USMLE Blog
USMLE Step 2 CK High-Yield Musculoskeletal Topics
I hope you enjoy reading this blog post.
If you want our team’s expert help with your USMLE prep, click here
Musculoskeletal
High Yield USMLE Step 2 CK Notes
Welcome to the Musculoskeletal High-Yield Notes for Step 2 CK.
These are the most commonly tested topics on the exam—ideal for quick review in your last 2 weeks before the exam, when you’re short on time, or when you’re just starting out and want to focus on what is high yield. Created and peer-reviewed by physicians who scored 260+ on Step 2 CK in a Q&A style to reinforce active learning.
How to use this file
- Read the question ➔ cover the answer ➔ self-quiz before revealing.
- Review the NOTES ➔ they include high-yield details you don’t want to miss.
- Need tutoring? The Match Guy USMLE Tutoring.
- Don’t forget to watch the video lessons that go with this file. Learn more here.
Table of Contents
Spine
1. A 47-year-old woman presents with 1 week of low back pain radiating to the left buttock and lateral left leg, starting after lifting furniture. The exam shows paraspinal tenderness, normal reflexes, intact strength and sensation, and pain-limited movement. What is the most appropriate next step in management?
➔ Oral NSAIDs (e.g., ibuprofen)
- Note: Likely acute nonspecific low back pain → No neurologic deficits, no red-flag signs that require imaging as:
○ Saddle anesthesia
○ Urinary retention or incontinence
○ Rapidly progressing weakness
○ History of cancer, IV drug use, or trauma - Management:
○ Reassurance, physical therapy, and NSAIDs (e.g., ibuprofen). Most patients improve within 4 weeks.
○ Encourage early mobilization
○ Imaging is not needed unless red-flag signs develop or symptoms persist beyond 6 weeks
Differential Diagnosis of Low Back Pain
| Condition | Key Features |
|---|---|
| Mechanical (muscle strain) | Localized pain and tenderness of paraspinal muscles, no neuro signs, triggered by movement/lifting |
| Disc herniation | Radiculopathy, positive straight leg raise, dermatomal pain |
| Spinal stenosis | Pain worse with walking/standing, relieved by sitting/flexion |
| Vertebral osteomyelitis | Fever, IVDU, back tenderness, ↑ESR/CRP |
| Metastatic cancer | Constant pain, night pain, weight loss, history of malignancy |
| Epidural abscess | Triad: Fever + back pain + neurologic deficit |
| Cauda equina syndrome | Urinary retention, saddle anesthesia, decreased rectal tone (surgical emergency) |
2. A 77-year-old woman presents with chronic low back pain that worsens with prolonged standing or walking and improves with leaning forward. The exam shows decreased range of motion in all directions, positive straight-leg raise at 60°, and absent lower extremity reflexes. What is the most likely diagnosis?
➔ Lumbar spinal stenosis (Chronic back pain + neurogenic claudication + improves with flexion → think spinal stenosis)
- Note: Keys:
○ Back pain radiating to buttocks/legs with numbness, paresthesia, or weakness.
○ Worse with extension (e.g., walking, standing)
○ Improves with flexion (e.g., sitting, leaning forward) - Diagnosed by MRI of the lumbar spine
- Treated with NSAIDs and physical therapy. Surgery (decompression/laminectomy) if conservative management fails.
3. A 42-year-old man presents with acute right low back pain radiating to the buttocks and down the posterior leg after lifting heavy items. He has positive straight-leg raise and crossed-straight-leg raise tests but intact strength, reflexes, and sensation. What is the most appropriate next step in management?
➔ Conservative management (eg, NSAIDs, physical therapy, activity as tolerated) (Acute back pain + radiculopathy + no neurologic deficit → think Lumbar Disc Herniation → conservative treatment)
- Note: Diagnosis: Clinical (classic history + straight-leg raise test)
- Classic findings:
○ Pain radiates below the knee in a dermatomal pattern, worse with sitting or hip flexion.
○ Positive straight-leg raise test - No red flags (e.g., saddle anesthesia, incontinence, motor weakness) → No imaging needed initially
- Treatment:
○ NSAIDs or acetaminophen, maintain activity as tolerated (avoid bed rest), physical therapy, and reassess in ~6 weeks.
○ If red flags or no improvement after 6 weeks → MRI.
| Nerve Root | Motor Deficit | Reflex Affected | Sensory Loss |
|---|---|---|---|
| L4 | Knee extension (quads), hip adduction | ↓ Patellar | Medial leg, medial foot, hallux |
| L5 | Dorsiflexion (foot drop), toe extension | None | Lateral leg, dorsum of foot, big toe |
| S1 | Plantarflexion, hip extension | ↓ Achilles | Posterior leg, lateral foot, sole |
4. A child with Down syndrome presents with behavioral changes, new-onset urinary incontinence, and signs of upper motor neuron dysfunction. What is the most likely diagnosis?
➔ Atlantoaxial instability (Down syndrome + UMN signs + incontinence → suspect spinal cord compression from C1–C2 instability)
- Note: Excessive mobility between C1 (atlas) and C2 (axis) vertebrae → subluxation → spinal cord compression. Also seen with rheumatoid arthritis.
- Symptoms:
○ Urinary incontinence.
○ Gait disturbance or weakness.
○ UMN signs: Hyperreflexia, Babinski sign, and spasticity. - Diagnosed with Lateral neck flexion-extension radiographs and MRI if neurologic symptoms are present.
- If symptomatic → surgical fusion of C1 and C2
5. A 68-year-old man presents with progressive lower back pain for 3 months. He describes the pain as deep, dull, and constant, worse at night, and not relieved by rest or analgesics. He has no history of trauma. He also reports unintended weight loss and fatigue. What is the most likely diagnosis?
➔ Metastatic bone disease (Persistent, non-mechanical back pain + systemic symptoms in elderly + current or past history of cancer → suspect metastasis)
- Note: Red flags for spine metastasis: Age >50, Night pain, weight loss, and pain unrelieved by rest or activity. Common cancers are Prostate, breast, and lung.
- Next step is MRI spine → preferred imaging for spinal metastases. Administer steroids first if the are signs of nerve compression.
- DD: Vertebral osteomyelitis: focal tenderness, fever, night sweats, IVDU, high WBCs, ESR/CRP.
- DD: vertebral fracture: post-menopausal woman, focal bone tenderness. The next step is imaging “x-ray”.
Prefer learning from crisp, printable PDFs?
Unlock the Entire High-Yield PDF Library — For FREE!
Joints
6. A 62-year-old woman presents with 9 months of finger joint pain and stiffness that worsens with activity. Exam shows asymmetric bony enlargement and tenderness in the DIP and PIP joints, with limited range of motion. What is the most appropriate initial treatment?
➔ Acetaminophen (First-line for osteoarthritis, especially in the elderly)
- Note: Key clues for osteoarthritis (OA):
○ Pain worsens with use, improves with rest
○ Asymmetric joint involvement
○ DIP & PIP joint involvement (vs MCP in RA)
○ Heberden (DIP) & Bouchard (PIP) nodes in fingers.
○ No systemic symptoms or morning stiffness. - First-line therapy:
○ Weight loss, exercise especially for the quadriceps muscle.
○ Acetaminophen (esp. in elderly to minimize NSAID risks)
○ Oral NSAIDs if no contraindications (GI ulcers, renal insufficiency) - RA vs OA:
○ RA → MCP & wrist, symmetric, morning stiffness >1 30 minutes.
○ OA → DIP/PIP, asymmetric, stiffness <30 mins.
7. A 54-year-old woman presents with 6 months of joint pain and morning stiffness. She reports bilateral hand and wrist pain that is worse in the morning and improves with activity. The exam shows swelling and tenderness of the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints bilaterally. What is the most likely diagnosis?
➔ Rheumatoid Arthritis (RA)
- Note: It presents with morning stiffness > 1 hour, Symmetric joint involvement. Affects small joints first: MCPs, PIPs, wrists and spares DIP joints (distal interphalangeal).
- Systemic autoimmune disease → can also cause fatigue, weight loss, fever, and anemia.
- Diagnosis:
○ Positive RF (rheumatoid factor), Positive anti-CCP (cyclic citrullinated peptide antibody) → high specificity. Elevated ESR/CRP
○ X-ray: joint space narrowing, erosions, periarticular osteopenia
8. A 58-year-old woman with rheumatoid arthritis presents with painful mouth ulcers. She has been on methotrexate for 6 months. Labs show neutropenia and anemia. What is the cause of her symptoms?
➔ Methotrexate toxicity
- Note: Methotrexate (1st-line DMARD for RA): Inhibits dihydrofolate reductase → ↓ DNA synthesis in fast-dividing cells.
- → Side effects: oral ulcers, bone marrow suppression (↓ WBC, anemia, ↓ platelets), hepatotoxicity, pulmonary fibrosis. Prevented by folinic acid (leucovorin); monitor CBC, LFTs, PFTs.
- TNF-α Inhibitors (2nd-line DMARDs): infliximab,adalimumab. they increase the risk of latent TB reactivation (need TNF-α to maintain granulomas)..
9. A 56-year-old man has sudden overnight pain, redness, and swelling in his right big toe. He drinks alcohol regularly. Joint aspiration shows needle-shaped, negatively birefringent crystals. What is the most likely diagnosis?
➔ Gout
- Note: Caused by monosodium urate crystal deposition with triggers: alcohol, red meat, thiazides, CKD, and Overproduction of uric acid (tumor lysis syndrome)
- Most commonly affects the 1st MTP joint (podagra) with asymmetric red, swollen painful joints and tophi (often on the external ear, olecranon bursa, Achilles tendon)
- Aspiration: needle-shaped, negatively birefringent crystals
- Acute attack is treated with NSAIDS, Colchicine, Steroids in this order. Chronic treatment aims to decrease uric acid production with Allopurinol and febuxostat.
10. A 67-year-old man presents with acute right knee pain, swelling, and warmth for 3 days. X-ray shows chondrocalcinosis. What is the most likely mechanism of this condition?
➔ Calcium pyrophosphate dihydrate (CPPD) crystal deposition → Pseudogout
- Note: Clues for pseudogout:
○ Acute monoarthritis, similar to gout (especially knee)
○ Chondrocalcinosis on imaging (calcification of cartilage)
○ Associated with hypothyroidism, hemochromatosis, and hyperparathyroidism - Rhomboid-shaped, positively birefringent crystals (under polarized light) on synovial analysis
- Acute attack is treated with NSAIDS, while Colchicine is used for chronic use.
11. A 47-year-old woman with type 1 diabetes presents with 1 week of left knee pain, swelling, warmth, and erythema. Passive motion is severely painful. Temperature is 37.8°C. X-ray shows periarticular osteopenia and medial joint space narrowing. What is the most appropriate next step in management?
➔ Arthrocentesis (rule out septic arthritis)
- Note: Key clues for septic arthritis:
○ Acute monoarticular pain + swelling + fever + severe pain with passive movement
○ Risk factors: diabetes, obesity, immunosuppression, joint disease as osteoarthritis or gout. - Next step → Joint aspiration (arthrocentesis):
○ Purulent fluid, WBCs > 50,000/mm³ (mostly neutrophils)
○ Gram stain & culture & Crystal analysis (to exclude gout/pseudogout). - Common organisms: (Staph aureus (most common), Nisseria, and Borrelia (Lyme disease), you will see erythema migrans”.
- Treated with IV antibiotics (empiric until culture results: vancomycin + ceftriaxone) and Surgical drainage or lavage if indicated.
12. A 22-year-old woman presents with a right wrist pain and swelling. She is sexually active with multiple partners and inconsistently uses barrier protection. Vital signs are normal. Physical examination shows tenderness and swelling of the right wrist with limited range of motion. Small pustules are seen on both hands. Synovial fluid aspiration is performed, but Gram stain is negative. What is the most likely diagnosis?
➔ Disseminated gonococcal infection (DGI) “Neisseria gonorrhoeae”
- Note: Common in young, sexually active individuals
- It can present as Purulent monoarthritis with negative Gram stain or triad of: (Polyarthritis, Tenosynovitis (e.g., wrist pain, finger flexor tenderness), and Pustular skin lesions).
- It is diagnosed with Nucleic Acid Amplification Test (NAAT) of urogenital, rectal, or pharyngeal samples. Synovial fluid gram stain may be negative
- Treated with IV ceftriaxone + oral doxycycline (to cover possible chlamydia co-infection)
13. A 35-year-old man has chronic low back pain worse in the morning, improving with activity. He has occasional red, painful eyes. Exam shows limited spinal flexion; X-ray shows sacroiliac fusion. What is most likely associated?
➔ HLA-B27 positivity
- Note: Ankylosing spondylitis present with chronic inflammatory back pain, Morning stiffness >30 min, improves with exercise
- Extra-articular features as Uveitis (painful red eye), Aortic regurgitation, Restrictive lung disease (from costovertebral joint involvement), osteoporosis, and vertebral fracture.
- X-ray shows sacroiliitis, bamboo spine (vertebral fusion).
- Treated with NSAIDS, TNF-a inhibitors if resistant.
14. A 57-year-old postmenopausal woman with a history of wrist fracture after a fall, smoking, and a family history of hip fracture presents for osteoporosis risk assessment. What is the most appropriate next step in management?
➔ Order a DEXA scan now (she has multiple risk factors and prior fragility fracture → early screening indicated)
- Note: DEXA is used for screening and diagnosis of osteoporosis, “T-score ≤ –2.5”
- Routine screening starts at age 65. Before 65 if ≥1 risk factor: (Prior fragility fracture – Family history of hip fracture – Smoking ≥30 pack-years – Low BMI).
- Preventive steps: Calcium + Vitamin D, Smoking cessation, and exercise.
- Start treatment (e.g., bisphosphonates) only if T-score ≤ –2.5 (osteoporosis)
- Common presentations like Vertebral compression, hip (femoral neck) fracture, Colles fracture (distal radius), and wrist fracture. Age, race, and menopausal state are the most important risk factors.
15. 72-year-old man presents with worsening headaches, hearing loss, and an enlarged skull. Physical exam shows frontal bossing. Lab studies reveal normal Calcium and phosphorus levels but high Alkaline phosphatase (ALP)
What is the most likely diagnosis?
➔ Paget disease of bone
- Note: Paget disease of bone (osteitis deformans) is a disease causing Disorganized bone remodeling → ↑ osteoclasts, then chaotic osteoblast activity(marked by high ALP levels)
- It presents in older adults (>60) with Bone pain, enlarged skull, cranial nerve compression (hearing loss), Fractures and can cause High-output heart failure (↑ AV shunts), and increased osteosarcoma risk.
- Imaging shows mixed lytic and sclerotic lesions or thickened, and deformed bone.
| Disorder | Serum Ca²⁺ | PO₄³⁻ | ALP | PTH |
|---|---|---|---|---|
| Osteoporosis | Normal | Normal | Normal | Normal |
| Paget disease of bone | Normal | Normal | ↑ | Normal |
| Secondary hyperparathyroidism | ↓ | ↑ | ↑ | ↑ |
| Osteomalacia / Rickets | ↓ | ↓ | ↑ | ↑ |
| Hypervitaminosis D (sarcoidosis) | ↑ | ↑ | Normal | ↓ |
Ace Your Step 2 CK with Expert Guidance.
Struggling with Step 2 CK preparation? Get personalized 1-on-1 coaching from top scorers and experienced tutors.
Upper Limb
16. A 42-year-old man presents with right shoulder pain that began after a day of painting. He cannot actively abduct his arm, though passive range of motion is full. X-ray shows no dislocation or fracture. What is the most likely diagnosis?
➔ Supraspinatus tendon injury “Weakness= Tear → MRI”
- Note: (Rotator cuff tendinopathy) → Repetitive overhead activity → leads to overuse injury of the supraspinatus, part of the rotator cuff → Painful active abduction, positive “empty can” test. No muscle weakness “excludes tear”.
- Imaging:
○ X-ray is usually normal (used to exclude fracture/dislocation)
○ MRI/US may confirm a tendon tear “muscle weakness”. - Treated with rest, NSAIDs, Physical therapy, and Corticosteroid injection if persistent. Surgery in case of a tear.
- The suprascapular nerve can be compressed by carrying heavy bags or playing volleyball, leading to shoulder pain and weakness with arm abduction and external rotation.
17. A patient presents to the emergency department after falling on an outstretched hand during a football game. He complains of pain and swelling in the right wrist. On examination, there is point tenderness in the anatomical snuffbox. What is most likely to happen if the diagnosis is missed?
➔ Avascular necrosis secondary to Scaphoid Fracture
- Note: Results from Fall on outstretched hand (FOOSH) and Presents as Anatomical snuffbox tenderness (A triangular depression on the lateral (radial) dorsal wrist) → proximal pole at risk of avascular necrosis.
- Next step is X-ray → thumb spica splinting even if negative initial X-ray → serial X-ray.
- Hamate hook fracture: may injure the ulnar nerve, while Lunate dislocation: can compress the median nerve.
Scaphoid fracture
18. A 30-year-old woman presents with pain near the base of her right thumb. She works as a nanny and frequently lifts a 6-month-old infant. Examination shows tenderness over the radial side of the wrist and pain when the thumb is grasped and the wrist is ulnarly deviated. Which of the following is the most likely diagnosis?
➔ De Quervain tenosynovitis
- Note: Results from Overuse of thumb tendons (e.g. lifting infants) → presents with Pain localized to the tendon sheath due to inflammation of abductor pollicis longus & extensor pollicis brevis tendons “Pollicis”.
- Key test: Finkelstein test – thumb in fist + ulnar deviation → pain at radial wrist.
- Treated with thumb splint, NSAIDS, and steroids in refractory cases.
19. A 29-year-old man with anterior shoulder pain for 3 weeks has tenderness over the bicipital groove and pain with elbow flexion against resistance. He plays softball and lifts weights. What is the most appropriate next step in management?
➔ Rest from overhead activity (biceps tendinitis)
- Note: Inflammation of the long head tendon in the intertubercular groove. Common with repetitive overhead use (softball, gym)
- Exam clues:
○ Tenderness over the bicipital groove.
○ Pain with resisted supination or elbow flexion. - Managed by rest & activity modification (stop throwing/lifting), ice, NSAIDs.
- Imaging: MRI only if biceps tendon rupture “weakness with flexion + palpated mass anterior to the arm”.
20. A 34-year-old woman who works long hours at a computer presents with numbness and tingling in the thumb, index, and middle fingers. Symptoms worsen at night. Physical exam reveals a positive Tinel sign. What is the most likely diagnosis?
➔ Carpal tunnel syndrome
- Note: Causes: Repetitive use (typing), pregnancy, hypothyroidism, acromegaly and dialysis-related amyloidosis.
- Presents with paresthesia (lateral 3.5 digits), thenar atrophy, weak thumb opposition. Positive Phalen/Tinel.
- Treated with a wrist splint, followed by a steroid if no improvement. Surgery for refractory cases.
21. A 3-year-old girl refuses to move her left arm after being pulled up by the hand. She holds the arm slightly flexed and pronated; no swelling or bruising is seen. What is the most likely diagnosis?
➔ Radial head subluxation
- Note: Caused by traction injury to an extended arm with the Annular ligament slipping over the radial head
- Common in toddlers (1–4 years) presenting with the arm held in a pronated and slightly flexed position.
- Tx: Supination + flexion or hyperpronation technique.
22. A 25-year-old woman presents with a painless, smooth, round swelling on the dorsal aspect of her right wrist that has gradually increased in size and transilluminates on examination. What is the most likely diagnosis?
➔ Ganglion cyst
- Note: Benign, fluid-filled swelling over a joint capsule or tendon sheath, most common on the dorsum of the wrist.
- Transilluminates on exam = means fluid filled.
- Reassurance and observation.
Esturcke at English Wikipedia (https://commons.wikimedia.org/wiki/File:Ganglion-cyst.jpg), „Ganglion-cyst“,
Lower Limb
23. A 77-year-old woman presents with the inability to bear weight after a fall. Exam shows her left lower limb is shortened and externally rotated. What is the most likely diagnosis?
➔ Femoral neck fracture (classic for elderly fall + shortened & externally rotated leg)
- Note: Likely elderly woman with fragility fracture due to osteoporosis following a low-energy trauma (eg, ground-level fall).
- Diagnosed with X-ray of the pelvis/hip.
- Managed with open reduction and internal fixation.
24. A 42-year-old man on high-dose prednisone daily. He denies recent trauma or fever. On exam, there is pain with internal rotation of the hip. X-ray is unremarkable, but MRI reveals a crescent sign and segmental flattening of the femoral head. What is the most likely diagnosis?
➔ Avascular necrosis of the femoral head (Steroid use + normal X-ray + crescent sign on MRI → Think AVN)
- Note: Caused by impaired blood supply to femoral head → bone ischemia & collapse
- The Patient presents with Gradual groin/hip pain with weight-bearing.
- MRI is most sensitive → showing flattening of the femoral head and crescent sign
- Causes include: steroid, chronic Alcohol use, Sickle cell disease, SLE, decompression disease, Legg-Calvé-Perthes disease, Gaucher Disease, and Slipped capital femoral epiphysis
25. A soccer player presents with knee pain after a tackle. The Lachman test shows increased anterior translation of the tibia. Which ligament is most likely torn?
➔ Anterior cruciate ligament (ACL)
- Note: Prevents anterior tibial translation; injured by pivoting, deceleration.
- PCL: Prevents posterior displacement of tibia; tested with the posterior drawer test.
- McMurray test: Flex and rotate the knee → pain/click/popping sound = meniscus tear
- LIME mnemonic: Lateral meniscus → Internal rotation; Medial meniscus → External rotation (during McMurray test).
26. A 46-year-old construction worker presents with a swollen, tender area over the anterior aspect of his right knee. He reports that the swelling started gradually after kneeling for long periods. On exam, there is localized erythema and fluctuant swelling over the patella. Knee range of motion is full but painful. Which of the following is the most likely diagnosis?
➔ Prepatellar bursitis
- Note: Bursitis is caused by repetitive trauma or prolonged kneeling (e.g., “housemaid’s knee”).
- Presents with Localized swelling, erythema, tenderness, pain with active movement(no pain with passive movement excludes septic arthritis) and No weakness → helps exclude joint pathology like arthritis or ligament tears.
27. A 13-year-old boy presents with anterior knee pain that worsens after running and jumping during basketball practice. Exam shows tenderness over the tibial tubercle and mild swelling. No joint effusion or instability is noted. What is the most likely diagnosis?
➔ Osgood-Schlatter disease
- Note: Repetitive strain on the tibial tubercle apophysis during growth in adolescent athletes (running, jumping) leads to pain at the tibial tubercle.
- Patient presents with Pain with knee extension, relieved by rest.
DD.
1. Iliotibial band syndrome: pain at the lateral knee.
2. Pes anserine bursitis: pain at the medial knee.
3. Patellar tendinopathy: pain at inferior pole of patella.
4. Patellofemoral syndrome: anterior knee pain with squatting or climbing stairs in young females.
28. A 17-year-old boy twists his ankle during football. He can bear weight but has swelling and tenderness distal to the lateral malleolus, without bony tenderness or joint instability. What is the most appropriate next step in management?
➔ Conservative management with rest, ice, compression, elevation (RICE), likely lateral ankle sprain
- Note: Inversion of a plantar-flexed foot leads to→ injury to anterior talofibular ligament→ Pain & swelling over the lateral ankle, no bony tenderness (rules out fracture per Ottawa Ankle Rules), can bear weight → no x-ray needed.
- Managed with RICE (Rest, Ice, Compression, Elevation), early mobilization encouraged, and NSAIDs for pain control.
- Avoid steroid injection → impairs tendon/ligament healing
29. A 45-year-old woman presents with heel pain that is worse when taking her first steps in the morning or after prolonged rest. The pain improves gradually with activity but returns after periods of inactivity. Physical exam shows point tenderness over the medial plantar surface of the calcaneus. What is the most likely diagnosis?
➔ Plantar fasciitis (worst with first steps in morning or after rest + inferior heel tenderness → classic for plantar fasciitis, clinical diagnosis)
- Note: Microtrauma and inflammation of the plantar aponeurosis (fascia) at its insertion on the medial calcaneus. Common with obesity, prolonged standing/walking (eg, occupational), and pes planus (flat feet).
- Diagnosed clinically and Treated with stretching exercises, Ice massage and NSAIDs, heel pads, and orthotics.
- DD: 1. Achilles tendinopathy; pain proximal to heal at the Achillis tendon. 2. Achilles rupture: weakness with planter flexion. 3. Calcaneal stress fracture → pain worsens with activity+ local tenderness on heel squeeze.
30. A 15-year-old boy presents with bone pain and a mass in his femur. X-ray shows a sunburst pattern and Codman triangle. What is the most likely diagnosis?
➔ Osteosarcoma
- Note: It commonly affects the Metaphysis of long bones (often around the knee region). X-ray: sunburst, Codman triangle (elevation of periosteum).
- Chondrosarcoma is a malignant cartilage-producing tumor of the Medulla (often pelvis, ribs, long bones), showing atypical chondrocytes in cartilage matrix on biopsy and glistening masses on imaging.
- Ewing Sarcoma: comes at the diaphysis with Small round blue cells on biopsy. Associated with t(11;22) translocation.
- Osteoid osteoma: benign tumor at proximal fumer. It produces PGs leading to nocturnal pain that responds to NSAIDS
Prefer learning from crisp, printable PDFs?
Unlock the Entire High-Yield PDF Library — For FREE!
31. A 52-year-old man presents with a painless, slowly enlarging mass in his right thigh that he noticed 3 months ago. He denies trauma, fever, or weight loss. On exam, there is a firm, non-tender, immobile 5-cm mass deep in the anterior thigh muscle. What is the most likely diagnosis?
➔ Soft tissue sarcoma (gradually enlarging + painless deep soft tissue mass → always evaluate for possible soft tissue sarcoma
- Note: Red flag features: (Painless, firm, deep mass in soft tissue, with progressive enlargement over time).
- Initial workup:
○ MRI of the extremity → to define local extent and relation to neurovascular structures
○ Core needle biopsy → required for pathologic diagnosis. If positive, do CT chest looking for lung metastasis. - Treated with wide surgical excision followed by chemotherapy or radiation.
32. A 19-year-old man is brought to the ER after being trapped under debris for 2 hours. His left leg is swollen, tense, and extremely painful, especially with passive toe movement. Pulses are palpable. What is the next best step?
➔ Perform emergent fasciotomy
- Note: Crush injury → bleeding + edema in closed fascial space → ↑ Intracompartmental pressure → ↓ Venous outflow → ↓ Capillary perfusion → Muscle & nerve ischemia and tissue necrosis. Also common after reperfusion of a limb.
- 6 Ps: Pain (out of proportion), Paresthesia, Pallor, Paralysis, Pulselessness, Poikilothermia, Pain with passive stretch, and neuropathy are early findings
- TTT→ emergency fasciotomy to avoid necrosis
33. A 27-year-old woman presents with a malar rash, oral ulcers, and RBC casts in urine. On physical exam, a malar rash sparing the nasolabial folds is found. What is the diagnosis?
➔ Systemic Lupus Erythematosus (SLE)
- Note: It presents with Malar rash, photosensitivity, oral ulcers, Arthritis, Serositis (pleuritis, pericarditis), Renal involvement(glomerulonephritis), Hematologic: anemia, leukopenia, thrombocytopenia.
- Joint involvement in SLE tends to be symmetric, migratory, non-erosive, and associated with brief morning stiffness.
- Labs: +ve ANA (sensitive), +ve Anti-dsDNA, anti-Smith (specific), anti-Histone if drug induced lupus “hydralazine, sulfa drugs, INH, and procainamide”.
34. A patient with recurrent thrombosis and miscarriages tests positive for anticardiolipin antibodies. PTT is prolonged but not corrected by mixing. What is the diagnosis?
➔ Antiphospholipid syndrome
- Note: Autoimmune hypercoagulable state, often linked to SLE with recurrent thrombosis and miscarriage.
- Labs: anticardiolipin, anti-β2 glycoprotein, lupus anticoagulant (↑ PTT, not corrected by mixing with plasma).
- A pregnant woman with antiphospholipid syndrome should take aspirin and heparin.
35. A woman presents with dry eyes, dry mouth, difficulty swallowing dry foods, and bilateral parotid swelling. Schirmer test is positive. What is the most likely mechanism?
➔ Lymphocytic infiltration of exocrine glands “Sjögren Syndrome”
- Note: Autoimmune destruction of exocrine glands, especially lacrimal and salivary glands. patient has Xerophthalmia (dry eyes), Xerostomia (dry mouth), dry vagina, Parotid gland enlargement
- Positive Schirmer test (measures tear production) and Positive Anti-SSA (Ro), Anti-SSB (La) antibodies
- Associated with: Other autoimmune diseases (e.g., RA, SLE) and ↑ Risk of non-Hodgkin lymphoma.
36. A 45-year-old woman has tight skin on her hands and face, difficulty swallowing, and cold-induced finger color changes. The exam shows sclerodactyly and facial telangiectasias. Labs: positive ANA, anti-centromere antibodies. What’s the diagnosis?
➔ Scleroderma (Systemic sclerosis)
- Note: Autoimmune fibroblast activation → fibrosis and collagen deposition in various organs.
- limited scleroderma CREST syndrome: Calcinosis, Raynaud, Esophageal dysmotility, Sclerodactyly, Telangiectasia→ Anti-centromere Ab.
- Diffuse scleroderma: Widespread skin + Renal(scleroderma renal crisis with severe HTN and treated with ACE inhibitors) -Lung(interstitial fibrosis or pulmonary HTN), Heart might be affected→ Anti-Scl-70 (anti-topoisomerase I).
37. A woman presents with muscle pain and stiffness in the morning in her shoulders. She has no weakness, normal CK, but ESR is elevated. What is the likely diagnosis?
➔ Polymyalgia rheumatica
- Note: Proximal muscle stiffness in shoulders/hips with normal strength.
- More common in females > 50 and associated with giant cell arteritis
- ↑ ESR/CRP (unlike fibromyalgia which has normal inflammatory markers) normal CK.
- Responds to low-dose steroids.
38. A female patient has progressive difficulty climbing stairs and lifting her arms. She also has a reddish-purple rash on her eyelids and knuckles. Labs show ↑ CK and positive anti-Mi-2 antibodies. What is the most likely diagnosis?
➔ Dermatomyositis
- Note: (muscle + skin symptoms): muscle weakness (not pain) mainly affects Proximal muscles → difficulty lifting her arms, difficulty climbing stairs (weakness not tenderness) and Heliotrope rash(rash on the eyelids), Gottron’s papules(rash on the knuckles) and “shawl and face” rash
- Labs show elevated CK and +ve ANA, specific antibodies like anti-Jo-1, anti-SRP and anti-Mi-2. Associated with occult malignancy
- Polymyositis has a similar presentation without the rash
- Screen for internal malignancy.
39 A woman presents with widespread pain, fatigue, and difficulty sleeping and concentrating. She has multiple tender points in different muscles. ESR and CRP are normal. What is the most likely diagnosis?
➔ Fibromyalgia
- Note: Chronic widespread pain with fatigue and tender points.
- Labs are normal: ESR, CRP, and CK.
- Treat with exercise, TCAs, SNRIs.
Become a Researcher in the United States 
No Experience Required! Just join the live & interactive workshop to learn all the secrets of landing a research position in the U.S
Vasculitis
40. A 60-year-old woman has a new-onset unilateral headache, jaw pain when chewing, and proximal muscle stiffness. ESR is 110. What is the best next step?
➔ Administer steroids followed by temporal artery biopsy
- Note: Granulomatous inflammation of large arteries (temporal artery), women >50.and associated with polymyalgia rheumatica (proximal muscle stiffness).
- The patient presents with unilateral headache, jaw tenderness, and episodic vision loss. elevated ESR, IL-6 levels.
- It can also cause ischemic optic neuropathy → irreversible blindness so give high-dose steroids immediately before biopsy results to prevent blindness.
41. A 38-year-old Japanese woman presents with upper limb claudication, asymmetric BP, and neck bruit. Biopsy shows granulomatous thickening of the aortic arch. What is the diagnosis?
➔ Takayasu arteritis
- Note: Large vessel vasculitis with granulomatous inflammation of the aortic artery and its branches, more common in young Asian females.
- Presents with fever, arthritis, myalgia and ESR elevated. BP differences between arms with arterial bruits and pulse deficits. MRI shows thick aortic walls, narrow lumens, and widened mediastinum.
- Treatment is glucocorticoid
42. A smoker male patient has painful foot ulcers, gangrene, and Raynaud phenomenon. What behavioral change is most essential?
➔ Smoking cessation
- Note: Buerger disease (thromboangiitis obliterans): medium vessel vasculitis in smokers causing thrombosis, gangrene, autoamputation of the fingers and Raynaud’s phenomenon.
- The strongest risk factor is tobacco use.
43. A 3-year-old child has fever for 6 days, bilateral conjunctivitis, strawberry tongue, and swollen hands and feet. What life-threatening complication may develop?
➔ Coronary artery aneurysm
- Note: Kawasaki disease “vasculitis in asian children”, Presents with CRASH: Conjunctivitis, Rash, Adenopathy, Strawberry tongue/mucositis, Hands/feet edema + Fever >5 days
- High risk of coronary aneurysm and occlusion leading to MI. also heart failure.
- Echo is performed at diagnosis time and after treatment. Treat with IVIG + aspirin (only condition where aspirin is given to children despite the risk of Reye’s syndrome)
44. A middle-aged patient has weight loss, fatigue, abdominal pain, melena, hypertension, livedo reticularis, and hematuria. Labs: ↑ ESR, ↑ creatinine, negative ANCA. Biopsy: transmural inflammation with fibrinoid necrosis. What infection is associated with this condition?
➔ Hepatitis B
- Note: Polyarteritis nodosa: medium-vessel vasculitis with Segmental necrotizing inflammation and fibrinoid necrosis associated with HBV and HCV.
- Presents with fever, weight loss, fatigue, and multi-system involvement: GI (abdominal pain ), Renal (nephropathy and renal microaneurysms appear as “string of pearls” on imaging ), Skin lesions (livedo reticularis and palpable purpura ), Neuropathy, but spares the lung.
45. A patient has oral ulcers, genital ulcers, erythema nodosum, and a history of DVT. Likely diagnosis?
➔ Behçet syndrome
- Note: Small vessel vasculitis with recurrent oral/genital ulcers. Often post-viral trigger.
- Associated with HLA-B51.
46. A child presents 2 days after an upper respiratory infection. with palpable purpura on the legs, abdominal pain, and joint swelling. UA shows hematuria and RBC casts. Diagnosis?
➔ Henoch-Schönlein purpura (HSP)
- Note: IgA vasculitis is the most common vasculitis in children and presents as IgA nephropathy (Berger’s) with hematuria days after upper respiratory infection (hematuria weeks after is PSGN).
- HSP is another association with IgA vasculitis + Triad of: palpable purpura on extensor surfaces(buttocks), arthralgia, abdominal pain(intussusception).
47. A man with asthma develops sinusitis, peripheral neuropathy, and palpable purpura. Labs show eosinophilia and p-ANCA. What is the diagnosis?
➔ Eosinophilic granulomatosis with polyangiitis
- Note: Small-vessel necrotizing vasculitis with granulomas, patients present with asthma, eosinophilia, neuropathy palpable purpura.
- It can also cause nephritic syndrome as RPGN (rapidly progressive glomerulonephritis) with crescent formation on biopsy.
- MPO-ANCA/ p-ANCA positive and elevated IgE level and eosinophilia.
48. A patient presents with chronic sinusitis, nasal ulceration, hematuria, and hemoptysis. Labs reveal elevated creatinine, hematuria with RBC casts, and positive c-ANCA. What is the most likely diagnosis?
➔ Granulomatosis with polyangiitis (Wegener)
- Note: Necrotizing granulomatous vasculitis of small vessels. patient presents with the Triad of: upper airway (sinusitis, nasal ulcerations) Lungs and small airways (hemoptysis and cavitary lesions), Kidney (rapidly progressive glomerulonephritis (hematuria, red cell casts).
- Labs: PR3-ANCA/c-ANCA positive.
49. A 41-year-old woman presents with fatigue, double vision, difficulty chewing, and ptosis by the end of the day. Which medication improves symptoms?
➔ Cholinesterase inhibitor
- Note: Myasthenia gravis: autoantibodies (type 2 HSN) against post-synaptic Ach receptors.
- Presents with Fluctuating muscle weakness (worse with use (fatigability) and at the end of the day), ptosis, diplopia, and bulbar symptoms
- Associated with thymoma and improves with AChE inhibitors as pyridostigmine, and removal of thymoma if associated.
50. A 60-year-old man with a heavy smoking history has difficulty rising from chairs and climbing stairs. The exam shows decreased reflexes and proximal muscle weakness that improves with use. Chest CT shows a hilar mass. What’s the most likely cause?
➔ Autoantibodies against presynaptic calcium channelsending on severity
- Note: Lambert-Eaton Syndrome is an autoimmune disease with Autoantibodies against presynaptic Ca²⁺ channels → ↓ ACh release.
- Muscle weakness that improves with use also Hyporeflexia and autonomic symptoms (dry mouth, impotence) are common.
- Associated with small cell lung cancer.
🏁 Final Thoughts
You made it to the end—well done! These high-yield notes are designed to save you time and keep you focused on what actually matters for Step 2 CK. Review these vignettes regularly—steady practice beats cramming.
Need one-on-one tutoring? Visit The Match Guy USMLE Tutoring — we’ve helped hundreds of students reach their score goals.
Don’t forget to watch the video lessons that go with this file. They are part of our 7-day high-yield review of Step 2 CK.
Join this RISK FREE live bootcamp 👉 Sign up here
Good luck and we’re rooting for you all the way to Match Day! 🎯
Disclaimer
Version 1.0 August 2025. No part of this document may be reproduced or distributed without written permission. For personal study only. Medical information herein is for educational purposes and does not constitute clinical advice. Always confirm with current guidelines and your institution’s policies.
Latest Articles
ERAS Application 2027 Guide! How to Fill Out ERAS Residency Application?
Malke Asaad July 13, 2023
Best Resources for USMLE STEP 1! How to Study and Prepare for STEP1?
Malke Asaad August 12, 2022
2026 Residency Personal Statement The Ultimate Guide to Crafting Your Residency Personal Statement
Malke Asaad July 8, 2024
Need Help?
About TheMatchGuy
The Match Guy is a premier medical consulting firm trusted by over 35,000 students worldwide. We help medical students and graduates excel on the USMLE (Step 1, Step 2 CK, and Step 3) and strengthen their residency applications through proven study strategies, expert tutoring, and personalized guidance from elite 260+ scoring tutors who have helped countless students achieve their goals. Whether you’re aiming for a competitive specialty or navigating the Match as an IMG, we help you prepare smarter, avoid burnout, and position yourself as a strong applicant from exam day through Match season. Schedule a FREE discovery call now.
RECOMMENDED ARTICLES
Best Electives in the US
Best Resources for USMLE STEP 1! How to Study and Prepare for STEP1?
United States Clinical Experience for IMGs
