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Diagnostic Reasoning Process Case Study

Info: 4200 words (17 pages) Nursing Case Study
Published: 18th May 2020

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Tagged: pneumonia


Diagnostic reasoning process is vital when formulating diagnosis and essential to managing the patient’s medical problem effectively (Pelaccia, Tardif, Triby, & Charlin, 2011). It is critically important as it prevents patient harm and aids in providing quality health care (Benner, Hughes, & Sutphen, 2008). This assignment aims to explore the understanding of the diagnostic reasoning process. A case study will be used to determine how the diagnosis of a patient has been established. The pathophysiology of the diagnosis will be explained. A thorough health history and physical examinations that are associated with diagnosing the medical problem will be described. The diagnostic tests that were done will also be discussed. Lastly, the formulation of the diagnosis will be analyzed, using both the physical examination and diagnostic tests.


Mr Smith (pseudonym) is a 75 year old Samoan patient who was transferred to the rehabilitation ward from the stroke ward. Seven days after his admission to the rehabilitation ward, Mr Smith had presenting complaints of chest pain with worsening cough with sputum production, became febrile and tachypneic. Mr Smith was diagnosed with necrotizing pneumonia after several diagnostic testing were conducted.

Pneumonia is an infection of the lung parenchyma caused by either bacteria, viruses, or fungi (Brown, Edwards, Seaton & Buckley, 2015). According to Brown and colleagues (2015), when the defence mechanisms of the body are overcome by the large number of pathogens, pneumonia is highly likely to occur.

There are numerous ways that organisms that cause pneumonia such as mycoplasma pneumoniae and staphylococcus aureus, can enter the lungs. (Brown et al., 2015). It includes transmission of another infection in the body via blood, inhalation of micro-organisms present in the air, and aspiration of common microorganisms in the oropharynx or nasopharynx (Brown et al., 2015). According to Brown et al., (2015), vascular response happens when most pathogens that cause pneumonia initiate an inflammatory response.

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Activated neutrophils destroy and engulf the infectious organisms and they fill the alveoli which causes a disruption in oxygen transportation (Brown et al., 2015). This results in hypoxia which is a common sign and symptom of pneumonia (Brown et al., 2015). Consolidation is a common characteristic of bacterial pneumonia and this occurs when debris and fluid fill the alveoli (Brown et al., 2015).In addition, the production of mucus is increased, resulting in airflow obstruction that further reduces the exchange of gas (Brown et al., 2015).If there are no complications, the infection would be resolved when the macrophages ingest and process the debris (Brown et al., 2015). This then restores the lung tissue back to normal and normal gas exchange can occur again (Brown et al., 2015).

Necrotizing pneumonia is a severe but uncommon complication of bacterial pneumonia (Tsai & Ku, 2012). It is characterized by liquefaction of consolidated lung parenchyma and necrosis (Marostica & Stein, 2012). The pathogenesis of this uncommon complication is not yet well known, however, several studies have suggested that the infecting pathogen produces toxins that cause an inflammatory response, which then resulted in tissue necrosis (Tsai & Ku, 2012).

The most common signs and symptoms of pneumonia include fever, pleuritic chest pain, tachypnoea, dyspnoea and cough which may be productive or not (Brown et al., 2015). If the cough is productive, sputum may appear yellow, green, or bloody (Brown et al., 2015). Pneumonia caused by viruses may be mistaken as influence at first, with respiratory symptoms developing and/or worsening 12 to 36 hours after onset (Brown et al., 2015). Confusion may also occur which is possibly related to hypoxia (Brown et al., 2015). In some cases with older patients, hypothermia instead of a fever, may be noted (Brown et al., 2015). Other signs and symptoms that are non- specific are fatigue, headache, abdominal pain, diaphoresis and myalgias, (Brown et al., 2015).


The diagnostic reasoning process starts with history taking (Bickley & Szilagyi, 2017). History taking is a significant part of the assessment as it enables the health professionals to develop a better understanding of the problems of patients, thereby allowing them to provide a high-quality and safe care (Fawcett & Rhynas, 2012).

Mr Smith was admitted to the hospital when his daughter found him to be weak on his left side with drooling and facial asymmetry. However, he did not experience loss of consciousness and no seizure nor trauma. Upon his admission, he was diagnosed with right thalamic haemorrhagic stroke secondary to hypertension and decreased cognition. He has no prior history of stroke but has a significant medical history. This includes hypertension, impaired glucose tolerance, hyperlipidaemia, gout, obesity, non-alcoholic fatty liver disease on the basis of metabolic syndrome, peritonsillar abscess and intraoral cellulitis to hard palate, asymptomatic left kidney outlet obstruction. He has no notable cognitive issues prior to hospitalisation. Mr Smith’s daughter reported that he was unwell one week prior and he had a chest infection with cough, body ache and decreased in mobility. He went to see his General Practitioner and was given one week of antibiotics. Mr Smith has completed his dose of antibiotics; however, his cough was not resolved up until his admission to the hospital.

Mr Smith is a current heavy smoker who had no intention of stopping and drinks alcohol excessively. His daughter reported that he smokes 15 times self rolled cigarettes per day and drinks 8 cans of beer per day. He lives in a rented accommodation along with his daughters and son in law who give him great support. Mr Smith’s family medical history is unknown. His medications prior to his hospitalisation include cilazapril, felodipine, allopurinol, NRT patches, and docusate and senna.

As mentioned earlier, Mr Smith is a 75 year old man who was diagnosed with necrotizing pneumonia whilst admitted to the hospital. According to Sjögren, Nilsson, Forsell, Johansson, & Hoogstraate (2008), in the elderly population, pneumonia is a common infection. Having a stroke increases Mr Smith’s risk of developing pneumonia and this is evident in the study conducted by Finlayson et al., in 2011. Finlayson and colleagues (2011) stated that pneumonia is the most common post-stroke medical complication and thus, increases hospital length of stay. Mr Smith is a current smoker and has reported of having no intention of stopping despite giving him an education. Due to its detrimental effects on the respiratory defence mechanisms of the body, smoking greatly increases the risk of development of respiratory infections such as pneumonia (Bilello, 2005). Mr Smith also has a high consumption of alcohol; and several studies (De Roux et al., 2006; Samokhvalov, Irving & Rehm, 2010) have found that alcohol consumption of alcohol also increases the risk of developing pneumonia. This is due to its effect on both pulmonary and systemic immunity of the body, and therefore, puts patients at a higher risk of acquiring respiratory infections such as pneumonia (De Roux, 2006).

Clinical examination

A thorough physical examination is critical in providing safe and high-quality of care (Talley & O’Connor, 2013). Physical assessment is the methodical collection of objective data by inspection, palpation, percussion, and auscultation (Fennessey & Wittmann‐Price, 2011). The development of the nurse-patient relationship is also vital in the assessment. A good rapport between healthcare professionals and patients is essential as the patients tend to cooperate more, thereby increasing the value evaluation data (Fennessey & Wittmann-Price, 2011).

Upon a general survey, Mr was awake, alert and responsive. He was in a pleasant mood. He had good eye contact but due to shortness of breath, was unable to speak long sentences. He has apparent left sided weakness due to him having a right thalamic haemorrhagic stroke. Mr Smith appeared to be in respiratory distress apparent by his laboured breathing as evident by his intercostal muscle retraction when breathing whilst in a semi-fowler’s position in his bed. He appeared to be well kempt and was wearing a hospital gown. He has a tattoo that covers his whole left arm. Mr Smith’s height was 168cm and weight of 87.5kg whilst admitted in the hospital. This results in a Body Mass Index (BMI) of 31.0 kg/m2 and according to the BMI scale, Mr Smith would considered as obese. (Brown et al., 2015).  According to Kirk et al., (2009), BMI is one of the key measures of patient’s health and well-being. Mr Smith is considered obese and Kornum et al. (2010) reported that an increased risk of pneumonia among the male population is associated with obesity.

According to Bickley & Szilagyi (2017), the vital signs give crucial initial information about the patient and this influences the direction of managing the patient’s condition. Mr Smith’s vital signs were temperature of 38.2C, respiratory rate of 24 breaths per minute, heart rate of 108 beats per minute, blood pressure of 112/68mmHg, and oxygen saturation of 94%. This gives him an Early Warning Score (EWS) of 5. He also reported of intermittent dull chest pain when he’s coughing and scored it as 5/10.

On inspection, Mr Smith was well-hydrated with no bruises visible on the skin. His sclera were white with no signs of jaundice. His conjunctivae were red, thus, showing no signs of anaemia. His lips were well-perfused and had moist mouth and tongue with no signs of dehydration. Mr Smith had no signs of clubbing of fingernails and no signs of oedema in his extremities. His chest appeared symmetrical with no visible bruises, redness or lumps. It was, however, noted that Mr Smith was tachypneic as evident by the rapid movement of his chest. Upon palpation of his chest, it was warm to touch and no pain nor tenderness noted on both anterior and posterior side, hence, no abnormal findings. On percussion, Mr Smith’s anterior lower right lung had a dull sound. According to Eisenstadt (2010), dullness to percussion is one of the clinical features of pneumonia. Bibasilar crackles were audible on the right lower anterior lung upon auscultation. Bohadana, Izbicki & Kraman (2014) reported that crackles are commonly heard in patients with pneumonia

Diagnostic tests

Diagnostic tests are utilized to gain supplementary information about the patient and these tests may aid in confirming diagnosis when used in addition to a thorough health history taking and physical assessments (Fischbach & Dunning, 2009). According to Brown et al., (2015), the common diagnostic tests for pneumonia include blood culture, sputum culture, Gram stain of sputum and chest X- ray.

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A sputum specimen and Gram stain are also valuable as they aid in identifying the infecting organism (Brown et al., 2015). They, therefore, help in managing and planning the right treatment for the patient (Brown et al., 2015). In Mr Smith’s case, his sputum specimen revealed small numbers of Gram positive bacilli, a moderate number of Gram positive cocci, and a large number of Gram negative bacilli. A study conducted by Anevlavis and colleagues in 2009 found that a Gram stain of sputum is a reliable diagnostic test for early diagnosis of pneumonia. This aids in identifying the infecting organism and, therefore, enables to plan an appropriate and correct treatment for the patient (Anevlavis et al., 2009).

One of the most common diagnostic tests used in identifying pneumonia is blood cultures (Kurowski et al., (2015). Elevated levels of white blood cells in blood culture indicate an infection (Ahmed, Marrie, & Huang, 2006). The findings from Mr Smith’s blood test revealed an elevated number of white blood cells, thereby suggesting an infection.

A chest X-ray is essential in the diagnosis of pneumonia. Brown et al., (2015) support this statement as they reported that chest X-ray shows pleural effusions and the distinctive pattern characteristic of the infecting organism in the lungs. Mr Smith had undergone a chest X-ray which revealed diffusely prominent lung markings, suggesting fluid overload, and therefore, causing consolidation. And as mentioned earlier, consolidation is one of the common characteristics of pneumonia (Brown et al., 2015).

When diagnosing pneumonia, it is vital to take a chest X-ray (Brown et al., 2015). The severity of the illness may be identified through a chest X-ray and find out the aetiology of pneumonia as pleural effusions and consolidation often suggest a bacterial aetiology (Watkins & Lemonovich, 2011).

Cherian et al., (2005) stated that chest X-ray is commonly accepted as the gold standard when confirming the diagnosis of pneumonia. Conversely, Staub, Biscaro, Kaszubowski & Maurici (2019) suggested that it should not be the gold standard as chest X-ray has insignificant sensitivity to detect acute heart failure from common respiratory illnesses such as pulmonary oedema and pneumonia. Several studies have shown that chest ultrasound has an important role in diagnosing pneumonia and provides more accurate information than chest X-ray (Khalil, ELMaraghy & Yousef, 2015; Nafae, Eman, Mohamad, El-Ghamry & Ragheb, 2013; Staub, Biscaro, Kaszubowski & Maurici, 2019; )

Formulation of diagnosis

There are several differential diagnoses that present similar clinical presentation to pneumonia. Hence, it is crucial to obtain a comprehensive health history, thorough physical examinations and appropriate diagnostic testing to formulate and confirm a diagnosis (Fischbach & Dunning, 2009).

In Mr Smith’s case, he has a high risk of developing pneumonia and this is due to his medical history of having a right thalamic haemorrhagic stroke and being of old age.

Eisenstadt (2010) reported pneumonia has a high prevalence among older adults and being a stroke patient increases the risk of aspiration. Mr Smith also smokes cigarettes and drinks large amounts of alcohol up until his hospital admission. Smoking actively increases the risk of developing pneumonia (Bello et al., 2014). In addition, excessive alcohol consumption is another risk factor for pneumonia (Samokhvalov, Irving & Rehm, 2010). Mr Smith is also considered obese and this again increases his chance of developing pneumonia as there is a significant association between obesity and pneumonia (Serrano, Khuder & Fath, 2010).

Mr Smith’s clinical presentation of having a cough, sputum production, febrile, lowered oxygen saturation and being short of breath were consistent with signs and symptoms of pneumonia. According to Mody, Sun & Bradley (2006), fever, new or increased cough, hypoxia, increase or difficulty in breathing, and sputum production are the signs and symptoms associated with pneumonia. Nevertheless, other studies have found that other respiratory tract infections such as influenza, acute bronchitis, and pulmonary oedema, can also exhibit similar signs and symptoms, and further investigations are therefore needed to confirm an accurate diagnosis (Eisenstadt, 2010; Son, Shin & Ryu, 2017).

The physical assessment performed on Mr Smith provided further evidence. There was dullness on percussion on his right lower anterior lung and Thiadens (2011) stated that dullness to percussion increases the likelihood of pneumonia. Furthermore, upon auscultation, bibasilar crackles were evident on Mr Smith’s lower right anterior lung. Crackles sounds also increases the probability of patients having pneumonia (Thiadens, 2011). There is no definite physical diagnostic findings that would immediately confirm pneumonia and Thiadens (2011) reiterates this in his study and reported that in order to confirm the diagnosis of pneumonia, all diagnostics need to be combined.

Further diagnostic testing was conducted to confirm the diagnosis. A chest X-ray was done and Mr Smith’s result displayed consolidation in his lung and this is a common characteristic of pneumonia (Brown et al., 2015). A sputum specimen was taken and sent to the laboratory. Mr Smith’s specimen showed a large number of Gram negative bacilli. Gram negative bacilli is one of the predominant pathogens that causes pneumonia and they are very common in health care settings (Falguera et al., 2009). A blood culture was gotten and the results displayed increased levels of white blood cells. Furthermore, Mr Smith was febrile with a temperature of 38.28C and these findings indicate an infection. All of these findings have been consistent with the diagnosis of pneumonia.

Obtaining the health history, performing the physical assessments and undertaking the appropriate diagnostic tests have all led to and verified Mr. Smith’s diagnosis of necrotizing pneumonia.


The diagnostic reasoning process comprises of taking comprehensive health history, performing thorough clinical examinations, and conducting appropriate diagnostic testing. These will then help healthcare professionals to formulate an accurate clinical diagnosis of the patient. In Mr Smith’s case, his diagnosis of pneumonia was able to confirm through his past medical history, current clinical presentation and diagnostic tests undertaken. Firstly, Mr Smith was already at high risk of developing pneumonia due to his medical background; being an elderly man who has had a stroke. Furthermore, he is a current smoker and drinks alcohol excessively. His clinical presentation indicated pneumonia and the results of his diagnostic tests have been consistent with the diagnosis of pneumonia. Establishing an accurate diagnosis enables healthcare professionals to implement the right treatment for the patient, hence, improving their quality of life.


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Pneumonia is an inflammatory condition of the lung which can result from infection with particular bacteria, viruses or other organisms. It is characterised by lung parenchyma inflammation and the filling of the air-filled sacs of the lung (alveoli) with fluid resulting in a decrease in elasticity which leads to inefficient gas exchange.

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