Pediatric Cardiology and Hematology Flashcards
The NEW, FANCY test for hereditary spherocytosis
- Eosin-5-maleimide binding test
- Analyzes the interaction between a dye and certain proteins on the RBC surface through flow cytometry
- Fast, highly sensitive, highly specific
- Now preferred to the osmotic fragility study for diagnosis of hereditary spherocytosis
Bleeding time is a simple but sensitive marker of ___
Bleeding time is a simple but sensitive marker of platelet function
Do not confuse this for a coagulation test
Eisenmenger syndrome may occur in. . .
- VSD (within months of birth)
- ASD (later in life, often young adulthood)
- Patent ductus arteriosus
- The three forms of acyanotic congenital heart disease
Why doesn’t VSD have fixed split S2?
Think about it this way:
An ASD allows for an increase in RV preload
A VSD does not increase RV preload by as much since the AV valve has closed and precludes the RV from filling through the pulmonary vein by way of the LA
You close an ASD with ___.
You close a VSD with ___.
You close an ASD with a device (interventional radiology).
You close a VSD with surgery.
Tetralogy of Fallot is a ___ associated with ___.
Transposition of the great vessels is a ___ associated with ___.
Tetralogy of Fallot is an endocardial cushion defect associated with Down syndrome.
Transposition of the great vessels is a failure of embryologic heart twisting associated with diabetes mellitus (not gestational).
TET spell
Kid who is blue and then pinks up when he squats
Pathognomonic for tetralogy of Fallot
Claudication in a child is highly suggestive of. . .
. . . coarctation of the aorta
Hemoglobin A2
Alpha2 Delta2
Found at low levels in normal adult human blood
Embryonic hemoglobin
- Four types:
- Hb Gower I: ζ2ε2
- Hb Gower II: α2ε2
- Hb Portland I: ζ2γ2
- Hb Portland II: ζ2β2
- The Gower forms are the main ones produce in the yolk sac blood islands during embryonic development
- The Portland forms are more scarce and unstable, present at only small amounts during embryonic and fetal development
A patient with sickle cell disease is expected to have a ___ creatinine
A patient with sickle cell disease is expected to have a low creatinine
This is due to the hyperfiltration that occurs in the early stages of sickle cell disease due to episodic microvascular renal obstruction from sickled cells, particularly in the medulla.
If a patient with sickle cell disease has a high-normal creatinine, it may indicate an AKI
A patient with sickle cell disease is much more likely to have __ gallstones
A patient with sickle cell disease is much more likely to have pigmented gallstones
What labs do you probably want baselines for in your sickle cell patients?
- Bili
- Hgb
- Retic count
- LDH
- Cr
Deferoxamine
Strong chelator of iron and aluminum
Given to patients with iron overload from chronic transfusions, such as sickle cell or thalassemia major patients
Transfusing 1 unit of red cells is roughly equivalent to having ___ worth of iron supplements
Transfusing 1 unit of red cells is roughly equivalent to having 1 years worth worth of iron supplements
So, if someone is getting transfused, they should NOT take supplemental iron
For all intents and purposes, you should assume that any patient with sickle cell disease has no ___.
For all intents and purposes, you should assume that any patient with sickle cell disease has no spleen.
Penicillin prophylaxis in sickle cell disease
Given from birth to age 5 due to poor splenic function
Some may need it until adulthood. They will also need full pneumococcal vaccination (13-valent and 23-valent).
How to think about osteomyelitis etiologies and sickle cell
Someone with sickle cell who gets osteomyelitis is still most likely to have Staph aureus, just like everybody else. S. aureus is just the most common cause of osteomyelitis in everyone, far and away. Salmonella is the second most common cause in those with sickle cell disease.
However, if someone presents with Salmonella osteomyelitis, you should ask yourself if they have sickle cell disease. Only people with sickle cell disease get Salmonella osteomyelitis. But, not every sickle celler with osteomyelitis has Salmonella.
Managing avascular necrosis of bone in sickle cell patients
- Often will involve the hip
-
Conservative management for 4-6 months (crutches, NSAIDs) is the approach of choice
- If no improvement, go to surgery
Indications for exchange transfusion in sickle cell disease
- Stroke
- Acute chest (chest pain, dyspnea,lung infiltrate)
- +/- Priapism (try drainage of penis first)
Treating sickle cell crisis
- Exchange transfusion emergently if indicated (acute chest, stroke, +/- priapism)
- Otherwise (most cases):
- IV fluids
- Oxygen
- Pain control
- If evidence of infection, treat appropriately
- Follow-up with psychosocial stressors if presenting in crisis with normal labs
Hb SC disease
Low Hb, but no or extremely rare sickle cell crises
Hb Sβ+
- One copy S, one β+ (β with slightly lower expression)
- Mild form of SS disease
Hb Sβ0
- One copy Hb S, one absent β allele
- Most severe form of SS disease
Who should get PGE1 therapy? (congenital heart disease)
- All unstable infants with suspected CHD of any etiology
Cyanosis correlates to. . .
. . . the absolute concentration of deoxygenated hemoglobin (~5 g/dL)
Initial workup of a cyanotic newborn
- Goal is to determine whther the goal is cardiac or non-cardiac in origin
- Workup includes:
- CXR
- EKG
- Hyperoxia test (FiO2)
When does rib notching appear on CXR for patients with coarctation of the aorta?
Beyond age 5 it becomes reliable
PFO treatment
None unless there is ever evidence of paradoxical embolism
VSD murmurs
- Holosystolic at L sternal border
- SOMETIMES an accompanying diastolic murmur at apex due to high flow through mitral valve
Tricuspid atresia
- Type of cyanotic congenital heart disease
- Will present as soon as ductus arteriosus begins to close (first 4 days of life)
- LVH will usually be present
- Treat w/ PGE1 as bridge to surgery
Patients with a VSD and slow progression of Eisenmenger syndrome may present with ___ found incidentally on labs taken for another purpose
Patients with a VSD and slow progression of Eisenmenger syndrome may present with polycythemia found incidentally on labs taken for another purpose
When considering whether indomethacin might be helpful for suspected PDA, you should take into account. . .
The total age gestational and post-gestational age of the child
If the child is premature, indomethacin is likely to succeed.
If the child is term and is past the first few days of life, surgery will likely be required.
Primary and secondary prevention of rheumatic fever
- Primary prevention: Prompt treatment of Streptococcus pyogenes pharyngitis (with penicillins)
-
Secondary prevention: Intramuscular penicillin G benzathine OR oral macrolides monthly
- If no carditis, for 5 years or until age 21
- If carditis, for 10 years or until age 21
- If carditis and permanent valve damage, for 10 years or until age 40
Acute treatment of rheumatic fever
Antibiotics (penicillin V usually sufficient) and NSAIDs (aspirin preferred for adults, but ibuprofen or naproxen for kids)
How long after streptococcal pharyngitis does rheumatic fever tend to set in?
2-4 weeks following pharyngitis
Best initial test for endocarditis
Obtain 3 sets of blood cultures
Treatment for acute re-entrant tachycardia of WPW syndrome
Procainamide
Duke criteria
Therapies for HOCM
- First-line: Beta blockers
- Second-line: NDHP CCBs
- Severe disease:
- Characterized by dyspnea and chest pain (NYHA III-IV), repeated exertional syncope or presyncope.
- Treat w/ surgical septal myectomy. If poor surgical candidate, dual chamber pacemaker may be considered. In end-stage obstructive disease, heart transplant may be only option.
First-line for congenital long QT syndrome
beta blockers
Howell-Jolly bodies
Red cells with nuclear remnants. Seen in patients with asplenia or poor spleen function (as in sickle cell, for example)
Renal pathophysiology in patients with sickle cell trait
- Associated with decreased ability to concentrate urine (hyposthenuria) and with renal papillary necrosis
- Hematuria associated with the above is a common finding
- Also higher risk of CKD, UTIs, and renal medullary carcinoma
Most frequent cause of priapism in children and young teens
Sickle cell disease
Diamond Blackfan Anemia
- Congenital syndrome of macrocytic anemia and short stature, webbed neck, low set ears, small jaw, and triphalangeal thumbs.
- Anemia is usually isolated (no leukopenia or thrombocytopenia) and VERY macrocytic (>120s, more so than megaloblastic anemia). There will be no multilobular neutrophils on smear.
Fanconi anemia
- Autosomal recessive defect in crosslink repair
- Wide variety of manifestations
- Often with pancytopenia, cafe-au-lait spots, microcephaly, strabismus, horseshoe kidney
- Predisposition to developing leukemias and myeloproliferative disorders at a young age
Drugs that may cause aplastic anemia
- Carbamazepine
- Methimazole
- Prophylthiouracil
- NSAIDs
- Cytostatic drugs
- Chloramphenicol
Normal ___ has a high NPV against iron deficiency anemia
Normal RDW has a high NPV against iron deficiency anemia
Hemoglobin Barts
γ4
Seen in alpha thalassemia. Levels are highest in complete alpha thalassemia and less so in the less severe forms of alpha thalassemia.
Characteristic findings of apslastic anemia vs myelofibrosis on BM biopsy
- Aplastic anemia: Few progenitor cells, lots of fate
- Myelofibrosis: Few progenitor cells, lots of collagen
Sepsis in a sickle cell patient
Most commonly S. pneumoniae, E. coli, Salmonella, or P. aeruginosa
Treat w/ ceftriaxone
When is exchange transfusion indicated in sickle cell patients?
- Acute chest syndrome (chest pain, respiratory difficulty, infiltrate in CXR)
- Multi-organ failure
Differentiating TTP and HUS
TTP presents in adults and is more likely to have a neurologic component
HUS presents in kids (usually following diarrhea) and may be due to shiga toxin or complement activation, less likely to have a neurologic component.
When do you start a pediatric patient on hemodialysis for AKI?
When significant acidosis is present in context of oliguria
Therapy for HUS
- DO NOT give abx or antimotility agents
- Dialysis needed in up to 50% of patients
- Plasma exchange therapy is for refractory cases
- Eculizumab if aHUS is suspected
- Report the case – HUS following diarrhea is a nationally notifiable condition
Diagnosis of malaria
Thick and thin blood smears
Thick: initial test to detect parasites
Thin: Confirmation and speciation of parasites
G6PD hemolysis often sets in ___ days following exposure to a trigger
G6PD hemolysis often sets in 2-3 days following exposure to a trigger
Diagram of congenital platelet defects
Patients with hereditary spherocytosis are at increased risk for ___. This is often how they present – their compensated anemia becomes decompensated due to ___.
Patients with hereditary spherocytosis are at increased risk for folate deficiency. This is often how they present – their compensated anemia becomes decompensated due to superimposed megaloblastic anemia.
They may also have glossitis, cheilitis, and dysphagia when they come in secondary to their folate deficiency.
HUS vs aHUS vs TTP
- HUS Triad: Acute renal failure, MAHA, thrombocytopenia in the setting of recent dysentery and without fever, in children
- aHUS Pentad: Prominent acute renal failure,MAHA, thrombocytopenia, fever, and sometimes neurologic symptoms,in adults without Hx dysentery
- TTP Pentad: Sometimes acute renal failure, MAHA, thrombocytopenia, fever, and prominent neurologic symptoms, in adults without Hx dysentery
- Neurologic symptoms = AMS
Etiologies of aHUS
- Congenital: Complement defect
- Acquired: Anti-complement factor H antibody
Quick takeaways for differentiating HUS, aHUS, and TTP
- HUS: Dysentery in Hx, may be afebrile
- aHUS: No dysentery, good ADAMTS13 activity (>10%), renal failure most prominent
- TTP: No dysentery, bad ADAMTS13 activity (<10%), altered mental status most prominent
Two uses for eculizumab
Eculizumab STOPS complement activity
So, it is used in:
1) aHUS
2) PNH
Treatment of TTP
Any case of TTP IS AN EMERGENCY
Treat with plasmaphoresis with FFP and cryosupernatant – DO NOT GIVE cryoprecipitate, this will cause a DIC-like picture
