Rheumatology Lab Evaluation Flashcards
- pain that is worse with inactivity, worse in AM and often awaken the patient from sleep
- pain is better with light activity (RA, Ankylosing spondylitis)
inflammatory pain
pain is better with rest and worse with activity (osteoarthritis, tendonitis)
Non-inflammatory
- inflammation of one joint
- hyper-acute: gout, infection
- subacute: inflammatory arthritis, pseudogout, infection
monoarthritis
is inflammation of multiple joints
Polyarthritis
associated with pain and limitation of BOTH passive and active ROM
articular process
like tendonitis and bursitis: associated with pain and limitation of active, but not much passive ROM
Extra articular process
pain in one area
regional pain
pain in both sides, above and below the diaphragm
diffuse pain
four major disease processes in rheumatology?
- mechanical processes: tendonitis, bursitis, mechanical low back pain
- inflammatory processes: like rheumatoid arthritis
- autoimmune processes like SLE
- diffuse pain syndrome (fibromyalgia)
- Rate (mm/hr) at which red blood cells settle in a test tube
- Elevation results from: Infection (most common), malignancy, autoimmune/inflammatory conditions
- levels slow to change (in contrast to c-reactive protein)
- used for disease monitoring in rheumatoid arthritis, polymyalgia rhematica, systemic vasculitis, and lupus
Erythroscyte sedimentation rate (ESR)
what falsely elevates ESR?
- end stage renal disease
- nephrotic syndrome
- anemia
- obesity; it is an inflammatory process
- oral contraception/pregnancy
- age
what decreases ESR?
- Low fibrinogen (i.e DIC)
- polycythenia vera
- sickle cell
- spherocytosis
- CHF
- cachexia
- severe leucocytosis
Small molecule that binds dying cells and or pathogens
- rapid rise within hours of tissue injury
- synthesized in liver
- plays a role in the innate immunity
normal is less than 0.3mg/dl
C-reactive protein
variables that affect C-reactive protein?
- Age
- sex
- race
- obesity
- smoking
- HTN
- alcohol
what should you think of with a very high CRP?
Bacterial infection
If there is a discrepancy between ESR and CRP what could that look like?
High ESR, Low CRP
- Falsely elevated ESR
- liver disease (not able to synthesize CRP)
- lupus, not fuly understood (related to high interferons) but active lupus tends to have a “muted” CRP response
Low ESR, high CRP
- early infection, procalcitonin could be helpful
- autoantibody that binds to Fc region of human IgG
- rheumatoid arthritis
- False positive-c hronic infections- (hepatitis C, bacterial endocarditis), sjrogens syndrome, primary biliary cirrhosis, multiple myeloma, healthy population
- High titers suggest more severe/aggressive disease and increased rate of extra-articular disease
Rheumatoid factor
- autoantibody against the posttranslational modification of arginine
- rare false positives: need to monitor patient for RA development, rarely psoriatic arthritis, autoimmune hepatitis
- associated with erosive damage and severe disease in general
- Do not need to follow RF or CCP titers for longitudinal monitoring of disease
Anti-cyclic citrullinated peptide antibody (CCP)
broad umbrella term for many different autoantibodies that react to antigens in the nucleus of cell
Antinuclear antigen antibodies (ANA)
what patterns of ANA are there? what diseases are associated?
Homogenous/diffuse
- systemic lupus
- drug induced lupus
- scleroderma
Speckled
- systemic lupus
- mixed connective tissue disease
- sjogrens
- myositis
nucleolar
- scleroderma
Centromere
- limited scleroderma
what are specific autoantibodies and their associated disease?
- double stranded DNA: systemic lupus
- SSA (RO): sjogrens systemic lub
- SSB (LA): Sjogrens
- RNP: mixed connective tissue disease
- smith: systemic lupus
- scl-70 scleroderma
- Jo-1: inflammatory myopathy
when should you not check ANA?
- isolated fatigue
- myalgia (unless objective weakness on exam or elevated CK)
- joint pains without inflammatory features or joint swelling
- back pain
- Positive ANA tests will often prompt testing for C3 and C4 components of the complement cascade
- levels tend to trend downward with increased lupus activity
- other nonrheumatic causes include: congenital deficiency, proliferative glomerulonephritis, endocarditis, hepatitis B &C
Complement
- fifth disease
- viral infection of childhood
- often asymptomatic in adults and red facial rash rare in children
- acute parvo infection often results in inflammatory polyarthritis similar to rheumatoid arthritis. Resolves completely
- Positive anti B-19 IgG of little significance as 50% of adults will test positive for previous exposure
- positive anti-b19 igM suggests recent infection
Parovirus
- weak acid and exists mostly in the ionized form
- at concentrations above 6.8 urate can begin to deposit as cystals in the body
- overproduction: inherited enzyme defects, myeloproliferative disorders, purine rich diet, alcohol
- underexcretion: renal failure, metabolic syndrome/obesity, diuretics
Uric acid
majority of people with high uric acid never develop gout
when to check uric acid level?
- should only be checked between gout flares to monitor uric acid levels when using urate lowering therapy (i.e, allopurinol)
- diagnosis of gout is based on joint or tophi aspiration and cystal exam
Often present as a “pulmonary renal syndrome”
* hemoptysis, respiratory distress with identified lung nodules or pulmonary infiltrates
* rapidly progressive glomerulonephritis
Other manifestations
- upper airway disease (sinus, ears, trachea)
- inflammatory eye disease
- arthritis
- rash
- bowel ischemia
- mononeuritis
Antineutrophil cytoplasmic antibodies (ANCA)
What can cause a false positve ANCA?
- Autoimmune hepatitis
- systemic lupus
- inflammatory bowel disease
- cocaine
- some medications
