Medicine is often described as an art, not a science, and it can certainly feel like that when a patient presents with symptoms and signs that could lead to a number of different diagnoses. Patients rarely present with the textbook list of features of a condition, and this is particularly true in the case of a pulmonary embolus (PE).

A missed diagnosis of pulmonary embolus can not only be catastrophic for the patient, but extremely distressing for the clinician involved. Patients or their families may feel let down in these situations, which can then lead to a complaint or claim. The doctor might also be asked to justify their management decisions as part of a coroner's inquest or fatal accident inquiry, or significant event investigation.

The MDU reviewed 108 cases from between 2010 and 2015, where there was an allegation that a pulmonary embolus could have been diagnosed sooner, where the final diagnosis was PE, and where we had sufficient information to answer the study questions. The review did not include cases of a missed diagnosis of deep vein thrombosis (DVT) leading to PE.

In this review we looked at:

1. the setting of the consultation
2. the outcome for the patient
3. the signs and symptoms recorded
4. the documented working diagnosis
5. the management.

MDU members had requested assistance with a variety of matters including clinical negligence claims, coroner's inquiries, complaints and significant event investigations.

Setting

The majority of cases involved in hours GP consultations, one of which included a practice nurse consultation. Only 16.7% related to GP out of hours consultations.

Table 1: setting

Setting	Number (percentage) of cases
In hours GP	69 (63.9%)
Out of hours GP	18 (16.7%)
Hospital ED/MAU	9 (8.3%)
Hospital other	10 (9.3%)
Other	2 (1.9%)

Symptoms and signs

The medical records were reviewed and unsurprisingly, the commonest presenting complaint was of shortness of breath, followed by chest pain and cough. Many patients had more than one symptom, but it was noteworthy that 22 (20.3%) reported shortness of breath alone, without any other recorded symptom, and 16 (14.8%) reported only chest pain, again without any other symptoms. Haemoptysis was only reported in 4.6% of cases. 

In 11 cases (10.2%), there was no record of the patient suffering from any of the typical symptoms of shortness of breath, syncope, chest pain or haemoptysis. These patients presented in a variety of ways, including 'off legs', diarrhoea and vomiting with palpitations, and apparent urinary tract infection.

Chest signs were reported in only 21.3% of cases, and the pulse was raised above 100 beats per minute in only 28 out of the 78 cases (35.8%) where it was recorded.

Oxygen saturations had been recorded in 63.9% of cases.

Table 2: signs and symptoms recorded

Signs/symptoms recorded	Number (percentage) of cases
Shortness of breath	68 (62.9%)
Chest pain	46 (42.6%)
Cough	43 (39.8%)
Haemoptysis	5 (4.6%)
Other symptoms	11 (10.2%)
Chest signs	23 (21.3%)
Pulse >100	28 (25.9%)
Pulse <100	50 (46.3%)
Oxygen saturations recorded	69 (63.9%)

Working diagnosis

In 39 (36.1%) cases, there is evidence in the notes that the clinician considered risk factors for PE, for example, by examining the legs for DVT, or questioning the patient about known risk factors such as immobility, smoking, hormonal contraception, pregnancy, family history or malignancy.

The most common working diagnosis was of chest infection in almost one third of cases, followed by asthma or COPD. Musculoskeletal chest pain was diagnosed in 12 cases, and in five of these cases, the doctor had documented chest wall tenderness.

In 5.6% of cases, the symptoms were attributed to anxiety or low mood.

Table 3: documented working diagnosis

Working diagnosis	Number (percentage) of cases
Chest infection/pleurisy	35 (32.4%)
Asthma/COPD	15 (13.9%)
Musculoskeletal pain	12 (11.1%)
Cardiac cause	4 (3.7%)
Gastrointestinal cause	4 (3.7%)
Anxiety/low mood	6 (5.6%)

Management

Two of the 108 patients were admitted to hospital; one for treatment of leg swelling, the other for a suspected myocardial infarction (MI).

This study focused on cases where there was an allegation of a failure to diagnose PE in a timely fashion. Therefore it is unsurprising that in only one case was the patient investigated for PE as a direct result of the consultation, but there is evidence that PE was considered as a possible diagnosis in another five cases.

Outcome

In 46 cases (42.6%) the patient died.

Conclusions

This review showed that pulmonary embolus can present in a variety of ways, and in 10% of our cases, the patient did not present with any of the typical symptoms of shortness of breath, chest pain, haemoptysis or syncope.

As well as this, some examination findings that might reassure a clinician - such as a normal heart rate and oxygen saturation - were often present. Of particular note, chest wall tenderness was present in some patients, which may also have falsely reassured the clinician.

Of course, it is also important to remember the context in which the patient was seen. The most common symptoms of PE are extremely common presentations in primary care and emergency medicine, and most of the time will not be associated with a diagnosis of pulmonary embolus. Many of these patients had other co-morbidities, such as chronic lung disease, mental health or cardiac problems, meaning that the symptoms may often be attributed to these.

This means that excluding a diagnosis of pulmonary embolus on a clinical basis has a significant risk of error. In addition, no convenient investigation exists to diagnose or exclude PE, with CTPA being the gold standard, but requiring admission to hospital.

This review demonstrates the high stakes involved in making an alternative diagnosis, with almost half of the patients in the files we reviewed having a fatal outcome.