Monoarthritis/Gout - 137 Flashcards
What is monoarthritis? What is it most commonly due to?
Inflammation of 1 joint at a time. It is most commonly caused by infection
Name some causes of monoarthritis
Gout/crystal arthritis
Trauma/haemarthritis
Osteoarthritis
What is septic arthritis?
Acute inflammation of a joint caused by direct infection.
Name some bacterial causes of septic arthritis
Most commonly caused by Staph. aureus. In younger adults can be due to gonococcus. Strep. and E.coli are also causes
What age group does septic arthritis affect?
Any age
How might septic arthritis present?
Sudden onset, pain, swelling, erythema.
What are some predisposing factors for septic arthritis?
Prosthetic joint, immunosuppression, rheumatoid arthritis, existing damage, IV drug abuse.
How do most septic arthritis infections spread?
Haematogenously
What is the outcome for untreated septic arthritis? How is it treated?
Untreated: joint destruction, sinus abscess formation, septicaemia, multi organ failure. 50% morbidity.
Treated: Abx. Rapid gram stain. 2 weeks IV Abx, 4 weeks oral.
What is gout?
Clinical syndrome caused by an inflammatory response to monosodium urate monohydrate crystals.
Caused by either an overproduction of urate or underexcretion of it.
90% of cases of gout are caused by what?
Decreased urate clearance. This could be due to renal impairment
Name some modifiable and non-modifiable risk factors for gout
Modifiable: Weight, hyperuricaemia, purine-rich diet, alcohol consumption, medications (diuretics)
Non-modifiable: age, male gender, genetics, imparied renal function
In chronic gout what complication can arise that accounts for most of the disability?
Tophi -> these are firm swellings
What patients can have urate lowering therapy (ULT)?
Those who have: had a second attack within a year, has renal impairment, urate stones, tophi and tissue damage.
Give an example of a urate lowering drug
Xanthine oxidase inhibitors -> these reduce uric acid production.
Allopurinol is the main drug used -> dose must be titrated up slowly. Interacts with warfarin.
How is pseudogout different to gout?
It is caused by calcium pyropphosphate crystals, has a different demographic (elderly women). Knees and wrists most commonly affected, attacks can last much longer
What is the treatment for pseudogout?
No specific treatment
What other morbidities is pseudogout associated with?
Hyperparathyroidism, osteoarthritis, haemochromatosis, diabetes, acromegaly.
What are the functions of calcium within the body?
1) Formation of calcified tissues (bones & teeth)
2) Normal activity of nerve and muscle
3) Neurotransmitter release, hormonal & glandular secretion
4) Excitation-contraction coupling
5) Cell membranes
6) Cell adhesion
7) Blood clotting
What is the primary purpose of calcium homeostasis?
To maintain a constant blood Ca concentration
What organs and hormones are involved in calcium homeostasis?
Gut, bone, kidneys
PTH, vitamin D and Calcitonin
Outline the process of vitamin D synthesis
SKIN: UV transforms 7-dehydrocholesterol into VItamin D3
LIVER: Vitamin D3 is hydroxylated into 25-hydroxyvitamin D3
KIDNEYS: hydroxylated in active form of 1, 25 (OH)2 Vitamin D3
What regulates the action of 1-alpha hydroxylate in the kidneys?
PTH
What is the function of vitamin D in the gut?
It stimulates transport of Ca and PO4 in the small intestine -> this increses serum calcium
What is the function of vitamin D in the bone?
Stimulates terminal differentiation of osteoclasts and increases serum calcium
What does hypercalcaemia cause?
Mostly causes suppression of activity -> this is because it blocks Na channels.
Name some signs & symptoms of hypercalcaemia
CNS: altered mental state, lethargy, confusion, depression
Renal: dehydration, ?stones
CV: cause/exacerbate hypertension, shotened QT
Skeletal: increased fracture risk
GI: anorexia, vominting, nausea, constipation
What is the rhyme for remembering problems associated with hypercalcaemia?
Stones, bones, groans, thrones and psychiatric moans
Name some causes of hypercalcaemia
Primary hyperparathyroidism
Renal failure
What must be measured in order to correctly measure total calcium levels?
Serum albumin
Name some signs & symptoms of hypocalcaemia
Pins & needles, tetany, facial spasms, hyperactive tendon reflexes, laryngospasm, arrhythmias
What are Rickets and osteomalacia disorders of? How are they different?
Disorders of calcium metabolism. Rickets is in childhood -> causes bowing of the long bones.
Osteomalacia -> in adulthood, causes decline in bone strength and fractures develop easily.
Name a disease that can causes PTH resistance
Pseudohypoparathyroidism
What type of cartilage lesion can show some spontaneous repair? Why is this?
Osteochondral, because the lesion penetrates through vascularised subchondral bone
Name the 6 functions of bone
Support Movement Protection Calcium reservoir Haematopoiesis Energy store
Name the 5 shapes of bone
Long, Short, Irregular, Flat, Sesamoid
What is the definition of a sesamoid bone?
A bone embedded within a tendon. Patella is the biggest in the body
Which populations are at risk for developing vitamin D deficiency?
- populations lacking sunlight
- populations with a poor diet
What are the 2 organisational compartments the skeleton is organised into?
Axial & appendicular
Embryonal bone development, longitudinal bone growth and fracture healing all make use of a process known as what?
Endochondral ossification
What are the 3 cells involved in bone metabolism
Osteoclast, osteoblast, osteocyte
What do tendons connect to what?
Bone to muscle
What do aponeuroses connect to what?
Muscle to muscle
The two sites of muscular/tendinous attachment to bone are known as what?
Origin and insertion
How can bone density be measured?
Dexa scan. USS, qCT
Osteocytes occupy canals called what?
Canaliculi
In terms of bone metabolism - Osteocytes respond to what?
Mechanical loading
What are osteocytes derived from?
Osteoblasts
Why do cartilage tears heal poorly?
Avascular
Double diffusion system
Loss of stem cell population in older people
What is the major proteoglycan of cartilage?
Aggrecan
