1.
Match the metabolic abnormalities listed (A-D) with the specific
corresponding disorder below:
Metabolic
Lactic
Acidosis Ketosis
Hyperammonemia
Acidemia
A.
-
-
+++
-
B.
++
+
+
-
C.
+
+
-
-
D.
+++
+
-
+++
____
Organic acidemia
____ Maple syrup urine disease
____
Urea cycle defect
____
Congenital lactic acidosis
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2.
All of the following statements regarding hyperammonemia in infants are
true except:
A.
In children, cytotoxic cerebral
edema and increased intracranial pressure may occur
B.
Its toxicity is reversible
C.
Ammonia is normally detoxified in
astrocytes by glutamate dehydrogenase and glutamine synthetase
D. The pronounced depletion of adenosine triphosphate in the brain reticular
activating system accounts for the altered level of consciousness
E. There is an active urea cycle within the brain
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3.
A newborn baby girl was a product of a full-term spontaneous vaginal
delivery after an uneventful pregnancy and is noted to have recurrent
intractable clonic and myoclonic seizures that have been resistant to therapy.
The baby has been breast fed only twice and has been afebrile. Sepsis workup has been negative so far. Arterial blood gases, blood glucose and blood ammonia and
serum urine ketones have all been within normal limits. At this juncture, one should think about:
A.
Ornithine transcarbamylase (OTL) deficiency
B.
Methylmalonic acidemia
C.
Non-ketotic hyperglycinemia
D.
Maple syrup urine disease
E.
Congenital lactic acidosis
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4.
All of the following statements are accepted hypotheses of hepatic
encephalopathy except:
A.
Synergistic effects of accumulation of toxins with coma producing
potential
B.
The false transmitter hypothesis
C.
The neural inhibition of gamma-aminobutyric acid
D.
Professor Mertz revelation
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5.
All of the following statements are true regarding the neuropathology of
metabolic encephalopathy except:
A.
Infarction is usually present with hypoglycemia
B.
Hypoglycemia causes superficial cortical layer necrosis
C.
Proliferation of the protoplasmic astrocyte (Alzheimer type II astrocyte) occurs
D.
Degenerative changes of cortical layers 5 and 6 develops
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6.
Match the following therapeutic interventions with the corresponding
disorder it is intended for:
A.
Arginine hydrochloride
B.
Biotin
C.
Vitamin B12
D.
Thiamine
E.
Riboflavin
____
Multiple carboxylase deficiency
____
Hyperammonemia due to urea cycle defects
____
Methylmalonic acidemia
____
Maple syrup urine disease
____
Multiple Acyl-COA dehydrogenase deficiency
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7.
A 13-year-old female with a history of chronic adrenal insufficiency
presents to the Pediatric ICU with a BP of 60/30 mmHg and a heart rate of 125/min.
All of the following suggest adrenocortical insufficiency except:
A.
Hyperkalemia
B.
Hyponatremia
C.
Hyperglycemia
D.
Hypercalcemia
E.
Anemia
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8.
Diabetic ketoacidosis is associated with insulin deficiency with
elevation of all of the following hormones except:
A.
Growth hormone
B.
Glucagon
C.
Somatostatin
D.
Epinephrine
E.
Glucocorticoids
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9.
Match the following answers with their correct descriptions:
pH
PCO2
PaO2
HCO3
A.
7.38
66
45
35
B.
7.04
18
120
5
C.
7.25
15
124
7
D.
7.15
78
60
26
E.
7.35
80
35
35
1.____ A 16-year-old female
with new onset diabetic ketoacidosis
2.
____ A 12-year-old with cerebral
palsy having severe scoliosis and excessive emesis due to bowel obstruction
3.
____ A 15-year-old male presenting
with paresis after eating strawberry jam that is over 1 year old
4.
____ A 16-year-old female who
recently separated from her boyfriend and came to the ER with nausea, vomiting, tinnitus, abdominal pain, and agitation
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10.
All of the following statements regarding the rapid ACTH stimulation test
are true except:
A.
A blunted cortisol response can be due to primary or secondary
adrenocortical insufficiency
B.
This test is only a screening procedure
C.
A normal response eliminates the possibility of primary adrenocortical
insufficiency
D.
A normal response eliminates the possibility of secondary adrenocortical
insufficiency
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11.
In sick euthyroid syndrome, all of the following statements are true
except:
A.
There is a decrease in serum T3 levels
B.
30-50% have low T4 levels
C.
There is a high TSH level
D.
There is an increase in reverse T3 level
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Answers
1.
B, C, A, D Slight elevation of
ammonia is noted with organic acidemias, however, this is usually minimal
compared to the significant hyperammonemia that is noted with urea cycle
defects. Maple syrup urine
disease (a disorder of branched chain amino:
lencine, isolencine, and valine) is characterized by metabolic acidosis
and ketosis and significant hypoglycemia.
The level of lactic acid will be significantly elevated with congenital
lactic acidosis. (Fuhrman BP, et al. Pediatric
Critical Care, 2nd Edition; pp 820-825)
2.
E
Urea cycle is present and is
active only within the liver. In
the brain there is no urea cycle that can detoxify ammonia. (Rogers MC, et al.
Textbook of Pediatric Intensive Care, 3rd Edition; pp
1299-1302)
3.
C
In a newborn who develops significant seizures within the first 24 hours
after birth, prior to having consumed a significant amount of protein in the
diet and who does not have significant metabolic acidosis or elevation of
ammonia levels, one has to think about non-ketotic hyperglycinemia. OTL deficiency is an x-linked disorder of ureacyte and is
usually associated with significant elevation of blood ammonia levels.
Methylmalmic acidemia, propionic acidemia, and isovolemic acidemia are
organic acid disorders and are usually characterized by high anion gap metabolic
acidosis. Maple syrup urine disease is discussed Question #1, and is a
disorder of branched chain amino acids due to defective branched chain ketoacid
dehydrogenase. Management of
glucose and pH is most important in these patients.
(Rogers MC, et al. Textbook
of Pediatric Intensive Care, 3rd Edition; pp 1299-1302)
4.
D
All other responses are appropriate.
The accepted hypotheses include:
1)
The synergistic neurotoxin hypothesis which states that hepatic
encephalopathy (HE) results from the synergistic accumulation of toxins,
including ammonia, mercaptans, and short chain fatty acids.
2)
The false neurotransmitter hypothesis states the Octopamine acts as a
false neurotransmitter and is taken up and released by neurones that normally
store norepinephrine and dopamine.
3)
The neural inhibitory hypothesis implicates GABA in the pathogenesis of
HE.
(Jones, EA. The neurobiology
of hepatic encephalopathy. Hepatology, 1984; Vol. 4:1235)
5.
A
Hypoglycemia produces selective necrosis of the superficial cortical
layers sparing the non-neuronal elements (unless hypoglycemia is profound and
prolonged). Infarction is usually
abent even after severe hypoglycemia. In
Reye’s syndrome, nonspecific cytotoxic cerebral edema is seen with swelling of
astrocyte foot processes. The
hallmark of hepatic encephalopathy is proliferation and enlargement of the
so-called Alzheimer –Type astrocyte which is basically protoplasmic astrocytes.
Longstanding heparin encephalopathy has been shown to be associated with
degenervation changes in layer 5 and 6t of the cerebral cortex.
(Rogers MC, et al. Textbook
of Pediatric Intensive Care, 3rd Edition, pp 792-794)
6.
B, A, C, D, E
These are some of the
co-factors that have been shown to be helpful in the various metabolic
disorders. (Batshaw M.
Treatment of ureacycle disorders. Enzyme,
1987; Vol. 38/242. Fuhrman BP, et
al. Pediatric Critical Care, 2nd Edition; pp 820-825)
7.
C
With adrenocortical insufficiency, hypotension is associated with low
levels of stress hormones. Thus, hypoglycemia is more of a possibility than
hyperglycemia. (DiAeage AM, Levine
LS. Nelson’s Textbook of
Pediatrics, 15th Edition; pp 1613-1617.
Kaplan SA. Clinical
Pediatric Endocrinology, 1990; pp 181-223)
8.
C
Diabetic ketoacidosis in the pediatric patient is a potentially
life-threatening event. Ketosis and
hyperglycemia result from an imbalance of glucagon and insulin levels with an
increase in catecholamines, growth hormones and glucocorticoids.
An increase in somatostatin is not associated with diabetic ketoacidosis,
but it down regulates the production and release of glucagon and growth
hormones. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd
Edition; pp 1261-1270. Kaplan SA. Clinical
Pediatric Endocrinology, 1990; pp 127-164)
9.
B, A, D, C Diabetic
ketoacidosis or any acute metabolic acidosis state will decrease PCO2
by 1.0 to 1.5 mmHg for each millimole change in bicarbonate concentration. In severe scoliosis, there is retraction of the chest wall
causing chronic alveolar hypoventilation, with the development of chronic
respiratory acidosis. A bicarbonate
rise of 4 mmol will occur with a rise in 10 mmHg of PCO2.
Here both pH and bicarbonate concentrations are higher than expected for
the level of PCO2 elevation suggesting a mixed acid base disorder –
metabolic acidosis superimposed or chronic respiratory acidosis.
Botulism will cause rapid onset of respiratory failure causing pure
respiratory acidosis. In acute
respiratory acidosis, the pH will fall by approximately 0.08 unit for each 10
mmHg of PCO2. Plasma
bicarbonate will increase 1 mmol/liter for each increase of 10 mmHg in PCO2.
Salicylate intoxication causes acute metabolic acidosis.
It also stimulates the respiratory center causing coincident respiratory
alkalosis. A decrease in PCO2
is out of proportion to the fall in plasma bicarbonate which is suggestive of
mixed acid-base disorder - metabolic acidosis and respiratory alkalosis.
(Kaplan SA. Clinical
Pediatric Endocrinology, 1990; pp 181-234.
Rogers MC et al. Textbook of Pediatric Intensive Care, 3rd
Edition; pp 351-363)
10.
D
The rapid ACTH stimulation test is only a screening test that should be
verified by a more definitive test when the patient’s condition stabilizes.
An abnormal response may be due to either primary or secondary
adrenocortical insufficiency. A false negative result has been reported in patients with
early ACTH deficiency. (Kaplan SA. Clinical
Pediatric Endocrinology, 1990; pp 181-234.
Furhman BP et al. Pediatric Critical Care, 2nd Edition;
pp 826-843)
11.
C
Nearly all critically ill patients have decreased serum levels of T3 and
50% have a decrease in the level of T4 concentration with normal or low TSH.
The reduction in T3 levels results from a decrease in deiodinase activity
that occurs in critical illness. This
is reflected in the increase in serum level of T3 that occurs during critical
illness. This enzyme is responsible
for the degradation reverse of T3, explaining the increase in serum levels of
reverse T3 that occurs in critical illness.
(Rogers MC, et al. Textbook
of Pediatric Intensive Care, 3rd Edition; pp 1290-1297.
Wilson D, et al. Serum free thyroxine values in term, premature and sick
infants. J Ped, 1982; Vol 101, p
113)