This article examines a case study from clinical practice from the perspective of a final-year trainee advanced clinical practitioner (ACP) working within the hospital out-of-hours team in an acute hospital. To maintain privacy and patient confidentiality in accordance with the Nursing and Midwifery Council (2018)Code, the patient will be given the pseudonym James.
James was a 38-year-old man with a past medical history of recreational intravenous drug use of approximately 13 years, asthma and a previous deep vein thrombosis (DVT). James had been prescribed an anticoagulant, oral apixaban 2.5 mg twice daily, to prevent the re-occurrence of the DVT; however, he admitted that his concordance with self-administering this was often poor. James had been admitted under general medicine with an infected groin abscess, caused by injecting into the femoral veins within the groin, and was commenced on a 6-week course of the intravenous antibiotic, benzyl-penicillin, via a central venous access device (CVAD) as his peripheral veins were inaccessible. This treatment regimen had been advised by the microbiologist, following discussions with the parent team on admission.
James had been admitted during the COVID-19 global pandemic and enormous strain had been placed on hospitals and their capacity levels (McCabe et al, 2020). Orthopaedic, surgical, and other specialty wards were required to admit medical patients to assist with capacity and patient flow. Although under the care of general medicine, James had been admitted to an orthopaedic ward, which was now predominantly occupied by medical outliers. Stylianou et al (2017) found that medical outliers had double the length of stay of patients admitted to medical wards. This could be attributed to a higher risk of contracting hospital-acquired infections, delays in medical re-assessments, lack of continuity of care and delays in tests or investigations being undertaken (La Regina et al, 2019).
Epidemiology
It is estimated that there are over 15.6 million intravenous drug users worldwide, although it is acknowledged that this may be a gross underestimation due to the illegality and stigma associated with the practice (Jain et al, 2021). Mortality in people who inject drugs is approximately 22 times higher than in the population of a similar age who do not inject drugs recreationally (Lavender and McCarron, 2013).
The groin being used as a site for injection is common due to its accessibility, limited choice of other peripheral veins, or as a way to hide the evidence of recreational intravenous drug use (Cornford et al, 2019). A quantitative study conducted by Hope et al (2015) surveyed intravenous drug users in three urban areas of England and found that 53% of respondents had injected into the groin, and three-quarters of those admitted using the groin as their first choice. Repeated use of the same site, the type of needles, syringes and solutions used in addition to poor hygiene are all risk factors for developing groin abscesses, with soft tissue and skin infections particularly in the groin being the predominant cause for hospital admissions in those who inject drugs (Hacking and West, 2009).
Groin abscesses
Groin abscesses increase the risk of limb- and life-threatening complications (Ameh et al, 2020). Coull and Sharp (2018) pointed out that injecting into the femoral vein contributes to the risk of lower limb vulnerability, and inadequate healing of wounds to the limb. It is understood that approximately 28% of people who inject drugs develop an injection site infection (Lavender and McCarron, 2013). In addition to groin abscesses, there is an increased risk of sepsis and in some cases developing necrotising fasciitis, a rare but rapidly spreading infection of the fascia with a 30% mortality rate (Centers for Disease Control and Prevention, 2022).
People who inject drugs are also at risk of developing chronic venous insufficiency, which can lead to lower limb ischaemia, chronic venous leg ulcers, peripheral oedema and varicose eczema, all of which place an additional burden on healthcare systems (Doran et al, 2022). Coull et al (2014) undertook a study in Scotland focusing on intravenous drug users under the age of 44, and found that 15% of the 200 participants had developed leg ulcerations, and an alarming 60% reported injection-related skin problems, including abscesses.
There is also increased risk of developing infective endocarditis, due to the endothelial damage caused by injected particulates, which can cause subsequent infection as a result of the high bacterial loads involved with recreational intravenous drug use (Lavender and McCarron, 2013).
Patient clinical assessment
During a night shift, the trainee ACP was asked to review an electrocardiograph (ECG) that the nursing staff had requested be undertaken on James, as his observations showed a tachycardia of 132 beats per minute. The trainee ACP interpreted the ECG as sinus tachycardia, characterised as a heart rate over 100 beats per minute and typically related to a secondary underlying condition that should prompt the clinician to investigate the primary cause (Burns and Buttner, 2021)
The observation chart showed increased respirations of 26 breaths per minute, an increasing heart rate of 130 beats per minute and an increasing temperature of 39.1 °C, progressing from earlier that afternoon. Blood pressure and oxygen saturations were within normal limits, with no new oxygen requirement.
Working within the hospital out-of-hours service is a unique and challenging environment, as clinicians are called on to review patients across many specialties, most of whom have treatment plans or investigations already in place from their parent team. Although it is important to understand the patient journey up to the point of being reviewed out of hours, clinicians must be wary of being exposed to bias, particularly diagnostic momentum, and be able to provide an independent assessment of the patient (O'Sullivan and Schofield, 2018). After briefly reviewing the notes to understand the reason for initial admission and current treatment plan, the trainee ACP opted to assess the patient at this point and gain a history and examination before reviewing the medical notes further.
On assessment, the patient disclosed experiencing pleuritic-sounding chest pain, characterised by sharp, stabbing pains across the chest on inhalation and exhalation (Reamy et al, 2017). James also reported he had been using his salbutamol inhalers more frequently than normal due to feeling increasingly breathless over the past 2 days. He reported no increased pain, swelling, redness or exudate from the groin abscess.
Physical examination further confirmed the tachycardia, regular in rhythm, and normal heart sounds, although it is acknowledged that murmurs can be difficult to auscultate (Alam et al, 2010). Auscultation of the lungs revealed reduced air entry and crackles to the left base, there was no wheeze present. The chest pain was not reproducible on palpation, but was evident on deep inspiration, localised to the left anterior chest wall. The patient reported having an intermittent dry cough and it was difficult to establish if this was a new symptom or not. There were no urinary symptoms, and the patient denied any abdominal pain. There was no pedal oedema, and bilateral calves were soft, non-tender and equal in size and shape.
Pyrexia and medicines management
The trainee ACP asked the patient when he last took paracetamol, as he still felt warm, and appeared flushed. James reported that he had not been given any that day but had some in a medicine pot from the day before that he had not taken. James reported that he had not requested any paracetamol as he did not believe it had any analgesic effect on him. The trainee ACP used this opportunity to explain that, in this case, paracetamol would be beneficial as an anti-pyrexial agent (Zentiva, 2023) and encouraged the patient to take the paracetamol. The mechanism of paracetamol as an antipyretic is not fully understood but is believed to be attributed to the action on the hypothalamic heat-regulating centre, which in turn triggers peripheral vasodilation, and therefore increased blood flow, heat loss and sweating (Zentiva, 2023).
The trainee ACP felt it was imperative to investigate concerns regarding medicines management with the nursing staff and felt there was a duty to escalate these concerns to the nurse in charge. The patient had medication in his room that had been given to him the day before and had not taken it, leading to inaccurate medical records as this medication had been documented as administered. In addition to this, the patient had a developing fever throughout the evening, which had not been addressed or managed appropriately. Furthermore, the identified tachycardia had not been linked to the rising pyrexia. It was important to ensure that James was being offered timely and effective care. As a person who injects drugs he fell into a patient group that is known to be prone to discrimination and prejudice and therefore at risk of sub-optimal treatment and care (Jain et al, 2021). ‘Preparedness to constructively challenge others’ and clinically acting as an advocate are fundamental for an ACP with standards as such being outlined in the multi-professional framework (Health Education England (HEE), 2017).
The relationship between pyrexia and tachycardia can be defined using the Liebermeister rule, dating back to 1868, where it was determined that for every degree centigrade/Celsius increase in body temperature, the heart rate increases by eight beats per minute (Cadogan, 2020).
Investigations
Blood samples for culture were taken by the trainee ACP through the CVAD line to rule out the CVAD as a source of infection, which is recommended in the case of patients who are systemically unwell, or have pyrexia and was set out in local trust guidelines. A repeat wound swab from the groin abscess had been taken earlier in the day, therefore did not require repeating at this time.
A comprehensive review of the medical notes showed that increasing inflammatory markers in the patient's blood samples had been noted by the parent team earlier that day, and following a discussion with the microbiologist, the parent team was advised to continue the current antibiotic regimen in the absence of additional sources of infection. The trainee ACP considered whether to escalate antibiotics at this time but decided to implement further investigations and to await the results before considering amending the treatment plan.
In addition to the blood cultures, a chest radiograph was requested to rule out the presence of infection or lung effusion considering the findings from the assessment and examination. A repeat swab test for COVID-19 was also requested, as due to the current pandemic and local guidelines at the time, fever and a history of increasing breathlessness warranted a repeat swab ahead of the planned asymptomatic monitoring.
Among the current differential diagnoses of worsening of current groin abscess infection, a potential new source of infection, likely of chest origin, or a potential COVID-19 infection, the trainee ACP also considered the possibility of a pulmonary embolism.
Although James was already prescribed an anticoagulant for previous DVTs, he remained at risk of developing further DVTs and pulmonary embolisms due to his intravenous drug use, therefore it was worth considering as a possible differential diagnosis if James' tachycardia persisted once his temperature was managed. Compliance with medication should be investigated in all patients as part of any medication review, and close monitoring of patients in hospital is vital to ensure compliance with essential medication such as antibiotics. It is well documented that there is a higher incidence of DVT in people who inject drugs, however, recreational intravenous drug use is not included in the Wells criteria, a commonly used risk stratification tool for screening for DVT (Jain et al, 2021). Therefore, there is a lack of screening tools for intravenous drug users, which can lead to missed diagnosis and disparity across patient groups.
ACPs are required to be accountable for their actions and omissions, therefore, the trainee ACP ensured they documented a clear rationale for the decision to await further investigations and to observe the effect managing the pyrexia had on the patient (HEE, 2017). Ensuring that clear and concise plans are made when seeing patients in the out-of-hours setting enables the nursing teams to monitor patients effectively and be able to identify signs and symptoms to observe for to ensure re-escalation to the medical team in a timely manner (Mathioudakis et al, 2016).
The nursing staff were asked to closely monitor the patient overnight, and to re-refer the patient if there was a further spike in temperature, which would indicate there might be a requirement to escalate the choice of antibiotic therapy, after re-discussing with the on-call microbiologist. The nursing staff were also asked to monitor the heart rate, as if it did not settle with a resolving temperature, considerations must be made whether to investigate for a suspected pulmonary embolism.
On reflection, the trainee ACP acknowledged that during this encounter they did not discuss James' case with a senior doctor, as they felt confident with decisions made, the management plan and the safety-netting advice given to both the patient and the nursing team. This shows that the trainee ACP was consciously aware of their limitations but also appreciating their developing level of confidence in decision making.
Working as part of the hospital out-of-hours team often means there is little opportunity for continuity with patients, and it can be challenging to follow up on decisions made or investigations requested overnight. The trainee ACP re-visited James during the following night shift to establish if any changes had been made to his treatment plan, to find that the chest radiograph had been performed and reported on by the radiology registrar. The report identified a suspected septic embolus in the left lower lobe, commonly characterised on a chest radiograph by multiple, bilateral cavitating peripheral pulmonary nodules (Goswami et al, 2014). On reflection, septic embolus was not on the list of differentials when the trainee ACP had assessed James, as it was not a condition that the trainee ACP was fully aware of.
Septic pulmonary emboli
A septic pulmonary embolus occurs from the embolisation of an infected thrombus, typically from an infected source such as an abscess, which enters the venous circulation, implanting in the pulmonary tissue of the lungs and in turn causing a parenchymal infection (Goswami et al, 2014). Prevalence and mortality rates for this condition are poorly researched, likely due to its uncommon nature, difficulty in diagnosis and vast range of symptoms (Goswami et al, 2014). Jiang et al's (2019) retrospective analysis of septic pulmonary emboli cases in China suggested that 21.4% of SPE cases developed as a result of skin and soft tissue infections, interestingly that developed as a result of clinical interventions undertaken in hospital, whereas in western countries intravenous drug use is the most common cause of septic pulmonary emboli (Yusuf-Mohamud and Mukhtar, 2022).
Ye et al (2014) suggested that most radiological findings of septic emboli have more than two manifestations, such as minor areas of consolidation, or cavities with irregular shaped, thick walls. Computed tomography (CT) scans of the chest may be required to more accurately diagnose or confirm the presence of septic emboli as this method of imaging is deemed more sensitive, particularly in the early stages of infection (Hakeem and Bhattacharyya, 2007; Stawicki et al, 2013). It is understood that the most common sign of a septic pulmonary embolus on CT imaging is a feeding vessel sign, a visible vessel that leads directly into the mass, or nodule, indicating that the lesion has been transported via the bloodstream, or has originated adjacent to small pulmonary vessels (Sharma, 2021). Peripheral bilateral nodular lesions were seen on James' CT scan, likely as a result of peripheral occlusion of the pulmonary artery branches caused by the septic emboli (Yusuf-Mohamud and Mukhtar, 2022).
Septic pulmonary emboli can be difficult to diagnose owing to the varied and non-specific symptoms they manifest, and are often found incidentally (Stawicki et al, 2013). Patients can present with pleuritic chest pain and respiratory symptoms, such as the patient focused on in this case study, or develop acute sepsis, whereas some patients may be asymptomatic (Stawicki et al, 2013) (see Table 1).
Table 1. Signs and symptoms of septic pulmonary emboli
| Signs | Symptoms |
|---|---|
|
|
In addition to radiological imaging, patients with septic emboli are likely to have positive blood cultures, with Staphylococcus aureus the most common pathogen in patients with soft tissue and skin infections, and intravenous drug users (Ye et al, 2014). The S. aureus pathogen can initiate an extreme inflammatory response, and can develop into metastatic infection, causing conditions such as septic pulmonary embolus, infective endocarditis and septic venous thrombosis (Goswami et al, 2014; Medina Pinon et al, 2018). Although blood samples for culture were taken when James was assessed by the trainee ACP, the results of any culture may be impeded by the patient already being on a course of intravenous antibiotics (Goswami et al, 2014; Elsaghir, 2023).
Risk factors for septic pulmonary emboli
Risk factors for septic pulmonary emboli include intravenous drug use, with studies dating back to 1978 indicating that over 70% of cases were in patients who injected illicit drugs (Macmillan et al, 1978). Right-sided endocarditis is also highly prevalent in people who inject drugs and is an additional risk factor for septic pulmonary emboli, due to the potential for vegetation on the cardiac valves to dislodge and travel through to the pulmonary system (Goswami et al, 2014)
It is suggested that the increasing use of CVADs may also contribute to the risk of developing septic emboli (Goswami et al, 2014; Ye et al, 2014). CVAD placements increase the risk of upper-limb DVT, and septic emboli can occur from this, as the CVAD also acts as a portal of infection (Twito et al, 2021). Incidence of the condition is thought to be higher in more affluent and densely populated areas with access to advanced medical care – this may be due to the technology required to diagnose septic pulmonary emboli, but also related to the risk factors of the insertion of such devices (Ye et al, 2014).
Complications of septic pulmonary emboli include severe dyspnoea, hypoxaemic respiratory failure, pneumothorax, pleural effusion and empyema, in addition to long-term pulmonary cavities (Ye et al, 2014; Elsaghir, 2023). Treatment of septic emboli is empiric antibiotics, usually over a course of 4–9 weeks in duration, typically broad-spectrum penicillins and cephalosporins, altered as required by the blood culture reports (Ye et al, 2014). It is acknowledged that there is limited evidence in the role of anticoagulants as an additional treatment for any septic emboli, however, in this case study, James had already been on long-term anticoagulation, and this had continued throughout his treatment (Goswami et al, 2014). Stawicki et al (2013) suggested that high clinical suspicion and early recognition are imperative when assessing patients with suspected septic pulmonary emboli, especially those who present with risk factors for the condition.
Conclusion
Septic pulmonary emboli is a rare diagnosis, and had not been considered as a differential diagnosis in the initial assessment of the patient. This case study reflects on the importance of a thorough assessment, and the role of both nurses and ACPs in medicines management.
Reflecting on this case study allowed the trainee ACP to acknowledge their development in clinical decision making and confidence in their practice. Having the opportunity to follow up this patient also enabled the trainee ACP to explore the rare diagnosis of septic emboli and its pathophysiology to enable awareness of this condition in the future.
KEY POINTS
- Septic pulmonary emboli (SPE) occurs via an embolisation of an infected thrombus, which enters the venous circulation and implants within the pulmonary tissue of the lungs
- SPE can be a difficult diagnosis due to the wide variety of non-specific symptoms
- People who inject drugs, patients diagnosed with right-sided endocarditis and those with a central venous access device are at higher risk of developing SPE
CPD reflective questions
- When administering paracetamol for an antipyretic effect, do you routinely explain this rationale to your patient?
- Would you have agreed with the differential diagnoses made on initial assessment by the trainee advanced clinical practitioner?
- If you were caring for this patient, is there anything you would have done differently?