Diagnostic Testing Rheumatologic and Connective Tissue Diseases

Diagnostic Testing Rheumatologic and Connective Tissue Diseases

Is it a rheumatologic or connective tissue disorder?

* The distinction between rheumatologic and connective tissue (collagen vascular) diseases is unclear.
* There is much overlap in disease presentation and laboratory testing
* In each, the body’s own proteins are recognized as foreign, and AUTO-antibodies produced


Case #1

Rheumatoid Arthritis Lab Work-up

* CBC (with diff)
* Sedimentation rate
* Rheumatoid Factor (RF)
* 40-60% have anemia of chronic disease; (suspect infection); mild WBC

Erythrocyte Sedimentation Rate (ESR)

* Nonspecific test for inflammatory process
* anticoagulated blood in calibrated tube; rate of sedimentation of RBCs in 1 hour
* normal <15m;<20f; add 10 past age 60
* Rate of sedimentation increases with
o increased fibrinogen 2 inflammatory process (occurs wi 12-24 hours)
o acute/chronic infection; tissue necrosis; tissue infarction; well established malignancy; rheumatoid/collagen diseases; abnormal serum proteins; pregnancy; obesity; anemia

Sedimentation Rate Uses

* An aid in detection and diagnosis of inflammatory condition (or to exclude)
* A means of following the activity, clinical course, or therapy of inflammatory diseases
* To demonstrate or confirm occult organic disease

Rheumatoid Factor (RF)

* RA and related diseases associated with increased immunoglobulins (autoantibodies):
o IgG variety antibodies
o IgM variety antibodies
o IgA variety antibodies
* RF is an IgM antibody directed against IgG
* Present in the sera of 75% of patients with Rheumatoid Arthritis
* Higher titer of RF are commonly associated with severe RA
* High titers also seen in syphyllis, sarcoid; infective endocarditis; TB; leprosy; parasitic infections; old age
* Presence of RF does NOT rule in RA
* Absence of RF does NOT rule out RA
* If the pretest probability of RA is high, the presence of RF is supportive of the diagnosis.
* If the pretest probability of RA is high, the absence of RF should not change your clinical diagnosis
* Order if symmetrical polyarthritis of uncertain origin
* There is no need to repeat RF testing once it is positive

Case #2

Systemic Lupus Erythematosus Lab Work-up
Antibodies in SLE
Antinuclear Antibody
(ANA)
ANA: peripheral pattern
ANA: solid/diffuse pattern
ANA: speckled pattern
Anti-nDNA Antibody
Anti-Sm Antibody

Case #3
Mixed Connective Tissue Disease Lab Work-up
Anti-RNP (ribonucleoprotein) Antibody
Case #4
Anti-RO/SSA and Anti-LA/SSB
Complement Levels
(C3, C4, CH50)
INFLAMMATION
Complement Activation Pathways
Complement Testing
HLA-B27 Antigen in Ankylosing Spondylitis
Case #5
Joint Aspirate Analysis
INFECTION

Diagnostic Testing Rheumatologic and Connective Tissue Diseases.ppt

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Polymyalgia Rheumatica &Temporal Arteritis

Polymyalgia Rheumatica &Temporal Arteritis
Presentation by: Anna Mae Smith, MPAS, PA-C

Polymyalgia Rheumatica

* A clinical syndrome characterized by aching and stiffness of the shoulder and hip girdle muscles affecting older patients, associated with an elevated ESR, lasting over 1 month and responsive to low dose steroids

Epidemiology

* Incidence/Prevalence in USA: Approximately 50/100,000 patients over age 50/year
* Predominant age: 60 or older. Incidence increases with age (rare under 50 years old).
* Predominant sex: Females > Male (2:1)

Signs & Symptoms

o Onset - abrupt or insidious
o Pain and stiffness shoulder and hip girdle
o Usually symmetrical
o Symptoms more common in the morning
o Gel phenomena (stiffness after prolonged inactivity)
o Constitutional symptoms - fatigue, malaise, depression, weight loss, low grade fever
o Arthralgias/arthritis (non inflammatory)
o No weakness (pain may limit strength)
o Muscle tenderness mild to moderate
o No muscle atrophy
o Decreased range-of-motion of joints on active motion usually due to pain
o May have signs and symptoms of giant cell arteritis

RISK FACTORS

o Age greater than 50
o Presence of giant cell arteritis

Differential Diagnosis

o Rheumatoid arthritis
o Other connective tissue disease
o Fibromyalgia
o Depression
o Polymyositis/dermatomyositis (check CPK, aldolase)
o Thyroid disease
o Viral myalgia
o Osteoarthritis
o Occult infection
o Occult malignancy (extensive search usually not necessary)
o Myopathy (steroid, alcohol, electrolyte depletion)

LABS

o ESR (Westergren) elevation greater than 50
o Anemia - normochromic/normocytic
o Creatine phosphdkinase (CPK)- normal
o Rheumatoid factor (RF) - negative (5-10% patients over 60 will have positive RF without disease)
o Mild elevations in liver function tests

TREATMENT
Patient Follow -up
PROGNOSIS

o Average length disease is 3 years (range 1-5 years)
o Exacerbation if steroids tapered too fast
o Prognosis very good if treated (may gradually remit even if no treatment)
o Relapse common
Henoch-Schonlein Purpura
Definition

* A vasculitis of small vessels characterized by nonthrombocytopenic, usually dependent, palpable purpura, arthritis, abdominal pain and nephritis
Epidemiology

SIGNS & Symptoms

o Onset can be acute or gradual
o 50% of patients have malaise and low grade fever
o Skin lesions occur in all identified patients:
+ Lesions appear on lower extremities and buttocks but may involve face, trunk and upper extremities
+ Begin as small wheals or erythematous maculopapular
o Lesions blanch on pressure but later become petechial or purpuric
o Lesions appear in crops
o Angioedema of scalp, lips, eyelids, ears, dorsa of hands and feet, back, scrotum and perineum may be seen
* Two-thirds of patients experience arthritis:
o Large joints (knees and ankles) are most commonly involved
* One-half of patients experience GI symptoms:
o Colicky abdominal pain associated with vomiting is most common
o Occult or gross blood in stool
o Hematemesis
o Intussusception, obstruction or infarction rarely occurs
o Pancreatitis
* Renal involvement is less common
o Hematuria, with or without casts or proteinuria
* Other manifestations
o Seizures, neuropathies
o Hepatosplenomegaly
o Lymphadenopathy
o Cardiac involvement
o Pulmonary hemorrhage
o Rheumatoid-like nodules

DIFFERENTIAL DIAGNOSIS

o Hemorrhagic diathesis
o Septicemia
o Intussusception
o Acute appendicitis
o Acute glomerulonephritis
o Familial IgA nephropathy
o Polyarteritis nodosa
o Systemic lupus erythematosus
o Inflammatory bowel disease
o Subacute bacterial endocarditis
o Rocky Mountain spotted fever
o Thrombocytopenic purpura
Labs

o Not diagnostic
o Sedimentation rate, white blood cell count may be elevated
o Coagulation studies, platelet count and complement determinations are normal
o Serum IgA elevated in 50%
o Urinalysis shows protein, red blood cells, white blood cells if renal

TREATMENT
COMPLICATIONS

o Hypertension
o Renal failure
o Intestinal hemorrhage
o Bowel obstruction or perforation
o Death very rare

PROGNOSIS

o Disease may last for a few days with transient arthritis; however, in many cases, the average duration is 4-6 weeks
o Occasionally recurrent
o 25% of patients with initial renal involvement will have persistently abnormal urine sediment

Polymyalgia Rheumatica &Temporal Arteritis.ppt

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Crystalline Arthropathies

Crystalline Arthropathies
Presentation by: Walter Eisenhauer MMSc, PA-C

Gout

* The Disease of Kings, The King of Diseases
o Predominately disease of adult men
o Females spared until postmenopause
o Uric Acid by product of Purine metabolism
o 10% of those with gout overproduce- the remaining 90% are underexcretors
* Urates circulate in plasma mainly in unbound form
o Referred to as urate pool
o Pool increases as Uric acid levels increase
o Excreted by two mechanisms
+ Renal
+ Bacterial oxidation in the gut
* Total Body urate Pool 1200 mg males/600 mg females
o 85% denovo synthesis
o 15% dietary intake of purines
o Purine restricted diet may only decrease serum urate level by 1-1.2 mg/dl
Urate – complete filtration

+ Presecretory tubular resorption 99%
+ Tubular excretion 50%
+ Post secretory resorption 80%
+ Excretion of 10% filtered load (600 mg/day)
+ Additional 1/3 excreted by pancreatic and intestinal juices
* Two Main Classifications
o Overproducers
o Under Excreters
* Overproducers
o 10%
o Primary
+ Idiopathic
+ Enzyme abnormalities in purine metabolism
o Secondary
+ Excessive dietary uptake
+ Myeloproliferative disorders
+ Severe muscle exertion
* Decreased excretion- 90%
o Primary Vs Secondary
+ Primary
# Unidentified defect in tubular secretion ( up to 40 % less)

* Secondary
+ Renal insufficiency
+ Diuretics
+ Low dose ASA
+ Cyclosporine
+ Ethambutol
+ Lead toxicity
+ Saturnine gout due to nephropathy
+ DKA
+ Starvation
+ Ketosis
+ Ethanol
+ Lactic acidosis
+ Predisposing illness- HTN, DM etc
+ Combined ETOH/G6PD deficiency
* Urate Pool substantially enlarged in Gout
o Non Tophaceous- 2-4gm
o Tophaceous 30 gm or more
* Urate solubility
o At physiologic ph 99% as urate not uric acid
o Soluability at 37degrees is 7.0 vs 30 degrees is 4.5 mg/dl
o Intrarticular temp at the knee is 33 degrees- ankle 29 degrees
* Acute Gout clinical features
o Males 4th-6th decade
o Consider enzyme abnormality if before 60
o 38% with normal uric acid
o Monoarticular 85-90%
o Podagra in 50%, ultimately 90%
o Primarily lower extremity joints
o Precipitated by
+ Surgery
+ Trauma
+ Febrile Illness
+ Excessive eating or ETOH consumption
* Systemic symptoms in polyarticular forms
o Fever
o Chills
o Elevated WBC/ESR
* Spontaneous resolution over days to weeks
* Females older, post menopausal
* Intercritical gout
o 7-10% only experience initial attack
o 62% with second attack within 1 year
o Majority with attack within 6-24 months
o Ultimately attacks more frequent and polyarticular

* Tophaceous Gout
o 3-21% develop
o Average 11.6 years after initial episode
o Typically ear, elbows, fingers, Achilles tendons but may appear anywhere
o Synovial tophi can lead to bone erosions
* Transplant Gout
o Primarily related to cyclosporine
o Acute gout often after one year
o Tophaceous gout within 5 years
o 13% decrease in ADL’s secondary to gout
* Renal Manifestations
o Stones presenting manifestation of up to 1/3
o Gouty Nephropathy-inter parenchymal deposits of monosodium urate crystals causing inflammation and scarring
o Acute Uric Acid Nephropathy caused by obstruction of tubules with uric acid crystals

* Diagnosis
o Can not make dx with blood studies
o Demonstrate crystals in synovial fluid
o Presence of tophi
o Presumptive on basis of clinical presentation
o Strongly negative birefringent, needle shaped, often intracellular crystals

* Xray
o Punched out lesions
o Asymmetric nodular soft tissue swelling
o Joint space narrowing- often asymmetric

* Treatment

Pseudogout

* CPPD- Calcium Pyrophosphate Dihydrate
* Chondrocalcinosis when calcium in cartilage
* Mimics presentation of Gout attacks
* Treat with NSAIDS
* Rule out Hyperparathyroidism

Crystalline Arthropathies.ppt

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