Immunology Flashcards
CREST syndrome
Calcinosis - calcium deposits in connective tissues
Raynauds -
Eosophageal motility - swallowing difficulty
Sclerodactyly - thick + tight skin on fingers from too much collagen build up
Teleangiectasia - red spots on hands + face
Anti-centromere antibodies
Connective tissue disease
Autoimmune disorder, where immune system appears to stimulate production of too much collagen which builds up in the skin and internal organs, impairing their function.
Sarcoidosis
Bilateral hilar lymphadenopathy, hypercalcaemia, erythema nodosum
Granulomas develop in the body
Commonly affects lungs, skin and eyes
Neutrophil dysfunction
Severe neutropenia - overwhelming sepsis
Dental sepsis + mouth ulcers can be an important indication there is an underlying defect in neutros
Antibody deficiency - clinical features
4-6m after full term delivery signs become apparent
- recurrent infections with encapsulated + non-encapsulated pyogenic bacteria (S pneumoniae, H influenza) - U + L RTI, middle ear, meninges, skin, joints
- viral infections unusual apart from enterovirus
- not usually fungal or intracellular bacteria or parasitic
- diarrhoea + malabsorption due to bacterial overgrowth in intestine (lack IgA)
- septic arthritis
- granulomatous lesions in lungs can give sarcoid picture
- onset of sx in X-linked hypogammaglobulinaemia is in 4th/5th month
Investigation of antibody deficiency
- measure total IgG, IgA and IgM
Investigation of complement deficiency
gross defects can be assessed by capacity of pt’s serum to lyse heterologous blood cells
if abnormal - possible to screen for individual components + do functional tests on discrete aspects of cascase
gross consumption of complement components often associated with low C4 and C3 levels
T cell deficiency
Most important cause now is HIV
Secondary lymphoma due to failure of T cells to control viruses such as EBV also a problem
- 2nd cause in adults is secondary to immunosuppressive therapy e.g. after transplantation
Investigation of T cell deficiency
T cell CD4 and CD8 count extremely useful for monitoring progress of AIDS
Infections associated with CD4 defiency
Protozoan e.g. pneumocytis carinii
Intracellular bacteria e.g. TB
Fungal/yeast e.g. candida, aspergillosis
Extracellular bacteria e.g. encapsulated pneumonia
Viruses e.g. CMV, EBV, herpes virus Kaposi’s sarcoma
Mediators of hypersensitivity reactions
Type 1: IgE, mast cell degranulation
Type 2: IgG, IgM, complement
Type 3: IgG, complement
Type 4: T cells
Examples of hypersensitivity reactions
Type 1: anaphylaxis, atopy, asthma, allergic rhinitis
Type 2: Graves, incompatible transfusions, autoimmune haemolytic anaemia
Type 3: SLE
Type 4: contact dermatitis, mantoux
Side effects of TB drugs
Rifampicin - orange red urine, hepatotoxicity, decreased effectiveness of oral contraceptives
Isoniazid - peripheral neuropathy (vit B6 given)
Pyrazinamide - gout
Ethambulatol - colour blindness + vision loss
Effects of mast cell mediators
Vasodilation
Increased vessel permeability
Gland secretion
Bronchoconstriction
Biphasic anaphylaxis
2 episodes 1-8hrs apart
Mast cells refill + degranulate again
Anaphylaxis management
ABCDE Adrenalin 1:1000 IM (repeat after 5mins) High flow oxygen Fluid challenge Bronchodilator Corticosteroids + anti-histamines
Tissue specific autoimmune conditions
Thyroid - Graves, Hashimotos
Adrenal - Addisons
GI - pernicious anaemia
What can predispose to autoimmunity?
Female sex autoantibodies HLA class DQ2 and DQ8
How can loss of tolerance occur?
Immune privelege lost e.g. penetrating eye injury
Failure of Treg cells
Molecular mimicry e.g. rheumatic fever may follow infection with haemolytic strep
Anti-ds DNA
SLE
Anti-mitochondrial
PBC
ASMA (Anti-smooth muscle antibody)
Chronic active hepatitis
pANCA
UC
cANCA
Wegeners granulomatosis
Anti-endomysial/gliadin/transglutamase
coeliac + dermatitis herpetiformis