MSK Flashcards
What is the mechanism of a type I hypersensitivity reaction?
Antigen reacts with IgE bound to mast cells
Give 2 examples of a type I hypersensitivity reaction
- Anaphylaxis
- Atopy
What is the mechanism of a type II hypersensitivity reaction?
IgG or IgM binds to antigen on cell surface
Give 3 examples of a type II hypersensitivity reaction
- Autoimmune haemolytic anaemia
- ITP
- Goodpasture’s syndrome
- Pernicious anaemia
- Acute haemolytic transfusion reactions
- Rheumatic fever
- Pemphigus vulgaris / bullous pemphigoid
What is the mechanism of a type III hypersensitivity reaction?
Free antigen and antibody (IgG, IgA) combine
Give 3 examples of a type III hypersensitivity reaction
- Serum sickness
- Systemic lupus erythematosus
- Post-streptococcal glomerulonephritis
- Extrinsic allergic alveolitis (especially acute phase)
What is the mechanism of a type IV hypersensitivity reaction?
T-cell mediated
Give 3 examples of a type IV hypersensitivity reaction
- Tuberculosis / tuberculin skin reaction
- Graft versus host disease
- Allergic contact dermatitis
- Scabies
- Extrinsic allergic alveolitis (especially chronic phase)
- Multiple sclerosis
- Guillain-Barre syndrome
What is the most appropriate management for the following injury:
A 24-year-old man falls sustaining an inversion injury to his ankle. On examination he is tender over the lateral malleolus only. On x-ray there is a fibular fracture that is distal to the syndesmosis.
Application of below knee plaster cast to include the midfoot
What is the most appropriate management for the following injury:
An 86-year-old lady stumbles and falls whilst opening her front door. On examination her ankle is swollen with both medial and lateral tenderness. X rays demonstrate a fibular fracture at the level of the syndesmosis.
Application of below knee plaster cast to include the midfoot
What is the most appropriate management for the following injury:
A 25-year-old man suffers an injury whilst playing rugby involving a violent twist to his left lower leg. On examination both malleoli are tender and the ankle joint is very swollen. On x-ray there is a spiral fracture of the fibula and widening of the ankle mortise.
Surgical fixation
What is the most likely diagnosis:
- Most common primary malignant bone tumour in children
- Commonly affects the metaphyseal region of long bones
- Radiographs classically show Codman triangle (a triangular area of new subperiosteal bone)
Osteosarcoma
Describe the clinical presentation of psoriatic arthritis
- Asymmetrical polyarthritis with >30 minutes of morning stiffness
- Typically affects the hands and feet
- Sacroiliitis
- DIP joint disease and dactylitis
- Psoriatic skin lesions
Name the antibody associated with lung fibrosis in myositis
Anti-Jo1 antibodies
How would you manage a flare of gout in a patient who is already on prophylactic treatment?
Continue allopurinol and commence colchicine
(allopurinol should be continued during an acute attack in patients presenting with an acute flare of gout who are already established on treatment)
What is the most likely diagnosis in a patient presenting with bone pain, tenderness, and proximal myopathy (→ waddling gait)?
Osteomalacia
How long must the symptoms of chronic fatigue syndrome be present before making a diagnosis?
3 months
Name 3 adverse effects of bisphonates
- Oesophageal reactions
- Osteonecrosis of the jaw
- Increased risk of atypical stress fractures
Which patient group are more at risk of osteonecrosis of the jaw when taking bisphonates?
Greater risk for patients receiving IV bisphosphonates in the treatment of cancer
What is the first line treatment for SLE?
Hydroxychloroquine
True/false: creatine kinase levels are elevated in temporal arteritis
False
A 72-year-old man is brought to the Emergency Department after falling at his nursing home. On arrival he complains of pain in the left hip.
What is the diagnosis?
Left subcapital fracture
What patient factors are accounted for in a Z-score (DEXA scan)?
Age, gender, ethnicity
What is the most appropraite management for a non-displaced patella fracture with an entact extensor mechanism (can perform straight leg raise)?
Conservative management with knee immobilisation
What drug is given to patients with systemic sclerosis following a renal crisis to prevent further renal complications?
ACE inhibitors
What is the drug treatment for moderate/severe psoriatic arthropathy?
Methotrexate
What are the motor functions of the femoral nerve?
Knee extension, thigh flexion
What are the sensory functions of the femoral nerve?
Sensation of the anterior and medial aspect of the thigh and lower leg
What are the typical mechanisms of injury to the femoral nerve?
- Hip and pelvic fractures
- Stab/gunshot wounds
What is the motor function of the obturator nerve?
Thigh adduction
What is the sensory function of the obturator nerve?
Sensation of the medial thigh
What is the typical mechanism of injury of the obturator nerve?
Anterior hip dislocation
What is the sensory function of the lateral cutaneous nerve of the thigh?
Sensation of the lateral and posterior surfaces of the thigh
What is the typical mechanism of injury of the lateral cutaneous nerve of the thigh?
Compression of the nerve near the ASIS → meralgia paraesthetica, a condition characterised by pain, tingling and numbness in the distribution of the lateral cutaneous nerve
What are the motor functions of the tibial nerve?
Foot plantarflexion and inversion
What is the sensory function of the tibial nerve?
Sensation of the sole of the foot
What are the typical mechanisms of injury to the tibial nerve?
- Not commonly injured as deep and well protected
- Popliteral lacerations, posterior knee dislocation
What are the motor functions of the common peroneal nerve?
Foot dorsiflexion and eversion, extensor hallucis longus
What are the sensory functions of the common peroneal nerve?
Sensation to the dorsum of the foot and the lower lateral part of the leg
What are the typical mechanisms of injury to the common peroneal nerve?
- Injury often occurs at the neck of the fibula
- Tightly applied lower limb plaster cast
- Injury causes foot drop
What is the motor function of the superior gluteal nerve?
Hip abduction
What are the typical mechanisms of injury of the superior gluteal nerve?
- Misplaced intramuscular injection
- Hip surgery
- Pelvic fracture
- Posterior hip dislocation
Injury to which nerve results in a positive Trendelenburg sign?
Superior gluteal nerve
What is the motor function of the inferior gluteal nerve?
Hip extension and lateral rotation
What is the typical mechanism of injury of the inferior gluteal nerve?
- Generally injured in association with the sciatic nerve
- Injury results in difficulty rising from seated position → can’t jump, can’t climb stairs
What is the preferred surgical management for an intertrochanteric (extracapsular) proximal femoral fracture?
Dynamic hip screws
When starting treatment with bisphonates, what must be corrected first?
Hypocalcemia/vitamin D deficiency
Name 3 causes of dactylitis (inflammation of a digit)
- Spondyloarthritis: e.g. psoriatic and reactive arthritis
- Sickle-cell disease
- Other rare causes include tuberculosis, sarcoidosis and syphilis
A 56-year-old man undergoes a low anterior resection with legs in the Lloyd-Davies position. Post operatively he complains of foot drop.
What nerve has likely been injured?
Peroneal nerve
A 23-year-old man complains of severe groin pain several weeks after a difficult inguinal hernia repair.
What nerve has likely been injured?
Ilioinguinal nerve
A 72-year-old man develops a foot drop after a revision total hip replacement.
What nerve has likely been injured?
Sciatic nerve
What are the Ottawa Rules for ankle x-rays?
An ankle x-ray is required only if there is any pain in the malleolar zone and any one of the following findings:
- Bony tenderness at the lateral malleolar zone
- Bony tenderness at the medial malleolar zone
- Inability to walk four weight-bearing steps
A woman with Crohn’s on azathioprine presents with a 3-day history of fever, lethargy, and coryzal symptoms. What is the most important investigation?
FBC - may cause myelosuppression
IVDU with infective endocarditis also has back pain. What is the diagnosis?
Discitis
6-year-old boy with a limp. His parents report that this has been getting steadily worse over the past few weeks. He complains of pain in the right groin/hip region. An x-ray shows widening of the right hip joint space with flattening of the femoral head.
What is the most likely diagnosis?
Perthes disease
A 7-year-old boy is brought in by his mother. For the past day he has felt generally unwell with a headache and nausea. This morning he complained of pain in his right hip and now just able to walk with a limp. On examination flexion, extension and rotation of the hip is painful and limited. Examination of the ears, throat and chest is normal. His temperature is 38.2ºC.
What is the most likely diagnosis?
Septic arthritis
4-year-old girl with a three month history of a limp. Her parents report that she has ‘not been right’ for a few weeks now. She typically complains of pain in her left hip and right knee in the morning which gets better during the day.
What is the most likely diagnosis?
Juvenile idiopathic arthritis
What is the management of an extracapsular hip fracture?
Intramedullary device
What are the typical features of antiphospolipid syndrome?
Arterial/venous thrombosis, miscarriage, livedo reticularis
What is the most useful rule out test for SLE?
ANA - over 99% of patients with SLE are ANA positive
What pre-op imaging should you perform on a patient with a medical history of rheumatoid arthritis
Anteroposterior and lateral cervical spine radiographs - to screen for atlantoaxial subluxation
What examinations make up the Simmonds’ triad (Achilles tendon rupture)?
Palpation, examining the angle of declination at rest and the calf squeeze test
What nerve is commonly injured following a posterior hip dislocation?
Sciatic nerve
What is the name given to the following fracture pattern:
- Transverse fracture of the radius
- 1 inch proximal to the radio-carpal joint
- Dorsal displacement and angulation
Colles’ fracture
What is the name given to the following fracture pattern:
- Volar angulation of distal radius fragment (Garden spade deformity)
- Caused by falling backwards onto the palm of an outstretched hand or falling with wrists flexed
Smith’s fracture (reverse Colles’ fracture)
What is the name given to the following frature pattern:
Intra-articular fracture at the base of the thumb metacarpal
Bennett’s fracture
What is the name given to the following fracture pattern:
Dislocation of the proximal radioulnar joint in association with an ulna fracture
Monteggia’s fracture
What is the name given to the following fracture pattern:
Radial shaft fracture with associated dislocation of the distal radioulnar joint
Galeazzi fracture
Describe the clinical presentation of osteochondritis dissecans
Knee pain after exercise, locking and ‘clunking’
What is the next stage in management for a rib fracture not controlled by normal analgesia?
Nerve blocks
What are the motor functions of the musculocutaneous nerve (C5-C7)?
Elbow flexion (supplies biceps brachii) and supination
What is the sensory function of the musculocutaneous nerve (C5-C7)?
Sensation to the lateral part of the forearm
What is the typical mechanism of injury of the musculocutaneous nerve (C5-C7)?
Isolated injury rare - usually injured as part of brachial plexus injury
What is the motor function of the axillary nerve (C5,C6)?
Shoulder abduction (deltoid muscle)
What is the sensory function of the axillary nerve (C5,C6)?
Sensation to the inferior region of the deltoid muscle
What is the typical mechanism of injury of the axillary nerve?
- Humeral neck fracture/dislocation
- Results in flattened deltoid
What is the motor function of the radial nerve (C5-C8)?
Extension (forearm, wrist, fingers, thumb)
What is the sensory function of the radial nerve (C5-C8)?
Sensation to a small area between the dorsal aspect of the 1st and 2nd metacarpals
What is the typical mechanism of injury to the radial nerve (C5-C8)?
- Humeral midshaft fracture
- Palsy results in wrist drop
What is the motor function of the median nerve (C6, C8, T1)?
LOAF muscles
What is the sensory function of the median nerve (C6, C8, T1)?
Sensation to the palmar aspect of lateral 3½ fingers
What is the typical mechanism of injury of the median nerve (C6, C8, T1)?
Wrist lesion → carpal tunnel syndrome
What are the motor functions of the ulnar nerve (C8, T1)?
- Intrinsic hand muscles except LOAF
- Wrist flexion
What is the sensory function of the ulnar nerve (C8, T1)?
Medial 1½ fingers
What is the usual mechanism of injury of the ulnar nerve (C8, T1)?
- Medial epicondyle fracture
- Damage may result in a ‘claw hand’
What is the motor function of the long thoracic nerve (C5-C7)?
Serratus anterior
What is the usual mechanism of injury to the long thoracic nerve (C5-C7)?
- Often during sport e.g. following a blow to the ribs
- Also possible complication of mastectomy
- Damage results in a winged scapula
What features would point to a diagnosis of spinal stenosis over peripheral arterial disease?
- Pain improving on sitting down or crouches down
- Weakness of the leg
- Lack of smoking history
- Lack of cardiovascular history
Describe the clinical features of a dorsal column lesion
- Loss vibration and proprioception
- Tabes dorsalis, SACD
Describe the clinical features of a spinothalamic tract lesion
Loss of pain, sensation and temperature
Describe the clinical features of a central cord lesion
Flaccid paralysis of the upper limbs
Describe the clinical features of spinal cord infarction
Dorsal column signs (loss of proprioception and fine discrimination
Describe the clinical features of cord compression
- UMN signs
- Malignancy
- Haematoma
- Fracture
Describe the clinical features of Brown-sequard syndrome
- Hemisection of the spinal cord
- Ipsilateral paralysis
- Ipsilateral loss of proprioception and fine discrimination
- Contralateral loss of pain and temperature
Describe the clinical findings of a clubfoot
Inverted + plantar flexed foot which is not passively correctable
Describe the clinical features of chondromalacia patellae
- Teenage girls, following an injury to knee e.g. dislocation patella
- Typical history of pain on going downstairs or at rest
- Tenderness, quadriceps wasting
What is the management of subluxation of the radial head?
Passive supination of the elbow joint whilst flexed to 90 degrees
What lab values are assocaited with osteoporosis?
All values normal
What lab values are associated with osteomalacia?
- Calcium: decreased
- Phosphate: decreased
- ALP: increased
- PTH: increased
What values are associated with primary hyperparathyroidism?
- Calcium: increased
- Phosphate: decreased
- ALP: increased
- PTH: increased
What lab values are associated with chronic kidney disease?
- Calcium: decreased
- Phosphate: increased
- ALP: increased
- PTH: increased