ORIGINAL

Niger J Paed 2015; 42 (2): 83-87

Oloyede I P

Ekanem AM

Udoh EE

Pattern of childhood pertussis in a

tertiary hospital in Nigeria: a five

year review (2007-2011)

DOI:http://dx.doi.org/10.4314/njp.v42i2.2

Accepted: 19th November 2014

Abstract: Pertussis is being in-

creasingly found in previously

immunized subjects. In Nigeria,

the immunization coverage rates

are low. This study was therefore

carried out to highlight the cases

of pertussis seen in a young Nige-

rian tertiary health facility, with

emphasis on the clinical features,

complications and the impact of

prior immunization in the affected

children.

Methods : This was a hospital

based retrospective study, in

which data were obtained from

case notes of children seen in the

Paediatric department of the Uni-

versity of Uyo Teaching Hospital

subjects were males while 32

(60.4%) were females. The mean

age of the subjects was 29.71 +

27.73 months. The most common

symptoms were Post-tussive vom-

iting and paroxysmal cough occur-

ring in 48(90%) and 39 (73.6%) of

the patients respectively. The aver-

age interval between onset of

symptoms and presentation at the

health facility was 3.35 + 2.84

weeks. Majority of the patients

(25; 47.2%) were adequately im-

munized for their age. Broncho-

pneumonia, either alone or in com-

bination with other complications

was the commonest complication

occurring in nine (52.9%) patients.

There was no mortality.

(

)

Oloyede I P

Udoh EE

Department of Paediatrics,

Ekanem AM

Department of Community Health,

University of Uyo and University of

Uyo Teaching Hospital P.M B 1136,

Uyo Akwa Ibom State

Email: isooloyede@yahoo.com

(

UUTH) from January 2007 to

December 2011 with a diagnosis

of pertussis. Information sought

included epidemiologic data, du-

ration of illness, signs and symp-

toms, treatment, complications

and outcome.

Results: Fifty three patients were

diagnosed with pertussis during

the five year period, with majority

Conclusion: Pertussis is still of

public health significance. Rou-

tine immunization should be

strengthened and booster doses of

vaccines should be considered for

older children whose immunity

may begin to wane.

Key words: Pertussis, pattern,

(

2

29; 54.7%) of cases in the year

011. Twenty one (39.6%) of the

childhood

Introduction

day and the communicability is highest during the first

two weeks of infection . After that the disease pro-

2

Pertussis is an acute bacterial infection affecting the

gresses through three stages of clinical illness: catarrhal,

1

respiratory tract . It is caused by Bordetella pertussis

paroxysmal, and convalescent each lasting approxi-

1

3

(

B.pertussis) and occasionally Bordetella parapertussis .

mately two weeks . Leukocytosis (20,000 to 100,000

The illness occurs principally in young unvaccinated

infants, but school-age children, adolescents and adults

cells/mL) with absolute lymphocytosis is characteristic.

A chronic cough may persist for several months . A di-

3

2

are affected . It is usually characterize_,₂d_,₃ by progressive,

agnosis of pertussis is usually made clinically, but the

bordetella DNA maybe detected in polymerase chain

reaction (PCR) for four weeks after symptom onset,

1

repetitive, and paroxysmal coughing . Atypical pres-

entations like low grade fever, dyspnoea, apneic epi-

sodes and seizures may occur in children less than two

years o_,l₄d_,₅while, older children and adults have persistent

6

except in infants . The infection can be confirmed by

culture of the pathogen from nasopharyngeal swabs or

secretions or by serological test but the latter method is

2

cough . These unusual forms of presentations often

6

,7

lead to misdiagnosis and poor outcome in the affected

not well standardized .

5

children . Older siblings are a frequent source of infec-

A nu_,m₈_,₉ber of complications may ensue from the dis-

3

tion but recent studies are revealing the role of previ-

ously immunized adolescents and adults as reservoir of

ease . the most frequent is pneumonia which is seen

8

in almost all fatal cases . Complications like subcon-

2

,3,4

.

infections

junctival haemorrhage, rectal prolapse, otitis media,

umbilical and inguinal hernias are common in older chil-

3

,9

Classic pertussis has an incubation period lasting 7 to 28

dren as against apnea, and encephalopathy in infants .

8

4

Treatment with antibiotics such as, the macrolides are

effective in eliminating the bacteria. Even though antibi-

otic therapy does not necessarily alter the clinical course

of the illness, it has the potential of reducing the period

of infectivity and modifying the complications of the

14 years. Nineteen cases were excluded because they did

not meet the inclusion criteria. Therefore fifty three

cases of pertussis were recorded within the five year

period (2007-2011). Of this number, 29(54.7%) were

seen in 2011. (Figure 1.) Twenty one (39.6%) of the

children were males while 32 (60.4%) were females;

giving a male to female ratio of 1:1.5. The mean age of

the children was 29.71 + 27.73 months with a range of 1

-108 months. The proportion of infants (39.6%), were

similar to those aged 12-59 months (37.7%).

1

0

disease . The recommended treatment is Azithromycin

for three to five days and Erythromycin and clarithromy-

1

1,12

.

cin for seven days

Primary vaccination with a combination vaccine is the

5

proven method of prevention. The period of immunity

induced by the pertussis vaccine tends to wane within 5

to 10 years and is shorter than that induced by the dis-

ease itself , hence booster doses are of importance in

Of the 53 cases, 16(30.2%) cases had a history of con-

tact with siblings, 25 (47.2%) were adequately immu-

nized for their age, 11 (20.8%) were inadequately immu-

nized for age, while 10 (8.9%) had no immunizations.

(Table 1).

1

3

presc₄hool children and adolescents with waning immu-

1

nity .

In spite of the fact that pertussis is a treatable as well as

a vaccine-preventable childhood illness, the national and

global incidence_,₂s_,₃of the disease has been on the increase

The average interval between onset of symptoms and

presentation at the health facility was 3.35 + 2.84 weeks.

The mean duration of illness was 6.1±3.66 weeks with a

range of two to 16 weeks.

1

in recent years . This has been attributed to persistent

low immunization coverage rates, frequent vaccine stock

outs and e₁r₅r_,₁a₆t_,i₁c₇ power supply leading to breaks in the

Table 1: Socio-demographic characteristics of Paediatric

Pertussis patients in UUTH from 2007 to 2011

cold chain

. Currently a waning immunity has

18

become a major factor .

Socio-demographic

characteristics

Frequency (n) Percent (%)

The aim of this study therefore was, to describe the pat-

tern of clinical presentation and complications of pertus-

sis in Nigerian children.

Age groups

0 -11months

21

20

12

39.6

37.7

22.6

1

6

2- 59 months

0 months and above

Gender

Male

female

21

32

39.6

60.4

Materials and methods

Contact history

Yes

No

Immunization history;

n=46

*Adequate for age

Not adequate for age

Nil

Data were obtained from case notes of children managed

for pertussis in the paediatric Outpatient clinic and the

Paediatric ward of the University of Uyo Teaching Hos-

pital (UUTH) from January 2007 to December 2011.

Information extracted from the case records included the

patients epidemiologic data, duration of illness, signs

and symptoms, treatment, complications and outcome.

The diagnosis of pertussis was based on the Centre for

Disease Control and Prevention clinical case definition

of 1997 . A case was defined as coughing illness lasting

for at least 2 weeks with at least one of the following:

paroxysms of coughing, inspiratory whoop or post-

tussive vomiting without other apparent cause. A prob-

able case was one that met the clinical case definition

but was not laboratory confirmed or epidemiologically

linked to a laboratory-confirmed case.

16

37

30.2

69.8

25

11

10

54.4

23.9

21.7

*

Twenty three (43.4%) subjects had been completely immu-

nized with three doses of DPT.

1

9

Table 2 shows that all the cases presented with cough,

which was paroxysmal in 39(73.6%). Post-tussive vom-

iting, occurred in 48(90%), fever in 19(35.8%), while a

whoop was present in 10(30.2%). The other symptoms

were catarrh 12(23.6%), difficulty in breathing

1(20.8%), weight loss in 6(11.3%) and red eye in

(9.4%) cases. The signs patients presented with were

flaring of alae nasi, coarse crepitations and hepa-

tomegaly in 2(3.8%) cases respectively and central cya-

nosis, rhonchi, Subcostal and intercostal recession in

1

5

Data was analysed using the SPSS version 17. Descrip-

tive statistics including the measures of central tendency

(

mean) and dispersion (standard deviation) were used.

Chi-square test was used to test for association between

categorical variables. A p-value of 0.05 was taken as

statistically significant.

1

(1.9%) case respectively.

Ethical clearance for the conduct of the study was

obtained from the Ethics committee of the UUT H.

There was a statistically significant association between

age and paroxysmal cough with infants having more

cases of paroxysmal cough than the older children

(

p =0.044). The association between age and post tus-

sive vomiting or age and occurrence of whoop was not

statistically significant.

Results

Of the Seventeen patients that had complications, the

commonest were bronchopneumonia 6(35.3%) and sub-

conjunctival haemorrhage in 6(35.3%) followed by a

Seventy two patients had a diagnosis of pertussis over

the five year period. Their age ranged from one month to

8

5

combination of bronchopneumonia and subconjunctival

haemorrhage in 2(3.8%) cases. (Table 2)

Discussion

There was no statistical significant association between

age groups of patients and development of complica-

tions (χ = 1.244; p= 0.537) but the association between

The importance of pertussis as a vaccine preventable

disease cannot be overemphasised. Most of the patients

with pertussis were seen in 2011. A probable explana-

tion for this local surge of pertussis, may be due to

2

gender and development of complications was statisti-

cally significant with more males having complications

increased awareness and an increased index of suspicion

among doctors. It may also be as a result of poor vaccine

quality due to poor storage or as a result₇_,₁o₈f the immunity

2

than females (χ = 6.582; p=0.010).

Twenty five (47.2%) of the subjects were treated with

Erythromycin, 18 (34.6%) received Azithromycin, while

two (3.8%) received a combination of Erythromycin and

Azithromycin. Other antibiotics received included

Cefuroxime and Cefpodoxime.

1

gaps being observed across the globe . Another rea-

son may be that the ongoing preparation for the replace-

ment of DPT with pentavalent vaccine in the National

Programme for Immunization may have led to a disrup-

tion in the supply of DPT vaccines in some states of the

country, thereby resulting in low DPT coverage. This

was noted in local records that from 2010 to November

There were no deaths recorded among the subjects as all

recovered.

Table 2: Symptoms and signs of pertussis in patients seen in

UUTH

2

011, there were no DPT vaccines in the state. This was

also corroborated by World Health Organisation (WHO)

when it noted that in the year 2011 an estimated 22 mil-

lion infants worldwide were not reached with routine

immunization services, with about half of them living in

Symptoms

Number

%

Signs

Number

(%)

Cough

53 (100)

Flaring of alae nasi

2(3.8)

Paroxysmal

Non-paroxysmal

39 (73.6) Sub-coastal recession 1(1.9)

20

three countries which included Nigeria . The prepon-

14(26.4)

Inter-coastal reces-

sion

1(1.9)

derance of infants with pertussis₄s_,₂e₁e_,₂n₂ in this study has

Post-tussive vomitting

Fever

Whoop

48(90.6)

19(35.8)

16(30.2)

12(23.6)

Coarse crepitation

Hepatomegaly

Central cyanosis

2(3.8)

1(1.9)

also been noted in earlier reports

. This is probably

because mothers provide little if any passive protection

3

to young infants Majority of the patients were females

Catarrh

23

as was also noted in an earlier study . The reason is

Difficulty in breathing 11(20.8)

unknown. In approximately 30% of the patients, a his-

tory of contact with a coughing older sibling was given.

This is in keeping with earlier reports that show that

older siblings are a frequent source of infection even if

they have been vaccinated, although in infants the

sou_,₅rce of infection cannot be detected in 30-69% of cas-

Weight loss

Red eye

6(11.3)

5 (9.4)

8 (15.1)

*Others

*other symptoms include impaired feeding, fast breathing, epistaxis,

chest pain and haemoptysis

2

Table 3: Pattern of complications seen in pertussis patients in

UUTH

es This is attributed to waning immunity in the

17

absence of booster vaccine and the fact that the symp-

1,2,5

Complications

Number (%)

tomatology in vaccinated individuals are atypical

.

Majority of cases were also seen in adequately immu-

nized patients with 43.7% of them having received

three doses of DPT vaccine. The explanation for this

may be due to frequent vaccine stock outs and erratic

power supply leading to breaks in the₁c₇o_,₂l₀d chain and

immunization with suboptimal vaccines . The aver-

age interval between the onset of symptoms and presen-

tation at the health facility of >21 days in this review

was longer than the median of 14 days in the study by

Bronchopneumonia

6(35.3)

2(11.7)

Subconjunctival haemorrhage

Bronchopneumonia with sub-conjunctival

haemorrhage

Bronchopneumonia with heart failure with

hernia

Apnoea

Bilateral inguinal hernia

Total

1(5.9)

1(5.9%)

1(5.9)

17(100)

1

Yaari et al in Isreal. This may be due to differences in

2

4

the treatment seeking behaviour of their caregivers .

Late presentation in health facilities is a common obser-

vation in the Nigeria especially among those of low

socio-economic status. It is well known that this interval

has an implicat₁i₀o_,₁n₁ on the infectivity and spread of the

causative agent . This is because though early treat-

ment with effective antibiotics does not alter the clinical

course of t₃h_,₁e₂ disease, it reduces the period of infectivity

Fig 1: Distribution of Pertusis cases by Years

of the case

.

The common symptoms noted were cough (100%), of

which 73.6% were paroxysmal in nature, post-tussive

vomiting in 90% and a whoop in only 30% of cases.

This sym₂_,₃p_,₁t₈oms are in keeping with the those of earlier

studies.

These symptoms are of great importance as

they have been shown to be highly sensitive and

8

6

moderately specific for culture confirmation of the diag-

nosis of pertussis . It is of note that there was a signifi-

may be much higher considering the poor health seeking

behaviour of our local populace and the presence of

alternative health providers.

3

cant association between paroxysmal cough a₂_,n₃_,d₁₈infancy

as other studies have reported this finding

. There

was a paucity of chest signs among patients in this

study, which was expected as chest examination find-

ings are usually normal between paroxysms except in

Conclusion

3

infants with secondary pneumonia .

Bronchopneumonia and Subconjunctival haemorrhage,

either alone or in combination were the commonest

complications noted. The only case of apnoea recorded

was in an infant less than three months of age. These

In conclusion, our study documents the clinical and epi-

demiologic pattern of pertussis in the Paediatric Depart-

ment of University of Uyo. We have documented the

high morbidity in infants, and our study suggests that the

source of infection may be older siblings and this may

be a consequence of the delivery of suboptimal vaccines

and waning vaccine immunity in the context of preva-

lent pertussis disease in the community. More detailed

studies in the community are needed on laboratory con-

firmed pertussis cases before evidence-based strategies

to control the disease in Nigeria can be made.

We therefore recommend the strengthening of our diag-

nostic capacity as well as our routine immunization ser-

vices. Additional research on laboratory confirmed cases

as well as on the current immunity of children, adoles-

cents and adults is also required in order to determine

the need for booster doses of vaccine and at which age

these boosters should be administered.

2

,3,9

.

findings are in keeping with earlier studies

The use of the macrolides in the treatment of pertussis in

majority of the patients showed that the clinicians were

aware of the₀_,₁r₁ecommended antibiotics for the treatment

1

of pertussis . However the total duration of the illness

in the patients was similar to those obtained in earlier

literature, an era wherein antibiotics were not instituted

for patients with the disease. This goes to buttress the

fact that antibiotic therapy does not alter the clinical

2

,3

course of the disease .

No mortality was recorded among patients in this study.

This could be attributed to the small sample size and to

the fact that majority of the patients were immunized

and so did not present with severe and life threatening

complications.

The major limitation of this study was absence of labo-

ratory confirmation of the cases. The additional limita-

tion is potential information bias which is common to

retrospective studies. Other factors that may account for

the presumed low incidence maybe underreporting due

to misdiagnosis especially in atypical cases in infants

Author’s contribution

Dr Oloyede I.P Conception and design of the study, ac-

quisition of data from case notes and writing up of the

manuscript. Dr Ekanem AM Data analysis. Dr Udoh EE,

Revision of the article for intellectual content. All au-

thors were involved in the final approval of the

version submitted.

(

no whoop), poor reporting of diseases generally, possi-

25

ble lack of awareness and lack of active surveillance .

Also as a hospital based study, this may not give a true

burden of the disease as the burden in the community

Conflict of interest: None

Funding: None

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