MDC PQE cheat sheet

Acute coronary syndrome: ST-elevation on ECG mandates immediate reperfusion (primary PCI within 90 minutes of first medical contact at a PCI-capable centre); do not wait for troponin results.

Community-acquired pneumonia severity: CURB-65 scores Confusion, Urea >7 mmol/L, Respiratory rate >=30/min, Blood pressure (SBP <90 or DBP <=60), Age >=65; score 0-1 = outpatient, 2 = consider admission, >=3 = inpatient, 4-5 = ICU assessment.

Diabetic ketoacidosis: pH <7.3, bicarbonate <18 mmol/L, ketonaemia, and anion gap >12 with glucose usually >11 mmol/L; management is isotonic saline, IV insulin after potassium is >=3.3 mmol/L, and potassium replacement.

Anaphylaxis: intramuscular adrenaline 0.5 mg (0.5 mL of 1:1000) into the anterolateral thigh for adults, repeated every 5 minutes as needed; antihistamines and steroids are adjuncts only.

Hyponatraemia correction: limit rise to <=10 mmol/L in the first 24 hours (<=8 in chronic or high-risk cases) to avoid osmotic demyelination; use hypertonic saline only for severe symptoms.

Hyperkalaemia with ECG changes: IV calcium gluconate first for cardiac membrane stabilisation, then insulin-dextrose and salbutamol to shift potassium intracellularly; dialysis for refractory cases.

Stroke: non-contrast CT excludes haemorrhage before thrombolysis; IV alteplase window is up to 4.5 hours from onset, and mechanical thrombectomy up to 6 hours (selected patients up to 24 hours with imaging).

Sepsis: qSOFA (respiratory rate >=22, altered mentation, systolic BP <=100 mmHg) flags risk; give broad-spectrum antibiotics within 1 hour of recognition of septic shock.

Thyroid storm: Burch-Wartofsky Point Scale >=45 is highly suggestive; treat with propylthiouracil or methimazole, beta-blocker, iodine load at least 1 hour after thionamide, plus supportive care and steroids.

Periodontal staging: Stage I = clinical attachment loss 1-2 mm, Stage II = 3-4 mm, Stage III = >=5 mm with tooth loss <=4, Stage IV = >=5 mm with >=5 teeth lost or need for complex rehabilitation.

Periodontal grading uses bone loss/age ratio: Grade A <0.25, Grade B 0.25-1.0, Grade C >1.0, modified upward by smoking status and HbA1c >=7.0%.

Pulp diagnosis terms: reversible pulpitis = provoked pain resolving after stimulus removal; irreversible pulpitis = spontaneous or lingering pain; symptomatic apical periodontitis = pain on biting with tender percussion.

Dental trauma: an avulsed permanent tooth is replanted immediately if extraoral dry time <60 minutes; store in milk, saline, or HBSS, and splint flexibly for 2 weeks.

Local anaesthetic maximum doses (adult): lidocaine 4.4 mg/kg (with adrenaline 7 mg/kg), articaine 7 mg/kg, mepivacaine 6.6 mg/kg, prilocaine 8 mg/kg; 1 cartridge of 2% lidocaine with 1:100,000 = 36 mg.

Antibiotic prophylaxis before invasive dental procedures is indicated for prosthetic heart valves, previous infective endocarditis, and certain congenital cardiac conditions; it is not indicated for prosthetic joints or routine mitral valve prolapse.

Caries risk and recall: recall interval is risk-based (high risk 3-6 months, low risk up to 12-24 months), and fluoride varnish 22,600 ppm is applied at least twice yearly for high-risk patients.

Odontogenic infection spread: submandibular or sublingual space involvement with floor-of-mouth elevation or dysphagia indicates a Ludwig angina emergency requiring airway assessment, IV antibiotics, and urgent surgical drainage.

Radiography selection: bitewings detect interproximal caries and crestal bone loss; periapicals are required when the apical region or full root length must be assessed.