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Flashcards in BCEM Deck (55)
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1
Q

Orotic Aciduria

Inher, Mech, Pres (Epi + 4), Micro Finding, RX?

A

AR.

Defect in UMP Synthase ->
Inability to convert Orotic acid -> UMP
(De Novo Pyrimidine Syn pathway).

PRES: Children

  • Failure to thrive
  • Megaloblastic Anemia CAN’T be cured by Vit B9 or B12
  • Glossitis
  • Orotic acid in urine

FINDING:
- Hypersegmented Neutrophils

RX = UMP (allows bypassing of mutated enzyme)

2
Q

a-amanitin Ingestion

(found in Amanita phalloides = “death cap” mushrooms)

Mech & Pres?

A

Inhibits RNA Polymerase II -> Severe hepatotoxicity

3
Q

I-Cell (Inclusion Cell) Disease

Classification, Mech (3 steps), Pres (3), Labs?

A

Inherited. Lysosomal Storage Disorder.

MECH:
Defect in Phosphotransferase -> Failure of Golgi to phosphorylate MANNOSE residues on glycoproteins (ie↓mannose-6P) -> Proteins secreted extracellularly rather than delivered to lysosomes.
** Often fatal in childhood. **

PRES:

  • Coarse facial features
  • Clouded corneas
  • Restricted joint movement

LABS:
- High lysosomal enzymes

4
Q

Chediak-Higashi Sx

Genetics, Mech (2), Pres (3)?

A

Mutation in LYST gene (lysosomal trafficking regulator).

  • ↓fusion of lysosomes & phagosomes
  • ↓microtubule sorting of endosomal proteins
5
Q

Kartagener’s Sx (1ry ciliary dyskinesia)

Mech, Pres (4), Comp?

A

Immotile cilia due to defective dynein arm.

PRES:

  • Infertility (ie immotile sperm and dysfunctional fallopian tube cilia)
  • Situs Inversus
  • Bronchiectasis
  • Chronic Sinusitis (particles and bacteria not pushed out)

COMP:
-↑risk of ectopic pregnancy

6
Q

Osteogenesis Imperfecta (“Brittle Bone Disease”)

Def’n, Inher, Mech, Pres (4)?

A

Congenital defect of bone RESORPTION -> structurally WEAK bone.

AD.

Deficiency (↓production) of Type 1 Collagen.
Inability to form Procollagen (defective glycosylation of
pro-a-chain hydroxylysine).

PRES:
- “Blue sclera” (thin collagen on sclera => can see underlying
choroidal veins = blue.
THINK: You can see veins under thin skin.)
- Multiple bone fractures with minimal trauma (may occur during birth)
- Hearing loss (fracturing of middle ear bones = ossicles)
- Dental imperfections (lack of dentin)

** May be confused with child abuse **

7
Q

Ehlers-Danlos Sx

Def’n, Mech (2 steps), Inher, Classification (3 types),
Pres (3), Comp / Assoc (3)?

A

Deficiency of Type III Collagen (faulty synthesis).

Mutation in Type V Collagen ->
Defective Tropocollagen CROSS-LINKING.

Autosomal.

CLASSIFICATION:

    • Hypermobility type
  • Classical type (mutation in Type V Collagen -> joint + skin pres)
  • Vascular type (Type III Collagen def -> vascular + organ pres)

PRES:

  • Hypermobile joints
  • Elastic skin
  • Easy bruising / tendency to bleed

COMP / ASSOC:

  • Aortic + Berry Aneurysms
  • Organ rupture
  • Joint dislocation
8
Q

Menkes Dz

Def’n, Mech (2 steps), Pres (3)?

A

Connective tis dz.

Impaired Cu abs + transport ->↓activity of Lysyl Oxidase.

PRES:

  • “Brittle + kinky hair”
  • Growth retardation
  • Hypotonia
9
Q

Alport Sx

Mech (2), Inher, Pres (3)?

A
  • Defective Type IV Collagen due to mutation.
  • Thin + split GLOMERULAR BM -> defective ability to filter blood.

XR (MC)

PRES:

  • Deafness
  • Cataracts / ocular disturbances
  • Nephritic Sx
10
Q

Marfan Sx

Mech, Pres (5), Comp (2)?

A

Fibrillin defect (Fibrillin-1 mutation).

PRES:

  • “Tall with long extremities” + Arachnodactyly (abnormally long + slender fingers and toes)
  • Hyperflexible / hypermobile joints
  • Lens dislocation + subluxation (usually upward + temporally)
  • Aortic incompetence (due to cystic medial necrosis of aorta)
  • Floppy Mitral valve

COMP:

  • Dissecting Aortic Aneurysm / Berry Aneurysm
  • Mitral
11
Q

Familial Hypercholesterolemia

Mech (2 steps), Pres (2)?

A

Absent / defective LDL receptor ->↑LDL.

PRES:

  • Severe atherosclerosis early in life
  • Achilles tendon xanthoma
12
Q

Mitochondrial Myopathies

List (3), Micro Finding?

A
  • Leber’s Hereditary Optic Neuropathy (acute loss of central vision)
  • Myoclonic Epilepsy
  • Mitochondrial Encephalopathy

FINDING:
- “Ragged red fibers”

13
Q

Cystic Fibrosis
* MC lethal genetic dz in Caucasians*

Inher, Genetics, Mech (5 steps, 3 effects),
DX, Comp (8: 2 Resp, 4 GI, 1 Repro, 1 Vit), RX (2)?

A

AR.

Defect in CFTR, chr 7.

MECH:
Defective CFTR ->
Defective Cl channels in lungs, GI tract + sweat glands ->
↑intracel Cl ->
Compensatory↑Na + H20 reabs ->
ECF Na + H20 losses / RENAL K + H wasting.
(Analogous to taking Loop Diuretic)

  • THICK MUCUS secreted into lungs + GI tract
  • Hypokalemia
  • Contraction Alkalosis

DX:
-↑Cl (> 60) in sweat

COMP:

  • Recurrent pulm infections and chronic bronchitis / bronchiectasis
  • Nasal polyps
  • Meconium Ileus in newborns
  • Malabsorption / Steatorrhea
  • Cholesterol Stones
  • Pancreatic insuf
  • Infertility in Males (absent sperm)
  • Vit A, D, E, K deficiencies

RX:

  • N-acetylcysteine (to cleave disulfide bonds w/in mucus glycoproteins)
  • DNAse / Dornase Alfa (to clear leukocytic debris)
14
Q

McCune-Albright Sx

Mech, Pres (4)?

A

Mosaic G-protein signaling mutation.

PRES:

  • Endocrine abnormalities
  • Precocious Puberty
  • Cafe-au-Lait spots
  • Polyostotic fibrous dysplasia
15
Q

Muscular Dystrophies

3 Types, Inher, General Pres (2)?

A
  • Duchenne
  • Becker
  • Myotonic Type I

INHER: XR (Duchenne + Becker’s)

GENERAL PRES:

  • Muscle wasting
  • Myotonia
16
Q

Duchenne Muscular Dystrophy

Genetics, Pres (Epi + 2), Lab Findings (2), DX (2), Comp?

A

FRAMESHIFT Deletion of Dystrophin gene.

PRES: Onset before 5 yrs

  • Weakness in pelvic girdle muscles that progresses superiorly
  • Pseudohypertrophy of calf muscles (due to fibrofatty replacement of muscle) -> Gower Maneuver

LABS:

  • ↑Aldolase
  • ↑CPK

DX:

  • Western Blot
  • Muscle biopsy

COMP:
- Dilated Cardiomyopathy

17
Q

Becker Muscular Dystrophy

Genetics, Pres (Epi)?

A

POINT mutation in Dystrophin gene.

PRES: Onset in adolescence / early adulthood
* Less severe than Duchenne *

18
Q

Myotonic Type I Dystrophy

Genetics, Pres (4)?

A

CTG trinucleotide repeat expansion in DMPK gene ->
Abnormal expression of Myotonin protein kinase.

PRES:

  • Frontal balding
  • Cataracts
  • Arrhythmia
  • Testicular atrophy
19
Q

Fragile X Sx

Genetics, Pres (4)?

A

Trinucleotide repeat disorder (CGG) ->
Defect affecting expression and methylation of FMR1 gene.

PRES:

  • Long face with large jaw + large everted ears
  • Autism
  • Mitral Prolapse
  • Testes enlarged
20
Q

Down Sx (Trisomy 21)

Genetics,
Pres (7: THINK: 4 above heart, heart, 2 below heart ),
1st Trimester U/S Findings (2), 2nd Trimester Quad Screen (4),
Comp (3)?

A
  • Meiotic ND (95%. Assoc w advanced maternal age)
  • Robertsonian Translocation (4%)
  • Mosaicism (1%)

PRES:

  • Intellectual disability
  • Flat facies and “single palmar crease”
  • “Gap between first two toes”
  • Brushfield Spots in eyes
  • Congenital HD (ASD or VSD)
  • Duodenal Atresia
  • Hirschsprung Dz

1st TRIMESTER U/S:

  • ↑nuchal translucency + hypoplastic nasal bone
  • PAPP-A↓

QUAD SCREEN:

  • a-fetoprotein↓
  • b-HCG↑
  • Estriol↓
  • Inhibin A ↑

COMP:

  • ASD (due to defects in ostium primum) + VSD
  • ALL + AML (AML usually before age 5)
  • Alzheimer’s
21
Q

Edwards Sx (Trisomy 18)

Pres (Epi + 6: 3 above heart, heart, 2 re extremities),
1st Trimester U/S Finding, 2nd Trimester Quad Screen (4)?

A

PRES: Infant. Death usually within 1 yr of birth.

  • Microcephaly
  • Severe intellectual disability
  • Micrognathia (small jaw), low-set ears + prominent occiput
  • Congenital HD
  • Clenched hands
  • “Rocker-bottom” feet

1st TRIMESTER U/S:
- PAPP-A ↓

QUAD SCREEN: Everything ↓

  • a-fetoprotein↓
  • b-HCG↓
  • Estriol↓
  • Inhibin A↓or normal
22
Q

Patau Sx (Trisomy 13)

Pres (Epi + 6: 3 above heart, heart, 2 re extremities),
1st Trimester U/S Findings (2)?

A

PRES: Infant. Death usually within 1 yr of birth.

  • Microcephaly / Holoprosencephaly
  • Severe intellectual disability
  • Microphthalmia + Cleft Lip / Palate
  • Congenital HD
  • Polydactyly
  • “Rocker-bottom” feet

1st TRIMESTER U/S:

  • ↑nuchal translucency
  • PAPP-A↓
23
Q

Williams Sx

Genetics, Pres (2), Lab Findings, Comp?

A

Congenital microdeletion of chr 7 long arm (incl Elastin gene).

PRES:

  • Intellectual disability, however good verbal skills and extreme friendliness with strangers
  • “Elfin” facies

LABS:
- Hypercalcemia (↑sensitivity to Vitamin D)

24
Q

Turner Sx (45 XO)

Pres (7)?

A

PRES:

  • Cystic Hygroma (cystic lymphatic lesion) at birth
  • Congenital Heart Disease
  • Lymphedema
  • Short stature
  • “Webbed neck”
  • “Horseshoe kidney”
  • “Streak ovaries”
25
Q

Angelman’s Sx

Mech, Genetics, Pres (4)?

A

Maternal allele should be active, however is not expressed.
Paternal allele inactivated.

Imprinting / Uniparental Disomy.

PRES: “Happy puppet”

  • MR
  • Inappropriate laughter
  • Seizures
  • Ataxia
26
Q

Prader-Willi Sx

Mech, Genetics, Pres (5)?

A

Paternal should be active, however is not expressed.
Maternal allele inactivated.

Imprinting / Uniparental Disomy.

PRES:

  • MR
  • Obesity
  • Hyperphagia
  • Hypotonia
  • Hypogonadism
27
Q

Glycogen Storage Diseases

4 Subtypes, Etiology, Path, Inher?

A
  • Von Gierke (Type I)
  • Pompe (Type II)
  • Cori (Type III)
  • McArdle (Type V)

ET = Enzyme deficiencies

PATH = Abnormal Glycogen METAB -> ACCUM of Glycogen in cells.

AR.

28
Q

Von Gierke Disease (Type I)

Deficient Enz, Mech, Pres (2), Labs, RX?

A

Def Enz = Glucose-6-Phosphatase.

MECH:↑Glycogen in Liver.

PRES:

  • Severe fasting hypoglycemia
  • Hepatomegaly

RX: Frequent oral glucose / cornstarch.
Avoidance of fructose + galactose

29
Q

Pompe Disease (Type II)

Deficient Enz, Locations Affected (3), Pres (2), Prog?

A

Def Enz = Lysosomal a-1,4-glucosidase (acid maltase) def.

  • Muscle
  • Heart
  • Liver

PRES:

  • Infantile Hypertrophic Cardiomyopathy
  • Exercise Intolerance

PROG = early death.

30
Q

Cori Disease (Type III)

Deficient Enz, Def’n?

A

Def Enz = a-1,6-glucosidase (Debranching Enz).

MILDER form of Type I / Von Gierke’s. Gluconeogenesis intact.
** Normal Lactate levels **

31
Q

McArdle Disease (Type V)

Def Enz, Mech, Pres (2), Urine?

A

Def Enz = Myophosphorylase (skeletal muscle glycogen phosphorylase).

MECH:↑Glycogen in Muscle, however can’t break it down.

PRES:

  • Painful muscle cramps / fatigue / myalgias
  • Arrhythmias (due to electrolyte abnormalities)

URINE: Myoglobinuria

32
Q

Lysosomal Storage Diseases

2 Subtypes, Etiology, Path, Inher, Common Pres (4)?

A
  • Sphingolipidoses
  • Mucopolysaccharidoses (Hurler + Hunter Sx)

ET = Lysosomal enz def.

PATH = Accum of abnormal substrates.

AR EXCEPT Fabry + Hunter (XR).

PRES:

  • Devel delay (T-S + Krabbe + Hurler/Hunter)
  • Progressive neurodegeneration (N-P + T-S)
  • Peripheral neuropathy (Fabry + Krabbe)
  • Hepatosplenomegaly (Gaucher + N-P + Hurler/Hunter)
33
Q

Fabry Dz

Def Enz / Substrate Accum, Pres (3)?

A

Def Enz = a-galactosidase A. Substrate = Ceramide trihexoside.

PRES: THINK: CARDIO

  • CV / Renal dz
  • Angiokeratomas
  • Peripheral neuropathy
34
Q

Gaucher Disease

Def Enz / Substrate Accum, Locations (4), Pres (3), Micro Finding?

A

Def Enz = b-glucosidase / Glucocerebrosidase.
Substrate = Glucocerebroside.

  • Brain
  • BM
  • Spleen
  • Liver

PRES:

  • Pancytopenia
  • Hepatosplenomegaly
  • Bone crises (eg “aseptic necrosis of femur”)

FINDING: Gaucher cells

35
Q

Niemann-Pick (N-P) Dz vs Tay-Sachs (T-S) Dz

Def Enz / Substrate Accum (N-P vs T-S), 
Common Pres (3), Distinguishing Pres (N-P),
Micro Finding (N-P vs T-S)?
A

N-P: Sphingomyelinase / Sphingomyelin.
T-S: Hexosaminidase A / GM2 Ganglioside.

COMMON PRES:

  • Devel delay
  • Progressive neurodegeneration
  • “Cherry-red spot on macula”
  • Hepatosplenomegaly (N-P ONLY)

FINDINGS:

  • N-P: Foam cells
  • T-S: Lysosomes with “onion skin”
36
Q

Krabbe Dz

Def Enz / Substrate Accum, Pres (3), Micro Finding?

A

Def Enz = Galactocerebrosidase.
Substrate = Galactocerebroside psychosine.

PRES:

  • Optic atrophy
  • Devel delay
  • Peripheral neuropathy

FINDING: Globoid cells

37
Q

Metachromatic Leukodystrophy

Def Enz / Substrate Accum, Pres (3)?

A

Def Enz = Arylsulfatase A. Substrate = Cerebroside sulfate.

PRES: THINK: NEURO

  • Demyelination
  • Dementia
  • Ataxia
38
Q

Hurler vs Hunter Sx

Def Enz (vs) / Substrate Accum (2), Inher (vs),
Common Pres (4), Distinguishing Pres (vs)?
A

Hurler: a-L-iduronidase
Hunter: Iduronate sulfatase

Substrates = Dermatan sulfate + Heparan sulfate.

AR (Hurler) vs XR (Hunter).

COMMON PRES:

  • Devel delay
  • “Gargoylism”
  • Hepatosplenomegaly
  • Airway obstruction
  • Corneal clouding (Hurler)
  • Aggression (Hunter)
39
Q

Classic Galactosemia

Def’n, Path, Pres (4), Comp (2), RX?

A

Absence of galactose-1-P uridyltransferase.

PATH = Accum of toxic substances (ie galactitol).

PRES:

  • Failure to thrive
  • Intellectual disability
  • Infantile Cataracts
  • Hepatomegaly + Jaundice

COMP:

  • Phosphate depletion
  • E coli sepsis (Neonates)

RX = Exclusion of galactose + lactose from diet

40
Q

Urea Cycle Enzyme Deficiencies (2)

Pres?

A
  • N-acetylglutamate def / Carbamoyl P Synthetase I def
    • Ornithine Transcarbamylase def

PRES:
- Hyperammonemia

41
Q

Hyperammonemia

Etiologies (2), Mech (3 steps), Pres (6), RX (3)?

A

ET:

  • Hereditary (eg Urea Cycle enzyme def)
  • Acquired (eg Liver dz)

Excess NH4 -> Depletion of a-ketoglutarate -> Inhib of TCA Cycle.

PRES: (‘Ammonia Intoxication’)

  • Cerebral Edema
  • Somnolence
  • Asterixis (tremor)
  • Blurred vision
  • Slurred speech
  • Vomiting

RX:

  • Limit protein in diet
  • Benzoate / Phenylbutyrate (bind a.a -> excretion -> ↓NH4)
  • Lactulose (acidification of GI tract -> NH4 trapping -> excretion)
42
Q

Ornithine Transcarbamylase Deficiency

Inher, Mech, Pres (Onset + 1), Labs (2)?

A

XR (*unlike other ‘urea cycle enz def’ which are AR).

EXCESS Carbamoyl P -> Orotic acid.

PRES: First few days of life, however sometimes later.
- Hyperammonemia

LABS:

  • Orotic acid↑in bl / urine
  • BUN ↓
43
Q

Phenylketonuria (PKU)

Subtypes (2), Inher, Mech (3 steps),
Pres (6), Urine, Screening / DX, RX (2 dietary)?

A
  • Maternal (-> pres in infant)
  • Malignant (↓tetrahydrobiopterin cofactor, NOT ph hydroxylase)

AR.

↓phenylalanine hydroxylase (= tyrosine becomes essential) ->
↑phenylalanine -> Excess phenylketones in urine.

PRES:

  • Growth retardation
  • Intellectual disability
  • Seizures
  • “Musty body odor” (disorder of AROMATIC a.a metab)
  • Fair skin
  • Eczema

URINE: Excess Phenylketones

SCR = 2-3 days after birth

RX:

  • ↑Tyrosine in diet (Tyrosine becomes essential)
  • ↓Phenylalanine in diet (eg aspartame)
44
Q

Maternal PKU

Etiology, Pres (in INFANT: 4)?

A

ET = Lack of proper dietary therapy during pregnancy.

PRES (INFANT):

  • Growth retardation
  • Microcephaly
  • Intellectual disability
  • Congenital HD
45
Q

Alkaptonuria / Ochronosis

Def’n, Inher, Pres (4)?

A

Congenital def of Homogentisate Oxidase.
(Enz in degradative pathway of tyrosine -> fumarate)

AR.

PRES: Benign. THINK: DARK

  • Dark connective tis
  • Brown sclerae
  • Urine turns black on exposure to air
  • Arthralgias (homogentisic acid toxic to cartilage)
46
Q

Albinism

Def’n, Etiology, Comp?

A

↓Tyrosine + Melanin.
Congenital def of either:
- Tyrosinase (no tyrosine -> melanin)
- Tyrosine transporters

ET (possible) = lack of migration of neural crest cells.

COMP =↑risk of skin cancer.

47
Q

Homocystinuria

Subtypes (3), Inher, Path,
Urine, Pres (7: 2 Neuro, 2 CV, 3 MSK)?

A
  • Homocysteine Methyltransferase / Methionine Synthase def
  • Cystathionine Synthase def
  • ↓AFFINITY of Cystathionine Synthase for Pyridoxal P

AR.

PATH = Excess Homocysteine.

URINE = Excess Homocysteine.

PRES:

  • Intellectual disability
  • Lens subluxation
  • Atherosclerosis (-> MI, Stroke)
  • Thrombosis
  • Tall stature
  • Kyphosis
  • Osteoporosis
48
Q

Cystinuria

Path, Locations (2), Inher,
Urine, DX, RX (3: 2 Meds)?

A

PATH = Defect of A.A transporters for “COLA”: Cysteine, Ornithine, Lysine, Arginine.

  • Transporter in Renal PCT
  • Transporter in Intestine

AR. Common

URINE: Hexagonal Cystine stones (due to excess cystine in urine)

DX: Urinary Cyanide-Nitroprusside test

RX:

  • Urinary Alkalinization (Acetazolamide, Potassium Citrate)
  • Chelating agents (↑solubility of cystine stones)
  • Good hydration
49
Q

Maple Syrup Urine Disease

Etiology, Path (3 steps), Urine, Pres?

A

ET = Vit B1 / a-ketoacid dehydrogenase def

PATH:
↓a-ketoacid dehydrogenase ->
Blocked degradation of BRANCHED A.A (Isoleucine, Leucine, Valine) ->
↑a-ketoacids in bl (esp Leucine).

URINE: “Smells like maple syrup / burnt sugar”

PRES: Intellectual disability + severe CNS defects. Death.

50
Q

Hyperchylomicronemia (Type I Familial Dyslipidemia)

Mech (2), Inher, Pres (3), Labs (3)?

A
  • Lipoprotein lipase def
  • Apolipoprotein C-II alteration

AR (other familial dyslipidemias = AD).

PRES:

  • Hepatosplenomegaly
  • Pancreatitis
  • Eruptive / pruritic xanthomas

LABS: ↑in:

  • Chylomicrons
  • Cholesterol
  • Trigylcerides
51
Q

Familial Hypercholesterolemia (Type IIA Familial Dyslipidemia)

Mech, Genetics (Hetero vs Homo), Pres (3), Labs (2)?

A

Absent / defective LDL receptors.

GEN:

  • Hetero: Chol ~ 300 mg/dL
  • Homo: Chol > 700 mg/dL (very rare)

PRES:

  • Accelerated Atherosclerosis (eg “MI before age 20”)
  • Corneal Arcus
  • Achilles xanthomas

LABS: ↑in:

  • Cholesterol
  • LDL
52
Q

Hypertriglyceridemia (Type IV Familial Dyslipidemia)

Mech, Pres, Labs (2)?

A

HEPATIC overproduction of VLDL.

PRES:
- Pancreatitis

LABS: ↑in:

  • VLDL
  • Triglycerides
53
Q

Lesch-Nyhan Sx

Mech, Pres (Epi + 3)?

A

HGPRT def.

PRES: Boy

  • Gout
  • Intellectual disability
  • Self-mutilating behavior
54
Q

Kwashiorkor (Malnutrition)

Def’n, Pres (4)?

A

PROTEIN malnutrition.

PRES: “Small child w swollen belly”

  • Liver malfunction (↓apolipoprotein syn -> fatty change)
  • Anemia
  • Edema
  • Skin lesions
55
Q

Marasmus (Malnutrition)

Def’n, Pres?

A

ENERGY malnutrition.

PRES:
- Tis/muscle wasting + loss of subcutaneous fat
- Variable edema