Friday, 12 January 2007

An Interesting Case

Yesterday was very interesting for me and it reinforced to me how important history taking really is. This next case has been anonymised for confidentiality purposes.

At another hospital, I hosted a conference, and a junior resident presented a history of a 45 year old female who presented to hospital with a seizure before New Year.

The patient had developed a fever four days before admission and apparently had no other symptoms until the day of admission, at which point, the patient had a seizure in her home toilet.

The patient had complained of some apparent neck stiffness on the day of the fever but not on admission.
The patient had no other medical ailments and took no regular medications. The patient is married, works as an airline hostess, smokes a box of cigarettes per day and consumes occasional alcohol in moderation.

At this point I stopped the Resident and asked for more history of the chief complaint before moving on with the previous medical history, but no more history was available, such as, had the patient had a recent cold, cough, sputum (and colour), any recent antibiotic therapy etc...

From here I heard the vitals which indicated a high temperature of 40 degrees C, SpO2 of 92%. Oxygen sats were too low for such a young patient.
At this point, it was possible to form differential diagnoses including the following:

Seizure and Fever: possible meningitis, encephalitis, cerebral asbcess, cerebral vasculitis, cerebral tumour / metastatic disease as examples.

Hypoxaemia and Fever: pneumonia, other respiratory infections, aspiration pneumonitis post-seizure, pulmonary embolism.

Bloods showed a high CRP>10 and raised white cell count of 18, although having a raised white count is not uncommon following a seizure.
Blood gas revealed a metabolic acidosis and hypoxaemia; urine analysis showed no sugar and 1+ ketones. Blood sugar was slightly raised at 187 but not diagnostic of DM on a random sample.

CT scan had revealed no abnormality, but lumbar puncture showed CSF pressure of 53cm water (normal <20),>

Hence, the diagnosis was confirmed to be meningitis, likely bacterial, from the CSF result, and I suggested from very little information and data at that time, that the patient had either a pneumonia causing meningitis, likely pneumococcal, or that the patient aspirated post-seizure.

I was then informed that the urinary pneumococcal antigen was POSITIVE. However, this does not itself rule out the possibility of a different organism having caused the meningitis, although it would seem highly likely that it was.

I considered that the acidosis and ketonuria could have been due to starvation or alcohol, but diabetic ketoacidosis was unlikely, as there was no sugar to be found in the urine and the serum glucose was not in the diabetic range.

Following this, we went to review the patient, and she had developed some retrograde amnesia from the illness and her husband was able provide an excellent history. She had developed a cough and green sputum before admission, and had seen her local doctor and a common cold had been diagnosed and antibiotics had probably been prescribed. The patient had only taken a few tablets, but she did not like to take medication and stopped it. The patient then drank alcohol following which she developed a seizure.

Examination yesterday was entirely normal in every respect except for a mild drug rash from antibiotics and some mild clubbing of her hands and feet.

The chest roentogen revealed some mild patchy alveolar change consistent with infection and the follow-on CT confirmed it was a pneumonia.

The acidosis was probably due to alcoholic ketoacidosis and / or starvation.
The fact that the patient had taken antibiotics prior to presentation explains the inability to find the bacteria in the CSF, but only thorough history taking was able to elucidate this information.

Thus, the chief complaint and in this case, limited history and simple vital sign recording even without knowing the full examination allowed us to formulate a differential diagnosis based on:

1) Knowledge of common causes of fever and seizures

2) Common causes of fever and hypoxaemia

3) Causes of metabolic acidosis and ketones with absent urinary glucose

In such cases, taking a thorough detailed history from a relative can save on time, allow a better idea of what is going on, and they can fill in the gaps that this patient could not possibly know due to her amnesia!

The simplistic way is to formulate a differential set of diagnoses, then ask the pertinent diagnostic questions to aim to prove or disprove the idea. If elements do not fit, then ask questions to try and find out why they don't fit and keep asking questions until you are satisfied.

Remember, a CT scan cannot ask a history!

Effective communication provides for effective history, which provides effective understanding and hence, treatment and understanding of patient presentations in hospital improves.

Basically, keep asking WHY and never be satisfied until you have the answers !

Finally, this patient has clubbing which suggests that she may have an existing underlying problem. However, clubbing is beyond the scope of today's long article, but I will endeavour to cover it in the future.