Immune System Disorders Flashcards
What is lupus pernio?
Classic cutaneous finding in sarcoidosis
- violaceous or infuriated erythematous papules, plaques or nodules
- picture from Q6 Exam 1 (608653)
Tx = infliximab and methotrexate
TNF-alpha mechanism
Important for macrophage activation, neutrophil and macrophage recruitment, granuloma formation and function
Gives protection from many pathogens that are sequestered within these granulomas and eliminated by multinucleated giant cells, macrophages, and lymphocytes
What is Type I Hypersensitivity Reaction?
Mechanism, examples
Mechanism: preformed IgE antibodies crosslink with free antigens to mediate degranulation of mast cells with release of mediators including histamine
Requires two separate exposures where first causes sensitization
Anaphylaxis, urticaria, angioedema, allergies (abx, foods, hymenoptera stings)
What is Type II Hypersensitivity Reaction?
Mechanism, examples
IgG or IgM antibodies react with cell antigens with resultant complement activation and cause direct cellular damage and lysis
Requires two separate exposures to antigen where first causes sensitization
Autoimmune hemolytic anemia, erythroblastalis fetalis, Goodpasture syndrome
What is Type III Hypersensitivity Reaction?
Mechanism, examples
IgG or IgM immune complex deposition and subsequent complement activation and depositing on vessel walls, causing inflammation and tissue damage
Serum sickness, SLE, RA, poststreptococcal glomerulonephritis, arthus reaction, polyarteritis nodosa, hypersensitivity pneumonitis
Typically pupuric rash and arthralgias
What is Type IV Hypersensitivity Reaction?
Mechanism, examples
Previously sensitized T helper cells activated by antigen initiate an inflammatory cascade against cell surface bound antigens
Contact dermatitis, TB skin test, Transplant rejection, SJS, TEN, DRESS
Tx for hereditary/acquired angioedema from deficient or dysfunctional C1-esterase inhibitor
FFP - replaces C1-esterase inhibitor
Airway management and standard anaphylaxis therapy as well
Reactive arthritis is most commonly associated with what infections?
- Campylobacter jejuni
- Shigella dysenteriae
- Chlamydia trachomatis
Clinical sx of Takayasu Arteritis
- Large artery inflammation (aorta and carotids) -> carotidynia (tenderness of carotid), absent or weak peripheral pulses, unequal BPs in arms, bruits, hypertension, retinopathy, limb claudication, angina, GI sx
- Constitutional sx = fever, malaise, weight loss
- Arthralgias
- Skin lesions resembling erythema nodosum or pyoderma gangrenosum
Four examples of small-vessel vasculitides
- Granulomatosis with polyangiitis
- Microscopic polyangiitis
- Eosinophilic granulomatosis with polyangiitis
- IgA vasculitis (Henoch-Schonlein purpura)
Dx of Takayasu arteritis
- Angiogram
- MRI
- CTA
Tx of Takayasu Arteritis
- Corticosteroids
- Immunosuppressive agents
What is the characteristic heart rate in patients who have undergone heart transplant?
Resting tachycardia (90-110) due to lack of vagus tone
Infections common in the FIRST month post transplant
- Staph
- MRSA
- Pseudomonas
- Strep
Most often related to the surgery itself (IV lines, intubation, nosocomial pathogens)
Infections common from FIRST to SIXTH month post transplant
- CMV (presents with pneumonitis, GI, renal, skin, or CNS infection and can trigger or exacerbate organ rejection - tx = IV ganciclovir)
- EBV (clinically similar to CMV, also causes a mononucleosis like syndrome)
- Hepatitis
- Listeria
- Pneumocystitis
- Aspergillosis
Infections common after SIX months post transplant
- CMV, EBV, HSV, hepatitis B &C
- Varicella-zoster (primary can result in disseminated disease. Seronegative patients should receive varicella-zoster immune globulin after exposure to chickenpox or zoster. Consider hospitalization in transplant patients with cutaneous zoster)
- Increased risk for community-acquired infections
- Strongyloides hyperinfection syndrome, TB, toxoplasmosis, fungal infections
Cyclosporine toxicity
Hyperkalemia
Nephrotoxicity
Azathioprine toxicity
- BM suppression
- Hepatotoxicity
- Pancreatitis
Hyperacute rejection
Minutes-hours post-transplant
Irreversible graft destruction due to preformed antibodies
Acute transplant rejection
1-12 weeks post-transplant
Humoral/T-cell mediated
Chronic transplant rejection
Months-years post-transplant
Graft vs. Host Disease
Post allogeneic BMT
Rash, diarrhea
Tx for hereditary angioedema
FFP contains C1 inhibitor
What is an adverse reaction to Crofab?
Serum sickness - type III hypersensitivity reaction
Presentation of serum sickness
- Fevers
- Polyarthralgias/Polyarthritis
- Rash
- Malaise
Typically 7-14 days after initial exposure
Causes of serum sickness
Therapeutic antibodies such as rituximab and infliximab
What are the unique laboratory findings of pleural effusions associated with rheumatoid arthritis?
Low glucose, low pH, and high LDH
What are the common causes of renal graft failure?
- Nephrotoxicity from immunosuppressants
- UTI or obstruction
- Renal vascular stenosis or thrombosis
- Progression of underlying disease (e.g. diabetes or hypertension)
Common organisms associated with reactive arthritis
- Chlamydia trachomatis
- Yersinia
- Salmonella
- Shigella
- Campylobacter
Less common:
- Chlamydia pneumoniae
- E. Coli
- Ureaplasma urealyticum
- Mycoplasma genitalium
Mechanism of vincristine and vinblastine
Inhibit microtubule formation
Which chemotherapeutic agent is classically known to cause hemorrhagic cystitis?
Cyclophosphamide
Pathophysiology of poststreptococcal glomerulonephritis
Immune complex deposition
What is a leading cause of morbidity and mortality in patients with systemic sclerosis?
Kidney disease
