A false-normal G6PD assay, a normal PaCO2 in severe lung disease, and the rash details that stop pityriasis rosea being called too quickly.
Normal G6PD testing during haemolysis can mislead; repeat it after recovery.
Start with G6PD deficiency. It gives the clearest practice change in today’s list: a normal enzyme assay during active haemolysis does not settle the diagnosis when jaundice or anaemia follows infection, broad beans, or an oxidant drug. Several of today’s stronger episodes warn against the same mistake: closing the case because one feature looks reassuring. That shows up again in fibrotic lung disease, where severe hypoxaemia can sit with a normal PaCO2, and in pityriasis rosea, where an apparently classic rash still needs a check for drug triggers, palms or soles, and secondary syphilis if the picture is off.
The rest of the page is broader. The oncology episode is a useful reset on treatment intent, supportive care, and palliative language, while the breast screening AI episode keeps attention on interval cancers rather than headline detection counts. If the jaundice story, the blood gas, or the rash course does not fit, check the exception before repeating the first diagnosis.
Jaundice or anaemia after infection, broad beans, or nitrofurantoin should slow the consultation down. The useful twist is that a G6PD assay can look normal during acute haemolysis, so this is the best place to start if you want one practice-changing point today.
Severe hypoxaemia with a normal PaCO2 is exactly the sort of blood gas that invites the wrong conclusion. This episode makes the physiology usable at the bedside and explains why a rising PaCO2 in pulmonary fibrosis or pneumonia should redirect attention to alveolar ventilation and ventilatory fatigue.
A herald patch, collarette scale, and a truncal Christmas tree distribution make pityriasis rosea easier to recognise. The reason to open this one is the second half: palms, soles, older adults, prolonged rash, or drug triggers should make secondary syphilis or a drug eruption harder to ignore.
Keep this one for the broader reset. It clarifies adjuvant versus neoadjuvant therapy, reminds clinicians that palliative care still means active treatment, and brings attention back to everyday supportive care, including fatigue planning, bowel regimens with oral opioids, and venous access.
Breast screening AI only matters clinically if it reduces interval cancers or catches aggressive disease, not just if it increases detections. The episode keeps attention on radiologist workload and automation bias, which makes it useful when someone claims software can safely replace readers.
When jaundice or anaemia follows infection, broad beans, or a new drug, do not stop at a single normal G6PD assay if the episode is still active. Check the trigger history, look at the blood film, and plan repeat testing after recovery if the clinical picture still fits.
When can a G6PD enzyme assay look normal even if deficiency is likely?
During active haemolysis, the most enzyme-deficient red cells may already have been destroyed. If the trigger history and blood film still fit oxidative haemolysis, repeat the assay after recovery.
What history should I take when jaundice or anaemia might be G6PD deficiency?
Ask about recent infection, broad beans, and new drugs such as primaquine, nitrofurantoin, cotrimoxazole, or sulfasalazine. That history makes oxidative haemolysis much easier to recognise.
How should I read severe hypoxaemia with a normal PaCO2 in pulmonary fibrosis or pneumonia?
That combination supports impaired oxygen transfer with preserved carbon dioxide clearance. A new rise in PaCO2 should shift attention to reduced alveolar ventilation or ventilatory fatigue.
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