Teaching Clinic - Secodary Immunodeficiency 101 Flashcards

Question

If you see diaphgram in pneumonia, which lobe can you exclude? If there is silhouette sign, which lobe is involved?

Answer 1

If you see see diaphgram, it is not lower lobe Silhouette sign: RML is consolidated. then its density becomes same as that of heart and it cannot be seen separately from the heart. (right lower lobe is not normal/atypical)

Answer 2

o Combined immunodeficiency § Patient IgG only 216 (N: 600) Combination of bacteria, fungi and virus The patient was given high-dose steroid, rituximab and MMF: § Rituximab leads to B cell deficiency · Does not alone explain the PJP and CMV § (+ MMF and steroid T cell deficiency)

Answer 3

Mx: § IV meropenem, ganciclovir, co-trimoxazole § Withold MMF § No need G-CSF because neutrophil count is normal (4.47) § Give IVIg due to low IgG · Can switch to subcutaneous Ig later on

Answer 4

Innate vs acquired immunity >60% are due to antibody deficiency

Answer 5

Predominantly antibody or cellular deficiencies B-cells [MORE COMMONLY EXAMINED]: Encapsulated bacterias (NHS) Giardia lamblia is almost pathognomonic of B-cell issue T-cells: smaller bacteria which gets inside cells (intracellular), viruses (enter the cells)

Answer 6

Usually multi-factorial - esp disease vs. medications - B-cell lymphoproliferative diseases: chronic lymphocytic leukemia, multiple myeloma, lymphoma - B-cell depleting therapies / conventional immunosuppression > 30x more common than primary antibody deficiencies - But fewer studies and available data - Practice mostly based from experience in PID Unlike primary immunodeficiencies...may be reversible! Antibody quality probably more important than quantity - Defect in production > antibody loss Disease phenotype similar to primary antibody deficiency - Frequent sinopulmonary / gastrointestinal infections - Encapsulated extracellular organisms Secondary: born with intact immune system. Either it is disease (blood disorder, leukaemia, MM), iatrogenic (chemotherapy, rituximab) or combination of both Not congenital Sinus, pulmonary, gut, CNS (when you colonise throat for too long, it may go to the prain)

Answer 7

B cell targeted therapies - - Rituximab – chimeric monoclonal Ab against CD20 - B cell depletion lasts 6-12 months even though the drug is no longer used o Variable: disease and patient dependent o Plasma cells are main source of IgG but do not express CD20 - Stem cells, pro-B cells, plasma cells do not express CD20 spared B cell recovery after anti-CD20 therapy - Hypogammaglobulinemia due to prolonged depletion of plasma cell precursors (rmb 40 and 1/4) o 40% in lymphoma o 1/4 in autoimmune diseases o Due to production problem! Lymphoma patients were already quite immunocompromised – rituximab will further increase the immunosuppression o Also due to combination therapy offered to these patients e.g. RCHOP kill off more cells

Answer 8

1. Severe infections 2. Persistent infections despite therapy 3. Unusual sites of infection or microbes 4. Recurrent infections 5. Family history 6. Unusual clinical presentation 7. Unusual phenotype suggestive of syndrome associated with immunodeficiency (DiGeorge Syndrome) 8. Infectious after biologics SPUR = Serious, Persistent, Unusual, Recurring Jeffrey Modell Foundation 10 Warning Signs of Primary Immunodeficiency

Answer 9

1. Think of non-immunological causes (anatomical lesions, functional disorders, i.e. cystic fibrosis) 2. Exclude secondary immunodeficiency - HIV - Chronic kidney disease, DM - Malignancy, lymphoproliferative diseaes (esp. CLL/MM) - Protein-losing states, malnutrition - Chemotherapy or immunosuppresive therapy (Rituximab) Administer live vaccinations with caution (Ask Dr Li before giving it in immunocompromised individuals)

Answer 10

X-linked recessive disorder: Ask at least 3 generations Plot a family tree Square for male Circle for female Patient and siblings, auntie's and uncle's siblings (one generation) Mom, dad, aunties, uncles (second generation) Patient's sibling's children (third generation)

Answer 11

Don’t just look at A/G ratio → need to look at absolute values for both a. Both AG very low, AG ratio still very low → protein losing state? Liver failure? b. Albumin very low, globulin very high → paraproteinemia c. Both very high → acute inflammatory states d. If globulin low → 99% IgG low (IgG 70% of total Ig)

Answer 12

M = age/2 F = age + 10 / 2 Must learn to calculate!!! Reflects acute-phase reactants ESR unit is mm/H ESR is very high in: GCA (high platelet, globulin, fibrinogen = clot clumps together, heavy = falls faster), polycythaemic ESR will be falsely low in anaemia, hypogammaglobulinemia

Answer 13

APR made by liver - ESR high CRP normal ⇒ LUPUS - Fibrinogen (e.g. consumed in HLH) - CRP super high and ESR inappropriately normal → think of hypogammaglobulinemia

Answer 14

GAME: IgG, IgA, IgM, IgE do not check D

Answer 15

SCIg ⇒ EVERY WEEK CAN DO AT HOME ● Replacement Ig start at 0.4-0.6 g/kg/month ● Either IVIg or SCIG ○ Weekly infusions (infusion pump) vs ‘daily push’ (no pump) at home ● More stable troughs, better patient (?± clinical) outcomes ○ Rate of adverse reactions (headache, muscle aches), infections, thrombotic risk (viscous blood) ○ C.f. IVIG less physiological, fluctuating total serum IgG concentration, extreme concentrations (too high/low) can have detrimental effects ● Flexibility and freedom for patients ● Cost saving (for patients & hospital) ○ Admissions/ bed occupancy ○ Manpower ○ Follow-up ○ Days off/productivity ○ QoL ○ (Risk of infections) Only do IVIg if patient has severe infection and you need to boost up immunoglobulins ASAP