Communicable Diseases Module: 35. Acute Respiratory Tract Infections

Study Session 35  Acute Respiratory Tract Infections

Introduction

In this study session, you will learn about acute respiratory tract infections (ARIs). The respiratory tract (or ‘airways’) includes all the parts of the body that enable us to breathe. ARIs are infections of the respiratory tract by either bacteria or viruses, and the term ‘acute’ indicates that the illness is of short duration (less than two weeks). ARIs are the leading cause of illness and death among young children everywhere in the developing world (Figure 35.1). Ethiopian children suffer four to eight episodes of ARI on average every year, with the highest occurrence in urban areas in overcrowded living conditions. In rural Ethiopia, 20% of the deaths of children aged under five years and more than 30% of the infant deaths under one year are due to ARIs. A better knowledge of ARIs will enable you to detect children with an ARI more quickly and give appropriate treatment, or refer them if the disease is severe.

View larger image

Figure 35.1  Estimates of the percentage of deaths in children aged under five years from ARIs in the year 2000. (Source: The Open University, Pathogens and People (S320 Book 1), Figure 1.13, p.32, based on data from Williams, B.G. et al. (2002), The Lancet Infectious Diseases, 2)

Learning Outcomes for Study Session 35

When you have studied this session, you should be able to:

35.1  Define and use correctly all of the key words printed in bold. (SAQs 35.1, 35.2, 35.3 and 35.5)

35.2  Identify the common causative agents, modes of transmission and risk factors for the common acute respiratory tract infections (ARIs): acute otitis media, pharyngitis and pneumonia. (SAQs 35.1, 35.2 and 35.5)

35.3  Describe the clinical presentations and complications of ARIs, and the danger signs of severe pneumonia, and explain how these conditions should be managed. (SAQs 35.2, 35.3 and 35.4)

35.4  Explain the most effective ways to prevent and control ARIs, including through community education. (SAQs 35.2 and 35.5)

35.1  What are acute respiratory tract infections?

Acute respiratory tract infections (ARIs) are bacterial or viral infections of the respiratory tract leading to breathing difficulties, fever and other complications, including infections in the ear and the membranes surrounding the brain. ARIs are classified according to whether they affect the upper or lower respiratory tracts (Figure 35.2). The upper respiratory tract consists of the airways from the nostrils to the vocal cords in the larynx (voice box), and includes the pharynx (back of the throat) and part of the internal structure of the ear (the middle ear). The lower respiratory tract refers to the continuation of the airways below the larynx and the branching airways throughout the lungs.

View larger image

Figure 35.2  Anatomy of the upper and lower respiratory tract. (Source: The Open University, 2008, Chronic Obstructive Pulmonary Disease (SDK125 Case Study 5), Figure 3.3, p.36)

Upper respiratory tract infections (URIs) are the most common of all communicable diseases. They are transmitted from one person to another by airborne droplets spread through coughing or sneezing. URIs include mild self-limiting infections such as the common cold (rhinitis), and more severe acute infections in the ear (acute otitis media), or in the pharynx (pharyngitis). Lower respiratory tract infections (LRIs) are the leading cause of pneumonia, which will be described in Section 35.4 of this study session. First, we discuss acute otitis media and then pharyngitis, both of which can cause severe complications in children.

35.2  Acute otitis media

Acute otitis media (AOM) is a severe infection of the middle ear (Figure 35.3), lasting less than two weeks. It is very common in babies and young children, but is rarely seen in adults. Studying this section will help you to prescribe the necessary treatments to a child with AOM, and know when to make a referral of more complicated or persistent cases for further investigation and specialist treatment at a higher level health facility.

It may surprise you to learn that infection inside the ear is classified as a URI. The explanation can be found in Figure 35.3. In each ear, the middle and inner ear are connected to the upper respiratory tract by a tube called the Eustachian tube, which leads to the pharynx. You can sometimes hear a soft ‘pop’ in your ears when you swallow as the pressure wave created by swallowing travels up the Eustachian tubes. Upper respiratory tract infection in the pharynx and tonsils can reach the middle ear if the infectious agents spread upwards along the Eustachian tubes.

View larger image

Figure 35.3  Anatomy of the ear and its connection with the upper airways. (Source: WHO, 2006, Primary Ear and Hearing Care Training Resource: Trainer’s Manual – Intermediate Level, p.16)

35.2.1  How does acute otitis media affect hearing?

In normal situations, the middle ear is filled with air, which transmits sounds from the outside world to tiny bones (called the ossicles, see Figure 35.3), causing them to vibrate. The vibration generates signals which the auditory nerve transmits to the brain. This process enables us to hear the sounds. If infection reaches the middle ear, the lining becomes red and inflamed, and it leaks sticky tissue fluid (mucus) into the ear. As the infection builds up, white blood cells crowd into the area to fight the infectious agents and the middle ear becomes filled by pus – a thick whitish-yellowish fluid, formed by mucus packed with living and dead bacterial cells and debris from damaged tissue in the ear.

35.2.2  Causes, transmission and risk factors for acute otitis media

The two predominant bacteria that cause otitis media include Streptococcus pneumoniae and Haemophilus influenzae type b, both of which can be prevented by immunization. It can also be caused by a viral vaccine-preventable disease, which you learned about in Study Session 4 of this Module.

AOM is transmitted by airborne spread of the causative infectious agents in droplets, sprayed into the air when a sick person coughs or sneezes. The infection in the new host usually begins with a common cold, sore throat or measles.The presence of certain risk factors makes babies and young children more vulnerable to developing AOM (see Box 35.1).

Figure 35.4  Smoke from indoor cooking fires escapes from these traditional Ethiopian round houses (tukul); indoor smoke pollution increases the risk of pneumonia and AOM. (Photo: Basiro Davey)

35.2.3  Clinical manifestations, diagnosis and complications of acute otitis media

The symptoms and signs of AOM are highly variable, especially in infants and young children. As a health worker in the community, you should check the following symptoms in children with upper respiratory tract infections:

• Ear pain, often manifested by irritability (the child is easily upset) and occasionally holding or tugging at the ear
• A change in sleeping or eating habits
• Symptoms associated with upper respiratory tract infection, such as a runny nose and sneezing typical of the common cold
• Hearing loss, which may manifest as changes in speech patterns; however, this often goes undetected if hearing loss is mild or in one ear only, especially in younger children.

You can diagnose AOM by careful history-taking and physical examination. Ask the child’s caregiver about any history of the above symptoms of AOM. Examine the ear thoroughly for redness or pus discharging from the ear canal (Figure 35.5).

Figure 35.5  Pus discharge as a result of chronic otitis media. (Photo: WHO, 2006, Primary Ear and Hearing Care Training Resource: Student’s Workbook – Intermediate Level, p.53)

Acute otitis media may progress to produce other complications. These include chronic otitis media, manifested by pus discharging from the ear for more than two weeks, which can lead to permanent deafness.

35.2.4  Treatment of acute otitis media

As a Health Extension Practitioner you need to know how to treat acute otitis media. Treat the child as an outpatient in the Health Post or at home. Give oral co-trimoxazole or amoxicillin for five days. The dose of these antibiotics in tablets or syrup preparations depends on the age or weight of the child, as given in Table 35.1. These dosages also apply to the treatment of pneumonia, which will be discussed in Section 35.4 of this study session.

If the child has ear pain or high fever (equal to or above 39°C or 102.2°F), which is causing distress, give 5 ml of paracetamol syrup up to three times per day.

If there is pus draining from the child’s ear, show the mother or another caregiver how to dry the ear by wicking (cleaning the ear using a twist of very clean cotton). Advise her to wick the ear three times daily, until there is no more pus (Figure 35.6). Tell the mother not to place anything in the ear between wicking treatments. Do not allow the child to go swimming or get water in the ear. If the pus continues to discharge from the ear after five days, refer the child to a health centre for further assessment and treatment.

Figure 35.6  Wicking pus from the ear of a child with acute otitis media. (Diagram: Dr Radmila Mileusnic)

Strategies for the prevention and control of acute otitis media, pharyngitis (the subject of the next section) and pneumonia (described in Section 35.4) are the same, and will be described at the end of this study session.

35.3  Pharyngitis

Pharyngitis refers to infection and inflammation (becoming hot, swollen and red) of the structures in the pharynx. In most cases, the tonsils are affected and become inflamed and ulcerated (tonsillitis). In this section, we will describe the clinical manifestations, complications and treatment of pharyngitis. A better understanding of these points will help you to identify a child with pharyngitis and know that you should refer them to a higher level health facility. Pharyngitis can be caused by viruses or bacteria, but the most important causes are bacteria of the type known as Group A Streptococci. Infection with Group A Streptococci is common among Ethiopian children. It can lead to severe complications, including heart disease.

35.3.1  Clinical manifestations and complications of pharyngitis

Pharingitis generally begins with the sudden onset of fever (temperature above 37.5^oC, measured with a thermometer in the armpit), and a sore throat, with redness and swelling of the tonsils at the back of the throat (Figure 35.7). Other symptoms include headache, cough, runny nose and pain during swallowing.

Figure 35.7 Sore throat and swollen tonsils due to pharyngitis. (Photo: CDC/PHIL, Strep Throat Picture 1, Hardin Library for the Health Sciences, University of Iowa, accessed from http://www.lib.uiowa.edu/hardin/md/cdc/strepthroat.html)

Infection of the pharynx by Group A Streptococci has many complications, which include otitis media and throat abscesses (swelling containing pus). In a minority of severe cases, a form of heart disease – called rheumatic heart disease – can develop as a result of the body’s attempt to fight the infection. The immune system recognises Group A Streptococci as ‘foreign’ and produces antibodies that attack the bacteria. Antibodies are specialised proteins made by specific white blood cells as part of the body’s defence against infection. However, in rare cases, the antibodies produced to fight Group A Streptococci can attack the heart muscle of the infected child. As a result, these children can develop rheumatic heart disease later in life.

35.3.2  Referral of children with pharyngitis for treatment

Educate mothers and other caregivers about the symptoms of acute otitis media and pharyngitis, and advise them to bring their child to you, or go to a health centre, if they suspect either of these conditions. Early diagnosis and correct treatment greatly improve the outcomes and reduce the risk of complications. Pharyngitis due to Group A Streptococci should be treated by doctors using a drug called Benzathine penicillin. This drug is given in the form of an injection, which is not authorised for use at Health Post level.

35.4  Pneumonia

A better understanding of pneumonia will help you to save many lives through early diagnosis and treatment or referral of cases, especially among children, and educating your community on effective prevention and control measures.

35.4.1  What is pneumonia and what causes it?

Pneumonia is a lower respiratory tract infection that mainly affects the lungs. The lungs are made up of small sacs called alveoli, which are filled with air when a healthy person breathes in. When an individual has pneumonia, the alveoli are filled with pus and fluid, which makes breathing painful and limits the amount of oxygen they can take into the body. Pneumonia is caused by a number of infectious agents, mainly by certain bacteria and viruses (Box 35.2). In children or adults whose immunity is weak, other organisms such as fungi can cause a rare form of pneumonia, which may be responsible for at least one quarter of all pneumonia deaths in HIV-infected infants.

Pneumonia is the number one cause of death among children in Ethiopia and worldwide: globally, it causes an estimated 1.6 million child deaths every year. It is also among the top five causes of illness and death in adults in Ethiopia. The Ethiopian Demographic and Health Survey (DHS, 2005) estimated that 13% of children had pneumonia during the survey year, and infants (children up to one year old) were more likely to have pneumonia than older children under the age of five.

Viral infections often come on gradually and may worsen over time. The common symptoms include cough, fever, chills, headaches, loss of appetite and wheezing.

As we mentioned earlier, immunization against measles also helps to protect children from complications, which include pneumonia and AOM.

35.4.2  Pneumonia transmission and risk factors

The infectious agents causing pneumonia may reach the person’s lungs through different routes. The most common modes of transmission are:

• Airborne droplets spread when the sick person coughs or sneezes, and inhaled into the lungs (breathed in) by a susceptible person;
• Direct oral contact with someone who has pneumonia (e.g. through kissing).
• During or shortly after birth, babies are also at higher risk of developing pneumonia from coming into contact with infectious agents in the birth canal, or from contaminated articles used during the delivery.

These modes of transmission help to explain why certain risk factors increase the probability that children or adults will develop pneumonia. Box 35.3 summarises the common risk factors, some of which also increase the patient’s susceptibility to fatal complications if pneumonia occurs.

35.4.3  Diagnosis and classification of pneumonia

Children with pneumonia may have a range of clinical presentations, depending on their age and the cause of the pneumonia. Children who have bacterial pneumonia usually become severely ill and show the following symptoms:

• Fast or difficult breathing (see Table 35.2)
• Cough
• Fever and chills
• Loss of appetite
• Wheezing.

Adults with pneumonia also have fever, cough, and fast or difficult breathing.

In severe cases of pneumonia, children under five-years-old may struggle to breathe and usually show chest in-drawing, which you can observe as drawing inwards or retracting of the lower chest (red arrows in Figure 35.8) during inhalation (taking air into the lungs).

Figure 35.8  Chest in-drawing during inspiration: the lower chest wall moves in sharply as the child breathes in. (Diagram: Dr Radmila Mileusnic)

Pneumonia in children and adults is classified into non-severe and severe pneumonia based on the features of the condition summarised in Box 35.4. This classification is very important because it determines what treatment is given to the patient (as you will see in Section 35.4.4).

If a child with pneumonia has fast breathing (Table 35.2), but no general danger signs, or chest in-drawing, or stridor, classify him/her as having non-severe pneumonia. Adults with pneumonia who do not have the severe signs given in Box 35.4, are also classified as having non-severe pneumonia.

35.4.4  Treatment of pneumonia

Severe pneumonia in children and adults is diagnosed if they exhibit the signs summarised in Box 35.4. You should refer all patients with severe pneumonia immediately to the nearest health centre or hospital, where appropriate drugs can be prescribed by doctors or health officers.

For adults with non-severe pneumonia, give amoxicillin tablets, 500 mg three times a day for seven days. Details of the treatment of severe and non-severe pneumonia in children are given in a separate Module on the Integrated Management of Newborn and Childhood Illness (IMNCI). Here we remind you of the oral antibiotics you can give children with non-severe pneumonia without any other danger signs. The course of treatment is for five days with either co-trimoxazole (the preferred antibiotic drug), or if co-trimoxazole is not available, give amoxicillin. The doses of co-trimoxazole or amoxicillin depend on the age or weight of the child, and were summarised earlier in Table 35.1. Look back at it now, and then answer the following question.

Co-trimoxazole for HIV-positive children should be prescribed by doctors as prophylaxis against opportunistic infections with bacteria, viruses and fungi that cause pneumonia. Part 3 of this Module includes a detailed discussion of the prevention and treatment of pneumonia in people living with HIV infection.

35.5  Prevention and control of acute respiratory tract infections

Finally, we turn to the methods of prevention and control of acute respiratory tract infections (ARIs). You need to know about them so you can teach members of your community how they can protect their children and vulnerable adults from acute otitis media, pharyngitis and pneumonia.

Prevention measures for ARIs include:

• Feeding children with adequate amounts of varied and nutritious food to keep their immune system strong.
• Breastfeeding infants exclusively (no other food or drinks, not even water) for the first six months (Figure 35.9); breastmilk has excellent nutritional value and it contains the mother’s antibodies which help to protect the infant from infection.
• Avoiding irritation of the respiratory tract by indoor air pollution, such as smoke from cooking fires; avoid the use of dried cow dung as fuel for indoor fires.
• Immunization of all children with the routine Expanded Programme on Immunization (EPI) vaccines in Ethiopia (Box 35.5).

Figure 35.9  Exclusive breastfeeding helps to protect babies from communicable disease, including pneumonia. (Photo: UNICEF Ethiopia)

You can help to control the spread of respiratory bacteria by educating parents to avoid contact as much as possible between their children and patients who have ARIs. You should also teach people with ARIs to cough or sneeze away from others, hold a cloth to the nose and mouth to catch the airborne droplets when coughing or sneezing, and disinfect or burn the cloths afterwards. Immunization also increases control, by reducing the reservoir of infection in the community and increasing the level of herd immunity (described in Study Session 1 in Part 1 of this Module).

Summary of Study Session 35

In Study Session 35, you have learned that:

1. Acute respiratory tract infections (ARIs) may affect the upper or lower respiratory tracts and are major public health problems in Ethiopia.
2. Malnutrition, under-nutrition, lack of exclusive breastfeeding, lack of immunization, indoor air pollution and HIV infection are the major risk factors for ARIs.
3. Acute otitis media is a common upper respiratory tract infection in young children, which is manifested by fever, ear pain, pus discharging from the ear and irritability. Children with symptoms of acute otitis media should be identified as soon as possible and treated by ‘wicking’ the pus from the ear, and giving antibiotics to prevent complications such as deafness,meningitis and pneumonia.
4. Pharyngitis is another common upper respiratory tract infection, which is manifested by fever, sore throat and swollen inflamed tonsils. Children with symptoms of pharyngitis should be referred to a higher level health facility for assessment and treatment.
5. Pneumonia is the major killer of children in Ethiopia and is among the top five causes of illness and death among adults.
6. Severe pneumonia in children is manifested by the presence of danger signs, which include fast breathing, fever, chest in-drawing and stridor. Children with severe pneumonia are at high risk of death, and should immediately be referred to a higher level health facility to save their lives.
7. Co-trimoxazole or amoxicillin are the antibiotics authorised at Health Post level to treat acute otitis media and non-severe pneumonia. Dosages are based on the patient’s age and weight.
8. Prevention and control of acute respiratory tract infections include adequate nutrition, exclusive breastfeeding for infants under six months of age, immunization, protection from indoor smoke pollution, keeping children away from patients with pneumonia, teaching people to cough and sneeze away from other people, and co-trimoxazole prophylaxis for adults and children with HIV infection.

Self-Assessment Questions (SAQs) for Study Session 35

Now that you have completed this study session, you can assess how well you have achieved its Learning Outcomes by answering the following questions. Write your answers in your Study Diary and discuss them with your Tutor at the next Study Support Meeting. You can check your answers with the Notes on the Self-Assessment Questions at the end of this Module.