ICU and You  ·  Aphorism Series  ·  Number 34

This week's aphorism
“In the immunosuppressed, the absence of signs is the sign.”

Preamble

A recipient with peritonitis may have a soft abdomen. A recipient with pneumonia may have a clear film for another day yet. The fever is absent, the white cell count unremarkable, the CRP flat — not because the infection is mild, but because the inflammatory response we rely on to announce it has been deliberately switched off. We disabled the alarm ourselves, then read its silence as reassurance.

That inverts ordinary clinical reasoning. The thresholds we carry around — for imaging, for cultures, for invasive sampling, for waking someone more senior — all have to come down, and they have to come down before the patient looks unwell, because by the time they look unwell the margin has gone. Ordinary vigilance is not wrong here. It simply feels adequate when it isn't.

And this is not just about transplant recipient patients. The same holds for the patient on long-term steroids, on a biologic, mid-chemotherapy, the cirrhotic, the asplenic, the very old.

Do you agree?  Yes / No / Maybe

Yes

In these patients a normal observation chart is uninformative rather than comforting. The clinical picture has lost its usual predictive value, and we should act on that.

No

Signs are still signs. Teaching people that nothing means something invites limitless investigation, scans, procedures and cost, and the objective markers that matter — lactate, blood pressure, oxygenation, imaging — usually do still work.

Maybe

It depends entirely on how immunosuppressed. A patient two weeks out from anti-thymocyte globulin is not the same patient as one on 5 mg of prednisolone in year eight, and the aphorism treats them alike.

Optional reflection

Which normal result do you find most reassuring in a sick patient — and should you?

Send it back to me either way, with your Yes, No or Maybe. Themes, and the best of your responses, go into Friday's newsletter.

Send your response

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