Juvenile Idiopathic Arthritis

The exact etiology of most forms of JIA is unknown; however, there are two theories about its causation. Genetics is believed to be a predisposing factor. Some genetic factors, such as human leukocyte antigen (HLA) alleles, appear to play a role in influencing the susceptibility to develop disease, and others influence disease severity. An external trigger such as infection or trauma seems to initiate the autoimmune reaction and cause an exaggerated immune response (Rabinovich, 2010).

The pathogenesis of JIA involves a combination of humoral and cell-mediated immunity responses with proliferation of macrophage-like and fibroblastoid synoviocytes. There is subsequent infiltration of neutrophils and lymphocytes, which is evidence of an autoimmune response. The humoral response is responsible for the release of autoantibodies (especially antinuclear antibodies), an increase in serum immunoglobulins, the formation of circulating immune complexes and complement activation. The cell-mediated reaction is associated with a T-lymphocyte response that plays a key role in cytokine production resulting in the release of tumor necrosis factor α (TNF-α), IL-1, and IL-6. B lymphocytes are activated by T-helper cells and produce autoantibodies that link to self-antigens. The B lymphocytes infiltrate the synovium with the end result of nonsuppurative chronic inflammation of the synovium that can lead to articular cartilage and joint structure erosion. Children with JIA have no demonstrable immunodeficiency (Rabinovich, 2010).

Systemic Lupus Erythematosus

Children with SLE exhibit a marked increase in the production of autoantibodies that attack the body’s deoxyribonucleic acid (DNA). This leads to immune complex formation and tissue damage from either direct bonding in tissues, immune complex deposition, or a combination of both (Klein-Gitelman, 2010). Various immune phenomena are associated with SLE, including altered immunologic reactions in the T- and B-lymphocyte function. There is a loss of T-lymphocyte control and hyperactivity of B lymphocytes resulting in nonspecific and specific antibody and autoantibody production. There is a strong link between a faulty immune mechanism and SLE because this disease is characterized by inflammatory damage to target organs brought on by autoantibodies attacking self-antigens. The exact etiology of SLE is unknown, but many factors including genetics, hormones, and environment are linked to the immune dysregulation that characterizes this rheumatic disease. Environmental factors that are thought to play a role in its pathogenesis are oral contraceptive use, pregnancy, microbials (viral agents mostly), temperate climates, exposure to ultraviolet light, and certain drugs (e.g., hydralazine and procainamide).

There is an association between HLA type and complement deficiency. Characteristic pathologic findings include the production of numerous autoantibodies and impairment in the normal suppression of autoreactive B-cell clones. Immune complexes are abundant, and their clearance may be impaired. In addition, fibrinoid deposits collect in blood vessel walls in many organs that result in ischemic damage (Haftel, 2011).

Atopic Disorders

Routine chest radiographs are not indicated in most children with asthma because most often they are normal or only show hyperinflation. However, chest radiographs can be useful in selected cases of asthma or suspected asthma. These should be performed with the first episode of asthma or with recurrent attacks; in a child with atypical signs or symptoms; if a secondary infection does not clear with standard therapy; or if there are signs and symptoms of significant pulmonary involvement (Lasley and Hetherington, 2011).

Pulmonary function tests, such as forced vital capacity, forced expiratory volume in 1 second, and forced expiratory flow, are important diagnostic tests to establish the diagnosis of asthma, especially in young children. Children older than 5 years can typically perform spirometry testing. Peak expiratory flow (PEF) rate and pulse oximetry measurements can be easily and quickly done in most pediatric settings and provide additional information useful to monitor and manage asthma.

Eosinophil count, determination of serum IgE concentration, in vitro serum testing (fluorescent enzyme immunoassay) (CAP-RAST, ImmunoCAP or CAP-FEIA), and in vivo skin testing (prick test) are not needed to confirm the diagnosis or to monitor treatment of the majority of children with an atopic disorder. Children with significant dermatitis or who are highly allergic may need additional or extensive diagnostic testing.

Rheumatic Diseases

Laboratory blood studies, including antinuclear antibodies (ANAs), anti–double-stranded DNA, anti-Smith (Sm) antibody, and determination of serum complement levels, are common tests ordered in children with SLE. Other related blood, serologic, and urine laboratory studies are indicated depending on organ involvement (e.g., renal involvement is a frequent complication). While there is no laboratory test that has 100% sensitivity and specificity, doing an ANA, rheumatoid factor (RF), and an anti-cyclic citrullinated peptide (anti-ccp) is recommended (Stanley and Ward-Smith, 2011). The anti-ccp is helpful for diagnosing JIA in the early stages of disease (Waits, 2010), Guidelines for the laboratory workup of SLE and JIA are discussed later in this chapter.

Imaging studies (MRI and radiographs) are done to assess and manage joint abnormalities.

Description

Asthma is a chronic respiratory disease characterized by the following features (National Heart, Lung, and Blood Institute [NHLBI], 2007).

• Immunohistopathologic responses that produce:

Shedding of airway epithelium and collagen deposition beneath the basement membrane

Edema

Mast cell activation

Inflammatory infiltration by eosinophils, lymphocytes (Th2-like cells), and neutrophils (especially in fatal asthma)

• Airway inflammation contributes to airflow limitations, including:

Acute bronchoconstriction

Airway edema

Mucous plug formation

• Airflow obstruction is often reversible, either spontaneously or with treatment.

• Persistent inflammation can result in airway wall remodeling and irreversible changes.

• Airway inflammation also triggers hyperresponsiveness (to any of a variety of stimuli, such as physical, chemical, or pharmacologic agents; allergens; exercise; and cold air) and is a factor in disease chronicity. Inflammation causes bronchospasms with resultant characteristic symptomatology of wheezing, breathlessness, chest tightness, or cough typically worse at night or after exercise (Sharma and Gupta, 2010).

Asthma in children is classified as intermittent, mild persistent, moderate persistent, or severe persistent depending on symptoms, recurrences, need for specific medications, and pulmonary function measurements (Table 24-1). Children classified at any level of asthma can have episodes involving mild, moderate, or severe exacerbations. Exacerbations involve progressive worsening of shortness of breath, cough, wheezing, chest tightness, or any combination of these symptoms. The degree of airway hyperresponsiveness is usually related to the severity of asthma. Children younger than 5 years of age experience greater airway hyperresponsiveness than older children. Airway remodeling can result from chronic inflammation caused by asthma. Irreversible structural changes take place and result in decreased pulmonary function (Lasley, 2006). A child’s classification can change over time.

TABLE 24-1 Classification of Asthma Severity in Children: Clinical Features Before Treatment

Many children experience early- and late-phase responses to their asthma episode. The early asthmatic response (EAR) phase is characterized by activation of mast cells and their mediators, with bronchoconstriction being the key feature. EAR starts within 15 to 30 minutes of mast cell activation and resolves within approximately 1 hour if the individual is removed from the offending allergen. The late-phase asthmatic response is a prolonged inflammatory state that usually follows the EAR within 4 to 12 hours after exposure to the allergen, is often associated with airway hyperresponsiveness more severe than the EAR presentation, and can last from hours to several weeks (Liu et al, 2004).

Exercise-induced bronchospasm describes the phenomenon of airway narrowing during or minutes after the onset of vigorous activity. Most asthmatics exhibit airway hyperirritability after rigorous activity and display exercise-induced bronchospasm. However, for some children, exercise is the only stimulus that triggers their asthma. Although asthma is not always associated with an allergic disorder in children, many pediatric patients with chronic asthma have an allergic component.

Epidemiology

It is not known for certain whether hyperresponsiveness of the airways is present at birth in genetically predisposed children or acquired. However, the genetic predisposition for the development of an IgE-mediated response to common aeroallergens, known as atopy, remains the strongest identifiable predisposing risk factor for asthma. A combination of genetic predisposition and exposure to certain environmental factors are the necessary components responsible for the pathophysiologic response associated with asthma.

The morbidity and mortality statistics of asthma in childhood demonstrate an alarming increase in the prevalence of asthma and its complications. In 2008, 8.7 million 5- to 17-year-olds had been diagnosed with asthma (American Lung Association [ALA], 2010). The prevalence rate for asthma is highest among children 5 to 17 years with the highest rate among African-American children (ALA, 2010). Occupational or environmental exposure can cause airway inflammation associated with asthma. Factors known to precipitate or aggravate asthma in children include the following:

Allergen-induced asthma results in hyperresponsive airways. The majority of children with asthma show evidence of sensitization to any of the following inhalant allergens:

There is a high prevalence of asthma in food-allergic children; egg and tree nut allergy is significantly associated with asthma (Gaffin et al, 2011).

Clinical Findings

Diagnostic Studies

Laboratory and radiographic tests should be individualized to the child and based on symptoms, severity or chronology of the disease, response to therapy, and age. Tests to consider include the following:

• Oxygen saturation by pulse oximetry to assess severity of acute exacerbation. This should be a routine part of every assessment on a patient with asthma. Pulse oximetry measures the oxygen saturation (Sao₂) of hemoglobin—the percent of total hemoglobin that is oxygenated—as follows:

Greater than 95%, mild

90% to 95%, moderate

Less than 90%, severe lack of oxygen

• A complete blood count (CBC) if secondary infection or anemia is suspected (also check for elevated numbers of eosinophils)

• Chest radiograph for the first episode, and then only if secondary respiratory infection or other pulmonary disorders are suspected or if child is less than 1 year old with persistent wheezing

• Sinusitis should be considered as a cause of an asthma exacerbation. However, imaging of the sinus is not routinely needed to make the diagnosis of sinusitis. (See Chapter 31 for a discussion on sinusitis and the criteria needed for ordering computed tomography [CT] scans, which are more sensitive and specific than sinus radiographs.)

• Allergic workup, including skin testing, IgE, or ImmunoCAP (refer child to pediatric allergist)

• Sweat test if cystic fibrosis is a possibility

• Pulmonary function tests:

Formal spirometry testing is the gold standard in children older than 4 years for diagnosing asthma.

Start with PEF assessment in children 4 to 5 years or older to monitor the effectiveness of β-agonist treatment (measurements before and after treatments) and assess the severity of airflow obstruction.

Consider the use of more sophisticated pulmonary laboratory studies for the child with severe asthma.

Pulmonary monitoring and typical findings include the following:

• PEF can be used in some children as young as 4 to 5 years. Noteworthy is the fact that values are instrument specific. Use child’s personal best value as a guideline to help detect possible changes in airway obstruction; can use predicted range for height and age if personal best rate is not available (Table 24-2).

• Interpretation of PEF reading (Box 24-1 describes use of peak flowmeter and interpretation of results)—if PEF is in the:

Green zone: More than 80% to 100% of personal best signals good control

Yellow zone: Between 50% and 79% of personal best signals a caution

Red zone: Between 0% and 50% of personal best signals major airflow obstruction

• Chest radiograph findings: Typically normal and may show hyperinflation of the lungs with flattening of the diaphragm and peribronchial thickening on radiograph with or without atelectasis (Liu et al, 2007)

TABLE 24-2 Predicted Average Peak Expiratory Flow for Normal Children and Adolescents

Height (Inches)	Males and Females (L/Minute)
43	147
44	160
45	173
46	187
47	200
48	214
49	227
50	240
51	254
52	267
53	280
54	293
55	307
56	320
57	334
58	347
59	360
60	373
61	387
62	400
63	413
64	427
65	440
66	454
67	467

note: It is recommended that peak expiratory flow (PEF) rate objectives for therapy be based on each individual’s “personal best,” which is established after a period of PEF rate monitoring while the individual is under effective treatment.

From National Heart, Lung, and Blood Institute (NHLBI): Executive summary: guidelines for the diagnosis and management of asthma, NIH Pub No 94-3042A, National Institutes of Health, 1994, Bethesda, Md; adapted from Polger G, Promedhar V: Pulmonary function testing in children: techniques and standards, Philadelphia, 1971, Saunders.

BOX 24-1 Use of the Peak Flowmeter and Its Interpretation

Steps to follow in using a peak flow meter:

1. Have child stand up.

2. Make sure that indicator is at the base of the numbered scale.

3. Ask child to take a deep breath.

4. Have the child place the peak flow meter in the mouth with the lips sealing the mouthpiece. Tell the child not to put his or her tongue in the hole of the mouthpiece.

5. Tell the child to blow out as hard and fast as possible.

6. Record the rate, but if the child coughs, do not write down that number.

7. Repeat steps 2 through 6, two more times.

8. Record the highest of the three values.

Peak Expiratory Flow Rate

The maximum flow rate that is produced during forced expiration with fully inflated lungs

Personal Best Value

The highest value that an individual achieves in measuring PEF rate over a 2-week period when his or her asthma is under good control is known as one’s “personal best” value or rate. Good control is defined as when one feels well without asthma symptoms. To determine personal best, take readings twice daily, in the morning and late afternoon or evening, and 15 to 20 minutes after taking an inhaled short-acting β₂-agonist. Using the personal best value is the most accurate gauge to use to interpret changes in peak flow measurements because the child’s own scores are used as the standard for comparison.

Differential Diagnosis

Numerous conditions can cause airway obstruction and be incorrectly confused with asthma, especially in young children and infants. Examples include the following:

Management

The Full Report of the Expert Panel: Guidelines for the Diagnosis and Management of Asthma (ERP-3) (NHLBI, 2007) provides the most recent standards for the treatment of asthma in children. Management strategies are based on whether the child has intermittent, mild persistent, moderate persistent, or severe persistent asthma (see Table 24-1). A stepwise approach is recommended. If control of symptoms is not maintained at a particular step of classification and management, the health care provider first should reevaluate for compliance and administration factors. If these factors do not appear to be responsible for the lack of symptom control, the health care provider should go to the next step. Likewise, gradual step-downs in pharmacologic therapy may be considered when the child is well controlled for 3 months. ICS may be reduced about 25% to 50% every 3 months to the lowest possible dose needed to control the child’s asthma (NHLBI, 2007).

In this chapter the outpatient management of intermittent, mild persistent, moderate persistent, and severe persistent asthma is discussed, as is the outpatient management of acute exacerbations. The practitioner should refer to other textbooks for management of severe asthma requiring hospitalization.

Chronic Asthma

Treatment of chronic asthma in children is based on general control measures and pharmacotherapy. General control measures include the following:

• Avoid exposure to known allergens or irritants.

• Avoid use of acetaminophen in children at risk for asthma (McBride, 2011).

• Administer yearly influenza vaccine.

• Control environment to eliminate or reduce offending allergen.

• Provide allergen immunotherapy.

• Treat rhinitis, sinusitis, or gastroesophageal reflux.

• See section on patient education for other measures.

The pharmacologic management of asthma in children is based on the severity of asthma and the child’s age. The stepwise approach to treatment (Figs. 24-1 and 24-2) is based on severity of symptoms and the use of pharmacotherapy to control chronic symptoms, maintain normal activity, prevent recurrent exacerbations, and minimize adverse side effects, and nearly “normal” pulmonary function. Within any classification, a child may experience mild, moderate, or severe exacerbations. NHLBI guidelines for assessing asthma control and initiating and adjusting asthma therapy for the various pediatric age groups are found in Figs. 24-3 and 24-4.

FIGURE 24-1 Stepwise approach for managing asthma in children 0 to 4 years of age and 5 to 11 years of age.

(From National Heart, Lung, and Blood Institute, National Asthma and Prevention Program: Expert panel report 3: guidelines for the diagnosis and management of asthma. Summary report 2007, NIH Pub No. 08-5846, 2007, Bethesda, MD, U.S. Department of Health and Human Services, p 42, www.nhlbi.nih.gov/guidelines/asthma/asthsumm.pdf.)

FIGURE 24-2 Stepwise approach for managing asthma in youths more than or equal to 12 years of age and adults.

(From National Heart, Lung, and Blood Institute, National Asthma and Prevention Program: Expert panel report 3: guidelines for the diagnosis and management of asthma. Summary report 2007, NIH Pub No. 08-5846, 2007, Bethesda, MD, U.S. Department of Health and Human Services, p 45, www.nhlbi.nih.gov/guidelines/asthma/asthsumm.pdf.)

FIGURE 24-3 Classifying asthma severity and initiating treatment in children 0 to 4 years of age and 5 to 11 years of age. (From National Heart, Lung, Blood Institute, National Asthma Prevention Program: Expert panel report 3: guidelines for the diagnosis and management of asthma. Summary report 2007, NIH Pub No. 08-6846, Bethesda, MD, 2007, U.S. Department of Health and Human Services, pp 40-41. www.nhlbi.nih.gov/guidelines/asthma/asthsumm.pdf.)

FIGURE 24-4 Classifying asthma severity and initiating treatment in children more than or equal to 12 years of age and adults. (From National Heart, Lung, Blood Institute, National Asthma Prevention Program: Expert panel report 3: guidelines for the diagnosis and management of asthma. Summary report 2007, NIH Pub No. 08-6846, Bethesda, Md, 2007, U.S. Department of Health and Human Services, p. 43.)

Important considerations to note in the pharmacologic treatment of asthma include the following:

• Control of asthma should be gained as quickly as possible by starting at the classification step most appropriate to the initial severity of the child’s symptoms or at a higher level (e.g., a course of systemic corticosteroids or higher dose of inhaled corticosteroid). After control of symptoms, decrease treatment to the least amount of medication needed to maintain control.

• Systemic corticosteroids may be needed at any time and step if there is a major flare-up of symptoms.

• Children with intermittent asthma may have long periods in which they are symptom-free; they can also have life-threatening exacerbations, often provoked by respiratory infection. In these situations a short course of systemic corticosteroids should be used (NHLBI, 2007).

• Variations in asthma necessitate individualized treatment plans.

• The β₂-agonist can be given by nebulization with a compressor. Nebulization can be a more effective route than metered-dose inhaler (MDI) therapy for young infants (2 years old or younger) or children who progress to moderate or severe airway obstruction.

• A spacer or holding chamber with an attached mask enhances the delivery of MDI medications to the lower airways of a child. Spacers eliminate the need to synchronize inhalation with activation of MDI. Older children can use the spacer without the mask.

• Dry powder inhalers (DPIs) do not need spacers or shaking before use. Instruct children to rinse their mouth with water and spit after inhalation. DPIs should not be used in children younger than 4 years old.

• Different inhaled corticosteroids are not equal in potency to each other on a per puff or microgram basis. Table 24-3 compares the daily low, medium, and high doses of the various inhaled corticosteroids used for children. Combination inhaled corticosteroid and long-acting β₂-agonist can be used in children from 4 years of age (NHLBI, 2007; Taketomo et al, 2010).

• For treatment of exercise-induced bronchospasm:

Warm up before exercise for 5 to 10 minutes.

Use either an inhaled short-acting β₂-agonist or a mast cell stabilizer (cromolyn or nedocromil) or both. Combination of both types of drugs is the more effective therapy. A long-acting β₂-agonist can be used in older children.

Use two puffs of a β₂-agonist and/or cromolyn MDI 15 to 30 minutes before exercise (Kelly and Oppenheimer, 2010). Tolerance may develop if a β₂-agonist is used more than a few times a week; it should not be used as a controller monotherapy. Those who exercise regularly should use controller medication, preferably an inhaled corticosteroid. Oral montelukast can also be used on a daily schedule at least 2 hours prior to exercise (Storms, 2010).

Using a scarf or mask around the mouth may decrease exercise-induced asthma (EIA) induced by cold.

TABLE 24-3 Estimated Comparative Daily Dosages for Inhaled Corticosteroids

Table 24-4 identifies the usual dosages for long-term control medications (exclusive of inhaled corticosteroids) used to treat asthma in children. Quick-relief medications are listed in Table 24-5.

TABLE 24-4 Long-Term Control Medications for the Treatment of Asthma

TABLE 24-5 Quick-Relief Medications for the Treatment of Asthma

Practice parameters are guides and should not replace individualized treatment based on clinical judgment and unique differences among patients.

Acute Exacerbations of Asthma

The treatment of acute episodes of asthma is also based on classification of the severity of the episode. Acute episodes are classified as mild, moderate, and severe. Signs and symptoms are summarized in Table 24-6. Early recognition of warning signs and treatment should be stressed in both patient or parent education, or both.

TABLE 24-6 Classifying Severity of Asthma Exacerbations^∗

Characteristics of a mild acute episode are:

• Wheezing, usually at the end of expiration

• Increased respiratory rate

• No signs of respiratory distress, cyanosis, or activity restriction

• PEF or forced expiratory volume (FEV₁) greater than 70% of expected value

• Ability to speak in normal sentences between breaths

Children with a moderate acute episode of asthma manifest the following:

• Audible wheeze

• Use of accessory muscles

• Increase in respiratory rate

• Unable to walk or utter more than three to five words between breaths

Manifestations of a severe acute episode of asthma in children include the following signs of severe respiratory distress:

• Cyanosis

• Use of accessory muscles plus lower rib and suprasternal retractions; nasal flaring

• Agitation and the ability to say only single words between breaths

• Loud wheezing on inhalation and expiration (NHLBI, 2007)

The initial pharmacologic treatment for acute asthma exacerbations is shown in Fig. 24-5. It consists of inhaled short-acting β₂-agonists, two to six puffs every 20 minutes for three treatments by way of MDI with or without a spacer, or a single nebulizer treatment (0.15 mg/kg; minimum 1.25 to 2.5 mg of 0.5% solution of albuterol in 2 to 3 mL of normal saline).

FIGURE 24-5 Management of asthma exacerbations: home treatment.

If the initial treatment results in a good response (PEF/FEV₁ greater than 70% of the patient’s best), the inhaled short-acting β₂-agonists can be continued every 3 to 4 hours for 24 to 48 hours. Consider a 7- to 10-day burst of oral corticosteroids.

An incomplete response (PEF or FEV₁ between 40% and 69% of personal best or symptoms recur within 4 hours of therapy) is treated by continuing β₂-agonists and adding an oral corticosteroid. The β₂-agonist can be given by nebulizer. Parents should contact their child’s health care provider for additional instructions. If there is marked distress (severe acute symptoms) or a poor response (PEF or FEV₁ <40%) to treatment, the child should have the β₂-agonist repeated immediately and should be taken to the emergency department. Emergency medical rescue (911) transportation should be used if the distress is severe and nonresponsive.

If children experience acute asthma exacerbations more than once every 4 to 6 weeks, their treatment plan should be reevaluated (NHLBI, 2007).

Complications

Complications from asthma can range from mild secondary respiratory infections to respiratory arrest. Unresponsiveness to pharmacologic agents can lead to status asthmaticus and ultimately to death. Chronic high-dose steroid use leads to growth retardation and other related side effects.

Patient and Parent Education and Prevention

The practitioner needs to remember that day-to-day management of asthma is the responsibility of the child or parent. Education should be tailored to meet the patient’s individual and family needs. Therefore the primary care provider should provide instruction on the following:

BOX 24-2 How to Use a Metered-Dose Inhaler

Adapted from National Asthma Education and Prevention Program: Facts about controlling asthma, NIH Pub No 97-2339. National Heart, Lung, and Blood Institute (NHLBI). Bethesda, Md. A reproducible handout.

Using an inhaler seems simple, but most patients do not use it correctly.

Steps for Using an Inhaler for Children Younger Than 5 Years of Age

1. The use of a mask chamber with a metered-dose inhaler (MDI) allows the delivery of inhaled medications even in an uncooperative child.

2. The child should be placed in the parent’s lap, and the mask placed around the child’s mouth.

3. Press down on the MDI while firmly holding the mask around the child’s mouth. The child will eventually take a deep breath and inhale the medication.

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