{"title": "Chapter 2: Common Symptoms and Clinical Decision-Making", "flashcards": [{"q": "Name the SOCRATES mnemonic for pain history.", "a": "Site, Onset, Character, Radiation, Associations, Time course, Exacerbating/relieving factors, Severity (0–10). A systematic approach ensures no dimension of the pain history is omitted and guides differential diagnosis."}, {"q": "What are the red-flag symptoms for new-onset headache?", "a": "SNOOP4: Systemic symptoms (fever, weight loss); Neurological deficit; Onset sudden ('thunderclap'); Older patient (new headache >50); Postural component; Papilloedema; Progressive or worsening pattern; Precipitated by Valsalva. Any red flag warrants urgent CT head ± LP."}, {"q": "Define syncope and distinguish it from pre-syncope and seizure.", "a": "Syncope: transient loss of consciousness due to global cerebral hypoperfusion, with spontaneous complete recovery. Pre-syncope: prodromal symptoms (lightheadedness, visual dimming) without full LOC. Key seizure distinguishing features: prolonged post-ictal phase, tongue biting, incontinence, tonic-clonic movements before LOC, or no prodrome."}, {"q": "What is Bayes' theorem in the clinical context?", "a": "Post-test probability = sensitivity × pre-test probability / [sensitivity × pre-test probability + (1−specificity) × (1−pre-test probability)]. Clinically: a positive test for a rare condition in a low-prevalence population has a lower positive predictive value than the same test in a high-prevalence population. Pre-test probability fundamentally determines clinical utility."}, {"q": "Name four causes of unintentional weight loss >5% over 6 months.", "a": "Malignancy (most feared; accounts for ~25% of cases); endocrine disease (T1DM, hyperthyroidism, Addison's); GI malabsorption (coeliac disease, IBD, pancreatic insufficiency); chronic infection (TB, HIV, IE); psychiatric causes (depression, anorexia nervosa); medication-induced; cardiac cachexia."}, {"q": "What is the clinical significance of pulsus paradoxus?", "a": "An inspiratory fall in systolic BP >10 mmHg. Causes: cardiac tamponade (most classic), severe asthma/COPD, tension pneumothorax, constrictive pericarditis. It reflects exaggerated ventricular interdependence — inspiratory right heart filling compresses the left ventricle in a fixed pericardial space or obstructed airway."}, {"q": "Describe the clinical features of anaphylaxis.", "a": "Rapid onset of: (1) skin/mucosa (urticaria, flushing, angioedema); (2) respiratory compromise (bronchospasm, stridor, hypoxia); (3) cardiovascular collapse (hypotension, tachycardia); (4) GI symptoms (nausea, vomiting). IM adrenaline 0.5 mg (1:1000) into anterolateral thigh is first-line treatment."}, {"q": "What is the likelihood ratio and how does it modify pre-test probability?", "a": "LR+ = sensitivity / (1−specificity). LR− = (1−sensitivity) / specificity. LR+ >10 or LR− <0.1 are clinically significant. Applied via Fagan nomogram: post-test probability = LR × pre-test odds / (1 + LR × pre-test odds). High LR+ 'rules in'; low LR− 'rules out'."}, {"q": "Name three conditions causing acute confusional state (delirium) in an elderly patient.", "a": "Infection (most common — UTI, pneumonia, sepsis); metabolic disturbance (uraemia, hepatic encephalopathy, hypoglycaemia, electrolyte abnormality); drugs (opioids, benzodiazepines, anticholinergics, steroids); alcohol withdrawal; intracranial event (stroke, SDH); urinary retention/faecal impaction; hypoxia."}, {"q": "What is the Ottawa Ankle Rule and when does it apply?", "a": "The Ottawa Ankle Rule indicates ankle X-ray only if bone tenderness at the posterior edge/tip of lateral or medial malleolus, OR inability to weight-bear four steps. It reduces unnecessary radiography by ~30–40% and has sensitivity approaching 100% for clinically significant fractures. Apply in acute ankle injury without deformity or neurovascular compromise."}], "quiz": [{"q": "A 72-year-old presents with acute onset confusion, fever 38.9°C, and a urinary catheter in situ. CRP is 180. What is the most important immediate step?", "opts": ["CT head", "Blood cultures before antibiotics, then empirical antibiotics", "LP", "ECG"], "ans": 1, "exp": "Sepsis from a urinary source is the most likely diagnosis. Blood cultures must be taken before antibiotics (ideally within 1 hour of recognition per SSC Hour-1 Bundle), then empirical broad-spectrum antibiotics started. Catheter should be changed. Do not delay treatment for imaging unless meningitis is the primary concern."}, {"q": "Which feature best distinguishes cardiac from vasovagal syncope?", "opts": ["Occurs in hot environments", "No prodrome, occurring during exertion or supine", "Brief post-ictal confusion", "Preceded by nausea and diaphoresis"], "ans": 1, "exp": "Cardiac syncope characteristically has no or minimal prodrome and may occur during exertion (aortic stenosis, HOCM, arrhythmia) or even when supine (arrhythmia). Vasovagal syncope has a typical warm, prodrome of nausea, diaphoresis, and greying of vision, often triggered by pain, prolonged standing, or emotion."}, {"q": "What does a Likelihood Ratio Positive (LR+) of 10 mean clinically?", "opts": ["Test is 10% sensitive", "A positive result is 10 times more likely to come from a diseased person than a non-diseased person", "The test has 90% specificity", "The test correctly classifies 10% of patients"], "ans": 1, "exp": "LR+ = sensitivity / (1−specificity). LR+ of 10 means that a positive test result is 10× more likely in someone with the disease than without. Combined with pre-test probability via Fagan nomogram, this produces post-test probability. LR+ >10 meaningfully 'rules in' disease."}, {"q": "What is the most common cause of acute diarrhoea in adults in the UK?", "opts": ["Campylobacter jejuni", "Norovirus (viral gastroenteritis)", "Salmonella", "Clostridioides difficile"], "ans": 1, "exp": "Norovirus is the most common cause of acute infectious gastroenteritis in the UK, responsible for ~3 million cases per year. It causes brief (24–72h) watery diarrhoea, vomiting, and low-grade fever. It is highly contagious and spread via faeco-oral route and contaminated food."}, {"q": "A 45-year-old woman presents with fatigue, weight gain, constipation, and cold intolerance. What is the single most useful initial test?", "opts": ["Full blood count", "TSH (thyroid stimulating hormone)", "ESR", "Cortisol"], "ans": 1, "exp": "The clinical picture is consistent with hypothyroidism. TSH is the best single screening test — elevated TSH with low T4 confirms primary hypothyroidism. TSH alone is sufficient for initial screening; free T4 confirms severity and is used in monitoring levothyroxine therapy."}, {"q": "What does the Wells score assess in the context of suspected DVT?", "opts": ["Severity of pulmonary embolism", "Pre-test probability of deep vein thrombosis", "Bleeding risk in anticoagulated patients", "Cardiac risk in surgery"], "ans": 1, "exp": "The Wells DVT score uses clinical features to estimate pre-test probability of DVT. Scores ≥2 = high probability → go directly to imaging. Scores <2 = low probability → D-dimer first. A negative D-dimer with low Wells score effectively excludes DVT without ultrasound."}, {"q": "Which investigation is first-line for suspected aortic dissection in a haemodynamically stable patient?", "opts": ["Chest X-ray", "CT aortogram with contrast", "Transthoracic echo", "MRI aorta"], "ans": 1, "exp": "CT aortogram (ECG-gated CT angiography) is the gold standard for diagnosing aortic dissection — fast, widely available, and delineates the extent of dissection, branch vessel involvement, and complications. CXR may show widened mediastinum but cannot diagnose dissection. TOE is useful in unstable patients who cannot safely undergo CT."}, {"q": "What is clinical reasoning by 'illness scripts'?", "opts": ["Following a fixed flowchart algorithm", "Pattern-matching to learned prototypical clinical presentations", "Ordering all tests before forming a differential", "Using only evidence-based guidelines"], "ans": 1, "exp": "Illness scripts are cognitive representations of disease built from clinical experience — comprising epidemiology, predisposing conditions, pathophysiology, and clinical features. Expert clinicians rapidly match a patient's presentation to a stored illness script, enabling efficient pattern recognition and diagnosis."}, {"q": "A patient presents with unilateral painless vision loss, described as a curtain descending. What is the most likely diagnosis?", "opts": ["Central retinal artery occlusion", "Retinal detachment", "Acute angle-closure glaucoma", "Temporal arteritis"], "ans": 1, "exp": "A curtain-like descending or ascending visual field defect is the classic description of retinal detachment as the detached retina progressively blocks the visual field. It is a ophthalmic emergency requiring urgent ophthalmology referral; delay risks macular involvement and permanent vision loss."}, {"q": "Which is the most common reason for polypharmacy-related adverse drug reactions in elderly patients?", "opts": ["Renal impairment reducing drug clearance", "Drug-drug interactions from multiple concurrent medications", "Patient non-compliance", "Incorrect dosing by the prescriber"], "ans": 0, "exp": "Age-related decline in renal function (reduced GFR) is the most important pharmacokinetic change in elderly patients, reducing clearance of renally excreted drugs (digoxin, metformin, LMWHs, many antibiotics). This leads to drug accumulation and toxicity at standard doses. The STOPP/START criteria guide medication review."}, {"q": "What is the test of choice to confirm iron deficiency anaemia when serum ferritin is equivocal?", "opts": ["Serum iron", "Transferrin saturation", "Soluble transferrin receptor (sTfR) or sTfR/log ferritin index", "Peripheral blood film"], "ans": 2, "exp": "Serum ferritin is an acute-phase reactant and may be falsely normal in iron deficiency coexisting with inflammation. Soluble transferrin receptor (sTfR) rises with iron deficiency regardless of inflammation, making it the most useful test when ferritin is equivocal in inflammatory states (CKD, malignancy, chronic infection)."}, {"q": "A 28-year-old woman has a 4-month history of widespread musculoskeletal pain, fatigue, and poor sleep. Examination and investigations are normal. What is the most likely diagnosis?", "opts": ["Systemic lupus erythematosus", "Fibromyalgia", "Rheumatoid arthritis", "Hypothyroidism"], "ans": 1, "exp": "Fibromyalgia presents with chronic widespread pain (≥3 months), fatigue, and non-restorative sleep, often with cognitive difficulties ('fibro fog'). Examination and standard investigations are normal. Diagnosis uses the 2016 ACR criteria (Widespread Pain Index ≥7 + Symptom Severity Scale ≥5). Management: exercise, CBT, amitriptyline."}, {"q": "What is the 'rule of thumb' for estimating Body Surface Area (BSA) affected in burn injuries?", "opts": ["Berkow formula", "Wallace Rule of Nines", "Lund and Browder chart", "Baux score"], "ans": 1, "exp": "Wallace Rule of Nines assigns 9% BSA to each arm, head, and neck; 18% to anterior and posterior trunk each; 18% to each leg; 1% to perineum. It enables rapid estimation for fluid resuscitation calculation. The Lund and Browder chart is more accurate in children."}, {"q": "Which symptom triad suggests Horner's syndrome?", "opts": ["Ptosis, miosis, anhidrosis", "Ptosis, mydriasis, anhidrosis", "Proptosis, lid retraction, ophthalmoplegia", "Nystagmus, ataxia, diplopia"], "ans": 0, "exp": "Horner's syndrome results from interruption of the oculosympathetic pathway: ptosis (partial — superior tarsal muscle), miosis (pupillary dilation fails), and anhidrosis (ipsilateral to the lesion). Causes include Pancoast tumour, carotid artery dissection, lateral medullary syndrome, and neck trauma."}, {"q": "What does a low serum albumin indicate in the context of clinical assessment?", "opts": ["Nephrotic syndrome exclusively", "Poor nutritional status, chronic inflammation, or hepatic synthetic dysfunction", "Haemoconcentration", "Vitamin D deficiency"], "ans": 1, "exp": "Hypoalbuminaemia reflects: reduced hepatic synthesis (cirrhosis, acute illness, malnutrition); increased loss (nephrotic syndrome, protein-losing enteropathy); or dilution (overhydration). Serum albumin is an independent predictor of morbidity and mortality in hospitalised patients and affects drug binding (particularly for phenytoin and warfarin)."}, {"q": "What is 'anchoring bias' in clinical reasoning?", "opts": ["Relying too heavily on the first information received when making decisions", "Over-testing to confirm a diagnosis", "Selecting tests based on cost", "Using guidelines without applying clinical judgement"], "ans": 0, "exp": "Anchoring bias occurs when a clinician fixes on an initial diagnosis and fails to update their assessment as new, contradictory information emerges. It is among the most common cognitive errors in medicine. Forced reconsideration ('diagnostic timeout') and structured differential generation mitigate anchoring."}, {"q": "Which scoring system is used to assess functional status and predict surgical risk?", "opts": ["APACHE II", "Eastern Cooperative Oncology Group (ECOG) Performance Status", "CURB-65", "Wells score"], "ans": 1, "exp": "ECOG Performance Status (0–5 scale) assesses functional ability: 0 = fully active; 1 = restricted strenuous activity; 2 = ambulatory, self-care, unable to work; 3 = limited self-care; 4 = completely disabled; 5 = dead. It is widely used in oncology and surgical risk assessment to guide treatment decisions."}, {"q": "What is the 'first do no harm' principle (non-maleficence) in clinical practice?", "opts": ["Always obtain informed consent", "Weigh potential benefits of treatment against risks of harm before intervening", "Refer all patients to a specialist", "Avoid prescribing any medication with side effects"], "ans": 1, "exp": "Non-maleficence (primum non nocere) requires that clinicians weigh the potential harms of an intervention against its benefits. It underpins decisions to withhold aggressive treatment in terminal illness, caution with high-risk procedures in frail patients, and rational prescribing minimising side effects."}, {"q": "A 62-year-old presents with a 2-month history of dysphagia to solids, 8 kg weight loss, and iron deficiency anaemia. What is the most likely underlying diagnosis?", "opts": ["Oesophageal stricture from GORD", "Oesophageal or gastric malignancy", "Achalasia", "Oropharyngeal dysphagia from stroke"], "ans": 1, "exp": "Progressive dysphagia beginning with solids, significant unintentional weight loss, and iron deficiency anaemia in an older patient constitutes a red-flag presentation for oesophageal or gastric cancer. Urgent upper GI endoscopy and biopsy is mandatory. Two-week wait (2WW) cancer pathway referral is appropriate."}, {"q": "What is the difference between sensitivity and specificity?", "opts": ["Sensitivity is for ruling in; specificity is for ruling out", "Sensitivity measures true positives; specificity measures true negatives", "Sensitivity applies to blood tests only; specificity to imaging", "Sensitivity is the positive predictive value"], "ans": 1, "exp": "Sensitivity = TP/(TP+FN) — probability of a positive test given disease is present (high sensitivity 'rules out' if negative: SnNOut). Specificity = TN/(TN+FP) — probability of a negative test given disease is absent (high specificity 'rules in' if positive: SpPin). Both are intrinsic test properties, independent of prevalence."}]}