Hem n Onc 8-6 (6) Flashcards Preview

Hematology and Oncology USMLE 1 > Hem n Onc 8-6 (6) > Flashcards

Flashcards in Hem n Onc 8-6 (6) Deck (30):
1

This patient presents to the emergency department with acute fever, productive cough, and crackles/fremitus in the left lower lobe. Additionally, his white blood cell count is elevated, and his chest X-ray shows a consolidation in the left lower lobe. These clinical signs point to?

lobar pneumonia. Yet, this patient also has signs of fatigue, bone pain, anemia, thrombocytopenia, and elevated creatinine. Further investigation reveals that his chest X-ray has several hypodense bone lesions in the vertebral bodies, and his serum protein electrophoresis shows increased levels of γ-globulin. His age, clinical picture, and test results indicate multiple myeloma.
Multiple myeloma (MM) is a neoplastic proliferation of plasma cells that disrupts the microenvironment of bone to promote osteoclast activity, leading to lytic lesions (like those in the CT here) and hypercalcemia. MM also results in an excess of immunoglobulin production, causing immunoglobulin light-chain deposits in the urine (Bence Jones proteins), which ultimately leads to renal insufficiency.

2

Making the diagnosis involves the following criteria: ≥10% of clonal plasma cells on bone marrow biopsy or biopsy-proven bony or soft-tissue plasmacytoma. MM is also characterized by the presence of monoclonal proteins in serum or urine, and myeloma-related organ dysfunction, such as?

hyperCalcemia, Renal insufficiency, Anemia), and lytic Bone lesions (CRAB mnemonic).

Other possible findings are leukopenia and thrombocytopenia.

3

Neoplastic proliferation of myeloblasts describes acute myelogenous leukemia. This WBC disorder causes rapid onset of myelosuppression, leading to anemia, neutropenia, and thrombocytopenia. Symptoms include weakness, susceptibility to infection, and a predisposition to mucosal bleeding; however, AML is unlikely to be the cause of the vertebral lesions seen in this patient. In AML, a higher WBC count would also be expected.

Unregulated proliferation of plasmacytoid lymphocytes describes Waldenström macroglobulinemia. An M protein spike is observed on serum protein electrophoresis, due to elevated IgM levels. Findings include proteinuria, hyperviscosity syndrome (eg, spontaneous bleeding, visual disturbances, vertigo, hearing loss, paresthesias, ataxia, headaches, and seizures), and the presence of Bence Jones proteins. This patient’s signs and symptoms do not suggest Waldenström macroglobulinemia.

Parathyroid carcinoma causes ?

hyperparathyroidism. Metabolic derangements include elevated parathyroid hormone levels, hypercalcemia, hypercalciuria, hypophosphatemia, and increased alkaline phosphatase levels. Parathyroid carcinomas lead to osteitis fibrosa cystica, renal calculi, and calcification of tissue such as the kidneys. This patient’s symptoms and test results do not indicate parathyroid cancer with metastatic bone disease.

Prostate cancer is the most common malignancy in men, and its incidence increases with age. When prostate cancer metastasizes, one of the most common locations is to bone. Yet prostate cancer does not cause lytic lesions in bone, but rather osteoblastic lesions. Prostate cancer does not cause a heightened risk for infection or an increase in γ-globulin on serum protein electrophoresis, as seen in this patient.

Squamous cell lung carcinoma with bone metastases can cause hypercalcemia secondary to the production of a parathyroid hormone-related peptide. Metastases of a lung carcinoma can also result in lytic bone lesions. Yet, squamous cell lung carcinoma will not cause an M protein spike on electrophoresis or its complications.

4

This patient’s clinical presentation, along with the serum protein electrophoresis results, points to a diagnosis of multiple myeloma, a neoplastic proliferation of plasma cells characterized by lytic bone lesions, hypercalcemia, renal insufficiency, and a monoclonal M spike. Multiple myeloma accounts for over 10% of hematologic malignancies, placing it second behind non-Hodgkin lymphoma in terms of frequency among blood cancers.
There is an association between the presence of?

Bence Jones proteins and the development of renal dysfunction in these patients. Bence Jones proteinuria, the presence in the urine of immunoglobulin light chains, is a common finding in patients with multiple myeloma. When Bence Jones proteins (antibody light chains) are produced in great quantities by the plasma cells, they result in renal damage and insufficiency by forming large, eosinophilic tubular casts that obstruct the renal tubular lumina and induce an inflammatory reaction.

5

A type II hypersensitivity reaction that occurs at the kidney is Goodpasture syndrome, in which autoantibodies directly adhere to the glomerular basement membrane.
Acute pyelonephritis typically presents with fever and costovertebral angle tenderness.
Deposition of IgM in the subendothelial space is associated with hematuria and other systemic symptoms.
Obstruction by a neoplastic mass would be?

common in renal cell carcinoma or prostate carcinoma.

6

This patient is presenting with hepatosplenomegaly and an eosinophilia with fevers, which are highly suggestive of a parasitic schistosoma infection. Eosinophilia is due to Th2-type inflammation against this extracellular parasite. High-risk behaviors include exposure to unsanitary drinking water. This patient has?

acute Katayama fever due to schistosomal infection acquired in Iraq. Schistosomiasis, caused by Schistosoma mansoni, is endemic to sub-Saharan Africa, the Middle East, South America, and the Caribbean.

7

Babesia microti, a blood parasite, is one cause of babesiosis, a malaria-like illness common in the United States and not seen in Iraq. Although babesiosis can feature a fever as seen in this patient, babesiosis rarely involves the liver. Furthermore, babesiosis, like malaria, is caused by parasites that multiply in red blood cells, causing a hemolytic anemia when replicated parasites are released. This patient's hemoglobin and hematocrit are within normal limits, making this very unlikely.

Guinea worm disease is contracted by drinking stagnant water containing Guinea worm larvae; however, this parasite causes skin and soft-tissue infections, rather than infecting the liver and intestines.

Toxoplasmosis is caused by?

an infection with the parasite Toxoplasma gondii. This parasite is classically contracted by eating undercooked meat or from an individual cleaning out a cat’s litter box. An acute infection in an immunocompetent individual may cause a mild flu-like illness, however people may remain colonized with the parasite. This colonization is unlikely to cause a serious illness unless a person becomes immunocompromised. This patient’s WBC indicates that she is not immunocompromised and she does not have a history of eating undercooked meat or cleaning up cat feces, making this answer choice unlikely.

Rather than causing hepatosplenomegaly, Trichinella infection would cause muscle inflammation and periorbital edema. Trichinella infection comes from eating undercooked meat. There is no mention of this patient having been exposed to undercooked meat, nor exhibiting classic Trichinella physical exam findings.

8

This patient is a 40-year-old male presenting with dysarthria and worsening headaches associated with nausea and vomiting. His head MRI shows an irregularly enhancing left-sided mass with areas of necrosis and localized edema. The biopsy shows foci of necrosis amid highly anaplastic pseudopalisading cells.
This patient likely has?

the most frequent malignant brain tumor in adults. Glioblastomas are typically found in the hemispheres and involve hemorrhagic and necrotic foci (shown in the outline in the image) surrounded by pseudopalisading cells. These tumors often result in neurologic symptoms due to mass effect.

9

Anaplastic astrocytoma has a histologic appearance similar to that of glioblastoma but lacks necrosis and vascular or endothelial cell proliferation. It is also less common than glioblastoma epidemiologically. On pathology, there is visible hypercellularity with nuclear atypia against a dense fibrillary background. Microvascular proliferation and necrosis are absent in anaplastic astrocytoma.

Anaplastic oligodendrogliomas are anaplastic tumors derived from oligodendrocytes affecting the frontal lobes. They are more aggressive versions of the relatively rare oligodendroglioma.

Pilocytic astrocytomas are a?

low-grade astrocytoma typically found in the posterior fossa of children and are uncommon in adults. Pathology would show bipolar neoplastic cells with elongated hairlike processes that are arranged in parallel bundles and resemble mats of hair. Pilocytic astrocytomas often have Rosenthal fibers, which are swollen pink axons.

Myxopapillary ependymomas arise adjacent to the ependyma-lined ventricular system and are made up of ependymal cells. They do not occur in the cerebral hemispheres. In adults, ependymomas more commonly involve the spinal cord, especially the filum terminale. They are typically found in the fourth ventricle in children. Myxopapillary ependymomas show papillary configurations which appear like islands of ependymal cells.

10

The hemoglobin electrophoresis results indicate that 40% of this infant's hemoglobin is abnormal, represented as hemoglobin S (HbS). On the basis of this finding, it is likely that the patient has sickle cell trait.
Sickle cell trait results from ?

a point mutation in one of the two genes encoding the β-globin chain. Specifically, this point mutation is a substitution in which valine replaces glutamate at the sixth position of the β chain. In heterozygotes (people with sickle cell trait), only 35% to 40% of the hemoglobin is abnormal (HbS), which is why such patients tend to be free of symptoms most of the time. A red blood cell (RBC) with less than 50% HbS will not sickle except in the renal medulla. Approximately 8% of African Americans are heterozygotes. In homozygotes (people with sickle cell disease), in whom both β-globin genes are mutated, nearly all hemoglobin is HbS.

11

Sickle cell trait (HbSA) is generally considered to be benign, although complications can arise under certain rare and extreme conditions, which can result in?

episodic hematuria, an inability to concentrate urine, and splenic infarcts at high altitudes. Sickle cell anemia (HbSS), on the other hand, can cause more severe complications, such as dactylitis, acute chest syndrome, and autosplenectomy at normal altitudes.

12

Acute chest syndrome, a serious complication of vaso-occlusive disease, is a result of sickle cell disease.
Aplastic crises can occur in patients with sickle cell disease, often in the context of a recent infection (classically with parvovirus B19).
Dactylitis is a typical presentation of early sickle cell disease that is not characteristic of sickle cell trait. Patients present with painful swelling of the hands and feet.
Although splenic sequestration and autosplenectomy are extremely common in patients with sickle cell disease, they are rare in people with ?

sickle cell trait. However, traveling to high altitudes can sometimes induce sickling and subsequent damage to the spleen in patients with sickle cell trait.
Stroke is a major complication in patients with sickle cell disease and develops when sickling of RBCs occurs in the vasculature feeding the brain parenchyma.

13

The whorled pattern of cell growth surrounding laminated areas of dystrophic calcification represents psammoma bodies (see image). This pathologic finding is most commonly seen in?

meningiomas, papillary thyroid tumors, and certain ovarian tumors.
Meningiomas are common, benign central nervous system tumors that arise from arachnoid cells outside of the brain parenchyma, and they may have a dural attachment. Given this patient’s symptoms of a seizure, headache, and visual field deficit, symptomatic meningioma is the most likely diagnosis.

14

Glioblastoma multiforme demonstrates nuclear atypia, nuclear pleomorphism, and central areas of necrosis.
Hemangioblastoma shows an abundance of closely packed, thin-walled vessels.
Oligodendroglioma has histologic features of?

round nuclei in the midst of clear cytoplasm.
Schwannoma demonstrates hypercellular Antoni A areas and hypocellular Antoni B areas.

15

The patient presents with several signs of a hematologic abnormality: pallor, fatigue, anemia, thrombocytopenia, and scattered bruising. Combined with splenomegaly and increased blasts on the peripheral smear, this generates a typical presentation of acute lymphoblastic leukemia (ALL), the most common cancer in young children. ALL is a malignant neoplasm of pre-B or pre-T lymphoblasts.
Treatment for children with ALL involves several phases, including induction, consolidation, maintenance, and CNS prophylaxis. Induction therapy is accomplished by ?

a four-drug regimen that includes (1) a steroid (commonly prednisone or dexamethasone), (2) asparaginase, (3) doxorubicin/daunorubicin, and (4) vincristine. Vincristine and vinblastine are plant alkaloid derivatives that act on cells specifically during the M phase of the cell cycle. They bind to tubulin and block polymerization of microtubules, preventing mitotic spindle assembly and promoting cell cycle arrest in M phase.

16

None of the other medications act in the M phase. Doxorubicin is another chemotherapeutic agent commonly used in the initial stage of ALL treatment. It inhibits DNA synthesis through the generation of free radicals that cause strand breaks. It also has the ability to intercalate (insert) between DNA base pairs, and therefore acts during multiple phases of the cell cycle but not during M phase. Methotrexate has a variety of indications and blocks?

DNA synthesis during S phase. Later in S phase and early in G2 phase, etoposide inhibits topoisomerase II. Cisplatin is not cell-cycle specific and is more commonly used to treat adult cancers.

17

This 63-year-old woman has fatigue, as well as evidence of cytopenias, including anemia (low hemoglobin, progressive fatigue, pallor), leukopenia (low leukocyte count), and thrombocytopenia (low platelet count, petechiae). This clinical presentation is most suggestive of acute myelogenous leukemia (AML), a hematologic malignancy commonly seen in patients older than 60 years. In patients with AML, the bone marrow fails because the normal, functional bone marrow is infiltrated and replaced by leukemic blast cells. As a result, patients with leukemia have symptoms of pancytopenia, including infections that develop because leukocytes are ineffective. This patient’s peripheral blood smear reveals the presence of multiple Auer rods within myelogenous cells (faggot cells), a finding that is highly suggestive of ?

acute promyelocytic leukemia (APL), the M3 subtype of AML.

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APL (the M3 subtype of acute myelogenous leukemia) shows faggot cells with numerous Auer rods in blood smears. Release of Auer rods can lead to ?

disseminated intravascular coagulation and microangiopathic hemolytic anemia.

19

Increased leukocyte alkaline phosphatase (LAP) is used to differentiate a physiologic acute inflammatory response to infection from acute and chronic myelogenous leukemias. This patient with APL would have decreased LAP.
Although the finding of more than 20% myeloblasts and the presence of multiple Auer rods are characteristic of APL, the finding of more than 20% lymphoblasts in bone marrow would be characteristic of acute lymphocytic leukemia.
Decreased plasma von Willebrand factor activity would be found in a patient with ?

von Willebrand disease, a mixed coagulation and platelet disorder. Although it would explain this patient’s signs of thrombocytopenia (eg, petechiae on lower limbs), a decrease in plasma von Willebrand factor activity would not explain this patient’s systemic illness and decreased leukocyte count.
The finding of blastic bone lesions on radiography of the lower extremities is associated with significant bone pain and can be seen in patients with certain cancers that metastasize to bone, including prostate cancer and breast cancer. The infiltration of normal, functional bone marrow by cancerous cells results in cytopenias due to loss of hematopoiesis in the bone marrow. Although this patient has cytopenias, she denies bone pain, which should prompt exploration of alternative diagnoses. Furthermore, the presence of blastic bone lesions would not explain the presence of Auer rods, which are characteristic of hematologic malignancy of myeloid origin.

20

An oncologist performed a new serum blood test on 1000 patients. Of the 100 patients with the cancer, 60 had positive test results and 40 had negative test results. Of the 900 patients without the cancer, 100 had positive test results. Based on this information:
60 patients are true positive (TP), meaning they have the cancer and tested positive with the new test
40 patients are false negative (FN) meaning they have the cancer, but tested negative with the new test
100 patients are false positive (FP), meaning they do not have the cancer, but tested positive on the new test
800 patients are true negative (TN), meaning that they do not have this cancer and tested negative
These values can be used to determine how?

sensitive or how specific a diagnostic test is or the positive and negative predictive value of a test. It is important to understand that the question is asking for sensitivity, which is used to rule out a disease (SNOUT =SeNsitive test, when Negative, rules OUT a disease).

21

Sensitivity is the proportion of people who have the disease and test positive out of all the people who have the disease, or the true positive rate. It is calculated by TP/(TP + FN) which is 60/(60 + 40) = 60% or 0.6 in this case. Screening tests theoretically aim to identify all those with the disease, and therefore high sensitivities are desired. In this case 60% represents a low number, and the ca-1panc blood test would not be a good screening test for the cancer.

It is important to correctly detect those without the disease to prevent them from ?

undergoing unnecessary treatment or studies that could be painful or harmful to the patients, which is where specificity comes in. It is the proportion of people without the disease who have negative test results, or the true negative rate. It is calculated as TN/(TN + FP), or 800/(800 + 100) = 88.8% or 0.888 and is used to rule in a disease (SPIN = SPecific test, when Positive, rules IN a disease).

Positive predictive value (PPV) is the proportion of positive test results that are true positive. In this case, it is the probability that someone with a positive test for ca-1panc truly does have the cancer. It is calculated by TP/(TP + FP) or 60/(60 + 100) = 37.5% or 0.375.

22

Negative predictive value (NPV) the probability that the person with a negative test does not actually have the disease. It is calculated as TN / (TN + FN), or 800 / (800 + 40) = 95.2% or 0.952.

Sensitivity and specificity are determined by test parameters and are thus intrinsic to the test itself. In contrast, PPV and NPV describe the predictive accuracy of the test within a specific population. PPV and NPV cannot be described as properties of the test alone.

Finally, prevalence is ?

the number of total number of people with the cancer in the population. It is calculated as TP + FN/(TP + FN + FP + TN), or 60 + 40/(60 + 40 + 100 + 800) for a prevalence of 10% or 0.1. If 10% of the sample have this cancer, then 90% or 0.9 of the sample does not.

23

Four days after beginning a cytotoxic chemotherapy regimen, this patient experiences significant pain in his left great toe, nausea, and multiple excoriations on his extremities. His labs also show increased potassium, phosphorous, and uric acid.
Based on his symptoms and chemistry changes, this patient has developed tumor lysis syndrome, a common complication of the treatment of lymphomas and other bulky cancers with cytotoxic therapy. In this condition, dying tumor cells spill their intracellular contents into the bloodstream, overwhelming the body’s processing ability.

Characteristic chemistry changes include increased uric acid (increased turnover of purine nucleotides), increased potassium, increased phosphate concentrations (from breakdown of intracellular ATP), and decreased calcium (precipitation with increased serum phosphate). Excess potassium and low calcium must be managed emergently, as both lead to heart arrhythmias and weakness, which can lead to ?

sudden death. Excess uric acid derived from purine nucleotide catabolism leads to gouty arthritis that commonly presents unilaterally on the great toe and may lead to renal failure.

24

This patient should be treated with allopurinol, a xanthine oxidase inhibitor which works to reduce uric acid production. Glucose/insulin should also be administered to permit intracellular uptake of potassium and reduce the extent of hyperkalemia. Rasburicase, a recombinant uric oxidase, may also be used to clear the blood of excess uric acid; it is frequently used as tumor lysis syndrome prophylaxis.

Disorientation/coma is most commonly associated with ?

hyponatremia, which is not a likely manifestation of tumor lysis syndrome. Furthermore, hemorrhagic cystitis, myelosuppression, and pulmonary fibrosis are not commonly associated with uric acid and electrolyte disturbances that are caused by tumor lysis syndrome.

25

This patient is presenting with classic signs and symptoms of aplastic anemia, which is the suppression of all blood cell lines: erythroid, myeloid, and thrombocytes. This suppression results in anemia, neutropenia, and thrombocytopenia, which present as ?

fatigue, predisposition to infection, and excessive bleeding, respectively.
Chloramphenicol is an antibiotic that is most often associated with aplastic anemia and is thus reserved for treating life-threatening diseases such as bacterial meningitis, rickettsial diseases, or in patients with life-threatening diseases who are allergic to other antibiotics. This drug is rarely used in the United States due to these adverse effects, but is still used in the developing world due to its broad spectrum of activity and low cost.

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Aplastic anemia accounts for approximately 70% of cases of blood dyscrasias due to chloramphenicol. Sulfonamides may also cause aplastic anemia, but the association is less strong.

The other drug choices have their share of side effects, but aplastic anemia and other blood disorders are not among them:

Moxifloxacin can cause GI upset, heart conduction abnormalities, and tendinitis
Penicillin can cause ?

nausea, rash, dermatitis, and anaphylaxis
Vancomycin can cause ototoxicity, nephrotoxicity, and “red man syndrome”

27

This pediatric patient has developed petechiae as a result of a low platelet count, and her CBC shows low values in white blood cells, hemoglobin, and hematocrit. This reduction in all essential cellular blood components is the definition of pancytopenia. However, the reason she came to the doctor is is because of an adverse reaction to cyclophosphamide, which was being used to treat her juvenile rheumatoid arthritis. The administration of alkylating agents such as cyclophosphamide is known to cause hemorrhagic cystitis in patients with?

Fanconi anemia. Fanconi anemia manifests with marrow hypofunction, leading to pancytopenia. It is due to increased chromosomal breakage caused by a defect in a multiprotein complex required for DNA repair, which makes patients more sensitive to chemotherapy and radiation.

28

Ataxia-telangiectasia is due to the knockout of the ATM gene, leading to immunodeficiency, radiation sensitivity, lymphoid malignancy development, and sensitivity to DNA-damaging agents. Eponymous symptoms include cerebellar ataxia and development of telangiectasias.
Hemophilia A results as a deficiency or defect in coagulation factor VIII, which leads to excessive bleeding, classically in joint spaces.
Idiopathic thrombocytopenic purpura follows a viral infection and causes an?

isolated low platelet count, though patients are often asymptomatic and rebound within 6 months.
von Willebrand disease is the most common hereditary bleeding disorder, leading to easy bruising and bleeding, with no effect on the CBC.

29

The pregnant woman's history is consistent with von Willebrand disease (vWD), an autosomal dominant coagulation disorder characterized by mucocutaneous bleeding and often menorrhagia in women. Von Willebrand factor (vWF) is involved in platelet aggregation and is a carrier protein for factor VIII. A lack of vWF increases the partial thromboplastin time and the bleeding time, whereas platelet count and prothrombin time remain normal.
We know that the patient is heterozygous for vWD because there is only a history of the bleeding disorder on her mother's side of the family. Because she has one defective allele and one normal allele, there is ?

a 50% chance that she may pass the defective allele to her offspring. Because the baby's father does not manifest the disease, he will not pass on a defective allele. Therefore 50% of their offspring will have one defective allele, and because it is an autosomal dominant trait, the bleeding disorder will be passed to 50% of their children.

30

0% is incorrect, because the mother has a history consistent with vWD, which is autosomal dominant.

25% would be correct if?

vWD were an autosomal recessive disorder and both parents had the disease. However, vWD is an autosomal dominant disorder.

Regarding autosomal recessive disorders, 67% is the chance that an unaffected sibling of an affected child of two heterozygous parents is heterozygous for the disease.
100% would be correct if both parents manifested vWD.