Lenz & Pugh Theory of Unpleasant Symptoms

Description of the Theory

The Theory of Unpleasant Symptoms, abbreviated as TOUS, is an example of a middle range nursing theory developed and intended for use and application by nurses. Middle range nursing theories are sufficiently concrete to link practice and research. As Chen & Tseng (2005) points out, the first concept paper of the TOUS appeared during 1995 and was later revised during 1997. TOUS argues for the presence of several symptoms that interact and may be multiplicative. This implies that managing one symptom is likely to play a pivotal role in the managing other symptoms. TOUS was developed from two concepts regarding the symptom models for fatigue and dyspnea. Dr. Linda Pugh was working on the symptom model for fatigue whereas Dr. Audrey Gift was working on the symptom model for dyspnea, after which they realized several similarities between their symptom models. In 1997, Lenz partnered with Pugh to publish their integrated concepts under the Theory of Unpleasant Symptoms, which was put forward as a means of integrating the existing information regarding numerous disease manifestations. TOUS was as a result of a collaborative initiative of four nurses (Linda Pugh, Elizabeth Lenz, Renee Milligan, and Audrey Gift) during 1995 and later improved during 1997. TOUS places emphasis on the symptom experience having several symptoms occurring concurrently, instead of looking at a single symptom in isolation (Lenz, Pugh, Milligan, Gift, & Suppe, 1997). TOUS draws on the presumption that there are adequate commonalities between symptoms. As a result, TOUS deals with the concurrent occurrence of at least a single symptom that may possibly have a multiplicative impact on the symptom performance, distress and experience.

Lenz et al (1997) points out that TOUS has three main components, which include the symptoms that the patient experiences, the influencing factors that cause or have an effect on attributes of the symptom experience, and the outcomes associated with the symptom experience. According to the TOUS, these components interact with one another and influence each other. In addition, multiple symptoms resulting from a single cause can be viewed either alone or in combination. Situational, psychological and physical factors are precursor variables that have an influence on the symptom experience. Performance is the outcome of symptoms, and entails the cognitive and functional activities.

Symptoms are the focal point of TOUS and are defined as the “perceived pointers of alterations in the normal body functioning that a patient experiences” (Fox & Lyon, 2007). Symptoms can be analyzed either in combination or isolation; however, in most cases, patients experience multiple symptoms. Symptoms are also considered multiplicative and not addictive. In the initial TOUS model, only one symptom is illustrated, implying that the model is purely linear. Nevertheless, the updated TOUS model suggests that symptoms can either occur in isolation or concurrently. In addition, the updated TOUS model points out more interaction between the core components of the model (outcomes, influencing factors and symptoms). Several symptoms can be experienced concurrently because of one event. A single symptom is perceived to comprise of a multidimensional experience that can be measured and conceptualized independently or together with other observed symptoms. The dimensions of symptoms include intensity, timing, distress and quality. Intensity is the amount, strength or severity of the symptom that the patient is experiencing. The time component of symptoms entails the frequency of the symptom’s occurrence, the time duration that the symptom persists, or a combination of both duration and frequency. The distress component of symptoms is the degree to which a patient is bothered by or reacts to the symptom(s). The quality component of a symptom refers to the descriptors utilized in characterizing the symptom (Motl & McAuley, 2009).

Regarding the influencing factors, TOUS model proposes three groups of factors, which include environmental/situational, psychological and physiological factors that have an influence on a patient’s predisposition to an unpleasant symptom experiences or how the unpleasant symptom is manifested. Physiological factors are mostly linked to symptoms that cause variations in the normal body functioning and are use in characterizing the severity of the ailment such as abnormal laboratory results and comorbidities. Psychological factors entail a patient’s mood and mental state (depression), the level of knowledge and uncertainty regarding the symptoms including their likely meanings (patient’s perception of the symptom experience), and the patient’s affective response to the symptom or illness. The environmental/situational factors entail the components of the physical and social environment that are likely to have an impact on the patient’s experience resulting from the symptom. With respect to the relationships between the influential factors, in the original TOUS model, influential factors are perceived to exert a unidirectional effect on the experience resulting from the symptom. In addition, there are no interrelationships between the influential factors. However, in the updated TOUS model, improvements have been incorporated to ensure there is an accurate depiction of the relationships between the influential factors. It is evident in the updated TOUS model that the influential factors are interrelated. In addition, situational, psychological and physiological factors tend to interact with each other with respect to symptoms.

The outcome of the symptom experience is the last element of TOUS, wherein performance is perceived to comprise of functional performance, physical performance and cognitive functioning. Functional performance broadly comprises of physical activities, daily living activities, social interaction and activities and role performance in work related activities. Cognitive performance entails problem solving, thinking and concentrating. TOUS model suggests that performance depends on the nature and level of the experience associated with the symptom.

With respect to the relationships between the core components, the updated TOUS model has a more accurate illustration of the relationships existing between the symptom experiences, outcomes, and influential factors. First, the updated TOUS model gives a picture of reciprocal relationships between the core concepts. Second, TOUS also points out that the experience associated with symptoms are likely to change depending on the patient’s situational, psychological and physiological status. In addition, the updated TOUS model suggests the outcomes (performance) of symptoms are reciprocally related to the symptom experience. It is also hypothesized that reduced performance levels exert a negative feedback loop on the influential factors. Furthermore, influential factors interact with the symptom experience, which is likely to mediating effect on the relationship between outcomes and influential factors (Motl & McAuley, 2009).

Published Studies that have tested or used TOUS

Chen, M., & Tseng, H. (2005). dentification and Verification of Symptom Clusters in Cancer Patients. Journal of Supportive Oncology , 6 (Suppl 4), 28-9.

The study by Chen & Tseng (2005) had the primary objective of identifying cancer-related symptom clusters as well as exploring the conceptual meanings associated with the symptom clusters identified. The study was guided by the theory of unpleasant symptoms on assumption that several symptoms can be manifested concurrently and that they are interrelated. The study used 151 having different cancer diagnosis. The findings reported by Chen & Tseng (2005) indicated that dry mouth was the most widespread symptom, which was followed by fatigue and then lack of appetite. Breath shortness, numbness and vomiting were the least dominant symptoms. Regarding severity, fatigue was reported to the most severe symptom, which was followed by distress and dry mouth whereas breath shortness, numbness and remembrance problems were the least severe symptoms. In addition, about 70% of the participants stated that their symptoms disrupted life enjoyment, work, mood, or general activity; 47% stated that symptoms disrupted their relationships with other people; and 59% stated that symptoms interfered with their walking ability. Working was the most interfered daily activity function whereas relationships with other people were the least interfered. Regarding the symptom clusters, Chen & Tseng (2005) developed a symptom cluster comprising of comprising of pain-related factors (drowsiness, lack of appetite, sleep disturbance, fatigue and pain); chemotherapy-related factors (vomiting and nausea); and emotion-related factor (sad and distress). It is evident from the findings that there is a fit between the findings reported regarding the symptom clusters in Cancer patients and the theory of unpleasant symptoms. TOUS functioned extremely well as regards the identifying of symptom clusters, which may play a pivotal role in having an understanding of how symptoms interrelate. In most cases, symptoms are treated individually; however, the findings reported that patients may exhibit multiple symptoms. As a result, clustering the symptoms together could help reveal a common cause, which would have an impact on how treatment is administered. Consistent with the TOUS model, the findings by Chen & Tseng (2005) emphasizes on the significance of clustering symptoms, which may help in understanding the mechanisms that tend to aggregate the symptoms; this helps in managing the patient’s underlying issues more effectively when compared to treating symptoms individually.

Fox, S., & Lyon, D. (2007). Symptom Clusters and Quality of Life in Survivors of Ovarian Cancer. Cancer Nursing , 30 (5), 354-361.

Fox & Lyon (2007) had the main objective of describing a symptom cluster for women having ovarian cancer and how it relates to the quality of life for the patients. The concept of symptom cluster is relatively new, with the working definition suggesting that symptom clusters comprise of at least 2-3 illustrated symptoms. For instance, fatigue and depression, or fatigue, sleep disturbance and pain make up a symptom cluster if a significant correlation exists between them. In the TOUS model, it is suggested that symptom clusters affect patient outcomes such as the quality of life; this proposition guided the study by Fox & Lyon (2007). The findings pointed out that all the participants stated that they have a little bit of all the three symptoms taken into consideration (pain, fatigue and depression). Regarding the severity of symptoms, depression was the most severe symptom followed by pain and fatigue. Basing on the current working definition for a “symptom cluster”, the findings reported by Fox & Lyon (2007) with respect to fatigue and depression confirmed the existence of a symptom cluster, which comprised of fatigue and depression. Overall, the TOUS model was helpful in describing the likely symptom interrelationships as well as the development of symptom clusters for patients suffering from ovarian cancer. The study pointed out that one symptom cluster comprising of fatigue and depression exists for ovarian cancer, which accounted for a significant variance regarding the quality of life for a person having ovarian cancer. Consistent with the TOUS model, the findings by Fox & Lyon (2009) emphasize on the significance of clustering symptoms, which may help in understanding the mechanisms that tend to aggregate the symptoms; this helps in managing the patient’s underlying issues more effectively when compared to treating symptoms individually.

Motl, R., & McAuley, E. (2009). Symptom Cluster as a Predictor of Physical Activity in Multiple Sclerosis:Preliminary Evidence. Journal of Pain and Symptom Management , 38 (2), 270-280.

The study by Motl & McAuley (2009) had the primary objective of examining the symptom cluster of depression, pain and fatigue, and its indirect and direct prediction role in physical activity behavior among patients having multiple sclerosis. The theory of unpleasant symptoms served as a conceptual framework that guided the study, which involved 292 patients with multiple sclerosis. The findings reported that pain, depression and fatigue was a symptom cluster of multiple sclerosis and that this symptom cluster has a strong but negative predictive relationship to physical activity behavior among patients with multiple sclerosis. The findings also pointed out that functional limitations with the exception of self-efficacy, explained the predictive association existing between physical activity behavior and symptom cluster. It is evident from the findings that there was a fit between the TOUS model and the findings reported by the study, which implies that the TOUS model functioned extremely well in this study. The findings are consistent with the propositions of the TOUS model, which emphasize on the significance of taking into account symptom clusters as a vital link to physical activity behavior among patients with multiple sclerosis. In other words, clustering symptoms may help in understanding the mechanisms that tend to aggregate the symptoms; this helps in managing the patient’s underlying issues more effectively when compared to treating symptoms individually.

Clinical Case That Is Appropriate for Application of the Theory of Unpleasant Symptoms – Reducing the fear, anxiety and pain of Immunizations

This clinical case is a community-level case for the application of the theory of unpleasant symptoms. The pain associated with childhood immunizations results in distress and anxiety to children and their parents as well as the healthcare personnel charged with the responsibility of administering immunizations. Some children tend to develop the fear of needles during adulthood, which stems from the painful immunization experiences. As a result, they are likely to refrain from seeking healthcare services involving the use of needles. In addition, some parents fail to take their children for immunization because of the pain that the child have to endure during the process. This trend light result a public health crisis in situations involving the outbreaks of vaccine preventable diseases. In the United States, it is estimated that 10 percent of the population fear needle procedures (needle phobia); which can be linked back to childhood experiences regarding needle procedures such as immunization. As Fox & Lyon, (2007) explains, needle phobic behaviors can result in people avoiding seeking medical care, blood donations, dental procedures, and results in poor immunization compliance. In addition, the fear of needles among patients may also instill fear and anxiety among nurses and doctors. In addition, some parents are consumed with duplicity and fear for allowing their children to experience a painful medical procedure. The outcome of this is that parents might delay the immunizations for their children. Similarly, physicians have conflicting views regarding the pain experienced during immunizations as well as during the administration of several injections at a single visit. Physicians are also likely to undergo stress, especially when compelled to frequently administer injections. This implies that the anxiety and fear of needles is sufficiently severe to warrant an intervention to address the problem. This community-level case is an appropriate situation to apply the theory of unpleasant symptoms to develop evidence-based interventions that can help physicians to find a devise methods of reducing pain, anxiety and fear when involved in the administration of immunizations and when performing needle medical procedures in infants and children, adolescents as well as adult patients.

Applying TOUS to the Clinical Problem Above

TOUS can be utilized a tool to analyze the symptoms associated with pain, fear and anxiety during needle procedures and factors that tend to have an impact on these symptoms. There is the need to analyze the situational, physiological and psychological factors that can either increase or decrease the impacts of pain reception (Berberich & Landman, 2009). The physiological factors relate to the actual entry of the needle into the body and injection of the medication using the needle. Psychological factors relate to the anxiety and fear instilled by the needle procedures, which are as a result of past experiences including the psychological damage that could be impose by the current procedure. Situational factors relate to the physical and social environment, wherein social support ought to be considered. By drawing upon the TOUS model, nursing interventions have the goal of reducing the distress, timing, quality and intensity of symptoms, which in this case are anxiety, fear and pain experienced during needle procedures. All of these can be quantified. For instance, time aspect can be quantified by determining the duration of pain after the injection. A literature review points out several approaches to reduce fear, anxiety and pain associated with needle procedures. The nursing interventions will be based on the TOUS factors (physiological, psychological and situational).

Interventions to Tackle Physiological Factors

It is has been established that the length of the need has an impact of the pain experienced; longer needles are more likely to reduce the pain perceived. Current recommendations are 0.625 inch needles for infants and newborns, 1 inch needles to be used for toddlers and adolescents, and 1.5 inch needles to be used for adults. The recommended needle gauge has been established to be 23-25. In addition, rapid injection has been established to lessen the pain experienced. In addition, it has also been found that when administering several injections, the pain scores experienced during the first needle is significantly lower than the pain scores experienced during the last injection. Lastly, using the Z-track administration technique lessens pain by reducing leakage and irritation of the medication in the needle into the subcutaneous tissues (Abdel Razek & El-Dein, 2009). Z-tracking technique involves pull the skin about 2-3 centimeters aside before injection, followed by releasing the skin immediately after removing the needle, which results in a disjointed pathway that locks down the medication in the intended place.

Interventions to Tackle Psychological Factors

Patients who are more anxious towards needle procedures are tend to experience more pain and fear. The first intervention to address psychological factors involves the use of distraction techniques, which functions by competing for attention the patient requires to process to the evaluative, emotional and physical aspects of pain reception. Some of the distraction techniques that have been proven to be effective include skin-to-skin contact and suckling; these have been proved to be comforting to infants. Breast feeding is also a distraction technique applicable to infants to reduce discomfort and pain during needle procedures. Another effective distraction technique for children is the cough trick, whereby the patient provides a warm up cough, which is followed by a second cough coinciding with the needle stick. Children can also be provided with toys as a diversion technique; this has been proved to reduce momentarily pain experience associated with needle procedures (Ahmed, Ahmed, Imran, & Ahmed, 2004).

Interventions to Tackle Situational Factors

During immunization and medical procedures involving needles injection, emotional and social support have been considered as playing a pivotal role in reducing the unpleasant symptoms experiences associated with injections. One of the nursing interventions regarding the situational factors is that immunization and needle procedures should be done in a child friendly and calm environment (for infants and children) (Ahmed, Ahmed, Imran, & Ahmed, 2004). This enhances patient comfort through the manipulation of the environment via improving ambience and reducing noise. Children can be allowed to watch cartons when the needle is being injected; this increases their coping behaviors and reduces pain perception.


Abdel Razek, A., & El-Dein, N. A. (2009). Effect of breast-feeding on pain relief during infant immunization injections. International Journal of Nursing Practice , 99.

Ahmed, O., Ahmed, A., Imran, D., & Ahmed, S. (2004). Coughing to distraction. British Journal of Plastic Surgery , 57 (4), 376.

Berberich, F., & Landman, Z. (2009). Reducing immunization discomfort in 4- to 6- year-old children: A randomized clinical trial. Pediatrics , 124 (2).

Chen, M., & Tseng, H. (2005). dentification and Verification of Symptom Clusters in Cancer Patients. Journal of Supportive Oncology , 6 (Suppl 4), 28-9.

Fox, S., & Lyon, D. (2007). Symptom Clusters and Quality of Life in Survivors of Ovarian Cancer. Cancer Nursing , 30 (5), 354-361.

Lenz, E., Pugh, L., Milligan, R., Gift, A., & Suppe, F. (1997). The Middle-Range Theory of Unpleasant Symptoms: An Update. Advances in Nursing Science (19), 14-27.

Motl, R., & McAuley, E. (2009). Symptom Cluster as a Predictor of Physical Activity in Multiple Sclerosis:Preliminar y Evidence. Journal of Pain and Symptom Management , 38 (2), 270-280.

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