Today’s collection is linked by a common clinical discipline: recognising when an apparently reassuring result, familiar presentation or promising intervention answers the wrong question. Multi-site bleeding can be mistaken for local urinary disease, a sodium concentration can distract from water–solute physiology, an awake electroencephalogram can miss infantile spasms, and a within-group trial change is not the same as a treatment effect.

Today’s acute-care thread begins with superwarfarin toxicity. Flank pain and haematuria may suggest renal pathology, but accompanying gingival bleeding, unexplained bruising or spontaneous internal haemorrhage should prompt early coagulation studies. A profoundly raised international normalised ratio has a narrow differential, so ask about prescribed anticoagulants, rodenticides and possible repeated or remote exposure. Superwarfarins inhibit vitamin K recycling, preventing activation of factors II, VII, IX and X. Their tissue accumulation and slow release can sustain anticoagulation for weeks or months.

Management depends on bleeding severity rather than the laboratory result alone. Life-threatening haemorrhage requires immediate factor replacement, usually four-factor prothrombin complex concentrate, together with intravenous vitamin K. Vitamin K supports new factor synthesis but acts too slowly to replace immediate reversal. Severe coagulopathy without major bleeding may be treated with vitamin K alone. A normalised international normalised ratio at discharge does not mean the toxic effect has ended, so prolonged oral treatment, serial monitoring and early toxicology or poison-centre involvement remain important.

Hyponatraemia also resists one-number management. Hypotonic hyponatraemia reflects excess free water relative to body solute, and urine measurements are a snapshot of a changing process. In true hypovolaemia, isotonic crystalloid restores circulating volume, suppresses antidiuretic hormone release and allows retained water to be excreted. In syndrome of inappropriate antidiuretic hormone secretion, the practical question is whether the kidneys can excrete electrolyte-free water under the proposed restriction.

Urine osmolality above 500 mOsm/kg or a urine sodium-plus-potassium to serum sodium ratio above 1 predicts that fluid restriction alone is unlikely to succeed. This should prompt earlier consideration of another strategy rather than several days of ineffective restriction. Every drink counts, and a measured daily allocation makes the plan tangible. Dietary protein or urea can increase urinary solute, while loop diuretics reduce the medullary concentration gradient needed for passive water reabsorption. Review medicines carefully when a new antipsychotic or anticonvulsant may be contributing, and match endocrine tests or repeat imaging to clinical features and previous results.

The paediatric material focuses on infantile epileptic spasms syndrome. Brief flexion or extension movements become concerning when they are stereotyped, cluster around waking, increase in frequency or accompany developmental plateau or regression. Caregiver video can improve recognition. A normal awake-only electroencephalogram does not reliably exclude the diagnosis, so urgent video electroencephalography should capture sleep and, where possible, a typical cluster.

Assessment includes developmental, neurological and skin examination, with attention to hypopigmented ash-leaf macules, followed by brain magnetic resonance imaging and genetic testing after diagnosis. Treatment should not wait for the full historical triad when the clinical or electrographic appearance is convincing. High-dose prednisolone is commonly used first line when tuberous sclerosis and steroid contraindications are absent; vigabatrin is particularly effective when tuberous sclerosis is present. Review clinical response after about one week and repeat electroencephalography at two weeks, changing treatment promptly when spasms or the abnormal EEG pattern persist.

The emergency and prehospital evidence review applies the same caution to pulmonary embolism, transfusion and resuscitation. Suspected pulmonary embolism should move through documented pre-test probability, D-dimer testing where appropriate and CT pulmonary angiography when indicated. A reassuring bedside echocardiogram does not exclude pulmonary embolism; it mainly assesses right-heart impact after diagnosis. In haemodynamically unstable disease, no single advanced reperfusion strategy is established for every patient, so senior case-by-case decisions should integrate physiology, bleeding risk, imaging and local capability.

Whole blood may simplify prehospital storage and administration, but the neutral SWIFT trial does not demonstrate a clinical advantage over plasma plus packed red cells, nor prove equivalence in every dose or setting. Helicopter emergency medical service provision and 24-hour physician coverage vary, creating unequal access to enhanced prehospital care. Physiological guidance during cardiopulmonary resuscitation may show whether compressions generate useful pressure, but small studies with late transoesophageal echocardiography deployment do not establish survival benefit. Ultrasound-guided pericardial catheter drainage remains a rescue option only for carefully selected non-arrest patients with traumatic tamponade when definitive surgery is unavailable.

The specialist evidence update examines cemdisiran, a small interfering RNA treatment targeting complement C5 in antibody-positive generalised myasthenia gravis. In the phase 3 trial, monotherapy reduces the Myasthenia Gravis Activities of Daily Living score by 4.5 points, compared with 2.2 points for placebo. The 2.3-point placebo-adjusted difference meets the stated two-point threshold for clinical meaning. Combination treatment produces a 4.0-point reduction, challenging the assumption that two C5-targeting treatments must outperform monotherapy. Respiratory infections occur in active and placebo groups, no meningococcal infections are reported, and the mechanism producing benefit remains uncertain. The findings apply to the selected adult, antibody-positive population with a baseline score greater than 6.

Across the collection, the practical lesson is consistent: define the clinical question, choose the test or intervention that answers it, and separate temporary correction, operational advantage or within-group change from demonstrated patient-centred benefit.