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Three Part Question

In [adult patients presenting to the ED with heat-stroke] is [procalcitonin] a [useful marker of disease severity]?

Clinical Scenario

A 50 year old male is brought in by ambulance after a collapse. It is a hot day and the patient had been playing 5-aside football when he collapsed. In the Emergency Department he is a assessed, having a rectal temperature of 41.5C and a GCS of 4. The patient is hot and not sweating. A diagnosis of heatstroke is made. You wonder if the patient’s serum procalcitonin might be a useful indicator of disease severity.

Search Strategy

Ovid Medline® 1950 to June Week 2 2009
Ovid Embase 1980 to 2009 Week 25
Ovid EBM Reviews- Cochrane Central Register of Controlled Trials 2nd Quarter 2009
Ovid EBM Reviews - Cochrane Database of Systematic Reviews 2nd Quarter 2009
EBSCOHost CINAHL Plus

Medline® & Embase search strategies;
1. heat stress disorder.mp. or exp Heat Stress Disorders/
2. exp Calcitonin/ or procalcitonin.mp.
3. 1 and 2
4. limit 3 to (english language and humans)

Cochrane search strategy;
1. heat stress disorder.mp. or exp Heat Stress Disorders/
2. exp Calcitonin/ or procalcitonin.mp.
3. 1 and 2

Cinahl Plus search strategy;
1. (MH "Heat Stroke") or (MH "Heat Exhaustion") AND (procalcitonin OR calcitonin)

Search Outcome

The search returned 13 results (Medline 3, Embase 8, Cinahl 1), of which 2 were deemed to be of suitable quality for inclusion.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Hausfater P., Hurtado M., Pease S., Juillien G., Lvovschi V.-E., Salehabadi S., Lidove O., Wolff M., 2008 France	53 patients diagnosed with heatstroke in the ED. Conducted during France’s 2003 heat wave. Serum PCT on admission and 30-day mortality investigated.	Cohort Study	14 (26%) admitted to ICU. At 30days 24 (45%) had died.	Admission PCT +ive if >0.2 μg/l, median PCT value 0.58μg/l Median PCT in deceased group 1.4μg/l (0.16–4.71) Median PCT in surviving group 0.18μg/l (0.12–1.61) All ICU admissions had elevated PCT values. Microbiological/clinical infection not more frequent in PCT+ive group.	Variable of temperature >40.0°C significantly associated with fatality.
Nylen E.S., Al Arifi A., Becker K.L., Snider Jr. R.H., Alzeer A. 1997 Saudi Arabia	25 patients admitted for heat illness during Hajj pilgrimage, 10 of which had minor illness and no pyrexia- acted as controls.	Comparative Study	Serum PCT every 6hrs for 24hrs. Patients cooled with standard evaporative measures.	Mean serum PCT was >20x elevated in heatstroke group than controls. PCT plateau at 6hrs remained increased at 24hrs. 77% heatstroke patients survived. The 23% that died had significantly higher PCT concentration. PCT concentration >0.5μg/l at 6hrs predicted survival.

Comment(s)

Both exertional and classical heatstroke are characterised by neurological involvement and rectal temperature >40.6°C, requiring prompt diagnosis and immediate cooling interventions. The value of serum procalcitonin does not seem to be as a marker for mortality but does seem quite useful in indicating the severity of heatstroke. Elevated procalcitonin is seen in a range of systemic inflammatory responses syndromes, it is possible that the elevation of procalcitonin in heatstroke is linked to its synthesis along a non-septic pathway. The source of this procalcitonin requires further investigation.

Clinical Bottom Line

Elevated serum procalcitonin is a useful marker of heatstroke disease severity. It ought to be measured where a suitable assay is readily available. The cornerstone of dealing with a heatstroke patient remains to be rectal temperature monitoring and rapid cooling techniques, with serum procalcitonin currently an aside to core management.

References

1. Hausfater P., Hurtado M., Pease S., Juillien G., Lvovschi V.-E., Salehabadi S., Lidove O., Wolff M., Bernard M., Chollet-Martin S., Riou B. Is procalcitonin a marker of critical illness in heatstroke? Intensive Care Medicine. 34(8)(pp 1377-1383), 2008. Date of Publication: August 2008.
2. Nylen E.S., Al Arifi A., Becker K.L., Snider Jr. R.H., Alzeer A. Effect of classical heatstroke on serum procalcitonin. Critical Care Medicine. 25(8)(pp 1362-1365), 1997. Date of Publication: August 1997