Understanding immunodeficiency diseases on the USMLE Step 1 exam

Tyler York

Immunodeficiency disorders can be due to defects in T cells, B cells, phagocytes, complement or combined. They cause recurrent pyogenic, viral and fungal infections. Some of them predispose to autoimmune disorders and cancers.

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Full Understanding immunodeficiency diseases on the USMLE Step 1 exam video transcript:

Hello everyone. I'm so Jetta in this video, we will be covering primary immunodeficiency disorders. Immunodeficiency disorders, may be due to defects of the T cells, B cells combined immunodeficiency. Sweet cuz of defects in the T and B cells. It may be due to complement efficiencies or phagocyte deficiencies.

In this video, we will discuss about T-cell deficiencies b-cell deficiencies and combined immunodeficiency.

Clinically be so deficiencies. Can be differentiated from T-cell deficiencies due to the increased risk of recurrent, pyogenic infections, and infections with encapsulated bacteria, on the other hand, in T-cell deficiencies. There is an increase risk of infection with intracellular bacterial organisms, and other interested of microorganisms, as well as fungal, and viral infections. They're all so predisposed to devil of malignancies and autoimmune disorders in Combined, T, and B cells deficiencies. What we see is a very severe form of immunodeficiency.

Let's look at the B Salomon the deficiencies first.

Selective IGA deficiency. It is the most common primary immunodeficiency and characterized by a complete or total lack or absence of IGA. In the bloodstream since idea provides mucosal immunity such patients are prone to recurrent infections of the mucosal track. For example, recurrent upper respiratory tract, infections recommend GI infections causing diarrhea Exedra since I do not have IGA in the bloodstream. They should not be given blood transfusions or immunotherapy because they may develop severe allergic reactions like anaphylaxis.

Common variable. Immunodeficiency, it is characterized by the deficiency of at least two types of immunoglobulin in the plasma, for example, deficiency of IgA and IGG, a deficiency of IGM, and IGG, excetra clinical, biogenic infections. Some people are at increased risk of autoimmune disorders and certain malignancies like lymphomas and gastric carcinomas.

Hyper IGM. Syndrome syndrome is characterized by excessively high levels of IGM in the bloodstream. At the same time low levels of other immunoglobulins like IGG IGA except the defectors in the gene that codes for cd40 legend, the city fertilization is present on the surface of CD for helper T cells, and the slides and interacts, with cd40 from B cells. This interaction between cd14 cd40 lightened is important for class. Switching means conversion of a GMC type into other stereotypes. Like IGG, IGA excetera, that leads to recurrent pyogenic infections. Some people may be at increased risk of autoimmune disorders and cancer.

Boutin's are x-linked agammaglobulinemia. This is an inherited disorder which has caused you to a defect in bruton's tyrosine kinase. This is a special kind of tyrosine kinase that is important in the development of B cells because of the defect in this specific enzyme. What happens is B cells, cannot develop in the bone marrow as a result, the lab finding will be a complete to Total, lack of B cells as well as immunoglobulins in the blood. Therefore, they will be neutropenia clinical lead for president with recurrent pyogenic infection, which began after two months of life. Since the new unit will be protected by Mattingly acquired idg from the placenta in the initial two months of life,

In the next section we will be looking at T Cell immune deficiencies or cell mediated immunity deficiency.

Wiskott-aldrich syndrome, syndrome is caused by a defect in was Gene that codes for its product wasp or where is this product is a signaling molecule. That is important in the interaction between cells and cytoskeletal structures like acting, which play an important role in cell mobility and sell a decision. Because of that, they will be immune deficiencies which involve mainly the B cells, but also the details in some cases it presents in the form of a classical Triad of immunodeficiency along with thrombocytopenia and eczema. There are micro platelets on blood smear and because of the Tumblr, cytopenia bleeding is also seen in some patients along with the pageant, Confections.

DiGeorge syndrome in Detroit syndrome also called as below cardio facial syndrome or timing a place where there is a defect in the development of the third and fourth pharyngeal pouches. So development of the time it's which is responsible for Metro station of T cells and development of parathyroid glands leaving to hypocalcemia is the leading clinical feature in this the doctor.

There is a deletion in chromosome, 22. The syndrome can be remembered by the mnemonic Catch-22 which stands for cardiac defect abnormal. Facial features, like low-set ears, George effects, timing, a Play, Sia, or hypoplasia, cleft palate and hypocalcemia.

Chronic mucocutaneous, candidiasis. This disorder is due to defective cell mediated immunity and is characterized by recurrent. Chronic persistent candida infections involving only the skin and subcutaneous structures like skin mucous membrane and Nails deficiency with this congenital or acquired like hiv-positive Aid syndrome, or DiGeorge syndrome may present with chronic Maquoketa Aeneas Canada's

Job syndrome or hyper ige syndrome in this syndrome. That is a very high level of IG in the bloodstream, along with recurrent called abscesses and eczema. It is due to a defect in production of gamma interferon by the helper T-cell which then leads to a reduced function of the macrophages, leading to the record and collapses th1 responses are affected in th to response gets out of control, leading to high ige levels in my present with abnormal signs and symptoms like sepsis and Persistence of molluscum contagiosum infections.

Let's talk about the combined, immunodeficiency.

Severe combined immunodeficiency is caused by a defect in T-cell and B cell function for the severe immunodeficiency. And features like recurring Parts in a Confections, recommend fungal and intracellular, my throat infection viral infections cancerous autoimmune disorders and failure to thrive.

Physical examination. May show the lack of a tonsils and lymph nodes. Most of the common reasons for skin are due to enzyme defects in various enzymes like that. 70 recombinase one and two enzymes also called as a rag, 1 and drag do enzymes Ada, or anyting deaminase deficiency PRP enzyme deficiency. Excetra some defects me because by abnormality in interleukin-2 receptor,

Woman syndrome, which is caused by recombinase enzyme defect is characterized apart from the unit, efficiency by editor Derma skin, peeling, Etc.

Immunoglobulin levels are low in all cases of skid and at the same time live vaccines are contraindicated.

Thanks for watching the video. Hope this helps. You clear some Concepts on immunodeficiency disorders.
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