A 75-year-old female, with a past history of Parkinson's disease and a recent admission for behavioural disturbance, presents with a fluctuating conscious state. Her temperature is 37.2°C, respiratory rate 26 breaths/min, blood pressure 100/80 mmHg, pulse rate 100 beats/min, and Sp02 98% on 0.4 Fi02.
Her investigations are as follows:
Parameter |
Patient Value |
Normal Adult Range |
Haemoglobin |
85 g/L* |
115 - 160 |
White Cell Count |
20.9 x 1O\l/L* |
4.0 - 11.0 |
Platelets |
82 x 1O\l/L* |
150 - 400 |
Albumin |
34 q/L |
35 - 50 |
Total Bilirubin |
10 µmol/L |
< 20 |
Alanine aminotransferase |
421 U/L* |
< 35 |
Alkaline phosphatase |
60 U/L |
30 - 110 |
y-Glutamyl transferase |
23 U/L |
< 40 |
Sodium |
140 mmol/L |
135 - 145 |
Potassium |
3.4 mmol/L* |
3.5 - 5.2 |
Bicarbonate |
12 mmol/L* |
22 - 32 |
Chloride |
103 mmol/L |
100 - 110 |
Urea |
3.6 mmol/L |
3.0 - 8.0 |
Creatinine |
88 umol/L |
45 - 90 |
Lactate |
17 mmol/L* |
< 2 |
International normalised ratio |
2.9* |
0.9 - 1.3 |
Activated partial thromboplastin time |
58.0 sec* |
25 .0 - 37.0 |
Fi02 |
0.4 |
|
pH |
7.21* |
7.35 - 7.45 |
PC02 |
25 mmHg (3.3 kPa)* |
35 - 45 (4.6 - 6.0) |
P02 |
204 mmHq (26.8 kPa) |
|
Bicarbonate |
10 mmol/L* |
22 - 26 |
a) Comment on her acid-base status. (20% marks)
b) List three differential diagnoses for this patient's presentation, with confirmatory investigations for each. (50% marks)
a)
Raised anion gap metabolic acidosis, lactic acidosis, with appropriate respiratory compensation (Anion gap 143 – 115 = 28)
b)
Let us dissect these results systematically.
Thus, this is a pure lactic acidosis.
b)
Causes of such extreme lactic acidosis?