Hem n Onc 8-5 (1) Flashcards Preview

Hematology and Oncology USMLE 1 > Hem n Onc 8-5 (1) > Flashcards

Flashcards in Hem n Onc 8-5 (1) Deck (30):
1

After being diagnosed with lung cancer, this patient presents with purple streaks on the abdomen, moon face, facial hair above the upper lip, and fatty tissue deposits between the shoulder, among other symptoms. Weight gain and redistribution of body fat (in contrast to the cachexia typical of cancers alone), buffalo hump (fatty tissue deposits between the shoulders) and moon facies are classic signs of?

Cushing syndrome

2

The patient’s Cushing syndrome is a paraneoplastic syndrome due to underlying small cell lung carcinoma (SCLC). SCLC is notorious for production of adrenocorticotropic hormone (ACTH) and antidiuretic hormone (ADH). Excessive ACTH production leads to excessive glucocorticoids, and can result in?

Cushing syndrome. Poor wound healing (due to inhibition of collagen synthesis by glucocorticoids) and facial plethora are also part of Cushing syndrome.

3

The increased glucocorticoid activity in Cushing syndrome would more likely cause decreased, not increased, bone density. Cold intolerance and constipation are symptoms of hypothyroidism, whereas proximal muscle weakness, diarrhea and palpitations are symptoms of ?

hyperthyroidism. Nipple discharge would be explained by a diagnosis of prolactinoma, a benign tumor of the pituitary gland.

4

The patient has breast cancer, which is the second leading cause of cancer-related mortality among women, after lung cancer. Whereas primary disease prevention measures aim to prevent the onset of specific diseases, secondary disease prevention measures promote ?

Early detection and treatment of a disease
Among the choices offered, annual mammography is the best secondary prevention measure and has been shown to reduce breast cancer mortality rates by promoting early detection. In this case, the disease has already been detected by biopsy; so annual mammography would prevent the recurrence of local or metastatic disease.

5

Monthly breast self-examination, annual breast ultrasound, and annual screening X-ray of the chest also serve as?

secondary disease prevention measures. However, none of those methods has been shown to reduce breast cancer mortality rates. Prophylactic bilateral mastectomy in high-risk patients and smoking cessation help reduce the risk of breast cancer onset. Thus, they serve as primary disease prevention measures.

6

Thalassemia is an inherited mutation in one or more of the genes involved in hemoglobin production. Hemoglobin is transported throughout the body by RBCs. So in effect, this question is asking, what organ is responsible for RBC production in a 7-month-old infant?

in utero, RBC production (called erythropoiesis) begins in the yolk sac at week 3 and continues until week 8. The liver takes over erythropoiesis from weeks 6 until birth, with help from the spleen during weeks 10 to 28.
Starting at 18 weeks’ gestation ?

The bone marrow steps up and begins to take over this crucial job. Up to about age 20 years, erythropoiesis occurs mainly in the marrow of the long bones such as the femur and tibia. After that, most erythropoiesis occurs in the pelvis, vertebrae, sternum, and ribs.

Bone marrow remains the site of erythropoiesis throughout life, including the 7-month-old infant in this question.

7

Thalassemia is the result of abnormal hemoglobin production. The liver is not involved in the production of hemoglobin in a 7-month-old infant.

Thalassemia is the result of abnormal hemoglobin production. The lungs help get oxygen into the bloodstream, but are not involved in the production of hemoglobin in a 7-month-old infant.

Thalassemia is the result of ?

abnormal hemoglobin production. The spleen is not involved in the production of hemoglobin in a 7-month-old infant.

The yolk sac protects and feeds an embryo through the first trimester of pregnancy. After that, the yolk sac shrinks and disappears. It would not be involved in the pathophysiology of this 7-month-old’s disorder.

8

This patient is a BRCA1 carrier treated for breast cancer with chemotherapy. The low values of her initial CBC strongly suggest that this patient was experiencing myelosuppression from her chemotherapeutic treatment.

The patient’s improved CBC values after she was placed on leucovorin indicate that her chemotherapy was most likely?

Methotrexate. Methotrexate is a chemotherapeutic agent associated with myelosuppression. It is an S phase-specific antimetabolite that acts as a folic acid analog and reversibly inhibits dihydrofolate reductase, interfering with nucleotide synthesis.
Common adverse effects of methotrexate include diarrhea, nausea and vomiting, alopecia, damage to the liver and kidney, and myelosuppression that is reversible with leucovorin (folinic acid). Leucovorin bypasses the block created by methotrexate by supplying folinic acid, the necessary factor for DNA synthesis, and allowing for bone marrow repletion.

9

5-Fluorouracil inhibits thymidylate synthesis; cyclophosphamide acts by cross-linking DNA; doxorubicin is an intercalating agent; and paclitaxel stabilizes?

microtubules. Tamoxifen, a selective estrogen receptor modulator, is not associated with myelosuppression.

10

Methotrexate is a folic acid analog that inhibits dihydrofolate reductase and causes myelosuppression. This complication can be reversed with?

leucovorin rescue therapy, which supplies folinic acid. Other common adverse effects of methotrexate are diarrhea, vomiting, and liver and kidney damage.

11

This patient is presenting with recurrent severe knee pain with restriction of motion and ecchymoses. The hematocrit, leukocytes, thrombocytes, bleeding time, and international normalized ratio values are all within normal limits, making infection and platelet deficiency less likely. The combination of recurrent ecchymosis and knee pain in a male child with absence of trauma, platelet deficiency, or infection places hemophilia high on the differential. Hemarthrosis of weight-bearing joints, as seen in this patient, is a common complication of?

hemophilia A, because these and other joints are principal sites of bleeding. Partial thromboplastin time would be elevated. In a patient with hemophilia A, the factor VIII assay would reveal a deficiency.

12

Factor VIII deficiency (hemophilia A) is inherited as an X-linked recessive disorder. Up to 30% of cases result from a de novo mutation. A deficiency of factor VIII results in?

Easy bruising and hemarthrosis. The severity of symptoms depends on the percentage of activity of factor VIII. Mild is greater than 5% but less than 40%, moderate is between 1% and 5%, and severe is less than 1%. The disease can be treated with factor replacement and/or desmopressin.

13

Extensive trauma from any etiology would result in an inflammatory reaction of the knee, and erythema and warmth would be observed on physical examiantion.
Inflammatory signs would also be found in septic arthritis caused by Staphylococcus aureus colonization, including fever, pain, leukocytosis, impaired range of motion, and warmth and erythema over the joint.
Coagulopathies from immune destruction of platelets or a decrease in?

von Willebrand factor may result in microhemorrhages of the mucous membranes (nasal passages, gums) and skin. However, it is very unlikely that hemarthrosis would occur.

14

The patient presents with constitutional B symptoms (fever, night sweats, and weight loss), and he is going to be treated with a bone marrow transplant; these facts strongly support a diagnosis of Hodgkin lymphoma. Chemotherapy is often effective in treating the disease, but high-dose chemotherapy can destroy the bone marrow. One way to manage this adverse effect is for the patient to undergo?

Autologous grafting by having his stem cells harvested (remember, Hodgkin lymphoma is not a neoplasm of stem cells), undergoing chemotherapy, then replacing the harvested stem cells back into the patient to help replenish the bone marrow.

An autogeneic graft, also known as an autologous or self-graft, involves transplantation of the patient's own tissue from one site to another. These grafts are commonly used for skin grafts, coronary artery bypass surgery (vein), and bone or cartilage transplants. There is no need for immunosuppression after autogenic grafts.

15

An autogeneic graft, also known as an autologous or self-graft, involves transplantation of the patient's own tissue from one site to another. These grafts are commonly used for?

skin grafts, coronary artery bypass surgery (vein), and bone or cartilage transplants. There is no need for immunosuppression after autogenic grafts.

16

Allogenic grafts are the most common type of graft, in which another member of the same species provides the tissue to the recipient. This process carries the possibility of rejection, especially when compared with an autologous graft. Syngeneic grafts are taken from an?

Identical twin and are very successful, but may still cause transplant rejection. A xenogeneic graft is a graft from a different species and has a high propensity to cause transplant rejection.

17

This infant patient is brought to the pediatrician by her parents, who are worried about her decreased activity and lethargy. The reported diet of largely breast milk with small amounts of baby formula supplementation, and the laboratory finding of anemia, together suggest an?

anemia due to the infant’s diet.

Breast milk contains very little iron, approximately 0.35 mg/liter. After 6 months, most infants’ iron stores have been depleted, so this iron needs to come from complementary foods, in addition to breastmilk or formula. Infants from 6–12 months old require 11 mg of iron per day. Fortified breast milk with baby formula may contain additional vitamins, but it is unlikely to meet the daily iron requirement needed.

18

Iron-deficiency anemia is characterized by the presence of small red cells, whose cell volume decreases due to heme synthesis impairment caused by a lack of iron. This is reflected by a?

decreased mean corpuscular volume (MCV), which is the average volume of the red cells in a patient. Normal red cells have an MCV between 80 and 100, while cells smaller than 80 fL are considered microcytic.

19

In iron-deficiency anemia (IDA), the number of available iron-binding sites on transferrin is increased, so the total iron-binding capacity (TIBC) would be elevated, not decreased.
IDA would also not result in hypocellular bone marrow. Bone marrow failure can be inherited or acquired and can involve a single hematopoietic stem cell line or all three cell lines.
Ferritin would be?

Decreased in this patient due to decreased consumption of iron in the diet. Microcytosis, not macrocytosis, is seen in iron deficiency anemia.
The reticulocyte count would be decreased rather than increased in this patient, since RBC production is being reduced due to iron deficiency anemia.

20

The patient presents with a significant smoking history, painless hematuria, weight loss, and night sweats. This presentation isparticularly concerning for bladder cancer. About 90% of bladder cancers are?

Transitional cell carcinoma (TCC). TCC can occur in the renal calyx, renal pelvis, ureters, and bladder. On histopathology, an increased number of epithelial cell layers occur within the papillary foldings of the mucosa, as well as loss of cell polarity, abnormal cell maturation from basal to superficial layers, and increased nuclear:cytoplasmic ratio, prominent nucleoli, and an increased number of mitoses.

21

Patients with renal clear cell carcinoma present with flank pain, hematuria, and a palpable abdominal mass.
Patients with small cell carcinoma of the urinary bladder show typical signs of bladder cancer; however, histologically, neurosecretory dense core granules are present.
Wilms; tumor occurs in children aged?

2–4 years with a unilateral flank mass.
The histology of squamous cell carcinoma of the bladder is characterized by infiltrative nests and islands of pleomorphic squamous epithelial cells.
A renal oncocytoma manifests with painless hematuria, flank pain, and an abdominal mass.

22

This patient presents with an itchy rash on his foot and eosinophilia after returning from a trip in which he walked barefoot in the sand. The history and presentation are classic for cutaneous larva migrans, an infection caused by?

Hookworm larvae. The most common causative species is Ancylostoma braziliense. These parasites live within the intestines of cats, dogs, and other animals and are transmitted via contact with feces of these animals. When the larvae penetrate the skin, they migrate underneath to produce a “creeping eruption” as seen on this patient’s foot. Patients who travel to tropical regions are at risk, especially if they come into direct physical contact with the larvae (walking around barefoot in the sand). Children playing in sandboxes are also at risk if infected animals have defecated in the sandboxes.

23

The eosinophil (shown in the image at right) is an important cell in the immune response to helminthic and protozoan infections. This cell, identified by intense eosinophilia on hematoxylin-eosin stain, is composed of eosinophilic granules containing ?

Major basic protein, a potent helminthotoxin.

24

Myeloperoxidase is a lysosomal enzyme within neutrophils.
Birbeck granules are organelles found within Langerhans cells, which provide cell-mediated immunity in the skin. However, cell-mediated immunity is not the primary host response to cutaneous larva migrans.
CD14 is a surface marker found on?

Macrophages, which play important roles in both innate and adaptive immunity.
Histamine is a compound secreted by basophils, mast cells, and eosinophils. Degranulation of histamine granules plays a key role in allergic responses. However, neither basophils nor mast cells are the key cell types in this patient’s immune response and histamine is not a principal helminthotoxin.

25

These clinical and laboratory findings (hypersegmented neutrophil in the blood smear) are characteristic of megaloblastic anemia. The clinical features of megaloblastic anemia are weakness (due to the anemia) and tingling (due to vitamin B12 deficiency causing subacute combined degeneration of the spinal cord). The laboratory features of megaloblastic anemia are the macrocytic anemia (mean corpuscular volume [MCV] finding) and the hypersegmented neutrophil in the blood smear. This chronic progressive anemia is caused by?

A deficiency of intrinsic factor, a protein produced by gastric parietal cells. Once vitamin B12 is released from food, it binds R-proteins from saliva before traveling to the duodenum. In the duodenum, vitamin B12 is released from R-proteins by pancreatic enzymes and then complexes with intrinsic factor. The intrinsic factor/B12 complex binds to receptors in the terminal ileum, where it undergoes endocytosis by enterocytes.

26

Pernicious anemia is a disorder in which the parietal cells of the stomach make insufficient amounts of intrinsic factor, a protein required for vitamin B12 absorption. Decreased serum B12 leads to a ?

Megaloblastic anemia. A Schilling test can be used to identify patients who have vitamin B12 deficiency because of a lack of intrinsic factor

27

A deficiency in transcobalamin II, the protein that binds free vitamin B12 in ileal cells for transport through the bloodstream, would result in symptoms similar to those experienced by this patient, but they would have begun in infancy rather than adulthood.
An exocrine pancreatic insufficiency would not allow for the separation of the R-protein and vitamin B12 complex in the duodenum, so no B12 would be absorbed or detected in the urine.
One of the enzymes that splits vitamin B12 from its exogenous ingested protein-bound form is pepsin, which is not secreted by?

the pancreas. It is secreted by the stomach.
Defects in the vitamin B12–intrinsic factor receptor would show B12 deficiency not corrected by administration of intrinsic factor or pancreatic enzymes, with symptoms occurring in early childhood.

28

The patient is presenting with acute dyspnea and chest pain. Vitals reveal tachycardia and hypoxia. Fianlly, the patient has a vague history of a “blood problem” in her family with a past medical history of cholecystitis. This vignette is highly suggestive of complications of?

sickle cell disease.
Patients with sickle cell disease are prone to vaso-occlusive crises such as acute chest syndrome. Functional asplenia predisposes patients to infections with encapsulated organisms and is represented by Howell-Jolly bodies on peripheral blood smears.

29

Heinz bodies are precipitated, denatured globin chains associated with glucose-6-phosphate dehydrogenase (G6PD) deficiency.
Degmacytes (eg, bite cells) are RBCs with semicircular “bites” missing from the cell membrane. When denatured hemoglobin persists in RBCs (eg, Heinz bodies), splenic macrophages remove the aberrant denatured hemoglobin.
Ringed sideroblasts result from?

iron accumulation in the mitochondria secondary to defective heme synthesis (eg, chronic alcoholism, vitamin B6 deficiency, and lead poisoning).
Spherocytes are RBCs that appear round and lack the central indentation found normally in mature RBCs. Spherocytes may be acquired or congenital.

30

Sickle cell disease is an autosomal recessive disorder more common in people of African descent. It arises from a missense mutation on the ß-globin chain (glutamic acid to valine substitution). Under certain conditions such as dehydration, acidosis, and hypoxemia, sickle cell patients are at risk for?

RBC sickling, leading to microvascular occlusions and tissue ischemia.

In this patient with chest pain and hypoxemia, vasoocclusion of the pulmonary capillaries is causing acute chest syndrome. This is one of the leading causes of death in patients with sickle cell disease, and must be emergently recognized and treated. Treatment includes broad-spectrum antibiotics to cover common respiratory infections, pain control, blood transfusion, and exchange transfusion in extreme cases.