Case 23 An anxious young woman with hyperventilation

Kathy, about 13 weeks pregnant, consulted Dr Shah complaining of tiredness, recent work stress, and anxiety. She had had cystitis several days previously and been given some antibiotics for that by an Out of Hours service. During the consultation with Dr Shah she appeared anxious and was hyperventilating.

What would you do now?

Dr Shah asked about the onset of her problems, which the patient thought were recent. Dr Shah reviewed the history but there were no previous instances of significant anxiety. There was a discussion about the work problems and Dr Shah advised Kathy to return if the situation did not improve, when blood tests for thyroid function would be considered.

What would be your differential diagnosis and how would you discriminate between them?

Next day Kathy was admitted as an emergency via Accident and Emergency, having collapsed at work. The admitting doctor noted a history of becoming significantly unwell over a couple of weeks with thirst, polyuria and weight loss. In the past few days she had been anxious and breathless. She was diagnosed with diabetic ketoacidosis and was very seriously unwell. However she did recover and required continuing treatment with insulin. Unfortunately the illness caused her to miscarry.

Kathy brought a case against Dr Shah alleging that he should have carried out urinalysis and that this would have avoided her miscarriage.

Do you think her claim will succeed?

Expert comment

Fortunately the patient survived, but 3–5% of patients with diabetic ketoacidosis (DKA) do still die.

Delayed diagnosis of DKA is a relatively common cause of claims against general practitioners, although the general practitioner may only encounter an undiagnosed diabetic presenting with DKA once or twice in a career.

More commonly the patient is known to have Type 1 diabetes, has been unwell for a few days, and the general practitioner fails to check a urinalysis. This is a commoner but less understandable error. 14% of patients with Type 1 diabetes who are unwell and have a blood glucose over 14 mmol/l will have DKA (Schwab, 1999). If the patient has 1+ ketones or less they can usually be managed in the community with close supervision and advice about ‘sick day’ insulin rules. If they have 2+ or more ketonuria they need admission. DKA can occur with a blood glucose as low as 14 mmol/l.

What went wrong in this case?

Hyperventilation is a well-recognized component of anxiety. It is associated with ‘panic attacks’ which may either be reported to the GP or else actually witnessed, often as a result as an urgent request for attention.

However, significant, objectively measured and sustained hyperventilation is not particularly common in primary care (it is probably seen more often in A+E). It is necessary to consider the differential diagnosis.

The differential diagnosis of hyperventilation (i.e. an increase in both respiratory rate and tidal volume) does include anxiety, but also respiratory infections, pulmonary oedema, fever generally, pulmonary embolus, thyrotoxicosis and any cause of metabolic acidosis. Metabolic acidosis in turn can result from sepsis, uraemia, or diabetes.

A person with anxiety who is hyperventilating will commonly (although not always) develop symptoms such as tingling in the hands and feet, and dizziness. There will usually be a prior history of anxiety and panic episodes. The complaint of breathing difficulty will often form part of the presenting complaint, rather than (as here) being noticed by the doctor. Patients with anxiety causing hyperventilation are usually seen as an ‘urgent’ appointment. This patient had made the appointment two days previously. Patients with anxiety-induced hyperventilation usually settle during the course of a medical consultation.

In this case Kathy presented, as many patients do to GPs, with symptoms of tiredness and work stress. Dr Shah assumed that the hyperventilation was the result of this, but did not pay attention to the incongruous features, which were:

• no previous history of anxiety;
  
• hyperventilation not complained of;
  
• appointment made 2 days earlier.

It was possible that Kathy’s symptoms were hyperventilation due to anxiety. However, Dr Shah needed to consider other possibilities such as pulmonary embolism (she was pregnant), sepsis, thyrotoxicosis or DKA. It was necessary to measure respiratory rate, temperature, pulse and blood pressure. It was necessary to listen to the chest and lungs, check the legs for swelling and carry out urinalysis. Many general practitioners now would check pulse oximetry. Hyperventilation due to anxiety should really be a diagnosis of exclusion.

Legal comment

It seems that Dr Shah’s failure to consider other possible causes of Kathy’s hyperventilation has exposed him to this claim for the distress of a miscarriage.

In order to assess the value of the claim, Dr Shah’s lawyers will ask Kathy to be examined by a psychiatrist. The case will be settled by reference to evidence of the effect on Kathy of her experience. The compensation could range from about £3000 for minor post-traumatic distress, up to about £12 000 for moderate PTSD, or even more for a severe case.

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