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Neonatal-Perinatal Boards Review > Heme/Onc > Flashcards

Heme/Onc Flashcards

1
Q

Most common malignancy in neonates (and it’s origin)

A

Neuroblastoma

Neural crest cells

Usually the primary identifiable location is liver

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2
Q

Findings of neuroblastoma and most common lab abnormalities

A

From catecholamines, but also depends on areas of metastasis

Catecholamine signs: hypertension, diarrhea, tachycardia

Usually in liver: hepatomegaly, jaundice, hypertension (second most common site is skin/SC)

Most common finding: urine HVA and VMA (homovanillic and vanillylmandelic acid)

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3
Q

Site of erythropoetin synthesis in preemie vs. term infants

A

Liver (and therefore insensitive to hypoxic stimulation) in preemies vs. kidney in term

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4
Q

Most sensitive lab marker for iron stores

A

Ferritin

Protein binding iron, regulated by intracellular Fe stores

Low ferritin indicates iron deficiency

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5
Q

Hepcidin’s role

A

Primary regulator of iron uptake (from placenta in-utero and from GI postnatally)

When high, blocks iron uptake

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6
Q

Which type of immunoglobulin crosses the placenta and causes hemolytic disease of the newborn?

A

IgG

Transplacental movement increases with gestation (greatest after 22 weeks)

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7
Q

In pregnancies with Rh incompatibility, _____ is actually protective

A

ABO incompatibility

Fetal cells more quickly destroyed after entering maternal circulation, reducing maternal immune system exposure to Rh antigen

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8
Q

When does OB give Rhogam to Rh-negative mothers

A

28 weeks–this is because most fetal-maternal hemorrhage happens at >28 weeks

Post-partum (if neonate was Rh +)

Any other exposures that could cause sensitization

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9
Q

Two mainstays of treatment for significant hemolytic disease of the newborn

A
  1. Intensive phototherapy (higher priority than IVIG)
  2. IVIG (1g/kg over 2h, can repeat 12-24h later)

Double-volume exchange transfusion: invasive and reserved for a) kernicterus or b) bilirubin at exchange level and recalcitrant to above treatments

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10
Q

How many alpha-globin genes does one have, and on what chromosome?

A

Four (two from each parent)

Chromosome 16

If you like the “alpha-four”, start with the “sweet (chromosome) 16”

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11
Q

What comprises Hemoglobin F and when does it “go away”

A

Two alpha- and two gamma-globin chains

Around 6 months

Higher oxygen affinity (its curve shifted to left) vs. normal Hb

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12
Q

What are the thalassemias?

A

Hemoglobinopathies with at least one mutation in the globin genes (of which everyone has two beta and four alpha genes)

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13
Q

How many alpha genes are mutated in alpha-thalassemia minor

A

AKA alpha-thalassemia trait 2 (of 4)–therefore have little/no anemia

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14
Q

What is Hemoglobin H?

A

Hb H is beta-chain tetramers

It’s the form of alpha-thalassemia where 3 of the 4 alpha genes (chromosome 16) are mutated

(Hb Barts AKA alpha thalassemia major is the worst)

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15
Q

Alpha thalassemia major’s synonym and cause

A

Hemoglobin Bart (gamma tetramer)

Loss of all 4 alpha-globin alleles

Causes hydrops/stillbirth, if survive need almost immediate bone marrow transplant

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16
Q

How many mL of O2 can 1g of hemoglobin carry?

A

1.34mL

Reason for this number in the O2 consumption and carrying capacity equations (always found multipled by [Hb])

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17
Q

What test can be performed to detect fetal-maternal hemorrhage

A

Kleihauer-Betke

Hb F stains red and adult Hb “ghosts out” from citrate-phosphate buffer

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18
Q

What is the difference between a direct and indirect Coombs (and which is normally done as the initial step in newborns)

A

Direct: detect antibodies already bound directly to patient’s RBCs

Indirect: detect antibodies in patient’s serum

On newborns you’re doing a direct test, in mothers for the screen you’re doing an indirect

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19
Q

D is the most antigenic of the Rh antigens–at what anti-D titer are you worried?

A

>1:32

Most fetal-maternal hemorrhage happens at >28 weeks which is the reason for the first Rhogam to be given then

20
Q

What is the second-most antigenic of the Rh antigens

A

Rhc: 20-30% of Rhc+ infants [born to Rhc- mothers) will need phototherapy

21
Q

While Rh antibodies require previous blood exposure to develop, A and B do not–why?

A

A and B are expressed on multiple tissue surfaces, so O individuals are “immediately” exposed and develop anti-A and anti-B by one year of age

22
Q

Of the two sequelae (jaundice and anemia), anti-Kell antibodies cause which?

A

Cause significantly worse anemia than jaundice, unclear why

23
Q

Why do gram-negative/polymicrobic infections result in anemia

A

T-cell mediated hemolysis from ubiquitous activation

24
Q

Three categories of hemoglobin pathologies that’re predominantly in Mediterranean or African patients

A

Alpha mutations: alpha-thalessemia spectrum

Beta globin mutations: Sickle cell disease

Enzyme deficiency: G6PD

25
Q

One type of hemoglobin pathology that’s more common in Caucasians

A

Hereditary spherocytosis (and elliptosis)

Compared to the three in African/Mediterraneans, THIS is autosomal dominant

26
Q

What two hemoglobin diseases result in Heinz bodies

A

G6PD (most classic)

Alpha-thalassemias

Heinz bodies are clumps of denatured hemoglobin

27
Q

What test (other than genetics) is diagnostic of Hereditary Spherocytosis

A

Osmotic fragility test

HS caused most often by Spectrin mutation

28
Q

G6PD facts

A
  1. X-linked recessive
  2. See Heinz bodies on specific [supravital] stain
  3. RBC G6PD activity: can be falsely elevated in times of hemolytic crisis
29
Q

What makes methemoglobinemia patients cyanotic

A

MetHb is oxidized form of Hb, can’t bind O2

Cyanosis evident at level >10%, treat with methylene blue if >20%

30
Q

What is the cause of Fanconi anemia

A

Defective DNA repair so increased chromosomal fragility

Absent thumbs AND radii, pancytopenia, renal anomalies (but NOT Fanconi syndrome)

(Remember TAR has just absent radii and just thrombocytopenia)

31
Q

Of the bone marrow failure syndromes that can present in neonates, which two can cause pancytopenia

A

Fanconi Anemia (and less commonly Schwachman-Diamond)

Diamond-Blackfan Anemia, Kostmann’s and TAR affect only one lineage

32
Q

Equation for partial-volume exchange transfusion

A

Volume exchanged= ([Pt Hct - desired Hct] x blood volume) / Pt Hct

(Used for polycythemia, exchange patient blood for normal saline)

33
Q

Two most common causes of Neonatal Alloimmune Thrombocytopenia

A

HPA-1a and HPA-5b

(NAIT is most common cause of severe thrombocytopenia [<50])

34
Q

Group of IEMs that’re associated with thrombocytopenia

A

Organic acidemias

(Propionic, methylmalonic acidemia)

35
Q

Neonates are relatively deficient in which coagulation factors

A

Everything but factor VIII; but also deficient in anticoagulants so balance is relatively maintained

36
Q

Facts for Hemophilias

A

A: factor VIII, B: factor IX

Both X-linked recessive

Rarely present in neonatal period, if they do it’s oozing and ICH

Hemophilia C: factor XI–associated with Noonan’s

37
Q

Cause of Hemorrhagic Disease of the Newborn and part of clotting cascade it impacts

A

Vitamin K deficiency

Extrinsic pathway (II, VII, IX, and X)–see prolonged PT

Usually presents at 2-7 days with oozing, bloody stools, can see intracranial hemoorrhage (ICH)

38
Q

Most common artery affected in neonatal stroke

A

Left MCA (believed to be way left carotid gets preferential flow from placenta)

(Any stroke tends to present–if symptomatic–with apnea, seizures and/or feeding difficulties)

39
Q

Most common site of venous thrombosis

A

Renal vein: see thrombocytopenia, flank mass, hematuria, and hypertension

(Risk factors: asphyxia, maternal diabetes)

40
Q

What is the blood volume of a neonate

A

80-100mL/kg

41
Q

What coagulation deficiencies might present as purpura fulminans

A

Protein C or S deficiency

(Always consider infection–GBS and N. meningitidis)

42
Q

The level of methemoglobinemia that warrants treatment (and the treatment)

A

MetHb >40%

Methylene bue

43
Q

What is a hereditary cause of a hemolytic anemia with structurally normal RBCs

A

Pyruvate Kinase Deficiency (PKD)

Variable presentation at birth, usually normochromic anemia with high reticulocyte count and “echinocytes” on smear (can be bad enough to cause extramedullary hematopoeisis and hydrops)

Gold standard test is pyruvate kinase enzyme activity

44
Q

What is the most common laboratory abnormality in hemorrhagic disease of the newborn (AKA vitamin K deficiency bleeding), and what’s the most specific

A

Most common: prolonged PT (usually with a less but still prolonged PTT)

Most specific: high undercarboxylated factor II

What vitamin K is needed for is carboxylation (ie functionality) of coagulation factors

45
Q

Oral vitamin K prophylaxis is not good at preventing which of the three timings of vitamin-K deficient bleeding (VKDB)?

A

Late bleeding, ie >7 days

46
Q

Which of the clotting times is abnormal in Hemophilia (A and B)

A

aPTT

Neonatal-Perinatal Boards Review (11 decks)

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