Trauma Flashcards
(34 cards)
Question:
Initiation of enteral nutrition in mechanically ventilated patients within 24 to 48 hours of admission
to the intensive care unit has been strongly associated with reduction of which of the following?
Answers:
A. Bowel perforation
B. Venous thromboembolisms
C. Mean arterial blood pressure
D. Mortality
E. Pneumonia
D. Mortality
Early initiation of enteral nutrition has been associated with reduced ICU and hospital mortality,
especially in the sickest patients. However, an increased risk of ventilator associated pneumonia
has been associated with early initiation of enteral nutrition.
A 55-year-old man sustains severe multisystem injuries in a motor vehicle collision. On the fourth
day postinjury, PaO2 is 75 mmHg on 100% oxygen, with 10 cm H2O positive end-expiratory
pressure. Pulmonary capillary wedge pressure is 8 mmHg. Chest x-ray is shown. Which of the
following is the most likely diagnosis?
A. Pulmonary contusion
B. Pneumothorax
C. Pleural effusion
D. Empyema
E. ARDS
E. ARDS
This patient fits the Berlin criteria for acute respiratory distress syndrome. His respiratory distress
began within 1 week of clinical insult and the chest x-ray demonstrates bilateral opacities. The low
wedge pressure is not consistent with fluid overload or cardiac failure. The PaO2/FiO2 is <= 100
mmHg on more than 5 cm H20 PEEP, which is consistent with severe ARDS. Using a consensus
process, a panel of experts convened in 2011 (an initiative of the European Society of Intensive
Care Medicine endorsed by the American Thoracic Society and the Society of Critical Care
Medicine) developed the Berlin Definition, focusing on feasibility, reliability, validity, and objective
evaluation of its performance. Using the Berlin Definition, stages of mild, moderate, and severe
ARDS were associated with increased mortality (27%; 95% CI, 24%-30%; 32%; 95% CI,
29%-34%; and 45%; 95% CI, 42%-48%, respectively; P < .001) and increased median duration of
mechanical ventilation in survivors (5 days; interquartile [IQR], 2-11; 7 days; IQR, 4-14; and 9 days;
IQR, 5-17, respectively; P < .001).
The Berlin definition of acute respiratory distress syndrome
Timing: Within 1 week of a known clinical insult or new or worsening respiratory symptoms
Chest imaging: Bilateral opacities — not fully explained by effusions, lobar/lung collapse, or
nodules
Origin of edema: Respiratory failure not fully explained by cardiac failure or fluid overload.
Need objective assessment (e.g., echocardiography) to exclude hydrostatic edema if no risk factor
present
Oxygenation:
Mild 200 mmHg < PaO2/FIO2 ≤300 mmHg with PEEP or CPAP ≥5 cmH2Oc
Moderate 100 mmHg < PaO2/FIO2 ≤200 mmHg with PEEP ≥5 cmH2O
Severe PaO2/FIO2 ≤100 mmHg with PEEP ≥5 cmH2O
The use of positive end-expiratory pressure during mechanical ventilation produces which of the
following effects?
Answers:
A. Increased intrathoracic pressure
B. Increased cardiac output
C. Decreased risk of pulmonary barotruma
D. Increased ventilation-perfusion mismatch
E. Decreased DLCO
Increased intrathoracic pressure
Extrinsic positive end-expiratory pressure (PEEP) during mechanical ventilation increases
oxygenation, decreases work of breathing, and can improve areas of ventilation-perfusion (V/Q)
mismatch. However, PEEP can cause increase in intrathoracic pressure and pulmonary
barotrauma. PEEP can also decrease cardiac output, preload, and venous return.
A 45-year-old man in the ICU is recovering from a severe head injury and being considered for
extubation. He demonstrates spontaneous breathing and maintains oxygenation during a two-hour
continuous positive airway pressure trial. Which of the following factors is most likely to result in
failure of extubation and the need for reintubation?
Answers:
A. Normal chest x-ray
B. Presence of a cuff leak
C. Serum pH of 7.40
D. PaO2 > 60
E. Rapid Shallow Breathing Index > 105
E. Rapid Shallow Breathing Index > 105
The Rapid Shallow Breathing Index (RSBI) was originally described as a physiological
measurement that could be used to predict successful extubation in mechanically ventilated
patients ready to be liberated from the ventilator. It is calculated by dividing the respiratory rate by
the tidal volume. Patients that were likely to fail extubation had a RSBI > 105. Higher values for the
RSBI signify a pattern of breathing often seen in patients with respiratory muscle fatigue who tend
to have weak inspiratory efforts and consequently higher respiratory rates. However, the observed
RSBI value can be increased by recent suctioning, anxiety, fever, and the size of the endotracheal
tube.
Positive pressure ventilation most commonly affects cardiac function through which of the following
mechanisms?
Answers:
A. Increased SVR
B. Decreased pulmonary vascular resistance
C. Decreased LV function
D. Decreased venous return
E. Increased venous return
Decreased venous return
In contrast to spontaneous breathing, mechanical ventilation with positive pressure results in a
positive pleural pressure during inspiration. The positive intrathoracic pressure induced by
mechanical ventilation will decrease the pressure gradient needed for venous return to the right
atrium. Reductions in cardiac output after initiation of positive pressure ventilation may be
particularly prominent in patients who are not adequately volume resuscitated and are preload
dependent. This decrease in cardiac output may be offset by increased left ventricular function
occurring due to a lower transmural gradient caused by increased intrathoracic pressure.
Mechanical ventilation should not have significant effects on SVR but may result in a small
increase in pulmonary vascular resistance, affecting RV afterload.
Which of the following molecules has been most strongly implicated in the large vessel
vasoconstriction seen following aneurysmal subarachnoid hemorrhage?
Answers:
A. Interleukin-4 (IL-4)
B. Hypoxia-inducible factor-1alpha (HIF-1alpha)
C. Nuclear factor erythroid 2-related factor 2 (Nrf2)
D. Interleukin-17a
E. Endothelin-A
E. Endothelin-A
Subarachnoid Hemorrhage (SAH) results in transient global ischemia due to Intracranial Pressures
(ICPs) that near Mean Arterial Pressure (MAP). In addition to triggering a catecholamine surge,
this ischemic event has been shown to result in vascular dysfunction. This results in the stimulation
of the endothelin-1 pathway. Data have suggested that plasma endothelin-1 concentrations have
correlated with delayed cerebral ischemia (DCI) and inhibition seemed to reverse SAH induced
vasospasm. Clinical trials have been conducted using the endothelin-1 antagonist clazosentan.
While the CONSCIOUS-1 trial showed some improvment in radiographic vasospasm,
CONSCIOUS-2 and CONSCIOUS-3 showed no improvement in outcomes after SAH with a
possible increase in pulmonary complications, anemia, and hypotension. HIF-1a and Nrf2 have
been shown to play a role in stroke pathophysiology. While systemic cytokines have been shown
to play a role in the pathophysiology of DCI and vasospasm after SAH, IL-4 and IL-17a have not
been shown to be the major effectors.
A 68-year-old woman returns to the intensive care unit in respiratory distress two weeks after a
large left middle cerebral artery stroke. Based on the chest x-ray shown, which of the following is
the most appropriate initial management?
A. Retract the tracheostomy.
B. Emergent bedside bronchoscopy.
C. Start empiric broad spectrum antibiotics.
D. Left side thoracostomy tube placement.
E. Right side thoracostomy tube placement.
B. Emergent bedside bronchoscopy.
The chest radiograph shows significant atelectasis of the left lung; the mediastinum and the right
subclavian central line is seen pulled towards the same side of the radiopaque abnormality seen.
Bedside flexible bronchoscopy is a common procedure in the ICU; atelectasis and presence of
retained secretions are some of the most common indications for bedside bronchoscopy.
Thoracostomy (on the left or right side) will not help, given the pathology causing the shift of the
mediastinum and white-out of the left lung is likely in the airway and not outside the lung. There is
no pneumothorax on the right side because lung vasculature can be seen throughout the right
lung. The patient will likely require antibiotic therapy, but antibiotics will not improve her acute
respiratory distress, which is likely caused by a mucus plug in the left bronchus which can be
resolved by bedside flexible bronchoscopy.
Glutamate excitotoxicity is most commonly mediated by which of the following processes?
Answers:
A. Neurokinin A receptor stimulation
B. Gamma-aminobutyric acid receptor inhibition
C. N-methyl-D-aspartate receptor stimulation
D. N-methyl-D-aspartate receptor inhibition
E. Gamma-aminobutyric acid receptor stimulation
N-methyl-D-aspartate receptor stimulation
N-methyl-D-aspartate receptors are glutamate-gated ion channels widely expressed in the central
nervous system, with high density in the hippocampus and the cerebral cortex, that have key roles
in excitatory synaptic transmission. The NMDA receptor, along with other glutamate-gated ion
channels, plays an important part in synaptic plasticity and thus in cognitive performance.
Glutamate excitotoxicity is a cell death mechanism triggered by excessive glutamate release from
neurons, causing persistent activation of glutamate-gated ion channels (i.e. NMDA receptor),
resulting in influx of extracellular calcium. Other options are not mediated by glutamate.
Which of the following enzymes must be present for the formation of CSF?
Answers:
A. Gammaglutamyl transpeptidase
B. NADH dehydrogenase
C. Na+-K+ ATPase
D. Pyruvate kinase
E. Succinate dehydrogenase
Na+-K+ ATPase
CSF is formed primarily by the choroid plexus, with a smaller amount being formed
extrachoroidally. Water and ions are transferred into the ventricles by either intracellular movement
across epithelial cells or intracellular movement across apical tight junctions. A number of ion
transporters are necessary for CSF production by the four main choroid plexuses. The Na+-K+
ATPase is located in the apical membrane of epithelial cells from the choroid plexus and accounts
for the active transport of Na that is necessary for secretion of CSF. Small molecules that inhibit
the Na+-K+ ATPase, such as ouabain, have been shown to decrease CSF production. Several
other enzymes also play a critical role in CSF production, such as carbonic anydrase, which is
inhibited by acetazolamide.
A 70-year-old man has a myocardial infarction after undergoing surgery. Echocardiogram shows
an ejection fraction of 60%. This finding indicates that which of the following is within the normal
range?
Answers:
A. Left ventricular diastolic function.
B. Left ventricular systolic function.
C. Aortic valve function.
D. Heart size.
E. Right ventricular systolic pressure.
B. Left ventricular systolic function.
The ejection fraction, or left ventricular ejection fraction (LVEF), is the measurement of the left
ventricular systolic function. Per the American College of Cardiology (ACC), a normal LVEF is
between 50% and 70%. LVEF is the fraction of chamber volume ejected in systole (stroke volume)
in relation to the volume of the blood in the ventricle at the end of diastole (end-diastolic volume).
Stroke volume (SV) is calculated as the difference between end-diastolic volume (EDV) and endsystolic
volume (ESV). LVEF is calculated from: [SV/EDV] x 100.
The simplest classification as per the American College of Cardiology (ACC) that is used clinically
as follows:
A. Hyperdynamic = LVEF greater than 70%
B. Normal = LVEF 50% to 70% (midpoint 60%)
C. Mild dysfunction = LVEF 40% to 49% (midpoint 45%)
D. Moderate dysfunction = LVEF 30% to 39% (midpoint 35%)
E. Severe dysfunction = LVEF less than 30%
Which of the following sedative-hypnotic agents causes adrenal cortical suppression?
Answers:
A. Propofol
B. Phenobarbital
C. Ketamine
D. Etomidate
E. Pentobarbitol
Etomidate
Etomidate is a short-acting, sedative hypnotic that is commonly used for inducing short-term
anesthesia during rapid sequence intubation. It exhibits fewer detrimental side effects, mainly
hemodynamic compromise, when compared to other sedatives commonly used for induction such
as benzodiazepines.
A well-documented side effect of etomidate is suppression of the adrenal synthesis of cortisol. In a
dose dependent fashion, it inhibits adrenal mitochondrial 11-β hydroxylase, the enzyme
responsible for the final conversion of 11-deoxycortisol to cortisol. This side effect, shown to be a
risk factor for increased mortality, can be detrimental in septic patients who may have a baseline
adrenal insufficiency due to critical illness.
Barbiturates can cause induction of cortisol metabolism.
In pulmonary physiology, which of the following describes the primary action of surfactant?
Answers:
A. Reduce the surface tension at the air-liquid interface in the alveoli.
B. Regulate air temperature during inhalation.
C. Stimulate movement of cilia within the bronchus.
D. Increase the surface tension at the air-liquid interface in the alveoli.
E. Inhibit alveolar macrophage activity.
A. Reduce the surface tension at the air-liquid interface in the alveoli.
The main functions of surfactant include: lowering surface tension at the air–liquid interface
preventing alveolar collapse at end-expiration, antimicrobial activity and modulating immune
response. Pulmonary surfactant is a mixture of lipids and proteins that is secreted into the alveolar
space by epithelial type II cells. The main function of surfactant is to lower the surface tension at
the air/liquid interface within the alveoli of the lung. This is needed to lower the work of breathing
and to prevent alveolar collapse at end-expiration. The more hydrophilic surfactant components,
SP-A and SP-D, participate in pulmonary host defense and modify immune responses.
Specifically, SP-A and SP-D bind and partake in the clearance of a variety of bacterial, fungal, and
viral pathogens and can dampen antigen-induced immune function of effector cells. Emerging data
also show immunosuppressive actions of some surfactant-associated lipids, such as
phosphatidylglycerol. Deficiencies of surfactant components are classically observed in the
neonatal respiratory distress syndrome, where surfactant replacement therapies have been the
mainstay of treatment. However, functional or compositional deficiencies of surfactant are also
observed in a variety of acute and chronic lung disorders.
An 82-year-old woman receives an enteral feeding tube. Four hours later, she develops shortness
of breath and oxygen desaturation. She requires reintubation. A chest x-ray is shown. Which of the
following is the most appropriate next step in management?
A. Right sided thoracostomy tube placement.
B. Emergent bedside flexible bronchoscopy.
C. Left side thoracostomy tube placement.
D. Increase PEEP and tidal volume on ventilator.
E. Obtain emergent computed tomography angiography of the chest.
Right sided thoracostomy tube placement.
The chest radiograph is remarkable for moderate-sized pneumothorax on the right side. The
pneumothorax was likely iatrogenic after nasogastric tube placement. Emergent placement of a
right sided thoracostomy tube would be the most appropriate next step, after securing the airway.
To visualize a pneumothorax, one should look for a visible visceral pleural edge that is seen as a
thin sharp white line with no lung markings seen peripheral to this line. The peripheral space
should be radiolucent compared to the adjacent lung. The mediastinum should not shift away from
the pneumothorax unless a tension pneumothorax is seen.
Which of the following treatments is indicated for the patient whose chest x-ray is shown?
Answers:
A. Pericardiocentesis
B. Observation
C. Tube thoracostomy with pigtail catheter
D. Bronchoscopy
E. Tube thoracostomy with large bore chest tube
Tube thoracostomy with pigtail catheter
The chest X-ray demonstrates a left pneumothorax in an intubated patient. The best option for
treating this patient is tube thoracostomy with placement of a pigtail catheter. Current evidence
suggests that placement of a pigtail catheter is preferable to a large bore chest tube (PMID:
29452099). Histroically, large bore chest tubes have been considered to be preferable in patients
with hemothoraces and emphyemas, however recent evidence has also challenged this (PMID:
33843831, PMID: 19820073). While conservative management is often an option for
pneumothoraces, positive pressure ventilation is thought to promote expansion of
pneumothoraces, and traditional practice is to intervene upon all pneumothoraces in mechanically
ventilated patients. The recent OPTICC trial has suggested that cautiously watching small, occult
pneumothoraces may be an option in patients receiving mechical ventilation (PMID: 33641940). As
the pneumothorax in this patient is large and 40% of patients requiring prolonged ventilation
require eventual drainage, insertion of a pigtail catheter is likely preferable to conservative
management in this case.
In patients who have head injuries, the electrodiagnostic test that is most useful in assessing
damage to the brain stem is which of the following?
Answers:
A. EEG
B. BAERs
C. SSEPs
D. Q-SART
E. EMG
BAERs
Brainstem auditory evoked potentials (BAERs) can be used to assess brainstem function in
traumatic brain injury. There may be a role for somatosensory evoked potentials (SSEPs) in
selected patients. EMG, EEG, and Q-SART have no role in clinical assessment of brainstem
function. Changes in latency and amplitude represent either decreased number or efficiency of
axons. Therefore, BAERs provides a method for quantifying the extent of axonal damage. The
electrophysiological functioning of the early auditory network provides a model for understanding
how networks respond to injury more generally. The non-invasive technique allows for survival and
serial assessment, which can help elucidate the temporal evolution of recovery or persistent
dysfunction.
A 60-year-old woman has been treated in the intensive care unit for ten days for Hunt and Hess
Grade 4 aneurysmal subarachnoid hemorrhage complicated by severe vasospasm and
pneumonia. Her temperature increases to 39.7°C (103.5°F), her white blood cell count increases
to 20 × 109/L, and her blood pressure decreases to 70/40 mmHg without response to fluid
resuscitation. Administration of which of the following agents is the most appropriate next step?
Answers:
A. Initiation of broad spectrum antibiotics and vasopressin.
B. Initiation of milrinone.
C. Initiation of broad spectrum antibiotics and norepinephrine.
D. Administration of hydrocortisone.
E. Initiation of broad spectrum antibiotics and low-dose dopamine.
Initiation of broad spectrum antibiotics and norepinephrine.
The patient is most likely in septic shock given the known pneumonia, new high fever, new
leukocytosis, and severe hypotension unresponsive to IV fluid resuscitation. If not already started,
the patient should be started on broad spectrum antibiotics and vasopressors. Based on the 2021
Surviving Sepsis Campaign, it is recommended to use norepinephrine as first line, with a target
MAP of 65 mmHg. Norepinephrine is a potent α-1 and β-1 adrenergic receptor agonist, which
results in vasoconstriction and increased MAP with minimal effect on heart rate. When compared
to dopamine, norepinephrine is a more potent vasoconstrictor and is associated with decreased
mortality and lower risk of arrhythmias in patients with septic shock.
Which of the following most accurately describes the relationship of pCO2, pO2, and cerebral blood flow?
A. Increase in the pCO2 will decrease cerebral blood flow. pO2 has minimal effect on
cerebral blood flow
B. Increase in the pO2 will decrease cerebral blood flow. pCO2 has minimal effect on
cerebral blood flow
C. Increase in pCO2 and increase in pO2 together will cause increase in the cerebral blood
flow.
D. Decrease in the pCO2 will decrease cerebral blood flow. pO2 has minimal effect on
cerebral blood flow
E. Decrease in the pO2 will decrease cerebral blood flow. pCO2 has minimal effect on
cerebral blood flow
D. Decrease in the pCO2 will decrease cerebral blood flow. pO2 has minimal effect on cerebral blood flow
Carbon Dioxide has a marked and reversible effect on cerebral blood flow. Hypercapnia will cause
marked dilation of the cerebral arteries and arterioles, thereby increasing cerebral blood flow.
Hypocapnia will cause vasoconstriction of the arteries and arterioles, decreasing cerebral blood
flow. The potent vasodilator effect of CO2 is demonstrated by the finding that in humans 5% CO2
inhalation causes an increase in cerebral blood flow by 50% and 7% CO2 inhalation causes a
100% increase in cerebral blood flow. Although several mechanisms involved in hypercapnic
vasodilation have been proposed, the major mechanism appears to be related to a direct effect of
extracellular H+ on vascular smooth muscle. pO2 has minimal effect on cerebral blood flow.
Which of the following states is most likely to increase a patient’s susceptibility to ventricular
fibrillation?
Answers:
A. Low serum magnesium
B. QTc ≥ 492
C. Low serum potassium
D. Hypothyroidism
E. Hyperlipidemia
QTc ≥ 492
Among patients admitted to the neurocritical care unit, a QTc ≥ 492 has been strongly linked to the
development of ventricular fibrillaiton. Other risk factors included premature ventricular complexes,
atrial fibrillation, active myocardial infarction, CAD, and heart failure. Increased age, mechanical
ventilation, and sepsis have also been associated with ventricular fibrillation. Among neurological
disorders, supratentorial strokes have been most strongly associated with ventricular arrhythmias.
A 45-year-old woman is intubated and mechanically ventilated after her severe pneumococcal
pneumonia progressed to acute respiratory distress syndrome (ARDS). During the next 24 hours,
her PaO2 decreases to 38 mmHg despite a ventilator FiO2 setting of 1.0 and PEEP of 20 cm H2O.
Which of the following is the most appropriate next step in management?
Answers:
A. Start veno-venous extracorporeal membrane oxygenation.
B. Start high dose inhaled steroids.
C. Increase PEEP.
D. Start inhaled nitric oxide at 40ppm.
E. Start continuous albuterol inhalation for 48 hours.
Start veno-venous extracorporeal membrane oxygenation.
The patient has severe ARDS (P/F Ratio < 100mmHg) with significant hypoxemia despite FiO2 of
100% and PEEP of 20 cmH2O. Mortality in severe ARDS is around 45%. Interventions that can
improve clinical outcome are low tidal volume ventilation (<6mL/Kg [predicted body weight] with
goal plateau pressures of < 30cmH2O), prone positioning for 16 hours in combination with low tidal
volume ventilation, and the use of ECMO. Ninety-day mortality was significantly lowered with the
use of ECMO compared to standard care. The most appropriate next step in management is
transitioning the patient to veno-venous ECMO for oxygenation and ventilator support. The use of
nitric oxide would minimally aid with oxygenation, given the degree of hypoxemia seen in this
patient. Increasing PEEP above 20 cmH2O will increase the risk of the ventilator induced lung
injury and increase the risk of spontaneous pneumothorax. Continuous albuterol is helpful in
patients with status asthmaticus, not in ARDS. There is some recent data that using high dose
steroids can decrease the alveolar inflammation seen in ARDS and length of ventilator use, but in
this case it will not help correct the acute hypoxemia seen in this patient.
A 63-year-old woman becomes lethargic five days after undergoing clipping of a ruptured
aneurysm. Pulse is 90/min, blood pressure is 110/65 mmHg, and central venous pressure is 3
mmHg. Results of serum studies are shown: Na+ 129 mEq/L, K+ 3.9 mEq/L, Urea nitrogen 27
mg/dL, Creatinine 0.9 mg/dLTranscranial Doppler ultrasonography shows no abnormalities. Which
of the following is the most appropriate management for this patient’s condition?
Answers:
A. Intravenous nimodipine
B. Fluid restriction
C. Interarterial nimodipine
D. Fludrocortisone
E. Hypertonic saline
Hypertonic saline
Hyponatremia following aneurysmal SAH likely occurs via a different mechanism than with SIADH.
Increasing natriuresis may occur due to increased release of atrial natriuretic peptide (ANP) and
brain natriuretic peptide (BNP). Fluid restriction is not advised as first-line treatment of
hyponatremia in patients with aneurysymal subarachnoid hemorrhage (which could be due to
Cerebral Salt Wasting), as volume depletion could exacerbate hypotension and increase the risk of
vasospasm and ischemia. Nimodipine is not indicated as the transcranial doppler does not show
evidence of vasospasm. Fludrocortisone could be considered, but not as first-line treatment. The
best option is treatment with hypertonic saline.
A 62-year-old man is three weeks status post left carotid endarterectomy when he suffers a
cardiac arrest. He is comatose and was not cooled. Which of the following is most predictive of
death or vegetative outcome in this patient?
Answers:
A. Unilateral absent Somatosensory Evoked Potential (SSEP) N20 wave 72 hours after
return of spontaneous circulation.
B. Absence of EEG activity within the first 12 hours after return of spontaneous circulation.
C. Absence of pupillary light reflex at 72 hours after return of spontaneous circulation.
D. Serum neuron specific enolase level < 30μg/L 48 hours after return of spontaneous
circulation.
E. Absence of vestibulo-ocular reflex 72 hours after return of spontaneous circulation.
Absence of pupillary light reflex at 72 hours after return of spontaneous circulation.
In post-cardiac arrest patients that remain comatose and did not undergo targeted temperature
management, presence of myoclonus at 24–48 hours, bilateral absence of SSEP N20 wave or
absence of EEG activity > 20–21 μV at 24–72 hours, and absence of pupillary light reflex at 72
hours after return of spontaneous circulation each predicted death or vegetative state.
A patient with a severe closed head injury exhibits a decreasing serum sodium level over a 48-hour period to 125 mEq/L. Serum osmolality level is diminished, and urine sodium level is elevated. Monitoring of which of the following parameters is critical in the ensuing management of this patient?
Answers:
A. Volume status
B. Urine Potassium
C. Urine specific gravity
D. Serum ADH
E. Serum BNP
Volume status
Cerebral Salt Wasting is a syndrome defined by hyponatremia accompanied by elevated urine
sodium and hypovolemia in the setting of injury to the central nervous system. Careful monitoring
of volume status (via clinical examination, urine output, and laboratory testing) is required during
treatment of cerebral salt wasting syndrome. Bedside point of care ultrasonography assessment of
the inferior vena cava (IVC) and LV velocity time integral (VTI) can also assist in determining
volume status. Care should be undertaken to avoid inducing volume overload while correcting
serum sodium, which may exacerbate renal, cardiac, or pulmonary dysfunction. Conversely, undersupplementation
of blood volume may lead to clinical worsening in some conditions, notably
aneurysmal subarachnoid hemorrhage.
Dysfunction of which of the following hypothalamic-pituitary axes is most likely after aneurysmal
subarachnoid hemorrhage?
Answers:
A. Hypothalamic-pituitary-gonadal
B. Hypothalamic-pituitary-adrenal
C. Hypothalamic-pituitary-mammary
D. Hypothalamic-pituitary-thyroidal
E. Hypothalamic-pituitary-muscle bone and other tissues
Hypothalamic-pituitary-mammary
Hypothalamic-pituitary axis dysfunction is common after aSAH. Pituitary dysfunction occurs in
nearly 50% of patients acutely after aSAH, decreasing to about 25% chronically. The pituitary is
perfused by branches of the internal carotid artery, which forms a plexus of capillaries near the
median eminence of the hypothalamus. Blood then reaches the anterior pituitary via long and short
portal veins. The middle and inferior hypophyseal arteries perfuse the pituitary stalk and
neurohypophysis. Growth hormone has been shown to be the most commonly decreased pituitary
hormone. The differences in blood suppy may explain why GH, which is produced by the anterior
pituitary, is commonly affected. Adrenal insuffiency is common in critically ill patients and often
seen in the context of sepsis.
