12a Diseases of spleen, etc

Question 1

Functions of the spleen

Answer 1

phagocytosis of blood cells and particulate matter
antibody production (mononuclear lymphatic system)
extramedullary hematopoiesis (in fetal development and disease states)
sequestration of formed blood elements (spurious thrombocytopenia, leukopenia)

Question 2

Splenomegaly

Answer 2

Hypersplenism: anemia, thrombocytopenia, leukopenia (pancytopenia)

Question 3

Acute splenomegaly

Answer 3

timeline: days
pooling of blood leading to enlargement of spleen (400-500g)
white pulp is lost
thin splenic capsule -> rupture

Cause: infection, immunologic/inflammatory conditions

Question 4

Chronic splenomegaly

Answer 4

timeline: long time
1000-2000g enlargement
fibrosis: does not rupture, from slow flow of blood

Cause: secondary to chronic venous pressure (portal hypertension or liver cirrhosis) -> collagen deposition

Splenic infarcts: arise from the heart, prone to rupture, suppuration
Lymphohematogenous disorders (leukemia or lymphoma)
Storage disease (mucopolysaccharidoses, niemann-pick disease)

Question 5

Other associated conditions to spleen

Answer 5

Rupture: secondary to blunt trauma, mono, malaria, typhoid fever, lymphoid neoplams; thin capsule; precipitates intraperitoneal hemorrhage

Congenital anomalies
Hypoplasia
Spleniculi (accessory spleens)

Neoplasm

Question 6

Developmental thymic pathology

Answer 6

Digeorge syndrome: defect in cell-mediated immunity and hypoparathyroid
Thymic cyst: benign, can have neoplasm

Question 7

Thymic follicular hyperplasia

Answer 7

Benign
Induce proliferation of T cells
Can have infections, immunologic states, and autoimmune disorders
Goiter

Question 8

Thymoma

Answer 8

Benign tumor but can invade lungs, pericardial sac, etc
Benign: polygonal/spindle cells
Malignant: cortical type, squamous cell with reactive T lymph

Question 9

Categories of WBC disorders

Answer 9

Proliferative disorders: leukocytosis/lymphocytosis
Reactive: infections or inflammation
Neoplastic

Leukopenia: low WBC
infection, tumor

Question 10

Neutropenia/agranulocytosis

Answer 10

Susceptible to bacterial and fungal infections
Common infectious lesions: herpangina (ulcerative necrotizing lesions), candidiasis

Treatment: G-CSF
Causes: drugs, chemo drugs, myelodisplastic syndromes, inadequate granulopoiesis, increased destruction of neutrophils

Question 11

Neutropenia: Inadequate/ineffective granulopoiesis

Answer 11

Suppression of hematopoietic stem cells
Suppression of committed granulocytic precursors due to drug toxicity (chloramphenicol)
Infective hematopoiesis (myelodysplastic syndromes)
Congenital anomalies (Kostmann syndrome)

Question 12

Neutropenia: Accelerated removal/destruction of neutrophils

Answer 12

immunologically mediated injury to neutrophils
splenomegaly (sequestration of neutrophils)
increased peripheral utilization (sepsis)

Question 13

Leukocytosis

Answer 13

Most common cause: infection

Major mechanisms
1 increased production in the marrow (chronic infection, paraneoplastic, myeloproliferative disorders)
2 increased release from marrow stores (endotoxemia, infection, hypoxia)
3 decreased margination (exercise, catecholamines)
4 decreased extravasation into tissues (glucocorticoid)

Question 14

Types of leukocytosis

Answer 14

Neutrophilia: acute infection, burns, necrosis
Eosinophilia: allergic disorders, parasitic infection
Basophilia: myeloproliferative disease, CML
Monocytosis: chronic infection (TB)
Lymphocytosis: mono, chronic infection, viral infection)

Question 15

Reactive changes in neutrophils

Answer 15

Toxic granules
Dohle bodies: enlarged ER
Leukemoid reaction: increase WBC with diff maturities, no increase in basophils

Question 16

Lymphadenitis

Answer 16

Acute: neutrophils, tender and large, due to infection
Chronic: non-tender, due to immunologic stimuli

Other types:
Lymphoid follicle formation in non-lymphoid tissues
Chronic infection

Question 17

Lymphadenitis: follicular hyperplasia

Answer 17

Characteristics absent in follicular lymphoma:
1 mantle zone composed of naive B cells
2 Germinal center: light zone of centrocytes, dark zone of centroblasts (B cells presented with antigens)
3 Tingible-body macrophages: middle, many apoptotic debris

Question 18

Lymphadenitis: paracortical hyperplasia

Answer 18

Houses T lymph

usually virus induced (vaccines)

Question 19

Lymphadenitis: Sinus histiocytes/ reticular hyperplasia

Answer 19

Expansion of sinusoids at the center of lymph node
More macrophages = pale pink
Seen in lymph nodes with cancer