MSK diseases Flashcards
What are the 2 microscopic appearance of bone?
Explain them
Woven bone
- Made quickly (in fetal bone)
- Disorganised
- No clear structure
Lamellar bone
- Made slowly
- Organised
- Has a clear layered structure
What are the 5 different types of bones?
List examples
Long bones - Tubular shape with hollow shaft, - articulates with other bones (humerus, radius, ulna, metacarpals, phalanges)
Short bones - Cuboidal in shape (carpals in the wrist - scaphoid, lunate, triquetral)
Flat bones - plates of bone which are often curved and have a protective function (skull, pelvis, thoracic cage)
Irregular bones - appear in various shapes (vertebrae, bones in ears)
Sesamoid bones - round, oval nodules in a tendon (protects tendons from wear and tear) –> Patella, two sesamoid bones at the thumb, mcp joint
What are the 2 macroscopic appearances of bone?
Describe them
Cortical (Compact)
- Dense outer shell of bone
- Has lamellae which are organised into concentric circles that surround vertical haversian canals
- Vertical haversian canals are connected by horizontal volkmann’s canals
- Osteocytes are located in lacunae (cavities between lamellae) which are are connected by canaliculi
Trabecular (spongy)
- Makes up the interior of bone
- Contains many large spaces giving it a honeycombed appearance
- Spaces between trabeculae are filled with bone marrow
What are the categories of joints, give examples.
Synarthroses - Immovable joints –> skull sutures, teeth
- Mostly fibrous joints
Amphiarthroses - slightly moveable joints - intervertebral discs, pubic symphysis
- Mostly cartilaginous joints
Diarthroses - freely movable joints –> hip, knee, shoulder
- Mostly synovial joints
What are ligaments and tendons?
Ligaments - Bone - Bone
Tendons - Muscle - Bone
Osteoarthritis
RF
Pathology
Symptoms
Investigations
Treatment
NON INFLAMMATORY wear and tear of the joints
- Typically occurs in synovial joints
RF - Obesity, increased age, occupation (where there is high usage of particular joints), FEMALE, family history
PATHOLOGY
- A result of imbalance between cartilage worn down and the chondrocytes repairing the cartilage (leads to structural issues in the joint)
- There is increased (matrix) metalloproteinase which catalyse degradation of Type 2 collagen and proteoglycan. - produced by chondrocytes
- Bone attempts to compensate with Type 1 collagen –> resulting in abnormal bony growth which present as Osteophytes.
- Commonly affects hips and knee joints. Also DIP and CMC joint (hand)
SYMPTOMS
- Joint pain and stiffness which is worse on activity and transient/little in the morning (in contrast to inflammatory arthritis)
- Deformity of joints
- Instability
- Reduced function
- Limited range of motion (due to pain) - limited bilateral flexion of knees
Signs
- Heberden’s nodes - DIP joints
- Bouchard’s nodes - PIP joints
- Weak or reduced grip strength
- Squaring of base of the thumb (CMC joint)
(No extraarticular symptoms)
INVESTIGATIONS
X-ray - LOSS
L- Loss of joint space (bones are closer to each other)
O- Osteophytes (spurs of bone protruding from either end of the joint)
S - Subarticular sclerosis (increased density of the bone - causing bone to come into contact with each other)
S - Subchondral cysts (fluid filled holes in the bone along joint line)
MOSTLY A CLINICAL DIAGNOSIS (X-ray can help but not necessary if presentation is typical)
- >45 YEARS OF AGE
- ACTIVITY RELATED PAIN
- MORNING STIFFNESS <30 MINS
Treatment
1st (non pharmacological) Lifestyle changes- exercise, physiotherapy, occupational therapy
- patient education
1st (pharmacological) Analgesia - Topical NSAID (topical diclofenac) – if topical doesn’t work then Oral first
Definitive - surgery (Arthroplasty - knee/hip replacement)
Rheumatoid arthritis
-Biological therapies you could give
RF
Pathology
Symptoms
Investigations
Treatment
Complications
An autoimmune condition that causes chronic inflammation in the synovial lining of the joints (Type of inflammatory arthritis) - polyarthritis
RF - Females, genetics (HLA DR4), smoking, post menopausal
LESS
- Loss of joint space
- Erosion of bone
- Soft tissue swelling
- Soft bones
PATHOLOGY
- Affects multiple small joints symmetrically across both sides of the body –> Symmetrical polyarthrtitis (BILATERAL)
Citrullination - Conversion of arginine to citrulline by peptidylarginine deaminase (PAD). Anti CCP (cyclic citrullinated peptide) antibodies target citrullinated proteins - healthy tissue in joints. - autoimmune (anti-CCP antibodies are more sensitive and specific than rheumatoid factor)
Rheumatoid factor - mostly IgM targets the Fc portion of IgG
SYMPTOMS
- Pain that is worse in the morning and eases as the day goes on
- JOINT PAIN, STIFFNESS AND SWELLING - Symmetrical distal polyarthritis affects the small joints of hands and feet (MCP, PIP, wrist and MTP joint- foot) -
LESS COMMON SIGNS
- Swan neck deformity –> DIP hyperflexion and PIP hyperextension
- Boutonniere’s deformity –> PIP flexion with DIP hyperextension
(Z shaped deformity in the thumb)
Can lead to extra articular complications –> Lungs (PE, pulmonary fibrosis), heart (increased IHD risk), carpal tunnel syndrome
INVESTIGATIONS
FBC - Elevated ESR/CRP, normocytic normochromic anaemia (haemolytic anaemia)
GS - Serology - Anti CCP antibodies (80% specific), RF (70% specific)
TREATMENT
1st - Disease modifying anti-rheumatic drug (DMARD) (give folic acid alongside it)
- Methotrexate (sulfasalazine for PREGNANT patients)
Biological therapies
- TNF inhibitor - Infliximab (TNF- cytokine that stimulates inflammation)
- Anti CD20 on B cells - Rituximab
NSAID - analgesia
What score is used to monitor disease activity in rheumatoid arthritis and response to treatment?
Disease activity score 28 (DAS28–>joints)
Gout
Causes of hyperuricaemia
Treatment if patient was renally impaired
RF
Pathology
Symptoms
Investigations
Treatment
- Crystal arthropathy which is characterised by HYPERURICAEMIA and deposition of ,monosodium urate crystals in the joint causing acute inflammatory arthritis. (- hot, swollen and painful)
RF - Male, obese, diet high in meat and seafood (purine), alcohol, family history. cardiovascular/kidney disease, diuretics
PATHOLOGY
Causes of hyperuricaemia (urate is a metabolite of purine)
- Renal under-excretion of urate
- Medications - diuretics
- High consumption of seafood, meat, alcohol (high in purines)
Deposition of monosodium urate crystals in joints causes:
- Acute inflammatory arthritis
- Tophi around the joints (subcutaneous deposits of uric acid under the skin, not in the joints) - DIP most common, joints of ears and elbow
Common joints
- Base of the big toe (MTP joint)
- Wrist
- Base of the thumb (CPC joint)
(Knees, ankles)
SYMPTOMS
- MONOARTICULAR (single), acute, hot, swollen, painful joint
- Tophi
(Can’t put weight on it - usually big toe (MTP joint)
INVESTIGATIONS
- Joint aspirate (arthrocentesis) + polarised light microscopy –> Negatively birefringent needle shaped crystals (under polarised light) - monosodium urate crystals (yellow when parallel, blue when perpendicular to axis of the polarised light)
(if there is bacteria means –> Septic arthritis)
TREATMENT
Acute -
1st line - NSAIDS - ibuprofen
Colchicine in patients with renal impairment or heart disease (NSAIDS CI)
Prophylaxis
- Allopurinol (xanthine oxidase inhibitor - reduces conversion of purines to uric acid - reduce production of uric acid)
- Diet - reduce intakes of high purine containing food - seafood, meat, alcohol
Pseudogout
- Where does it usually occur?
- Treatment
RF
Pathology
Symptoms
Investigations
Treatment
A crystal arthropathy caused by the deposition of calcium phosphate crystals in the joints
RF - 70+ females, hyperparathyroidism, diabetes, haemachromatosis (deposition of iron in joints)
SYMPTOMS
- Hot, swollen, painful joint (DDX of septic arthritis)
–> typically in knee, wrist, shoulder (often polyarticular)
Investigations
GS - Joint aspiration + polarised light microscopy –> positively birefringent, rhomboid shaped crystals - calcium pyrophosphate crystals —> Should not have bacterial growth (excludes septic arthritis)
X-ray - calcium deposits in the joint cartilage.
TREATMENT
Acute - First line
- NSAIDS
- then if needed - Colchicine
- then if needed - intra-articular steroid injections (dexamethasone)
(no prophylaxis)
Osteoporosis (and osteopenia)
-Which tool to assess 10 year fracture risk?
RF
Pathology
Symptoms
Investigations
Treatment
Osteoporosis - A significant reduction in bone density (osteomalacia - decrease in bone mineralisation)
Osteopenia - A less severe decrease in bone density
Most likely a 50+ postmenopausal caucasion woman
RF- SHATTERED
Steroids
Hyperthyroidism/hyperparathyroidism
Alcohol + smoking
Thin (low BMI)
Testosterone
Early menopause
Renal/liver failure
Erosive/inflammatory disease
Diabetes Mellitus (Type 1)
PATHOLOGY
- An oversupply of osteoclasts or undersupply of osteoblasts
SYMPTOMS
- Possible fractures which may present as
+ Patient has recently had a fall (proximal femur fracture)
+ Colles fracture (radius fracture) - fall on outstretched wrist - forked wrist
+ Kyphosis - evidence of vertebral fracture
INVESTIGATIONS
GS - DEXA scan (dual energy x ray absorptiometry) - see how much radiation absorbed by bones to indicate how dense the bone is.
–> It is used to yield the T score
Also can use Fracture risk assessment tool (FRAX)/QFracture assessment - assesses 10 year fracture risk
TREATMENT
1st line - Oral bisphosphonates + calcium and vitamin D3 supplements- Alendronic acid - osteoclast inhibitors
If bisphosphonate CI in kidney disease- DENOSUMAB (monoclonal antibody targeting osteoclasts)
or
TERIPARATIDE - recombinant PTH
or
Consider hormone replacement therapy - estrogen/testosterone (usually younger postmenopausal women with higher risk of fractures)
or
RALOXIFENE - selective oestrogen receptor modulator
What is the T score for young adult bone density
Normal - > -1
Osteopenia - -1 - -2.5
Osteoporosis < - 2.5
Fibromyalgia
-Treatment
RF
Pathology
Symptoms
Investigations
Treatment
A syndrome characterised by widespread pain in the body for at least 3 months. (with all other causes excluded)
RF- Female, 20-60 years, family history, rehaumatological conditions, depression, stress
PATHOLOGY
(MSK equivalent of IBS)
SYMPTOMS
Usually a stressed and depressed 60 year old woman
- Widespread pain and stiffness for at least 3 months (back and neck)
- Sleep disturbance (wake up frequently in the early morning + difficult getting back to sleep)
- Possible allodynia (pain due to a stimulus that does not normally provoke pain)
INVESTIGATIONS
Serology test to exclude differentials
- No serological markers
- No elevated ESR/CRP
++++++ PLUS pain in 11 or more out of 18 palpated regions –> CLINICAL DIAGNOSIS
TREATMENT
1st line - Patient education (can help improve physical function and reduce pain) + referral to physiotherapy
Pharmacological - Antidepressants - Amitriptyline
Can consider specialist referral - cognitive behavioural therapy, occupational therapy
Polymyalgia rheumatica
-Key symptom
RF
Pathology
Symptoms
Investigations
Treatment
Differential of fibromyalgia
An inflammatory condition causing pain and morning stiffness in the shoulders, pelvic girdle (hips) and neck
RF - >50 years, white, females, giant cell arteritis (GCA)
PATHOLOGY
Strong association with giant cell arteritis.
SYMPTOMS
-Sudden Shoulder/hip stiffness and pain (morning stiffness)
- Bilateral proximal muscle weakness
- Sleep disturbance
- Weight loss, depression, malaise, anorexia, low grade fever
INVESTIGATIONS
1st - ESR+CRP elevated
Rapid response to corticosteroids - prednisolone (patients with PMR will have a dramatic improvement in symptoms within 1 week.
Treatment - Oral prednisolone
Sjorgen syndrome
RF
Pathology
Symptoms
Investigations
Treatment
A systemic autoimmune disorder characterised by the presence of dry eyes and dry mouth as a consequence of lymphocytic infiltration into the lacrimal and salivary glands.
RF- Female, SLE, Rheumatoid arthritis, scleroderma
PATHOLOGY
2 types:
Primary - occurs alone
Secondary - occurs in associated with another autoimmune disease - SLE, RA, scleroderma (systemic sclerosis)
SYMPTOMS
- Dry eyes (keratoconjunctivitis sicca)
- Dry mouth (xerostomia)
- Dry vagina
INVESTIGATIONS
First line - Serology for Anti SS A antibodies (anti-Ro) and Anti SS B antibodies (anti-LA).
GS - Schirmer test - filter paper placed in the lower eyelid –> after 5 minutes if <10mm of the paper is wet, the test is POSITIVE.
(Rarely done but salivary gland biopsy - lymphocytic infiltration)
TREATMENT
Based on clinical features
- Artificial tears
- Artificial saliva
- Vaginal lubricants
- Pilocarpine - Cholinergic agonist)
Hydroxychloroquine - given if patient has joint pain, fatigue, rashes.
Main complication of giant cell arteritis?
(Amaurosis fugax) Vision loss - often irreversible if not treated with IV methylprednisolone ASAP.
Giant cell arteritis
RF
Pathology
Symptoms
Investigations
Treatment
A granulomatous vasculitis affecting large sized arteries (sometimes medium)
- Most common form of systemic vasculitis in adults.
RF - >50 years, female, genetics, smoking
PATHOLOGY
- It mainly affects branches of the external carotid artery
e.g. Temporal branch (scalp tenderness), ophthalmic branch (vision), facial branch (jaw)
The temporal artery may be tender and thickened to palpation.
SYMPTOMS
- Unilateral headache - around the temple
- Scalp tenderness (e.g. when brushing the hair)
- Jaw claudication
- Blurred or double vision
(Amaurosis fugax - transient loss of vision in one eye - possible loss of vision if untreated)
INVESTIGATIONS
1st - ESR and CRP elevated
GS- Temporal artery biopsy - shows granulomatous inflammation (possible presence of multinucleated giant cells) - inflammation can be in segmental skip lesions
TREATMENT
1st line - Prednisolone (corticosteroids)
For patients with recent vision loss (amaurosis fugax)- ASAP aggressive treatment with IV METHYLPREDNISOLONE –> otherwise vision loss can become permanent
Polyarteritis nodosa
-Symptoms
-Associated with?
RF
Pathology
Symptoms
Investigations
Treatment
Systemic vasculitis that affects medium sized vessels
RF - Hep B infection, 40-60 years, males
PATHOLOGY
- Associated with HBV
SYMPTOMS
- MONONEURITIS MULTIPLEX- peripheral neuropathy in at least 2 different areas (causes tingling, numbness, pain and paralysis)
- Paraesthesia
- Abdominal pain
- Renal impairment
INVESTIGATIONS
First line - ESR/CRP elevated
CT angiogram - Shows beads on a string –> microaneurysms
GS - Biopsy of affected tissue –> transmural necrotising inflammation
TREATMENT
1st line - Prednisolone (corticosteroids)
(if need to treat hypertension - Ace inhibitors)
Hep B treatment after giving corticosteroids
Give 2 examples of large vessel vasculitis
- Giant cell arteritis - mainly affects branches of the external carotid artery
- Takayasu’s arteritis - mainly affects the aortic arch
Give 3 examples of medium vessel vasculitis
Polyarteritis nodosa - Associated with HBV (40-60 year males)
Buerger’s disease - affects arms and legs (male smokers 20-40, peripheral skin necrosis) - thromboangiitis obliterans
Kawasaki disease - seen in children, can cause coronary artery aneurysms
Give 3 examples of small vessel vasculitis
- Eosinophilic granulomatosis with polyangitis (Churg-Strauss syndrome) –> Tissue eosinophilia, granulomatous inflammation and vasculitis – pANCA positive
- Granulomatosis with polyangitis (Wegener’s granulomatosis) - has upper/lower respiratory tract involvement and glomerulonephritis. – cANCA positive
Henoch schonlein purpura - IgA vasculitis - IgA deposition in GBM on kidney biopsy (has purpuric rash on shins)
What is the general treatment for vasculitis and what should be considered when giving steroids (in general) for long term.
Corticosteroids (prednisolone)
In general, steroids can cause GI effects (peptic ulcer) and bone loss (osteoporosis). So necessary precautions must be taken.
Give PPI for GI symptoms and bisphosphonates to help protect bones.
Glaucoma, weight gain, insomnia, hypertension, diabetes mellitus, and Cushing’s syndrome
