A 63 year old man was admitted after a community cardiac arrest. He is currently day 5 post admission with uncertain neurological prognosis. He developed bilateral chest infiltrates yesterday and was started on Ampicillin/Clavulanic acid for a presumed nosocomial pneumonia. He has subsequently become progressively hypotensive requiring moderate dose noradrenaline, He is pyrexial 39.2C, he is anuric on dialysis and has an ALT495U/L (<40) and a blood glucose of 2.3 mmol/L (4 – 6).
a) List the likely causes of the pulmonary infiltrate.
b) List likely reasons for the raised ALT.
c) The patient has a plasma lactate of 6.2 mmol/L. What are the likely causes of the raised lactate in this patient?
a) List the likely causes of the pulmonary infiltrate.
• Cardiac Failure
• Nosocomial /aspiration Pneumonia
• Fluid overload secondary to renal failure
• ARDS
• Drug reaction (less likely)
b) List likely reasons for the raised ALT.
• Liver ischaemia at the time of the cardiac arrest
• Ongoing liver ischaemia with possible venous hypertension secondary to cardiac failure
• Septic hepatic dysfunction
• Drug reaction
c) The patient has a plasma lactate of 6.2 mmol/L. What are the likely causes of the raised lactate in this patient?
• Lactate overproduction
Catecholamine infusion
Low cardiac output state with global hypoperfusion
Organ ischaemia (bowel or other organ ischaemia)
Sepsis with mitochondrial dysfunction
• Decreased lactate catabolism
Liver failure
Renal Failure (especially lactate containing dialysate)
a) is a question about the differential diagnosis of a bilateral lung infiltrate. The college did not specify that the candidate limit themselves to a certain number of differentials.
One's approach should be systematic:
A raised ALT is almost always of hepatic origin. However, small
increases in ALT activity may occur in the following situations:
Thus, this is likely ischaemic hepatitis post cardiac arrest; other differential diagnoses of liver damage apply.
Causes of raised lactate are discussed in greater detail elsewhere.
In brief, they can be structured in the following way:
Increased production
Decreased clearance
A good monograph on ALT is available from the Association for Clinical Biochemistry and Laboratory Medicine (UK)