Transplant And Immunity Flashcards
(31 cards)
How many classes of MHC are there ?
- 1
- 2
- 3
- 4
3
Class 3 contains - Complement, lymphotoxin b, hsp 70, tnf alpha
Which of the following is not a type of PAMP which bond roll like receptors in innate immune system
1 LPS
- Flagellin
- Methylated CpG islands on DNA
- Double stranded Viral RNA
- Zymosan (beta flucan found on fungi)
- Heat shock proteins
Ans C
Unmethylated CpG islands are detected
Match the following
- Cyclosporine
- Mycophenolate mofetil
- Penicillin
- Tacrolimus
- Tolypocladium inflatum
- Penicillium stoloniferum
- Penicillium notatum
- Streptomyces tsukubaensis
Ans 1a, 2b, 3c and 4d
Streptomyces is a actinobacteria
All of the following are essential findings in brain death except
A. Coma
B. Absence of Brainstem reflexes
C. Cortical injury
D. APnea
Ans C -
Brain death is defined as irreversible loss of all functions of the brain, including the brainstem.
There are three essential findings in brain death - coma, absence of brainstem reflexes and apnea.
An evaluation of brain death should be considered in patients who have suffered a massive, irreversible brain injury of identifiable cause.
A patient determined to be brain dead is legally and clinically dead.
The diagnosis is primarily clinical. No other tests are required if -
full clinical exam including each of two assessments of brain stem reflexes and a single apnea test, are conclusively performed.
conditions which may confound clinical diagnosis of brain death include all of the following except
A. Shock/Hypotension B. Brain Stem Encephalitis C. Guillian Barre Syndrome D. Severe Hypercalcemia E. Hyperosmolar coma
Ans D -
The conditons that may confound clinical diagnosis of Brain death are -
- Shock or hypotension
- Hypothermia less than 32C
- Drugs known to alter neurologic, neuromuscular and EEG testing.
- Anesthetic Agents, neuroparalytic drugs, methaqualone, barbiturates, BZDs, high dose Bretylium, amitryptiline, meprobamate, trichloroethylene, alcohol
- Brain stem encephalitis
- Guillain Barre Syndrome
- Encephalopathy associated with Hepatic Failure, Uremia and Hyperosmolar Coma
- Severe Hypophosphatemia
Presence of which of the following is not necessary for the diagnosis of brain death
A. Absence of response to verbal stimuli
B. Absence of response to noxious stimuli delivered through cranial nerve pathway
C. Absence of spinal reflexes
D. Absence of spontaneous movement
Ans C -
Examination of the patient should reveal -
- absence of spontaneous movement
- decerebrate or decorticate posturing
- seizures, shivering should be absent
- absence of response to verbal and noxious stimuli delivered via cranial nerve pathway.
- during the examination spinal reflexes may be present.
Which of the following reflexes are not associated with brain stem death
A. WIthdrawal reflex B. Corneal reflex C. Cough reflex D. Gag Reflex E. Pupil reflex F. Oculocephalic reflex
Ans A -
Withdrawal reflex is a spinal reflex and spinal reflexes can be present during the examination for brain death.
Corneal reflex, oculocephalic reflex, cough reflex, gag reflex should be absent. Corneal reflex may be altered as a result of facial weakness.
Absence of pupillary reflex to direct and consensual light must be present. Pupils need not be equal or dilated. The pupil reflex may be selectively altered by eye trauma, cataract, high dose dopamine, glutethamide, scopolamine, atropine, bretylium or monoamine oxidase inhibitors.
All of the following are involved in oculocephalic reflex except -
A. VIII
B. III
C. VII
D. VI
Ans C -
Oculocephalic reflex or the Doll’s eye movement if present indicate that the brainstem is not the cause of the coma and the brainstem is intact.
It can only be tested in a comatose patient. If the head is moved from side to side, the eyes do not move with the head, rather remain fixed at the midline, similar to a doll’s eyes. This indicates an intact brain stem.
However if the eyes move with the head when the head is moved from side to side or up and down then it indicates brain stem death.
Therefore the absence of Oculocephalic reflex or Doll’s eye movements indicates brain stem death.
The nerves involved in the Oculocephalic reflex are CN VIII, III and VI.
Which of the following are true regarding clinical assessment for brain death
A. Oculovestibular reflex is tested using 20-50mL of ice water poured into EAC clear of cerumen, and after elevating the patient’s head to 30 degree
B. Failure of 1-2 mg atropine to raise heartrate by more than 5 bpm is indicative of absence of vagus nerve function
C. Absent of respiratory efforts in the presence of hypoxia.
D. Both A and B
Ans D -
Absence of oculovestibular reflex when tested with 20-50mL of ice water irrigated into the ext. aud. canal clear of cerumen and after elevating the patient’s head 30 degrees.
Labrynthine disease, anticholinergics, anti-convulsants, TCA and some sedatives can alter the response to Oculovestibular reflex.
Failure of heartrate to increase by more than 5 bpm after 1-2 mg of atropine intravenously indicates absence of the function of the vagus nerve and nuclei.
Absence of respiratory efforts in the presence of hypercarbia.
which of the following is false about apnea test
A. Apnea test usually performed after the second examination of brain-stem reflexes.
B. A pCO2 above 60 mmHg or increase of more than 20 mmHg over baseline is indicative of positive test
C. Usual duration of the apnea test is 5min
D. Pre-oxygenation is a necessary pre-requisite.
Ans C -
The apnea test is performed after the second examination of brainstem reflexes. The apnea test need only be performed once when its results are conclusive. Before performing the apnea test, the physician must determine that the patient meets the following conditions -
- Core temperature more than 36.5 C
- positive fluid balance in the previous 6 hours
- Normal pCO2 more than or equal to 40 mmHg
- Normal pO2 preoxygenation to arterial pO2 more than or equal to 200 mmHg
Ventilator is disconnected and a pulse oximeter is connected.
100% oxygen is delivered at 6L pre min. Closely look for any respiratory movements, and measure pO2, pCO2 and pH nearly 8 minutes after and reconnect the ventilator.
- absence respiratory movements and pCO2 more than 60 mmHg or more than 20 mmHg increase over baseline indicate a positive apnea test - i.e. brainstem is not functional
- if respiratory movements are observed, the apnea test results are negative.
during the apnea test the ventilator should be reconnected if -
- SBP <90
- significant oxygen desaturation
- cardiac arrhythmias develop
All of the following should be ensured before performing an apnea test except =
A. Core temperature should be >36.5 C
B. Positive fluid balance for the last 6 hours
C. arterial pCO2 more than 40 mmHg
D. Preoxygenation with pO2 more than 100 mmHg
ANS D -
Before performing the apnea test the physician must determine that the patients meets the following conditions -
- Core temperature 36.5C
- Positive fluid balance in the previous 6 hours
- Arterial pCO2 more than 40 mmHg
- Preoxygenation with arterial pO2 more than 200 mmHg
Duration of the apnea test is
A. 4min
B. 5min
C. 6min
D. 8min
Ans D -
Ventilator is disconnected and 100% oxygen delivered at 6L per minute, while the respiratory movements are looked for. Measure the arterial pO2, pCO2 and pH after approximately 8 minutes and reconnect the ventilator.
When appropriate a 10 min apnea test can be performed after preoxygenation for 10 min with an FiO2 of 1.0 and normalization of patients pCO2 to 40 mmHg.
which of the following is conclusive of brain stem death on apnea test
A. rise in pCO2 more than 20 mmHg over baseline
B. rise in pCO2 over 60 mmHg
C. absence of respiratory movements
D. all of the above
Ans D -
If pCO2 is more than 60 mmHg or pCO2 is more than 20 mmHg over baseline, and there are no respiratory movements present, then apnea test result is positive.
which of the following is involved in corneal reflex
A. CN III
B. CN V
C. CN VI
D. CN VIII
Ans B
Corneal reflex is mediated by CN V (Afferent) and CN VII (Efferent)
which of the following is false about vesitbuloocular reflex
A. 50mL of ice water irrigated
B. obersved after 1 min of irrigation
C. minimum 5min between testing on either side
D. None of the above
Ans D -
Oculovestibular reflex is mediated via the CN VIII (Afferent) and CN III and VI (Efferent).
No deviation of the eyes to irrigation in each ear with 50 mL of ice water (with tympanic membranes intact) allow 1 minute after injection and at least 5 minutes between testing on either side.
All of the following can be used to assess response to noxious stimuli
A. Deep pressure on nail bed
B. Deep pressure on supra-orbital ridge
C. Deep pressure on TMJ
D. Deep pressure on mastoid
Ans D -
No grimacing on deep pressure on nail bed, supra-orbital ridge or TMJ indicates absence of facial sensation and absence of facial motor response.
Cough reflex is tested by
A. Noxious vapors of citric acid
B. suctioning
C. irritation of posterior wall of pharynx
D. None of the above
Ans B -
Absence of cough reflex is tested using tracheobronchial sunctioning.
Nerves involved in pharyngeal and trachea reflexes include
A. CN IX
B. CN X
C. CN XI
D. Both A and B
Ans D -
CN IX and X are involved in the pharyngeal and tracheal reflexes.
all of the following can be present in a patient who is brain dead except
A. Absence of Diabetes insipidus
B. Sudden rise of blood pressure
C. Spontaneous movements of limbs other than pathologic flexion/extension
D. shoulder elevation and adduction, brack arching
E. grimacing to deep pressure on nail bed
Ans E
Following manifestations are occassionally seen and should not be misinterpreted as evidence of brain stem function -
- spontaneous movements of limbs other than pathologic flexion or extension
- respiratory like movements such as shoulder elevation and adduction, back arching, intercostal expansion without significant tidal volume
- sweating, flushing, tachycardia
- normal blood pressure without pharmacologic support or sudden increase in blood pressure
- absence of diabetes insipidus
- deep tendon reflexes, superficial abdominal reflexes, triple flexion response
- babinski reflex.
The criteria of clinical examination of brain death are applicable above what age
A. 6 months
B. 1 year
C. 5 year
D. 18 year
Ans B -
These guidelines apply to patients one year of age or older.
which of the following is not true regarding assessment of brain death
A. Consent must be taken from next of kin
B. No other tests are required if two assessments of brain stem reflexes and a single apnea test are positive.
C. observation period between two clinical exams is usually 6 hours
D. confirmatory test can be performed if the clinical assessment could not be completed
Ans A -
The facility must make diligent efforts to notify the person closest to the patient that the process of determining brain death in underway. Consent need not be obtained but requests for reasonable accomodation based on religious or moral objections should be noted and referred to appropriate hospital staff.
The patient should be observed for a defined period of time for clinical manifestations that are inconsistent with the diagnosis of brain death. Most experts agree that a 6 hour observation period is sufficient and reasonable in adults and children over 1 year of age.
Longer intervals may be advisable in younger children.
Full clinical examination, including both assessments of brain stem reflexes and the apnea test when conclusively performed, no additional test are required.
In some patients skull or cervical injuries, cardiovascular instability or other factors make it impossible to complete parts of the assessment safely. Confirmatory tests may be needed in these circumstances.
All of the following are confirmatory test for brain death except
A. Absence of intra-cerebral filling at the level of carotid bifurcation or circle of willis on MRAngio
B. Absence of electrical activity during atleast 30 minutes of recording of 16 channel EEG
C. Absence of isotope uptake in brain parenchyma or “hollow skull phenomenon”
D. Initial absence of doppler signals
Ans D -
Angiograph - can be Conventional, CT, MR or Radionuclide
- absence of intra-cerebral filling at the level of carotid bifurcation or circle of willis. The external carotid should be patent and filling of superior sagittal sinus may be delayed.
Radionuclide angiography - does not adequately image the posterior fossa vasculature, MRA difficult in ICU setting due to leads etc, Cerebral angiography difficult to perform in critically ill unstable patients.
EEG - Absence of electrical activity atleast 30 minutes of recording that adheres to minimal technical criteria for EEG. 16 channel EEG instruments used. The ICU setting can result in false reading due to electronic background noise creating artefacts.
Nuclear Brain scanning - brain death confirmed by absence of uptake of isotope in brain parenchyma and/or vasculature depending on isotope and technique used.
“Hollow skull phenomenon”
Somatosensory evoked potentials - bilateral absence of N20-P22 criteria for somatosensory evoked potentials.
Transcranial Doppler USG showing small systolic peaks in early systole without diastolic flow or reverberating flow indicating very high vascular resistance with greatly increase ICP
As many as 10% of patients may not have temporal insonation windows because of skull thickness, the initial absence of Doppler signals cannot be interpreted as consistent with brain death.
Observation period advisable in an infant more than 2 months old before second examination for certifying brain death
A. 6 hours
B. 12 hours
C. 24 hours
D> 48 hours
Ans C
the recommended observation period depends on the age of the patient and the laboratory tests used. It is assumed that the child was born full term.
Between the ages of 2 months and 1 year - two examination of EEG should be separated by atleast 24 hours. A repeat EEG examination is not necessary if a concomitant radionuclide or other angiographic study demonstrates no visualisation of cerebral arteries.
Between the ages of 7 days and 2 months, the minimum interval between two examination and EEG should be atleast 48 hours.
All of the following should be documented on the medical records of patient declared to be brain dead except -
A. Etiology and irreversibility of coma/unresponsiveness
B. Absence of motor response to pain
C. absence of brainstem reflexes during two separate examinations separated by atleast 6 hours
D. justification of second apnea test if used
Ans D -
All phases of the determination of brain death should be clearly documented in medical record. The medical record must indicate -
- Etiology and irreversibility of coma/unresponsiveness
- Absence of motor response to pain
- absence of brainstem reflexes during two separate examinations separated by atleast 6 hours
- absence of respiratory with pCO2 > or = 60 mmHg
- justification for and result of confirmatory tests if used.
