\n
The GP found she had glycosuria and arranged for her to be admitted to hospital for further tests. Later that day she became faint and vomited and acute admission was arranged.<\/p>\n\n\n\n
<\/p>\n\n\n\n
<\/p>\n<\/div><\/div>\n\n\n\n
You are the receiving doctor in the Emergency Department, which of these investigations would be most helpful to provide a diagnoses?<\/strong><\/p>\n\n\n\nChest x-ray<\/strong><\/button>\n
From the history provided there is no indication to undertake a chest x-ray for this girl. However is any abnormalities of the respiratory system was found on examination this should be considered.<\/p>\n<\/div><\/div>\n\n\n\n
Full blood count<\/strong><\/button>\n
Whilst an important test, this would not be likely to provide a diagnosis. It does form a part of initial investigations however it may not provide the diagnosis in this case.<\/p>\n<\/div><\/div>\n\n\n\n
Urea and Electrolytes<\/strong><\/button>\n
Whilst this is an important to determine if there is any organ dysfunction the rest of the U+Es do not form the most important diagnostic test.<\/p>\n<\/div><\/div>\n\n\n\n
Capillary blood glucose<\/strong><\/button>\n
Whilst useful to give an indication of blood glucose, a venous sample would be more appropriate to get an accurate level. NB BMs of around 30 will just read ‘high’ on a glucometer.<\/p>\n<\/div><\/div>\n\n\n\n
Arterial\/Venous blood gas<\/strong><\/button>\n
Blood gases can give results quickly and lots of them. This includes acid-base results. But the results also give some electrolyte levels. It does also show blood glucose however you will need to send an official blood glucose to the labs.<\/p>\n<\/div><\/div>\n\n\n\n
<\/p>\n\n\n\n
\n\n\n\n
An ABG was performed<\/strong><\/p>\n\n\n\n\n\n\n\nHer results were:<\/span>[H+<\/sup>] = 89 nmol\/L\u00a0\u00a0 pH = 7.05\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0Blood Glucose 34.4<\/span>PaCO2<\/sub>\u00a0=\u00a02.0 kPa<\/span>[HCO3<\/sub>] =\u00a05 mmol\/L<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n\n\n\n<\/p>\n\n\n\n
How would you describe the above result?<\/strong><\/span><\/p>\n\n\n\nMetabolic Alkalalosis<\/strong><\/button>\n
Look again, metabolic acidosis presented with elevated bicarbonate levels, is this picture seen above?<\/p>\n<\/div><\/div>\n\n\n\n
Metabolic Acidosis<\/strong><\/button>\n
Whilst partially correct, there is a better answer available. Above shows an acidotic picture with raised hydrogen ion concentration and low bicarbonate.<\/p>\n<\/div><\/div>\n\n\n\n
Compensated metabolic acidosis<\/strong><\/button>\n
This is correct. There is acidaemia with raised hydrogen ions. Bicarbonate is low indicating a metabolic cause. Carbon dioxide is also low, this indicates there is respiratory compensation.<\/p>\n<\/div><\/div>\n\n\n\n
Respiratory Acidosis<\/strong><\/button>\n
Typical respiratory acidaemia presents with increased PaCO2, usually in the context of respiratory distress. There may be a compensatory bicarbonate rise.<\/p>\n<\/div><\/div>\n\n\n\n
Respiratory Alkalosis<\/strong><\/button>\n
Look again, hydrogen ions are high. Respiratory alkalaemia usually occurs due to hyperventilation of the lungs and results in significant low PaCO2 and a fall in hydrogen ions.<\/p>\n<\/div><\/div>\n\n\n\n
General Feedback on question<\/strong><\/button>\n
Further compensation requires renal tubular mechanisms for regenerating bicarbonate. The function of these may be limited by the likely dehydration caused by an osmotic diuresis due to the presence of glucose and ketones in the urine.<\/p>\n<\/div><\/div>\n\n\n\n
For further information on interpreting blood gas pictures click here.<\/p>\n\n\n\n
What is the patient’s diagnosis? <\/span><\/strong><\/p>\n\n\n\n(Choose one of these and then click to see if you are correct)<\/em><\/p>\n\n\n\nPolydipsia<\/strong><\/button>\n
Polydipsia alone should not present with any acid base disturbance.<\/p>\n<\/div><\/div>\n\n\n\n
Anorexia<\/strong><\/button>\n
There is no suggestion of anorexia which usually presents with normal acid base picture or metabolic alkalaemia due to vomiting or use of diuretics. (hydrochloric acid loss in vomit)<\/p>\n<\/div><\/div>\n\n\n\n
Diabetic Ketoacidosis<\/strong><\/button>\n
In view of her age, symptoms and laboratory results it is the most likely diagnosis.<\/p>\n<\/div><\/div>\n\n\n\n
Diarrhoea<\/strong><\/button>\n
Diarrhoea usually presents with a metabolic acidaemia due to bicarbonate and electrolyte loss via the stool.<\/p>\n<\/div><\/div>\n\n\n\n
Severe Anaemia<\/strong><\/button>\n
Severe anaemia should not change the acid base picture<\/p>\n<\/div><\/div>\n\n\n\n
General feedback <\/strong><\/em><\/span><\/button>\n
The glycosuria suggests diabetes mellitus, the acidaemia being due to \u201cketone body\u201d production. Diabetic ketoacidosis would be confirmed by the detection of ketones in the urine on dip-stick analysis. DKA would be expected to produce a significant anion gap.<\/p>\n<\/div><\/div>\n\n\n\n
\n\n\n\n
Would you be worried about this patient? Explain your reasoning<\/strong><\/span><\/p>\n\n\n\nTake a minute to write down your answers to this question<\/em><\/p>\n\n\n\n<\/p>\n\n\n\n
Reveal<\/strong><\/button>\n
\n
\n
DKA is a life threatening emergency and should be treated promptly. Patients become really dehydrated as our bodies try and restore balance \u2013 hence why patients get polyuria and polydipsia. <\/p>\n\n\n\n
One complication is Cerebral Oedema so if they have reduced consciousness you should escalate to a senior (also at risk of aspiration pneumonia)<\/p>\n\n\n\n
They get disturbances in electrolytes which can lead to cardiac arrhythmias amongst other things. They\u2019re at risk of: Hypokalaemia, Hypomagnesiumia and Hypophosphataemia<\/p>\n\n\n\n
DKA is a pro-thrombotic state so patients are at increased risks of thromboembolism<\/p>\n<\/div><\/div>\n<\/div><\/div>\n<\/div><\/div>\n\n\n\n
Can you think of other causes of metabolic acidosis? (think about your answer before clicking on the reveal)<\/em><\/strong><\/span><\/p>\n\n\n\nReveal<\/strong><\/button>\n
\n
Metabolic acidosis can occur as a result of either:<\/p>\n\n\n\n
Increased acid production or acid ingestion<\/p>\n\n\n\n