42.3 Chronic Disease and Chronic Illness

Chronic Disease

Long-standing definitions describe chronic disease as a state of being that includes a biomedical disease (Martin, 2007). The CDC classifies a disease state as chronic when a condition lasts 1 year or longer. Although disease presentations and circumstances vary widely between individuals, most chronic diseases require ongoing medical treatment and intervention and may affect a person’s ability to perform daily activities (CDC, 2022a). Several diseases affect individuals over an extended period and are considered chronic. Common chronic diseases in the United States include heart disease, hypertension (HTN), epilepsy, stroke, mood disorders, cancer, diabetes, asthma, chronic obstructive pulmonary disease (COPD), arthritis, dementia, psoriasis, osteoporosis, obesity, autoimmune disorders, and chronic pain.

Some chronic diseases are preventable based on lifestyle factors. Although there is some debate regarding whether a communicable disease passed from person to person is a chronic disease, most definitions include these conditions. Examples of communicable diseases that may be considered chronic diseases are HIV and acquired immunodeficiency syndrome (AIDS), malaria, and hepatitis C. Chronic diseases typically develop over a prolonged period, sometimes without overt symptoms. Chronic diseases are often implicated in the onset of more acute health complications. Others are hereditary or genetic without any other identifiable cause. Chronic diseases may have an identifiable cause, such as epilepsy, diabetes, and asthma. In others, it may be challenging to identify a specific cause. Some chronic disease states are modifiable with lifestyle and treatment modalities. Chronic diseases typically are not cured by medical treatment but may be modified to an extent to create a remission, reduction, or disappearance of symptoms of a disease. Other conditions, disorders, and syndromes may meet some criteria of chronic disease but more commonly contribute to or result from chronic disease states (Table 42.3).

Chronic Illness

In contrast to chronic disease, chronic illness describes an individual’s experience with a chronic condition. Chronic illness may result from the onset or progression of a chronic disease. The outward expression of chronic illness is seen in the way individuals live and cope with chronic disease and the disruptions it causes in their daily activities. Individuals can have many symptoms of chronic illness, depending on the associated disease process. Symptoms may include fatigue, weakness, pain, headaches, negative self-image, social withdrawal, inability to work, decreased physical function, stress, mood disorders, anxiety, sleep disturbance, and cognitive changes.

There can be an overlap in some symptoms of certain chronic diseases and chronic illnesses. For example, an individual may experience migraine headaches as an independent chronic disease or as a symptom associated with chronic illness. These headaches may progress over time and create dysfunction in many aspects of life. Another individual may experience headaches as part of chronic illness experiences in response to a cancer diagnosis. These headaches may be caused by stress or treatment or may have a biophysical cause. Regardless of the cause of the symptoms, they are usually treatable and can often be modified with lifestyle modifications.

Causes of Chronic Conditions

Chronic conditions may result from a discrete cause or have a complex causality. Multiple factors often lead to single or multiple chronic conditions. Many chronic conditions arise from a few detrimental lifestyle factors, including tobacco use, secondhand smoke exposure, improper nutrition, sedentary lifestyle, and substance use disorders (CDC, 2022b). Genetic or hereditary factors are also responsible for certain chronic diseases. A family history of specific disorders puts an individual at a higher risk for these same chronic conditions. Some conditions are directly linked to specific genes that increase an individual’s risk, such as genes associated with colon and breast and ovarian cancers. Other chronic conditions may result from environmental exposures, infectious disease, and complications from injuries. Many chronic conditions have an overlap in symptoms, pathophysiology, and cause. One chronic disease may contribute to the onset or worsening of another.

Multiple Chronic Conditions

The CDC (2022b) reports that up to 40 percent of adults in the United States have two or more co-occurring chronic conditions. These conditions may stem from the same cause or risk factors or develop independently. In addition, some chronic conditions create secondary disorders that, over time, develop into additional chronic conditions. Consider an adult with obesity who develops type 2 diabetes; over time, this individual may experience the effects of diabetes, with impaired kidney function, heart disease, peripheral vascular disease, or retinal damage. Studies indicate that women, non-Hispanic White adults, older adults, and those adults receiving public insurance have higher rates of multiple chronic conditions (Boersma et al., 2020). The interaction between multiple disorders is responsible for many interrelated symptoms and comorbid medical conditions (multiple medical conditions that are simultaneously present). Because of this interplay of symptoms, it is sometimes difficult to differentiate or treat conditions separately.

Cancers

Cancers affect individuals of all ages, with the prevalence of different cancer types varying by age, demographic, and risk-exposure group. Although known risk factors for certain cancers are predictable, it is impossible to predict which individuals will develop cancer during their lifetime. Cancers are highly variable in their onset, progression, and treatment response. So many different factors play a role in the components of this disease. Although some cancers are more common in children and young adults, advancing age is the most significant risk factor for developing many types of cancer. In addition, the common risk factors for all chronic diseases also correlate with cancer risk, such as tobacco use, lack of physical activity, poor nutrition, and obesity.

Cardiovascular

Cardiovascular diseases (CVDs) encompass many disorders and are the leading cause of death. These conditions affect the heart and blood vessels, including large vessels and tiny capillaries. These conditions compound one another to create a progressively higher risk for acute disease and death. Common chronic diseases associated with the cardiovascular system include HTN, hyperlipidemia, coronary artery disease, peripheral vascular disease, heart failure, valvular disease, and atrial fibrillation.

Although CVD risk may be familial, poor lifestyle choices significantly increase an individual’s risk of developing CVD. In particular, a sedentary lifestyle and poor nutritional choices contribute significantly to plaque buildup in large vessels, leading to coronary artery disease. Other lifestyle factors that increase CVD risk include smoking and excessive alcohol use. Because of the effects of CVD on the vessels and heart, acute damage to these organs can occur and have a high risk of mortality and morbidity. These acute diseases include stroke, heart attack, aneurysm, and heart valve disease.

Cognitive

Chronic cognitive disorders are those disorders that affect the thinking process, memory, and brain processing. Cognitive disorders may be acquired from trauma or stroke, or may result from mental health disorders. Common cognitive disorders include TBI, stroke, dementia, Alzheimer disease, and Parkinson disease.

Cognitive impairments may also be seen in individuals with other chronic disorders that affect oxygenation. There is some overlap between cognitive disorders and neurological disorders. Aging may also be associated with some cognitive decline, such as mild cognitive impairment, and compounded with other chronic conditions. Cognitive disease in younger individuals may result from early-onset dementias as well as TBI. Although most TBIs are related to an acute event, repetitive brain injury is associated with long-term effects that may cause lasting and significant impairments in brain function (CDC, 2024). Cognitive impairments may also arise secondarily to primary benign or cancerous brain tumors or tumors associated with cancer metastases.

Mental Health

Although some mental health disorders present as an acute change in psychiatric stability, many mental health disorders are considered chronic conditions. Chronic mental health conditions include generalized anxiety disorder, social anxiety disorder, PTSD, depression, obsessive-compulsive disorder, bipolar disorder, schizophrenia, borderline personality disorder, and eating disorders.

Mental health disorders can be present in the absence of any other physical health conditions or can be triggered by these conditions. In addition, some mental health disorders are exacerbated or triggered by other chronic disorders, such as depression and anxiety. Nurses must address these topics with compassion and respect, thereby erasing the stigma that has been present historically regarding mental health disorders. Although there is often overlap in mental health conditions, treatment is undertaken by addressing each specific component. Mental health professionals, counselors, primary care providers, and nurses all play a role in maintaining health and quality of life in individuals with chronic mental health disorders.

Immune System

Chronic immune disorders originate in the immune system but can affect nearly all organ systems in the body. The immune system performs many functions in protecting the body and preventing illness. Disorders of the immune system can lead to specific conditions as well as the inability of the body to fight infection. Immune disorders can be classified into three major categories: immunodeficiency disorders, overactive immune disorders, and autoimmune disorders.

An immunodeficiency disorder is a condition or disease that is caused by a weakened immune system that impairs the body’s ability to fight off disease or infection. Immunodeficiency disorders can be congenital or acquired (resulting from exposure to a toxin or pathogen, such as HIV). Congenital immune disorders are often present at birth and are uncommon in the general population. Acquired immune deficiency disorders are much more common. Viruses, medications, and medical treatments trigger chronic immune deficiency disorders. Examples of acquired immune deficiency disorders include AIDS, cancers of the immune system, and multiple myeloma. Immune deficiency can also be triggered by toxins introduced into the body, as with smoking, alcohol consumption, and poor nutrition.

An overactive immune disorder occurs when the immune system develops a hyperresponse to normally harmless environmental substances. These are often more common disorders and are typically much easier to identify and treat. These disorders cause symptoms commonly experienced as breathing disorders, skin reactions, and nasal congestion. Some of these conditions include asthma, eczema, allergic rhinitis, and anaphylaxis.

An autoimmune disorder, or a rheumatological condition, arises from the body’s immune system attacking and damaging its cells and organs. Autoimmune disorders may be challenging to diagnose and have various presenting symptoms related to general inflammation in the body. These symptoms may include joint pain and damage, rash or other skin disorders, organ dysfunction, dry mouth, metabolic abnormalities, and chronic pain.

Specific autoimmune disorders can be diagnosed through clinical evaluation and blood testing. Autoimmune disorders affect various organs in the body, causing persistent and sometimes progressive damage, mainly if not treated (Table 42.5).

Endocrine

The endocrine system is spread among multiple organs and glands throughout the body (Figure 42.4). Because the endocrine system affects many organ systems simultaneously, an intricate balance is necessary to maintain health.

Figure 42.4 The endocrine system is a complex system spread throughout the body. (modification of “Blausen 0345 EndocrineSystem Female2” and “Blausen 0346 EndocrineSystem Male2” by “BruceBlaus”/Wikimedia Commons, CC BY 3.0)

Endocrine disorders are associated with hormone production and use within our bodies. Complex interactions between hormones produced by endocrine organs throughout the body affect metabolism. Examples of these complex interactions include sleep, reproduction, digestion, glucose metabolism, blood pressure, fluid balance, temperature regulation, and appetite (Table 42.6).

Many endocrine disorders can be discovered by evaluating blood tests for hormone under- or overproduction. Because symptoms of endocrine disorders may be subtle and similar, nurses must maintain diligence in recognizing possible signs of endocrine dysfunction.

Neuromuscular

Neuromuscular conditions arise from complex interactions between the neurological and muscular systems. These disorders can be congenital or acquired later in life. These conditions result from a dysfunction in the innervation of muscles throughout the body. Most neuromuscular disorders are associated with some level of progressive physical impairment. Examples of neuromuscular disorders include MD, amyotrophic lateral sclerosis (ALS), peripheral neuropathy, polymyositis, congenital myasthenia syndrome, and MS.

The commonality in neuromuscular disorders is muscle weakness and physical dysfunction. This can occur peripherally in the limbs, but, as in MD, it can also affect internal organs, causing complications in organ functions such as elimination and breathing. Muscular dystrophy is a progressive genetic disorder that results in the body’s inability to make appropriate proteins for muscles. Neuromuscular disorders can put individuals at risk for complications such as difficulty with running, jumping, and walking; abnormal gait; falls; delayed growth; and learning disabilities (Mayo Clinic, 2022).

Disorders such as ALS affect nerve cells in the brain and spinal cord, causing progressive loss of muscle control, including muscles that control vital life processes such as eating and breathing. Neuromuscular disorders are rarely curable, but many have effective and evolving treatments to improve quality of life and minimize associated disability.

Neurological

Neurological chronic diseases can be classified as strictly neurological or neurodevelopmental. Neurodevelopmental disorders include autism spectrum disorder (ASD), ADHD, or ADD. Neurodevelopmental disorders commonly coexist with mental health disorders such as anxiety and may be addressed and treated by a mental health professional. Some learning disabilities are also considered neurological disorders that require some treatment and accommodation over a person’s lifetime. Some neurological diseases develop over the life span, whereas others arise from injury. Examples of neurological disorders include Huntington disease, epilepsy, spinal cord injuries, headache syndromes, Guillain-Barré syndrome, and restless leg syndrome.

Neurological disorders frequently require prolonged medication treatments. Because these diseases may present slightly differently in each individual, they are notoriously difficult to diagnose and treat. The nurse's role is to maintain awareness of any new neurological symptoms that patients report, particularly symptoms that persist and change over time.

Kidney

Most CKD is acquired and results in a progressive loss of kidney function. Kidney disease typically has an insidious onset with few outward symptoms. If the disease progresses, the patient will begin to develop symptoms, which may include nausea and vomiting, fatigue, sleep disturbance, urinary changes, decreased cognition, muscle cramping, peripheral edema, pruritis (itching), resistant HTN, chest pain, and shortness of breath (CDC, 2022a). Kidney disease is closely tied to other metabolic disorders such as diabetes, HTN, heart disease, and obesity. For example, HTN and diabetes negatively affect the small vasculature in the kidneys, causing damage and progressive loss of function.

In addition, medical treatment and medication for other chronic disorders may put increased stress on the kidney, leading to a progressive decline in kidney function. Nurses must understand that early treatment of associated conditions is the key to preventing the progression of CKD and the need for dialysis.

Respiratory

Respiratory diseases are common chronic conditions. They include disorders of the nasal passages, trachea, and lungs. Chronic respiratory conditions range in severity from mild to life-threatening. Some common respiratory conditions include chronic rhinitis, asthma, COPD, sleep apnea, pulmonary fibrosis, and cystic fibrosis. These disorders cause problems with air exchange, inflammation in the lung and airway passages, and progressive lung remodeling. Some diseases, such as asthma, require long-term management but remain stable or improve during the life span. Others, such as COPD and pulmonary fibrosis, are typically progressive, causing increasing dysfunction and symptoms.

Pulmonary fibrosis may be idiopathic or related to environmental exposures such as silica, coal dust, or asbestos. Idiopathic pulmonary fibrosis develops without a known cause; however, age and smoking history do increase the risk. There is no definitive heredity component in pulmonary fibrosis. Chronic obstructive pulmonary disorder is a progressive lung disorder causing obstructive changes in the lungs. The most significant risk factor for COPD is smoking, followed by occupational exposure, air pollution, and a genetic α-1 antitrypsin deficiency. α-1 Antitrypsin deficiency is a complex disorder in which a person's body does not produce the protein α-1, which blocks enzymatic damage from the neutrophil elastase enzyme, which can cause damage to the lungs.

Cystic fibrosis is a disorder that significantly affects the lungs but also affects other organ systems, including the digestive tract. The inherited disorder is progressive and causes a thickening of mucous secretions within the body that can plug air passages and other internal ducts. Individuals with cystic fibrosis have a shortened life span of between 30 and 50 years (Mayo Clinic, 2021).

Sleep apnea and rhinitis are disorders of the upper airways. Rhinitis causes inflammation and increased mucous production, contributing to chronic cough and impaired air exchange if inflammation restricts air movement. Sleep apnea is a prevalent disorder that directly affects breathing patterns and oxygenation of the body. The primary cause is pharyngeal narrowing and weakened pharynx muscles that cause the pharynx to close during sleep. Increased neck circumference creates increased pressure on the pharynx, causing a repetitive partial collapse. Sleeping on one’s back, smoking, alcohol use, and sedatives can all contribute to sleep apnea. Risk factors for sleep apnea include obesity, male sex, and advancing age. Untreated sleep apnea can cause a host of additional problems in various organ systems, including congestive heart failure, coronary artery disease, HTN, stroke, atrial fibrillation, sudden cardiac death, headaches, daytime fatigue, reduced work productivity, and glaucoma (Blackwell et al., 2019).