How to prevent misdiagnosis of serious illnesses that have the same symptoms as Covid-19

Covid-19 is top of mind now, and it is unsurprising that much attention has been put on detecting and excluding infections in potential cases with similar symptoms. 

One of the major challenges, however, is that the symptoms of the coronavirus are similar and overlap with many other conditions, including some cancers.

For example, fatigue and high fever can be due to many conditions including various infections, and also non-infective conditions such as inflammatory conditions or even cancer. In fact, most patients with a high fever in Singapore do not have Covid-19 at all.

Many blood cancers can present with non-specific symptoms such as fever and fatigue.

As such, an over-emphasis on the diagnosis of Covid-19 by the medical community and a fear of such a diagnosis by the public can lead to a misdiagnosis, or delayed diagnosis as well as management and treatment of equally significant and life-threatening conditions such as blood cancers.

There are some overseas reports in the United States and United Kingdom to show that the diagnosis of some cancers has been missed as the symptoms of fatigue and fever were mistaken as Covid-19 infection.  

Let me illustrate with the following two scenarios which are hypothetical but yet highly probable in real life. 

SCENARIO ONE: HOW HARD IS IT TO DIAGNOSE ACUTE LEUKAEMIA IN A PANDEMIC?

James, in his mid-30s, developed a fever having been previously well. 

Despite taking paracetamol, his symptoms persisted, and he went to see a general practitioner (GP).  

A swab test confirmed that he did not have Covid-19. He was prescribed more paracetamol and told to rest at home for the following five days. 

His fever did improve briefly but recurred after five days. He also started to feel more fatigued.  

Deeply worried, James went back to his GP but another swab test again found him negative for Covid-19. 

Over the following week, he continued to have low grade fever and became increasingly fatigued.  

He also developed new symptoms of coughing and breathlessness. He returned to the GP for the third time and was admitted to hospital where he was isolated. 

Further investigations revealed that he had pneumonia and doctors were concerned that it could be Covid-19 related.  

Yet James again tested negative for Covid-19. 

But blood tests showed that he was anaemic with a high white cell count. Further tests confirmed that he had acute myeloid leukaemia. 

Acute leukaemia can present with a multitude of symptoms including fatigue, recurrent fever, recurrent infections, easy bruising, gum bleeding, loss of appetite and weight and breathlessness.  

However, most patients only have some of these symptoms. 

Covid-19 can also present with a multitude of symptoms including fever, running nose, cough, breathlessness, fatigue, headache, sore throat, muscle aches and vomiting.  

The overlap of symptoms between these two conditions made James’ diagnosis difficult.  

Generally, symptoms of Covid-19 develop rapidly over a few days, whereas symptoms of acute leukaemia develop more slowly over a few weeks.  

In James’ case, he eventually presented with pneumonia because of his low immunity due to the leukaemia.

This case illustrates the difficulties in diagnosis when there is an overlap of symptoms between conditions, and how a major pandemic weighing heavily on everyone’s mind can lead to a delay in diagnosis.

This challenge will likely persist but can be mitigated by a sensible and carefully balanced approach. 

For example, the likelihood that a fever is due to Covid-19 infection is relatively low in our local setting as the overall incidence of the coronavirus infection is low. 

Hence, both patients and physicians must be more vigilant in looking out for other causes of fever. 

A detailed history and careful physical examination will reduce the risk of misdiagnosis.

On many occasions, a simple blood test such as a blood count can easily uncover a serious condition such as acute leukaemia. 

SCENARIO TWO: WHEN THE FEAR OF GOING TO HOSPITAL RESULTS IN DELAYED DIAGNOSIS

Michelle, 42, saw a GP due to tiredness and fatigue.  

The GP found her to be pale and after performing a blood count test, confirmed that she was anaemic.  

Her platelet count was also slightly low, and her white blood count was slightly elevated.  

Her GP also found that her white blood cells were not normal and advised her to go to the emergency department of a tertiary hospital for further evaluation.

However, Michelle had been warned by her friends and family that it was too risky to go to a hospital due to the Covid-19 pandemic.  

She attributed her tiredness to anaemia which she assumed was due to her heavy menstrual flow. 

She decided to take iron supplements and remain at home, hoping that her condition would improve over the next two weeks.

Unfortunately, Michelle’s tiredness worsened and she started to lose her appetite and noticed she bruised easily. 

She eventually went to an emergency department as advised, and a repeat blood count revealed a markedly raised white blood cell count, a low platelet count and severe anaemia.  

Further tests confirmed the diagnosis of acute myeloid leukaemia. 

After receiving a blood transfusion, her symptoms improved significantly.   

She still had reservations about staying in hospital, but her doctor managed to convince her by offering her a new low intensity anti-leukemic therapy approach. 

She was discharged a week later and continued to receive outpatient treatment.  

Acute leukaemia is traditionally treated by intensive chemotherapy which requires a prolonged hospitalisation.  

Amid the pandemic, there has been a drive to treat patients in an outpatient setting to free up beds in hospitals for Covid-19 cases. 

A low intensity anti-leukaemic therapy such as azacitidine and venetoclax for treatment of acute myeloid leukaemia has gained much popularity among institutions in the US during the pandemic as it can be given as an outpatient therapy. 

Michelle’s case demonstrates a fear among some people in seeking medical treatment in tertiary institutions as most Covid-19 cases are admitted there for treatment. 

This could result in a delay in diagnosis and treatment of serious medical conditions, which can be even more life-threatening than the Covid-19 infection itself.  

The Ministry of Health has put in place very tight control measures within healthcare institutions to curb the spread of Covid-19. 

These include the need to wear N95 masks and regular routine Covid-19 swabs for all healthcare workers as well as non-healthcare workers who have direct contact with patients. 

It is fair to say that the risk of Covid-19 transmission in hospitals will be very low. 

The fear of Covid-19 infection is understandable but at the same time we should not let ourselves be overly consumed by it as the consequences can be detrimental. 

Do exercise common sense and seek medical advice early if we suspect our health is not going in the right direction. 

ABOUT THE AUTHOR:

Dr Ng Chin Hin is a senior consultant haematologist at the Centre for Clinical Haematology (Mount Elizabeth Novena Specialist Centre and Gleneagles Hospital).