UWORLD 2

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Henoch-Scholein purport
Path: IgA immune complexes-mediated (type III hypersensitivity) vasculitis. Generally follows upper respiratory or minor infections.
Clinical manifestation:
1. palpable purpura
2. arhtralgias
3. abdominal pain, intussusceptions
4. renal disease similar to IgA nphropathy (hematuria)
Diagnosis:
-usually made clinically
confirmed by skin biopsy showing IgA deposition in blood vessels.

deposition of these complexes in the walls of small vessels and the renal mesangium leads to recruitment of neutrophils and lymphocytes as well as activation of complement via the alternative/lectin pathway.

resulting inflammation leads to the organ dysfunction and palpable purport found in HSP The condition is self limited and resolves as the circulating immune complexes clear. Treatment is supportive unless specific complications (eg, intussusception) occur.

a. antibody dependent cellular cytotoxicity type II hypersensitive is part of the body's defense against viral and parasitic infections. Antibodies bound to antigens on the surface of infected cells are recognized by th eFc receptors on the effector cells (eg, NK, neutrophils and eosinophils) that then destroy the infected cells by releasing cytolytic granules

delayed hypersensitivity type IV are T-cell and macrophage mediated response. They occur in response to Mycobacterium TB infections and in certain allergic reactions, such as contact dermatitis and transplant rejection

a palpable skin rash is commonly seen with disseminated Nessiera infections (miningococcemia or disseminated gonococcus). Unlike the purport of HSP, which is generally limited to the lower extremities, the rash of disseminated Neisseria begins with petechiae on the trunk and spreads over the entire body. patients also have a fever, hypotension and tachycardia

IgE depended degranulation occurs in atopic and anaphylactic reactions type I hypersensitivity. IgE on the surface of mast cells and basophils binds the offering allergen and triggers degranulation with relate of histamine, serotonin and other vasoactive substances.

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758

A kid has abdominal pain and athralgias. He had a cough and runny nose lsat week but otherwise has been in good health. PE shows palpable purport over his buttocks and things. Auscultation of the lungs and heart is normal. His abdomen is diffusely tender to palpation without rebound or guarding. Both knees are tender but do no appear warm or swollen. A stool occult blood test is positive. Urinalysis reveal proteinuria, mild hematuria, traces of leukocyte esterase, negative for nitrates and RBC casts. Which of the following mechanism is the most likely underlying cause of this patient's condition?

a. antibody dependent cellular cytotoxicity
b. circulating immune complexes
c. delayed hypersensitivity reaction
d. disseminated bacterial infection
e. IgE dependent degranualtion

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Terms in this set (126)

Candida gives rise to true hyphae, termed "germ tubes," when incubated at 37 for 3 hours. These things are specific for candida albicans that are not seen with any other candida species.

all candida are yeast seen in tissue sections as single cells with pseudohyphae.

These guys are the most common opportunistic mycosis. It is also a frequent colonizer of human skin and mucous membrane.

Superficial candida infections are associated with antibiotic use, corticosteroid use, DM, HIV and other immunpsuppressing illnesses. these superficial infections include oral thus, vulvovaginitis, and cutaneous candidiasis. Disseminated candidiasis occur in neutropenic patients and most often affects the esophagus, heart, liver and kidney.

They don't usually cause lung disease. This patient's pulmonary symptoms might be d/t tuberculosis. He has TB, the candida is just an incidental finding and doesn't contribute to the diagnosis.

Aspergillum fumigates is a fungus that colonizes already existing lung cavities. it forms a fungus ball that may cause cough and hemoptysis.

many pathogens including bacteria, viruses and fungi can cause inflammation of the lung parenchyma. Candida associated pulmonary disease is very rare.

The trachea and large and small bronchi are normally sterile.

119

A 34 y.o immigrant has 3 months history of productive cough, night sweats and low grade fever. Sputum cultures grow budding yeast that form germ tubes at 37 degrees C. The most likely site of this organism before entering the sputum is which of the following?
a. fibrous lung cavities
b. inflamed lung parenchyma
c. bronchioles and small bronchi
d. large bronchi and trachea
e. oral cavity

Hep B infection progresses through two phases
1. proliferative: the entire vision and all related antigens of the episomal HBV DNA are present. ON the hepatocyte cell surface, viral HBsAg and HBcAGg are expressed in conjunction with MHC class I molecules. This expression serves to activate the cytotoxic CD 8 T lymph, which respond by destroying the infected hepatocytes. Note that the vision itself doesn't have a cytopathic effect
2. integrative : the HBV DNA is incorporated into the host genome of those hepatocytes that survived the immune response. Infectivity ceases and liver damage tapers off when the antiviral antibodies appear and viral replications stops. The risk of hepatocellular carcinoma, however, remains elevated because ofHBV dan that has been integrated into the host genome

a. HBV has no direct cytotoxic effect
b. host antibody HBsAb neutralizes HBV infecitivty by binding to the viral surface antigens HBsAg and preventing the antigen from interacting with hepatocyte receptors. Note that this neutralization occurs before the virus enter the hepatocyte, and therefore wouldn't be associated with hepatocellular damage.

c. antigen antibody complexes cause some of the early symptoms of HBV infections (eg, arthralgia, arthritis and urticaria) as well as some of the choir complications (eg, immune complex glomerulonephritis, cryoglobulinmeia, vasculitis). These complexes are not responsible for hepatocellular damage.

d. the pathogenesis of autoimmune hepatitis not hep B infection ivvloves antigen mimicry with genratio not self antigen receogzign CD 4 T lymph that damage hepatocytes

375

Patient has anorexia and fatigue. HIs ALT and AST are high. He is positive for HBsAg. Which of the following best describes the mechanism of liver injury in this patient?
a. viral cytotoxic effect and hepatocyte necrosis with following secondary inflammation.
b. antibody response to viral antigens on the cell surface with antibody-mediated cell damage
c. circulating viral antigen antibody complexes with small vessel deposition and immunologic vessel injury.
d. antigen mimicry with generation of self antigen recognizing CD4 t lymphocytes that damage hepatocytes
e. CD8 T lymph response to viral antigens on the cell surface resulting in hepatocyte damage

This patient has McArdle disease (GSD type V).
-caused by deficiency of myophosphorylase - an isoenzyme of glycogen phosphorylase present in muscle tissue.

Deficiency of this enzyme leads to decreased breakdown of glycogen during exercise, resulting in poor exercise tolerance, muscle cramps and rhabdomyolysis.

Prognosis is generally good and symptoms can be improved by consuming simple sugars before beginning physical activity.

During glycogenolysis, glycogen phosphorylase shortens glycogen chains by cleaving alpha-1,4-glycosidic linkages between glucose residues, liberating glucose 1-phospahte in the process. This occurs until 4 residues remain before a branching point (the limit dextrin). At this point, the debranching enzyme performs 2 enzymatic functions:
1. Glucosyltransferase cleaves the 3 outer glucose residue of the 4 that are left by glycogen phosphorylase and transfer them to a nearby branch
2. the enzyme alpha-1,6-glucosidase removes the single remaining branch residue, producing a free glucose and a linear glycogen chain that ca be further shortened by glycogen phosphorylase.

1032

A 15 y.o boys is easily fatigue during exercise. After several repetition on the bench his arms feel like jelly. He also has severe muscle cramping and urine discoloration after periods of intense straining. Further evaluation reveals that his exercise toelrcn can be greatly improved by drinking an oral glucose solution before beginning a strenuous activity. This patient is most likely deficient in what enzyme?

Dude has blunt aorta injury, which is most commonly caused by motor vehicle collisions.

Mechanical injury involves sudden deceleration that results in extremism stretching and torsional forces affecting the heart and aorta. Injury occurs most often at the aortic isthmus, which is tethered by the ligmentum arteriosum and is relatively fixed and immobile compared to the adjacent descending aorta.

The majority of patient die form aortic rupture before reaching the hospital. those who survive the intimal injury have nonspecific finding such as chest pain,b ack pain or shortness of breath. A widened mediastinum may also be seen on chest X-ray.

2130

a dude was involved in high speed motor vehicle accident. He complains of chest pain, abdominal pain and difficulty breathing. PMH is HTN, asthma, and type 2 DM. BP is 98/54 and HR 121. Dude died. What part of the thoracic aorta is messed up?