ICU AND YOU · Aphorism #34 — In the immunosuppressed, the absence of signs is the sign

ICU and You · Aphorism Series · Number 34

The aphorism for this topic

“In the immunosuppressed, the absence of signs is the sign.”

How to use an aphorism

An aphorism is a compressed argument, not a rule. It earns its shape by leaving things out, which is exactly what makes it memorable and what makes it arguable. Every one in this series is contestable, and chosen because it is.

Each is a mantra, a paradigm, a truism or occasionally a plain myth — something repeated in our units often enough that nobody examines it any more. The piece sets out the case for it, the case against it, and the case for something in between, and then asks which you hold.

There is no right answer waiting at the bottom. The point is to find out what you actually believe and why, because the beliefs that run your practice at three in the morning are mostly ones you have never said out loud.

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 a coming newsletter.

Send your response

The button opens a reply straight to me with the headings already in it. If your device blocks it, write to icuandyou@icloud.com instead.