other complications of the disease include pneumonia, encephalitis, pulmonary hypertension, and secondary bacterial superinfection.

Because neither vaccination nor infection confers long-term immunity, infection of adolescents and adults is also common. Most adults and adolescents who become infected with Bordetella pertussis have been vaccinated or infected years previously. When there is residual immunity from previous infection or immunization, symptoms may be milder, such as a prolonged cough without the other classic symptoms of pertussis. Nevertheless, infected adults and adolescents can transmit the bacteria to susceptible individuals. Adults and adolescent family members are the major source of transmission of the bacteria to unimmunized or partially immunized infants, who are at greatest risk of severe complications from pertussis.

management of pertussis

Management of Pertussis:

The disease can be recognised in two different states, catarrhal stage (which is where the patient is most infectious) or paroxysmal stage (which is where the characteristic paroxysms of coughing begin, about a week after catarrhal stage). The stage in which it is diagnosed will affect the method of treatment. If Pertussis is diagnosed in the catarrhal stage then treatment involves erythromycin (a type of antibiotic which slows the growth of and can sometimes kill bacteria), which will decrease the severity of the disease. If the disease is diagnosed in the paroxysmal stage then antibiotics have a very small role in altering the course of the illness. In some cases intravenous pertussis immune globulin therapy has been shown to decrease whooping, to improve oxygen saturation and to stop bradicardic episodes. Membrane oxygenation is widely used in the management of severe pertussis, but it has had limited success, and pertussis severe enough to require its use is in itself a predictor of a poor outcome. Affected individuals should be isolated to prevent the disease spreading.

References: http://www.cmaj.ca/cgi/content/full/172/4/509
http://www.drugs.com/erythromycin.html
Kumar and Clark

(Monica Abadier)

Diagnosis for Pertussis

The diagnosis is usually made on the clinical symptoms of pertussis. The general symptoms include:

• Cold or flu-like symptoms during the first 1-2 weeks: a runny nose, red runny eyes, a slight cough, and a temperature (usually mild)
• Bouts of coughing that become increasingly worse over the next 2-4 weeks. These episodes of coughing can be followed by the sudden effort to breathe, causing the characteristic ‘whoop’ sound of pertussis. Other symptoms during this period include coughing up thick mucus, and vomiting after the coughing attack, which is really more characteristic of pertussis that the ‘whoop’. Patients, especially infants, may turn blue, and afterwards they become very tired and may lose weight.
• The cough and whoop may last for many weeks or even months in the “classic illness”, especially if the patient simultaneously catches a cold or a throat infection

It is much harder to diagnose older children and adults suffering from mild pertussis, as the early symptoms are very similar to an ordinary cold; thus, the doctor may make the diagnosis on the basis of a characteristic history and the symptoms after several days.

The best method for diagnosis would be to take a sample from the back of the nose and culture it – that is, inoculate the sample on a growth medium so that the Bordetella pertussis bacteria responsible for whooping cough can proliferate. However, in some cases, the sample may fail to capture any of the bacteria present. Blood tests can only help if they show a high rise in pertussis antibodies, and this usually can only be seen if a blood test is taken quite early on in the course of the illness, and another blood test taken at the end of the illness. A large enough rise in antibodies must be shown in order to make the diagnosis.

- Maria Nguyen

Sources:

The Family Encyclopedia of Medicine and Health; 1996, The Book Company

http://www.pertussis.com/faq.html

Incidence of pertussis

Since 1993, pertussis has caused the greatest morbidity of any disease preventable by vaccines recommended for children on the National Immunisation Program (NIP) schedule. The highest numbers of pertussis notifications were seen in 2005, with many jurisdictions experiencing an epidemic in that year, followed by 1997 and 2001. Traditionally, hospitalisations in infants aged less than one year have exceeded notifications, indicating that notification rates tend to underestimate pertussis incidence.^3,149 However, in the 2003–2005 period, there were more notifications than hospitalisations in this age group, which may be a reflection of the increased use of PCR to diagnose pertussis in children. In children, hospitalisations coded as whooping cough have been shown to have a high correlation with clinical pertussis.¹⁹ The high proportion (greater than 50%) of hospitalised cases aged less than one year is consistently observed each year and demonstrates the increased morbidity of pertussis in this age group.

Nationally, the highest notification rates up to 1998 inclusive were among children aged less than one year, followed closely by children aged 5–9 and 10–19 years (Figure 26). Since 1999, notification rates have fallen significantly among 5–9 year olds, reflecting the impact of the fifth dose of pertussis vaccine, introduced since 1994 for four year olds because of waning immunity over time.¹⁵⁰ The number of cases reported to be vaccinated for age may be an over-estimate, as the calculation did not include those with an “unknown” status (it is more likely that those recorded as unknown were not vaccinated). Studies show that a primary three-dose course of acellular pertussis vaccine provides 80%–85% protection.⁷⁶

High incidence rates among 10–19 year olds continued to occur in 2003 and 2004. The susceptibility of this cohort is explained by a combination of low historical coverage (whole-cell vaccine safety concerns in the 1980s) and waning immunity (cohort not eligible for school entry booster dose).^150,151 There has been a downward trend in the notification rate for this age group since 2002 and a sharper decline in the rate since 2004. This is likely to reflect the impact of the fifth dose of pertussis vaccine reaching this older cohort and the impact of an adolescent booster vaccine (dTpa), introduced in November 2003. In response to the high incidence rate in adolescents, both New South Wales and Western Australia conducted whole of high school dTpa vaccination programs in 2004. The combined incidence rate for 10–19 year olds in these states decreased from an average of 85.7 per 100,000 population for 1999–2003 to 37.2 per 100,000 population in 2005.¹⁵² As Australian school-based dTpa programs mature and successive cohorts are vaccinated in future years, pertussis in adolescents should become well controlled, as occurred in 5–9 year olds following the introduction of the preschool booster.

In essence, pertussis is now a problem in two broad age groups: infants with the highest notification and hospitalisation rates, particularly those under 6 months of age who are too young to have received two or more doses of DTPa, and people aged 20 years and over, who account for 80% of pertussis notifications. The latter could be partly related to the increased use, especially in adults, of serology as a diagnostic tool (NNDSS data from 2000–2005 shows an increasing percentage of notifications diagnosed by serology (Quinn H et al, NCIRS, unpublished data)). In addition, recommendations for use of pertussis vaccine in adults make it increasingly likely that clinicians will consider pertussis as a potential cause of chronic cough in adults. Hospitalisations in adults are most likely to be related to complications, but could also be falsely inflated because of coding errors. Although severe morbidity and mortality are less likely in adults, increased circulation of pertussis can facilitate transmission to susceptible infants who are too young to be vaccinated.^153–155 The recent increase in the incidence and burden of pertussis notifications in persons aged 60 years and over warrants further investigation. As with parents, grandparents are an important source of pertussis transmission to infants.¹⁵³ It is also unclear whether the morbidity of pertussis in older people is more severe, or if complications are more likely to occur. With this in mind, it is interesting to note that two of eight pertussis deaths in the past five years have been recorded in people aged 60 years and over.³ The current adult pertussis immunisation strategy in Australia is aimed at cocooning infants, by recommending immunisation in adults who are most likely to come into contact with them (such as family members, health care workers and child care workers). It is hoped that, in time, this may have an impact on neonatal cases.

More info on http://www.healthconnect.gov.au/internet/main/publishing.nsf/Content/cda-cdi31suppl.htm~cda-cdi31suppl-3.htm~cda-cdi31suppl-3i.htm

-Satwik

Pregnancy and Termination

Pregnancy and Termination
PCL 07 – Sharon’s dilemma
Amber Hartley

Termination, or abortion, of pregnancy, may be deliberate or spontaneous. Deliberate termination of pregnancy can be performed at different stages of the pregnancy and in different ways.

The two main types of deliberate termination are surgical and medical. Terminations are generally not performed prior to 6 weeks gestation, due to the danger of incomplete abortion. Ideally, terminations should be performed before 12 weeks, and week 7 or 8 is generally considered the best time. Terminations can be performed between 12 and 16 weeks, although with more difficulty after 16 weeks. Terminations after 18 weeks are very rarely performed.

Surgical methods

Suction curettage
§ May be used up to 15 weeks gestation
§ Procedure involves dilating the cervix and then inserting a small flexible tube attached to a suction pump. The suction pump is then used to remove the products of conception and a curette is used to ensure that no products of conception remain. The procedure takes about 10 minutes.
§ Requires local or general anaesthesia
§ Failure rate is 2-3 per 1000 (this rate is higher prior to 7 weeks gestation)
§ Side effects include mild pain and bleeding, infections (up to 10% of suction curettage abortions result in infection), Cervical trauma (<10>

Manual vacuum aspiration

• May be used prior to 7 weeks
• Not really used much in Australia
• Lower failure rate for early abortion than suction curettage

Dilation and Evacuation (D & E)

• Used after 14 weeks
• Mild pain and bleeding may result, which are more prolonged than at earlier gestation
• Complication rates rise with gestation (ie. the later the termination, the greater chance of complications). Complications include cervical trauma (8-22 in 1000), Uterine perforation (2-4 in 1000), Haemorrhage requiring transfusion (2-4 in 1000).

Medical methods

Involves use of drugs: mifepristone (RU486) plus misoprostal.
Mifepristone not available in Australia (in 2005)
Can be used throughout first and second trimesters
Women are usually aware of the passage of products of conception. This may be accompanied by some pain.
Side effects:

• Bleeding
• Diarrhoea
• Nausea and vomiting
• Dizziness, hot flushes, chills
• Headache

Long term risks associated with Termination

• Some increased risk of later miscarriage, preterm birth, and placenta praevia
• No association with infertility, ectopic pregnancy or breast cancer.

Under Medicare, costs of having a termination range from $180 to $350.

Figure 1: Suction Curettage

References

http://www.whg.org.au/PDFs/Pregnancy%20termination%20brochure%20January%202007.pdf

http://www.ranzcog.edu.au/womenshealth/pdfs/Termination-of-pregnancy.pdf

http://survivors.la/images/sa-9-weeks.jpg

http://archives.cnn.com/2000/HEALTH/11/21/abortion.pill/ap.abortion.pill.uterus.gif

Teenage pregnancies in Australia

Teenage Pregnancy in Australia

Date for 15 – 19 year olds taken between 1997 -1999

For every 1000 woman between the age of 15 and 19 there are on average 23.9 abortions compared to 20.1 live births. The teenage pregnancy rate is the 6th highest in the world however we have the 3rd highest abortion rates in teenage girls with the USA and Hungary 1st and 2nd respectively.

Aboriginal teenagers account for 21.3% if indigenous births compared to Caucasian teenagers accounting for 4.2% of Caucasian births. Aboriginal teenagers are less likely to terminate births however they have poorer antenatal care.

Teenagers who become mothers are more likely to be:

Single
Smokers
Victims of domestic violence
Living in lower socio economic area’s
From rural and remote areas

Teenage Pregnancies carry the complications of:

Having underweight babies
Having premature babies

Teenage pregnancies often require neo natal care


Reference
Medical Journal of Australia (2003; 179(3): 158-161)
http://www.womhealth.org.au/studentfactsheets/teenagepregnancy.htm