--- module: 063-02 language: en chapter: 63 title: "Fever, Collapse, Dizziness, Weakness, and Undifferentiated Acute Illness" module_title: "Syndrome clarification, high-risk collapse, dynamic observation, and safe uncertainty" source_sha256: 40b0ebe926029bef8aca03d59afba96ab200705860ab32fc748b746fb9813fbe --- # Clarification, high-risk collapse, observation, safe uncertainty ## Clarifying vague labels ### Translate labels into failed functions and a timeline #### Collapse: syncope, seizure, fall, intoxication, sleep #### Dizziness: motion illusion, faint, imbalance #### Weakness: force, fatigue, pain, dyspnoea, initiative ### Clarify alongside stabilisation ## First observations and hidden shock ### Look before instruments are attached ### Interventions normalise numbers without removing cause #### Record lowest pre-intervention state ### Compensated shock with normal blood pressure #### Integrate pulse pressure, refill, oliguria, lactate trend #### Young and pregnant compensate strongly #### Beta-blocker or pacemaker prevents tachycardia ### Concealed haemorrhage, embolism, aortic disease ## Fever, hyperthermia, infection ### Cytokines raise hypothalamic set point #### Vasoconstriction and shivering cause chill #### Vasodilation and sweating when set point falls ### Hyperthermia: no raised set point #### Rapid cooling without waiting for infection tests ### Infection without fever in vulnerable groups ### Fever does not prove infection ### Cultures useful in sepsis, harmful if contaminated ### Antibiotics proportional, daily reassessment ## Syncope and high-risk collapse ### Global cerebral hypoperfusion, rapid recovery ### Witness detail on posture, trigger, recovery ### Reflex features: nausea, warmth, sweating, dimming ### Cardiac risk features #### Unheralded exertional or supine collapse ### Pregnancy: ectopic pregnancy and haemorrhage ### Postpartum: haemorrhage, embolism, cardiomyopathy ### Older people report a simple fall #### Facial injury, no protective reaction ### Exertional syncope: no sport or driving before diagnosis ## Seizure, orthostasis, rhythm ### Brief jerks do not prove epilepsy ### Seizure: aura, sustained tonic-clonic, sleep onset ### Normal interictal EEG does not exclude epilepsy ### Orthostatic heart-rate response #### Appropriate tachycardia: volume loss or pooling #### Small response: autonomic failure or drugs ### Brief normal measurement misses delayed hypotension ### Electrocardiogram cannot exclude intermittent arrhythmia ### Monitoring device matches event frequency ### Echocardiography answers a structural question ## Dizziness by timing and triggers ### Seconds, triggered by rolling: positional vertigo ### Spontaneous minutes to hours: migraine, Meniere, panic ### Continuous: neuritis or posterior-circulation stroke ### Triggered versus merely worsened by movement ### Central features raise stroke concern ### Head-impulse, nystagmus, skew: continuous syndrome only ### Imaging weak; repeat neurological and gait exam ## Weakness and respiratory threat ### True weakness after pain, effort, comprehension ### Upper motor neuron: brisk reflexes, plantar response ### Lower motor neuron: atrophy, fasciculation, low reflexes ### Junction fluctuates; muscle proximal, sensation kept ### Oximetry normal until late in ventilatory weakness #### Serial vital capacity, carbon dioxide, cough, swallow ### Measurements read as a trend #### Poor effort or mouth leak falsely low #### Fatiguing patient falls steeply ### Call intensive care before intubation is difficult ## Metabolic mimics and fatigue ### Potassium, phosphate, magnesium disorders ### Adrenal crisis treated before cortisol result ### Medication review and withdrawal ### Fatigue real but not muscle disease ### Untargeted panels entrench unsupported explanations ### Negative test does not invalidate disability ## Observation as a diagnostic intervention ### Specify duration, checks, escalation thresholds ### Nonspecific responses to fluid or antipyretic ### Predict in advance, then interpret ### Order states who re-examines and when ### Read laboratory values for direction ### Walking test checks pulse, oxygen, pressure ## Disposition, safety net, synthesis ### Integrate probability, reserve, function, support ### Normal test cannot make unsafe home safe ### Assign owner and deadline for pending results ### Teach-back and adapted written material ### Final synthesis states mechanism and alternatives ### Calibrated uncertainty is not failure #### False precision stops observation too early ### Temporary restriction of driving, swimming, heights