A 34 year old woman is transferred to your hospital with a history of a prolonged generalized tonic-clonic convulsion. She is intubated and ventilated. Blood samples have been collected for a full blood count, biochemistry and a coagulation profile. Her initial non contrast CT brain shows bilateral intracerebral hemorrhages. Her arterial blood gases and a haematology report are provided below
|
Parameter |
Patient values |
Normal range |
|
FiO2 |
0.5 |
|
|
pH |
7.15 |
7.35-7.45 |
|
PaCO2 |
35 mmHg (4.6 kPa) |
35-45 mmHg (4.7-6.0 kPa) |
|
PaO2 |
105 mmHg (14 kPa) |
75-98 mmHg (10-13 kPa) |
|
Bicarbonate |
10.3 mmol/l |
22-26 mmol/l |
|
Parameter |
Patient values |
Normal range |
|
Hb |
78 G/L |
(130-150) |
|
WCC |
14.5 x 106/mm3 |
(4.0-11.0) |
|
Platelets |
43 x 106 /mm3 |
(150-300) |
Blood picture: Thrombocytopaenia, fragmented cells and reticulocytosis
Coagulation profile: Normal
a) List the abnormalities on the blood gases. Give the most likely cause of each abnormality
b) Based on the history, CT scan and the hematology report, provide three possible differential diagnoses and give reasons
College Answer
a)
Metabolic acidosis: Lactic acidosis induced by status epilepticus
Respiratory acidosis (alternatively inappropriate respiratory compensation) - Central hypoventilation (alternative : inappropriate mechanical ventilation)
Increased A-a gradient : Aspiration pneumonitis (alternative : neurogenic pulmonary oedema)
b)
TTP
Eclampsia
HUS
Vasculitis
? Meningoencephalitis (lower mark)
There is evidence of MAHA with low platelets.
Discussion
This question is identical to Question 15.2 from the second paper of 2011, and Question 22.2 from the second paper of 2008.