APMLE Part II cheat sheet

Peripheral arterial disease: classic claudication is cramping leg pain reproducibly provoked by exercise and relieved by rest within 2–5 minutes; critical limb ischemia causes rest pain, often nocturnal and relieved by dependency.

Diabetic peripheral neuropathy screening: 10-g monofilament tests large-fiber protective sensation; vibration (128 Hz tuning fork) and proprioception assess large fibers; pinprick and temperature assess small fibers.

Ankle-brachial index (ABI) interpretation: 0.90–1.30 normal; 0.70–0.89 mild-to-moderate PAD; 0.40–0.69 moderate-to-severe; <0.40 severe; >1.30 suggests non-compressible calcified vessels (diabetes, CKD).

Ottawa ankle rules: ankle X-ray indicated if pain in malleolar zone plus bone tenderness at posterior edge or tip of lateral or medial malleolus, or inability to bear weight both immediately and in the ED.

Ottawa foot rules: foot X-ray indicated if pain in midfoot zone plus bone tenderness at navicular or base of fifth metatarsal, or inability to bear weight both immediately and in the ED.

Capillary refill >2 seconds, dependent rubor, and absence of hair growth over the dorsum of the foot suggest chronic arterial insufficiency; venous insufficiency shows hemosiderin staining, edema, and stasis dermatitis.

Charcot neuroarthropathy: acute presentation is a warm, swollen, erythematous foot without ulceration; history of minor trauma in a diabetic with neuropathy; skin temperature difference >2°C versus contralateral foot is suggestive.

Red flags for low back pain: age >50 with new pain, history of cancer, unexplained weight loss, fever, intravenous drug use, bowel or bladder dysfunction, saddle anesthesia, and progressive neurologic deficit.

Plain radiographs are first-line for acute trauma, foreign bodies, and bone lesions; they detect fractures, dislocations, and osseous alignment but not soft-tissue or early marrow pathology.

MRI is the modality of choice for osteomyelitis (marrow edema on T2/STIR, low T1 signal), soft-tissue abscess, and suspected Charcot; it is contraindicated with certain cardiac pacemakers and metallic foreign bodies.

Bone scan (three-phase) is sensitive but not specific for osteomyelitis; a positive scan in the setting of a diabetic foot ulcer requires clinical correlation because of false positives from Charcot or recent surgery.

Duplex ultrasound is first-line for suspected deep vein thrombosis and for evaluating lower-extremity arterial stenosis; it is noninvasive and avoids iodinated contrast and radiation.

CT angiography and MR angiography are used for preoperative arterial mapping; CT requires iodinated contrast (risk of contrast-induced nephropathy) and MR requires gadolinium (risk in severe renal impairment).

Erythrocyte sedimentation rate and C-reactive protein are useful adjuncts for osteomyelitis and septic arthritis but lack specificity; serial CRP is useful for monitoring treatment response.

Synovial fluid analysis: normal is clear, <200 WBC/mm³; noninflammatory <2,000; inflammatory 2,000–50,000; septic typically >50,000 with >90% neutrophils; crystals indicate gout (negatively birefringent) or pseudogout (positively birefringent).

Serum uric acid may be normal during an acute gout flare; diagnosis is best confirmed by synovial fluid crystal analysis, not by serum urate level alone.

Diabetic foot ulcer offloading: total contact cast is the gold standard for plantar neuropathic ulcers; removable cast walkers or healing sandals are alternatives when casting is contraindicated.

Osteomyelitis of the foot: obtain bone culture (not just wound swab) before antibiotics; typical pathogens are Staphylococcus aureus (including MRSA), streptococci, and in chronic or diabetic wounds, gram-negative rods and anaerobes.

Wagner classification of diabetic foot ulcers: grade 0 intact skin; 1 superficial ulcer; 2 ulcer to tendon/bone; 3 deep ulcer with abscess or osteomyelitis; 4 localized gangrene; 5 extensive gangrene.

Acute compartment syndrome: pain out of proportion, pain with passive stretch, paresthesia, pallor, paralysis, pulselessness (late); fasciotomy is emergent and should not be delayed for compartment pressure measurement when clinical suspicion is high.

Achilles tendon rupture: positive Thompson (Simmonds) test, palpable gap, and inability to plantarflex; acute repair is generally recommended in active patients; nonoperative management with functional bracing is an option in low-demand patients.

Ankle sprain: lateral ligament complex (ATFL most commonly) injured with inversion; grade I–II managed with functional bracing and early mobilization; grade III may require immobilization; chronic instability may need surgical reconstruction.

Plantar fasciitis: first-line management is stretching, orthoses, and night splints; corticosteroid injection provides short-term relief but repeated injections risk plantar fascia rupture.

Venous leg ulcers: compression therapy is the cornerstone; healing rates improve with multilayer compression; arterial disease must be excluded (ABI) before applying compression.

Windlass mechanism: dorsiflexion of the metatarsophalangeal joints tightens the plantar fascia, elevating the arch and stabilizing the midfoot during push-off.

Subtalar joint neutral position and forefoot-to-rearfoot alignment determine whether an orthosis is posted for pronation or supination; a rigid forefoot varus is compensated by rearfoot pronation.

First metatarsophalangeal joint hallux valgus angle >15° and intermetatarsal angle >9° define hallux valgus; severe deformity may require osteotomy (e.g., chevron or Scarf) with soft-tissue release.

Ankle mortise stability depends on the deltoid ligament medially and the lateral collateral ligaments laterally; the syndesmosis (AITFL, PITFL, interosseous membrane) must be evaluated in Weber C fractures.

Limb-length discrepancy: functional (pelvic obliquity, contracture) versus structural (true bone shortening); measured clinically by block test and confirmed by scanogram.

Gait cycle: stance phase ~60% and swing phase ~40%; double support ~10% each cycle; abnormal pronation is prolonged or excessive subtalar eversion during stance.

Screw-home mechanism of the knee: terminal knee extension is accompanied by external rotation of the tibia, locking the joint and reducing muscular work during stance.

Charcot foot biomechanics: loss of protective sensation and autonomic dysfunction lead to repetitive microtrauma, midfoot collapse, and rocker-bottom deformity; offloading and immobilization are essential in the acute phase.

Pressure injury staging (NPIAP): stage 1 nonblanchable erythema; 2 partial-thickness loss with dermis exposed; 3 full-thickness loss with subcutaneous fat visible; 4 full-thickness with fascia, muscle, tendon, or bone exposed; unstageable when eschar or slough obscures depth.

Wound bed preparation: TIME framework-Tissue debridement, Infection/inflammation control, Moisture balance, and Edge advancement.

Infected wound signs: increasing pain, erythema, warmth, purulent drainage, foul odor, and systemic signs; obtain culture after cleansing and debridement, not from superficial swab alone.

Moist wound healing is superior to dry healing; choose dressings by exudate level-hydrocolloids for low exudate, foams and alginates for moderate to heavy exudate, and hydrogels for dry wounds.

Tinea pedis: interdigital maceration and scaling; treat with topical azoles or terbinafine; coexisting onychomycosis may require oral terbinafine, and confirm diagnosis with KOH preparation or culture.

Cellulitis: acute, unilateral, warm, tender erythema with ill-defined borders; Streptococcus pyogenes and Staphylococcus aureus are common; mark borders and reassess; elevate the limb.

Venous stasis dermatitis: erythema, scaling, pruritus, and hemosiderin deposition in the gaiter region; treat with compression and emollients; avoid topical steroids long-term on thin skin.

Diabetic foot ulcer assessment: probe to bone (positive predictive for osteomyelitis), measure area and depth, assess for infection and ischemia, and document neurovascular status.

Diabetes mellitus diagnostic criteria: fasting plasma glucose ≥126 mg/dL, 2-hour OGTT glucose ≥200 mg/dL, HbA1c ≥6.5%, or random glucose ≥200 mg/dL with symptoms; confirm with repeat testing unless unequivocal hyperglycemia.

Diabetic foot examination annually (more often if high risk): monofilament, vibration, pulses, ABI when indicated, and inspection for deformity, callus, and ulceration.

Gout: monosodium urate crystals (needle-shaped, negatively birefringent) in synovial fluid; acute treatment with NSAIDs, colchicine, or corticosteroids; urate-lowering therapy (allopurinol, febuxostat) is not started during an acute flare in most patients.

Rheumatoid arthritis: symmetric polyarthritis of small joints, morning stiffness >1 hour, positive RF or anti-CCP; foot involvement commonly affects the MTP joints with subluxation and hammer toe deformity.

Peripheral arterial disease risk factors: smoking, diabetes, hypertension, hyperlipidemia, and chronic kidney disease; smoking cessation is the single most important modifiable intervention.

Chronic kidney disease: monitor eGFR and urine albumin-to-creatinine ratio; dose-adjust renally cleared drugs (e.g., gabapentin, many antibiotics) and avoid nephrotoxins such as NSAIDs in advanced CKD.

Hypothyroidism: fatigue, weight gain, cold intolerance, bradycardia, and delayed relaxation phase of deep tendon reflexes; screen with TSH and confirm with free T4.

Metabolic syndrome: central obesity, elevated triglycerides, low HDL, elevated blood pressure, and impaired fasting glucose; presence of three or more criteria increases cardiovascular risk.

NSAIDs: inhibit cyclooxygenase, reducing prostaglandin synthesis; adverse effects include GI ulceration, renal impairment, and increased cardiovascular risk; avoid in CKD and with anticoagulants when possible.

Acetaminophen: hepatotoxic in overdose; maximum adult dose generally 3–4 g/day; caution with chronic alcohol use and liver disease; useful when NSAIDs are contraindicated.

Opioids: risk of respiratory depression, constipation, and dependence; co-prescribe naloxone when risk factors are present; reassess benefit and consider tapering when function does not improve.

Antibiotic selection for diabetic foot infection: mild infections-oral agents covering staphylococci and streptococci; moderate-severe-parenteral broad-spectrum with MRSA coverage when risk factors exist; adjust to culture results.

Corticosteroid injection: provides short-term relief in plantar fasciitis and other tendinopathies; risks include tendon rupture, skin atrophy, and infection; limit frequency of injections.

Warfarin: monitor INR; vitamin K antagonists are affected by diet and many drugs; direct oral anticoagulants (apixaban, rivaroxaban) do not require routine INR monitoring but have renal dose adjustments.

Gabapentin and pregabalin for neuropathic pain: start low and titrate; renally dose-adjusted; adverse effects include sedation, dizziness, and peripheral edema.

Allopurinol: titrate to target serum urate (<6 mg/dL typically); screen for HLA-B*5801 in high-risk populations (e.g., Han Chinese, Korean, Thai) before starting to reduce risk of severe cutaneous reactions.

Informed consent requires disclosure of diagnosis, nature and purpose of proposed treatment, risks and benefits, alternatives, and consequences of refusal; the patient must have decision-making capacity.

Patient confidentiality is protected by HIPAA; disclosures require patient authorization or a legal exception (e.g., mandated reporting, serious threat to identifiable persons).

Mandated reporting: suspected child abuse, elder abuse, and certain communicable diseases must be reported to appropriate authorities per state law.

Conflict of interest: disclose financial relationships with industry; avoid accepting gifts that could influence clinical judgment; follow institutional and professional society policies.

Documentation: record history, examination, assessment, plan, informed consent discussions, and patient instructions; accurate and timely records are both a legal and ethical obligation.

Billing and coding: use accurate ICD-10-CM diagnosis codes and CPT procedure codes; upcoding and unbundling are fraudulent; maintain documentation that supports the level of service billed.

Impaired colleague: the duty to protect patients may require reporting a colleague whose impairment affects patient safety to the appropriate authority or impaired-physician program.

Cultural humility and shared decision-making: elicit patient values and preferences, use qualified interpreters when language barriers exist, and avoid relying on family members for interpretation of sensitive information.

Open-ended questioning (e.g., 'Tell me more about the pain') elicits the patient's agenda and improves diagnostic accuracy compared with leading questions.

The teach-back method: ask the patient to explain the plan in their own words to confirm understanding; it improves adherence and identifies gaps in comprehension.

Motivational interviewing: use open questions, affirmations, reflections, and summaries (OARS) to explore ambivalence and support behavior change, such as smoking cessation.

Breaking bad news: SPIKES framework-Setting, Perception, Invitation, Knowledge, Empathy, Strategy and summary.

Shared decision-making: present options with risks and benefits, explore patient values, and reach a decision together; document the discussion.

Health literacy: use plain language, limit information to 3–5 key points, avoid jargon, and supplement verbal instructions with written or visual materials.

Nonverbal communication: maintain eye contact, sit at the patient's level, and attend to facial expression and body language; these influence patient trust and satisfaction.

Difficult conversations: acknowledge emotion with empathic statements (NURSE: Name, Understand, Respect, Support, Explore) before providing further information.