Mixed Q’s 5 Flashcards

1
Q

Botulinum toxicity features?

A

Blocks presynaptic ACh
Impaired nicotinic and muscarinic neurotransmission
Symmetrical descending paralysis with cranial nerve involvement 2o eating home canned foods

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2
Q

Treatment of pts with cryptococcal meningitis?

A

Amphotericin B and flucytosine

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3
Q

Cryptococcal meningitis features?

A

Slowly worsening headache
Fever
Lethargy
LP: low glucose high protein, predominant lymphocytes

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4
Q

NMDA receptor excess activation ?

A

Is a glutamate receptor and Ca ion channel found in neurons
Excessive activation of the NMDA receptor causes neuronal death through uncontrolled Ca influx.
The receptor is blocked by Mg —> decreased influx of Ca and Na

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5
Q

Pathology behind raised intracranial pressure?

A

Idiopathic
2o cerebral venous sinus thrombosis decreased resorption of cerebrospinal fluid

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6
Q

What is the benefit of giving dexamethasone prior to Abx therapy in bacterial meningitis?

A

Decreases inflammatory response in the CSF

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7
Q

Virulence factor of Neisseria meningitidis?

A

Use Pili to attach to and colonise the nasopharyngeal epithelial surface

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8
Q

Negative equilibrium indicates the membrane is permeable to ?

A

K or CL-
Positive equilibrium indicated membrane is permeable to (Na and Ca)

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9
Q

Cryptococcus Neoformans appearance on histopathology?

A

Encapsulated yeast with thick polysaccharide capsule ( clean on H&E tissue stain)

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10
Q

Upregulation of which channels lead to pain at site of neuroma after nerve injury?

A

Na channel upregulation

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11
Q

Febrile seizures features?

A

6/12 - 5 years
Temp >38
Hyperthermia induced neuronal dysfunction triggering a short generalised seizure.

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12
Q

Age related sleep changes features?

A

Decreased total sleep time
Increased nighttime waking
Sleepiness earlier in the evening
Earlier morning waking
Increased daytime napping

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13
Q

Frontal lobe dysfunction?

A

Change in personality, languages, motor function and executive function. Abstraction ability ( asking about similarities between 2 related objects) affected

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14
Q

Buildup of very long chain and branched chain fatty acids is due to a dysfunction in which cellular structure?

A

Peroxisome

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15
Q

Multiple ring enhancing lesion in a patient with AIDS ?

A

Toxoplasmosis encephalitis

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16
Q

Cryptococcus Neoformans primary site of infection?

A

Lungs / inhalation
Soil contaminated by bird droppings

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17
Q

Shingles occurs because of ?

A

Reactivation of latent pathogen in neural ganglia

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18
Q

Influx of ca is important in voltage gated neurotransmission because ?

A

It’s essential for fusion and release of neurotransmitter vesicles

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19
Q

Drugs that bind to GABA-A receptors affect on resting membrane potential?

A

Will increase CL influx causing membrane potential to become more hyper polarised i.e. negative

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20
Q

Guillian Barre syndrome features?

A

Symmetric Ascending weakness
Immune mediated polyneuropathy
Follow campylobacter jejuni diarrhoeal illness

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21
Q

Hydrocephalus presentation?

A

Macrocephaly
Poor feeding
Poor growth
Developmental delays
Untreated —> muscle spasticity

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22
Q

Guillemot Barre Syndrome features?

A

Symmetric ascending weakness immune mediated polyneuropathy
Follows campylobacter jejuni
diarrhoea illness

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23
Q

Alzheimer’s disease pathogenesis ?

A

Neuro degeneration lead into cerebral atrophy
Beta amyloid plaques
Tau proteins microtuble associated protein polymerised and hyperphosphorylated

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24
Q

Rabies attaches to which receptor?

A

Nicotinic acetylcholine receptors present in neuromuscular junctions

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25
Tay-Sachs disease features?
AR Beta heoxsaminidase A deficiency Accumulation of GM2 ganglioside Progressive neurodegenreation ( developmental regression) Exaggerated startle reflex Cherry red macula
26
Osmotic demyelination syndrome (central pontine myelinosis features?
2o rapid correction if chronic hyponatremia esp alcoholic Quadriplegia Pseudobulbar palsy (dysarthria, dysphagia, dysphonia) Reduced level of consciousness
27
Myasthenia gravis pathogenesis?
Decreased number of functional acetylcholine receptors Reduced amplitude of motor endurance plate potential
28
Mgx of myasthenia gravis?
Cholinesterase inhibitor e.g pyramidine Selective muscarinic inhibitors e.g glycopyrollate can reduce the SE
29
Reye’s syndrome features?
Acute liver failure and encephalopathy in child who took aspirin Causing mitochondrial toxicity Diffuse astrocyte swelling
30
Commonest cause of bacterial meningitis?
Strep pneumoniae
31
Ectopic pregnancy should be suspected in ?
Abnormally rising b-hcg 2o amenorrhea Endometrium will be showing pregnancy changes
32
Raised Acetylcholinesterase and AFP in amniocentesis suggests?
Neural tube defect
33
DiGeorge is due to what genetic mutation?
Ch 22q11.2 microdeletion
34
DiGeorge features?
Hypo calacaemia/hypoparathyroidiam Thymic aplasia( T cell deficiency) Dysmorphic face ( cleft palate) Cardiac anomalies (tetralogy of fallout)
35
Frontotemporal dementia due to abnormal accumulation of ?
Pathologically ubiquinated TDP-43 and neurofibrillary tangles due to abnormal TAU protein
36
Rapid corrections of chronic hyponatremia leads to ?
Osmotic demyelination syndrome …a cerebral demyelination abnormality
37
Migraine features?
Episodic neurologic disorder resulting in severe, unilateral pulsatile headaches assoc with photophobia, photophobia N+V +/- aura
38
Cerebral palsy cause?
Periventricular focal necrosis / (Periventricular leukomalacia ( white matter necrosis)
39
Narcolepsy features?
Chronic sleep disorder characterised by daytime sleepiness cataplexy REM sleep related phenomenon (hallucinations, sleep paralysis)
40
Guillain barre histology ?
Endoneurial inflammatory infiltrate seen on light microscopy
41
Haemorrhage and necrosis of the mnamillary bodies causes?
Wernicke’s encephalopathy 2o thiamine deficiency By way of deficiency of erythrocytes transketolase activity impairing glucose production and use
42
Neuro imaging findings in Huntington’s disease?
Atrophy of the caudate nuclei and enlargement of the front horns of the lateral ventricle
43
Optic neuritis and intranuclear opthalmoplegia in MS is usually due to which mechanism?
Reduced saltatory conduction 2o demyelination
44
HSV-1 encephalitis features?
Headache Fever Altered mental state Seizure Pathology:- haemorrhagic necrosis of temporal lobe
45
Findings in irreversible ischaemic injury in brain ?
12-24hrs Shrinkage of cell body Pykinosis of nucleus Loss of nissl bodies Cytoplasmic eosinophilia
46
Route of entry of primary amoebic meningoencephalitis?
Caused by protozoa naegleria fowleri Penetrated olfactory mucosa and migrates retrograde through the olfactory nerve
47
Multiple sclerosis findings ?
Demyelinating plaques lesions Hyperintense lesions on T2 weighted MRI of the brain and spinal cord
48
ALS pathology?
Degeneration and atrophy of the corticospinal tract and precentral gyrus (UMN) Degeneration of anterior horn of the spinal cord and cranial nerve motor nuclei (LMN)
49
Glutamate neurotransmitter features?
Main excitatory neurotransmitter of the CNS Induces postsynaptic neuron depolarisation Calcium entry programs the neurons to be more sensitive with repeat stimulation Function long term learning and memory
50
Signs of vitamin A toxicity?
Benign intracranial HTN Headache Vomiting Papilloedema Dry skin Hepatomegally
51
Cholinesterase inhibitors (donepezil, galantamine) use in Alzheimer’s?
May temporarily improve cognitive function but do not alter the disease progression
52
Guillain Barre pathology?
Molecular mimicry Ab against infectious agents cross react with myelin and Schwann cells leading to immune mediated demyelination ( Tcell response) Microscopy:- segmental demyelination + endoneurial infiltration with lymphocytes and macrophages
53
Subarachnoid haemorrhage is usually due to?
Saccular ( berry) aneurysm
54
Essential tremor features?
Tremor worse on extension of arms and at the end of intended action Assoc with head tremor No other neuro findings AD +ve Fhx
55
Mechanism of action of B blockers in essential tremor and SE?
Blocks interaction of norepinephrine with at adrenergic synapse SE :- b2 block —> bronchoconstriction
56
Von Hippel Lindau disease features?
Mutation in VHL tumour suppressor gene on chromosome 3 Cerebellar haemangoblastoma Congenital cysts in kidneys, liver and/or pancreas AD
57
Treatment of trigeminal neuralgia?
Carbamazepine Increases Na channels inactivation by reducing high frequency firing
58
SE of volatile anaesthetics?
Increase cerebral bld flow ( risk of increase ICP)
59
Management of cerebral palsy?
GABA agonist CP —> symptoms of spasticity due to loss of descending inhibitory control. GABA is the inhibitory neurotransmitter
60
Weakening diaphragmatic contraction during maximal ventilation with intact phrenic nerve stimulation suggests?
Neuromuscular junction pathology Abnormally rapid 1o muscle fatigue
61
UMN facial palsy features?
Spares the forehead Contralateral
62
Which symptoms of Parkinson’s are helped with Carbidopa and which are not?
Blocks levodopa to dopamine in periphery Improve tremor and movement SE N+V No effect or worsen and agitation
63
Histopathology specific to MS ?
Demylinating plaques containing foci of periventricular inflammatory infiltrates made up pf T lymphocytes and macrophages
64
Pathogenesis of migraines?
Genetic predisposition to increased cerebral excitability —> activation of trigeminal afferents and release of calcitonin gene related peptide (CGRP) —> vasodilation and inc transmission of pain signals
65
Meningioma in the cerebellopontine angle features?
Can compress CN VIII causing hearing loss, tinnitus, imbalance
66
Loss of which neurotransmitter is found in Huntington’s disease?
GABA
67
Pathogenesis of irreversible CNS ischaemic injury?
Liquefactive necrosis
68
Restriction of which food group will help in impaired ornithine transport?
Protein ( decrease amino acid turnover for urea cycle)
69
Ependymomas features?
Childhood brain tumour Ependymal cells of ventricles ICP - headache, papilloedema 2o blocking flow of CSF
70
What is the genetic defect in ataxia telengectasia ?
Defect in DNA break repair Classic findings:- cerebellar ataxia, telangiectasia and recurrent sinopulmonary infections
71
Characteristics of REM sleep?
Dreaming Voluntary muscle paralysis Final 1/3 of night Nightmares / vivid dreams
72
Commonest cause of death in Friedrich’s ataxia ?
HCM
73
What are the compensatory mechanisms in prodromal Parkinson’s disease?
Upregulation of tryrosin hydroxlase activity Presynatic Dopamine reuptake is inhibited Dopamine levels is still low because of a loss in total dopaminergic neurons Proliferation of dopamine receptors
74
Speed of neuronal conduction down an axon depends on which 2 constants ?
The length (space) constant Time constant Demyelination in MS decreases the length constant and increases the time constant
75
Histologic appearance of Schwannoma?
2 types of cellular pattern Antoni A (hypercellular) Antoni B (hypocellular) and positive S-100
76
What is oppositional defiant disorder?
Behavioural disorder of childhood Argumentative and defiant towards authority figure >6/12
77
What is delusional disorder?
1 or more delusions for 1 or more months in the absence of other psychotic symptom. Outside of the delusion can function normally.
78
Transtheoretical stage of change what is preparation?
Pt has committed to behavioural change but has yet to institute a specific course of action
79
How to diagnose ADHD?
Evidence of inattentive / hyperactive, impulsive symptoms over >6/12 in >2 settings
80
What is body dysmorphic disorder?
Fixation on a perceived defect in appearance and repetitive behaviours in response to the fixation
81
What is transference?
Unconscious recreation and experience, thoughts, behaviours associated with past relationships
82
What is bulimia nervous?
Recurrent episodes of binge eating followed by compensatory behaviour to prevent weight gain ( fasting , exercising, vomiting, using laxatives)
83
What is tardive dyskinesia
Abnormal involuntary movement of the mouth, tongue, face , extremities and truck assoc with prolonged exposure to antipsychotics Hypersensitivity of D2 receptors following prolonged block
84
What is antisocial behaviour?
Pattern of violating rights of others, engaging in unlawful behaviour and lacking remorse. Must be >18 to diagnose
85
What is specific phobia?
Anxiety disorder High levels of anxiety and panic attack triggers by exposure or anticipation of exposure of feared stimulus
86
How do antipsychotics work and SE ?
Work by blocking D2 receptors in mesolimbic dopamine pathway Blockage in the tuberoinfundibular pathway can cause hyperprolactinaemia — > galactorrhoea and amenorrhoea
87
Enzymes that require B1 and co-factor?
Pyruvate dehydrogenase ( pyruvate to acetyl coA) Alpha ketoglutarate dehydrogenase ( citric acid cycle) (Alpha ketoglutarate to succinylco-A0
88
Symptoms of opioid withdrawal?
Mydriasis Abdo pain Diarrhoea Piloerection Lacrmiation Yawning
89
What is panic disorder?
Recurrent unexpected anxiety attacks assoc with Somatic symptoms And worry about additional attacks and avoidance behaviour
90
Obstructive sleep apnoea features?
Sleep related apnoea and chocking loud snoring Disrupted non restful sleep Excessive daytime somnolence
91
Schizoid personality disorder features?
Persistent pattern of social detachment, prefers solitary activities and Ltd emotional expression when interacting with others
92
What is projection?
Defence mechanism Attributing one’s unacceptable feelings of thoughts to another person who may not have them
93
What is reaction formation?
Defence mechanism Replacing unacceptable feelings and impulses with their extreme opposite
94
Features of fetal alcohol syndrome?
Facial dysmorphisim (short palpebral fissure, thing upper lip, smooth filtrum. Growth retardation Neurological abnormalities Behavioural difficulties
95
Neural tube defects causes?
Folate deficiency Valproate Methotrexate trimethoprim -suflamethoxazole
96
What molecular change is seen in labour as a result of rising oestrogen ?
Gap junctions which facilitate communication and coordination between cells and help in labour contractions
97
What is the function of primase?
It’s a DNA dependent RNA polymerase that incorporates RNA primers into replicating DNA By product is uracil
98
What is genomic imprinting?
Offspring’s genes are expressed in a parent specific manner. Caused by DNA methylation an epigenetic process where genes are silenced by attaching methyl groups to cytosine residues in DNA molecule
99
What is an ecological study?
Observational study analysing population level data rather than individual
100
What is epistasis?
The allele of one gene affect the phenotypic expression of alleles in another gene e.g. albinism masks the expression of skin hair, colour etc
101
What is pleitropy?
A single gene influences multiple phenotypes e.g PKU many effects - skiing pigmentation, learning difficulties
102
Naloxone works on which receptor?
Pure opioid receptor antagonist Greatest affinity for Mu receptor
103
Which medication can be used as a mood stabiliser and antiepileptic?
Valproate
104
What medication can be uses as 1st line for psychomotor agitation associated with alcohol withdrawal?
Benzodiazepines
105
What is the dysregulation in neuroleptic malignant syndrome?
Dopamine dysregulation
106
1st line therapy for alcohol use disorder and mechanism?
Naltrexone :- Mu opioid receptor blocker Inhibits reward and reinforcing effect of alcohol 2nd line disulfiram (aldehyde dehydrogenase inhibitor ) unpleasant SE if they drink
107
Mechanism of action of 2nd gen antipsychotics ?
Dopamine D2 antagonist 5HT2A antagonist
108
Mechanism of action of benzos?
Bind and allosterically modulate the GABA A receptor —> increase in CL ion channel opening and Cl influx
109
How can risperidone and similar drugs cause hyperprolactinaemia?
Prolactin controlled by inhibitory effect of hypothalamic dopamine. Blocked by these drugs ( D2 receptor blockers) — > high prolactin
110
Pathology in hypertensive crisis?
Increase in tackle of tyramine in pts taking MAO I —> failure of monoamine breakdown —> tyramine induced hypertensive crisis
111
Which drug interactions can cause lithium toxicity?
NSAIDS ACE I Thiazide diuretics Tetracycline Metronidazole
112
Management of bulimia?
Nutritional rehabilitation CBT SSRI (Fluoxetine)
113
Neuroleptic malignant syndrome features?
Adverse reaction to antipsychotic medication/ dopamine antagonist Severe lead pipe rigidity Hyperthermia, HTN Inc SNS activity Mental status changes
114
Buspirone mechanism of action and uses?
Nonbenzodiazepine anxiolytic (partial agonist 5HT1A receptor ) No muscle relaxant or anticonvulsant properties No risk dependence Use in general anxiety disorders
115
Potential SE of TCA?
Strong anticholinergic properties Confusion Constipation urinary retention Also Tremor Arrhythmias Hypotension Sedation
116
Mechanism of action of benzos?
Bind and modulate GABA A receptors Increased frequency of opening of Cl channel
117
Possible major SE of clozapine?
Agranulocytosis Need to check absolute neutrophil count
118
Management of OCD?
1st line SSRIs CBT
119
Which medications will increase concentration of methadone if taken concurrently?
CyP3A4 inhibitors Fluconazole, ketoconazole Ciprofloxacin Clarithromycin Cimetidine Fluvoxamine
120
Alcohol withdrawal is caused by increase in which CNS receptor?
NMDA glutamate receptor (Chronic Alcohol down regulates inhibitory GABA receptors and upregulates excitatory NMDA receptors)
121
Non bacterial thrombotic endocarditis features?
Valvular deposition of sterile plt rich thrombi. Seen in advanced malignancy and SLE
122
Causes of concentric left ventricular hypertrophy?
Aortic stenosis Prolonged HTN
123
Changes seen 0-4 hr after MI ?
Normal myocardium Changes seen after 4 hrs
124
Membranous nephropathy features?
Immune complex deposition in sub epithelial glomerular capillary wall causing diffuse thickening of the glomerular basement membrane no increase in cellularity. Spike and dome appearance on silver stain
125
Membranous nephropathy associations?
Malignancy Viral hepatitis SLE
126
Uterine sarcoma features?
Abnormal / post menopausal bleeding Bulk symptoms ( pelvic pressure, bloating) Uterine mass Histopathology:- nuclear atypia, abundant mitosis and areas of tumour necrosis
127
Temporal lobe epilepsy pathology?
Due to hippocampal sclerosis Atrophy of the hippocampal neurons with reactive gliosis ( astrocyte proliferation) in response
128
What are highly proliferative cells?
Skin Stem cells Haemotogenous progenitors Intestinal crypt cells
129
Pathologonomic cell finding in Hodgkin’s lymphoma?
Reed - sternberg cells ( owl eyes)
130
Causes of wide splitting of S2?
Pulmonic stenosis Pulmonary HTN RBBB
131
Ankylosing spondylitis features?
Inflammatory spondyloarthropathy charticterised but erosion and new bone formation mostly in vertebral body. Back pain Stooped posture Tender at tendon insertions Raised ESR Age <40
132
Tuberous sclerosis presentation?
AD Benign multiple hamartomas in the brain ( cortical glioneuronal hamartomas and subependymal nodules) and skin Hypopigmented macules (ash leaf spots ) Present with seizures
133
NAFLD features?
Asymptomatic Metabolic syndrome AST/ALT <1 Can progress to cirrhosis
134
CEA use in colon cancer?
Carcinoembryonic antigen (CEA) if still high after surgery indicates residual disease low sensitivity and specificity for screening and diagnosis
135
Hypersensitivity penumonitis features?
Exaggerated immune response to inhaled antigen (mold, animal protein) Cough, dyspnoea CXR diffuse interstitial opacities (interstitial fibrosis Brocheoalveolar lavage :- high lymphocyte count >20%
136
What do Granulosa cell tumours secrete and features?
Oestrogen They are ovarian sex cord stromal tumours Symptoms:- PMB, endometrial hyperplasia , large unilateral adnexal mass Histology :- cuboidal cells nuclear grooves
137
Cause of distal muscle hypertrophy in Duchennes muscular dystrophy?
Pseudohypertrophy - fibrofatty muscle replacement
138
Back pain features suggestive of malignant cause?
Persistent pain at night No relief with rest Onset at age >50 Systemic symptoms
139
UMN signs?
Spastic paralysis Hyperreflexia Upgoing planter reflex
140
What are chiari malformations?
Congenital disorder result from under development of the posterior fossa causing parts of cerebellum and medulla to herniate through the foramen magnum Chiari I benign in adults Chiari II severe in neonates
141
Administration of which would help in haemophilia?
Haemophilia A decrease factor VIII Haemophilia B decrease level IX Addition of thrombin helps bld to clot
142
What is a case control study looking at ?
Group of pts with disease and group of pts without the disease assess frequency of past exposure to estimate associated and risk factors and outcomes
143
Management of atypical ‘walking’ pneumonia?
Usually due to mycoplasma pneumoniae ( of chlamydia pneumoniae) Both organisms don’t have a cell wall Mgx requires a bacterial protein inhibitor e.g macrolide / tetracycline
144
Features of vertebral osteomyelitis and investigation?
Hx of new or worsening back pain with recent endocarditis or bacteraemia Initial investigation :- blood culture and spine MRI
145
Nontyphoidal salmonella features?
G-ve non lactose fermenting oxidase -ve rod Gastroenteritis fever, vomiting and diarrhoea After eating poultry, eggs Invasive disease causes osteomyelitis esp in sickle cell and impaired immunity, extremes of age
146
Haemolytic uraemia syndrome features?
Complication of EHES infection Renal insufficiency, thrombocytopenia and microangiopathic haemolytic anaemia Cause: shiga toxin producing bacterial E.coli O157:H7 (EHES) or shigella Bloody diarrhoea EHES from undercooked beef
147
Cryptosporidium presentation and features?
Severe watery diarrhoea and wt loss in pts with AIDS Self ltd watery diarrhoea <2/52 in healthy pts Diagnosis:- acid fast staining oocysts in stool Basophilic organism on mucosal intestinal brush border
148
Thayer martin medium
Chocolate sheep blood Agar used to identify neisseria organisms Infused with vancomycin to inhibit G+ve bacteria Colistin and trimethoprim to inhibit G-ve bacteria Nystatin to inhibit yeast
149
Tenofovir mechanism of action and complication
Nucleotide reverse transcriptase inhibitor Prevents transcriptase from converting HIV RNA into complementary double stranded DNA inhibiting viral replication Complication:- proximal tubule dysfunction ( loss of brush border)—> glycosuria, phosphaturia, proteinuria
150
What antiretroviral therapy do you use during pregnancy to reduce risk of transmission?
Triple therapy made up of 2 nucleoside/nucleotide reverse transcriptase inhibitors third drug :- protease inhibitor, non nucleoside reverse transcriptase inhibitor or integrase inhibitor
151
MALT lymphoma features ?
Due to chronic stimulation for gastric MALT lymphoma its H pylori MALT lymphoma are extranodal marginal zone lymphoma involving mucosa associated with lymphoid tissue —> aberrant B cell production Form of non Hodgkin’s lymphoma
152
CMV colitis features?
Common cause of colitis in AIDs pts Reactivation disease Abdo pain, fever, diarrhoea, wt loss Colonoscopy:- erythema, erosions, ulceration Biopsy:- large cells with prominent basophilic intranuclear inclusions
153
Protease inhibitors mechanism of action in HIV
Block viral protease from cleaving gag-pol polyproteins ( inhibits production of functional viral encoded enz.) resulting in immature virions that are non infectious
154
Mefloquine chemoprophylaxis fro malaria mechanism of action
Must continue for 4/52 after return Destroys replicating parasites within RBC but ineffective against schizonts in liver P. falciprum matures in liver for 8-30/7 Ovale and vivax can remain dormant in liver for months
155
G6PD deficiency
Assoc with fatty acid synthesis Rate limiting enz of the pentose phosphate pathway Major source of NADPH starting substrate :- glucose -6-phosphate End product:- rib u lose -5-phosphate Triggered by eating broad beans, haemolysis
156
Blotchy red muscle fibers on comprise trichome stain
Characteristics of mitochondrial myopathies Red ragged muscle fibers Show maternal inheritance
157
5 alpha reducatase deficiency
Impaired conversion of testosterone to DHT N testosterone and oestrogen levels Symptoms:- external female genitalia, internal male genitalia, 1o amenorrhoea , vagina ends in blind pouch, develop body hair but no breast development
158
Paget’s disease of the breast
Malignant breast condition / intraepithelial adenocarcinoma Unilateral painful/pruritic eczema toys rash on nipple and alveolar Biopsy :- infiltration of the nipple/ areolar epidermis by pagets cells
159
Herpes zoster opthalmicus
Reactivation of VZV in ophthalmic division of CN V1 Painful dermatomal rash and ocular involvement
160
What kind of medium is Thayer martin antibiotic media
Selective —> inhibits growth of contaminants isolates neisseria
161
What cellular process contributes to the formation of granuloma
Cytokines secretion by CD4 T lymphocytes Activate macrophages —> join together to form langhans giant cells
162
Severe combined immunodeficiency (SCID)
Genetic defect in T cell development which also leads to defect in B cell Causes:- recurrent infection with viral, fungal, opportunistic and bacterial infection + failure to thrive and diarrhoea
163
Candida skin test
Used to asssess the activity of cell mediated immunity if shows response incact CD4 cell response. No response in pts with SCID
164
Terminal complement deficiency
Deficiency of complements C5-C9 that form MAC Results recurrent infection with encapsulated bacteria S pneumoniae, N meningitidis
165
Chronic granulomatous disease
X linked affecting NADPH oxidase Child with recurrent infection by catalase positive organism N Ig No leukopenia Due to defective intracellular killing due to impaired respiratory burst
166
PECAM-1 is assoc with which part of neutrophil function
Transmigration
167
How does tetanus vaccine protect against developing neuro symptoms from future infection ?
Tetanus vaccine —> inactivated toxoid triggers production of antitoxin antibodies that neutralize the bacterial product i.e toxin
168
Toxic shock syndrome
Assoc with S. Aureus replicating and release > pyrogenic toxic superantigen (TSST-1) into the blood. Super Ag binds to MHC-II without processing lead to ++ release inflammatory cytokines Causes:- hypoBP, high fever, organ failure, diffuse erythematous rash
169
Congenital TORCH
Presentation:- growth restriction, microcephaly, hepatospleenomegally, diffuse blue rash Mother will show evidence of previous infection with encapsulated > IgG IgG crosses placental so new born will have IgG And evidence of active infection > IgM
170
Phenotypic mixing of viruses
Coinfection of a host cell by 2 viral strains resulting in a daughter virus that contains nucleocapsid(or envelope) of one parent and unchanged parental genome from the other strain. Because no genetic exchange — > the next gen vision reverts to original unmixed phenotype
171
Acute onset bloody diarrhoea in day care setting
Shigella Other causes:- E.Coli O157:H7, shigella, campylobacter
172
Aminoglycoside resistance
Methylation of the aminoglycoside binding portion of the ribosome —-> inhibits ability of aminglycoside to interfere with protein translation
173
Tuberculin skin test cellular reaction
Type IV hypersensitivity reaction In pts with previous infection already have CD4 T lymphocytes that recognise the protein —> activated with interaction between CD28 on the T cell and CD80/86 on APC
174
Type I hypersensitivity reaction
Initial exposure allergen promotes class switching to IgE Following exposure cross linking of IgE resulting in mast cell degranulation and release of histamine
175
Graft versus host disease
Donor T cells reject the host cells —> MHC Variable onset Usually following bone marrow and liver transplant Presentation:0 maculopapular rash, diarrhoea, jaundice, hepatomegaly
176
Acute transplant rejection
Occurs within weeks < 6/12 Predominantly cell mediated Sensitization of host T cell against donor MHC antigens Dense lymphocytic infiltrate
177
Defect in interferon gamma signaling
Disseminated mycobacterial infection in early childhood
178
How do inactivated/ killed vaccine prevent future infection
Produces humoral response —> forming neutralizing antibodies that prevent virus from entering the cell
179
How do live attenuated vaccine prevent future infections
Generate a strong cell mediated response that can result in destruction of infected cells
180
Serum sickness
Immune complex mediated Type III hypersensitivity reaction 7-10/7 after exposure Immune complexes deposit on skin and joints activating classical complement pathway Raised levels of C3a and C5a
181
Pathogenesis of asthma
Excess of Th2 resulting in excess IgE production Th2 cells released IL 4 stimulates B cells to produce IgE
182
Endotoxin and major virulence factor of G-ve bacteria
Endotoxin:- lipopolysaccaride Major virulence factor:- Lipid A Can lead to septic shock
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Causes of hepatic abscess
In underdeveloped countries - foodborne exposure —: entamoeba histolytica Developed countries :- S. Aureus via haematogenous seeding from the liver Klebsiella, E.col via ascending cholangitis Direct invasion G-ve bacteria
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How to diagnose C diff infection
PCR for bacterial toxin gene —NAAT (nuclear acid amplification test) Highly sensitive and specific
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Legionnaire disease
Caused by legionellae (G-ve bacillus) Exposure:- contaminated water source Symptoms:- high fever, GI symptoms, cough, confusion, hyponatraemia Sputum gram stain shows ++ neutrophils but no other organisms
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Walking pneumonia
Caused by mycoplasma pneumoniae CXR appears worse than the pt Symptoms:- low grande fever, chronic nagging cough Organism requires cholesterol to grow in medium
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Preformed inflammatory mediators released during anaphylaxis
Histamine Tryptase Leukotrienes
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Which mechanism triggers release of vasoactive substances in anaphylaxis
High affinity IgE receptor aggregation (clumping) Activates tyrosine kinase which triggers mast cell and basophils degranulation
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IL 10
Anti inflammatory Reduces Th1 cytokines ( IL2 and IFN gamma) and reduces MHC II
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Chronic granulomatous disease
Disorder of phagocytosis metabolism Defective NADPH oxidase / respiratory burst Recurrent infections with catalase +Ve organisms Dihydrorhodamine (DHR) test ( evaluates for phagocytosis oxidative response) is abnormal/ no increased fluorescence
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Polyclonal antibodies vs monoclonal antibodies
Plasma contains polyclonal antibodies that bid to different epitopes on antigens and are therefore better at neutralising complex antigens Monoclonal antibodies bind to single epitope on antigen therefor less potent immune response
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Calcineurin in immunosupression after transplant
Calcineurin is essential in activating Il-2 and promoting growth and differentiation of T cells. Immunosuppressants Tacrolimus, cyclosporine inhibit Calcineurin
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Atopic dermatitis
Mutation in epidermal barrier protein (filaggrin) Pruritic erythematous patches and papules Assoc:- allergic rhinitis, food allergy, asthma Labs:- raised IgE, eosinophilia Cytokines:- IL 4 , IL13 (stimulate IgE production)
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Late phase hypersensitivity type 1
Indurated skin lesion hours after exposure 2o IgE stimulating Th2 to release IL5 which activates eosinophils. Releasing major basic proteins causing damage to tissue and indurated lesion
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Acute haemolytic transfusion reaction
Antibody type II hypersensitivity reaction Preexisting anti-ABO antibodies With Complement activation Causes:- erythrocytes lysis, vasodilation, hypotension, fever, haemoglobinuria
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Sarcoidosis - cytokines seen
Non caesating granulomatous diseas Cytokines:- APC produce IL12 — stimulates Th1to produce IL 2 and IFN gamma which stimulate Th1 proliferation and macrophages activation —> granuloma formation
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Autologous haemopoietic stem cell transplant possible complications
Reinfuse host cells from pts peripheral blood No risk of transplant rejection Risk of reactivation of herpesviruses e.g EBV, VZV CMV, HSV because of temporary profound immunosuppression prior to transplant with chemotherapy
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Complement pathway in SLE
Activates the classical complement pathway Autoantibodies binned to host antigen Low C4 , Low C3, N factor/protein B Seen in other rheumatologist disease as well
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Serum sickness
Immune complex type III hypersensitivity reaction 1-2 weeks after exposure to non human antigen ( e.g .antivenom, MAB, or vaccine) Deposition of immune complex leads to complement activation Symptoms:- fever, arthralgia, uritcarial rash
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Hyperacute rejection
Antibody mediated type II hypersensitivity reaction Preexisting IgG antibodies in host recognise donor antigens Within minutes to hours Features:- mottling, cyanosis, necrosis and thrombosis
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TB skin test, candida extract skin reaction,contact dermatitis are types of
type IV hypersensitivity reaction T cell mediated Occurs within 24-48 hrs Tissue damage and swelling
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SLE
Autoimmune disorder Symptoms:- migratory arthralgia, pancytopenia, GN Haematologic abnormalities:- type II hypersensitivity reaction—> abs against bld cells Lupus neprhitis —> type III —-> immune complex deposition in glomeruli
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Hameolytic disease of the newborn
2o maternal sensitisation to RH antigens in RHD+ve fetus. In subsequent pregnancies maternal anti THD IgG ab cross the placenta causing fatal autimmune haemolysis in fetus
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IL 12 deficiency
IL12 stimulates Th1 Low IFN gamma Susceptible severe mycobacterial infections Cannot mount strong cell mediated granulomatous reaction Mgx:- IFN gamma
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False negative tuberculin skin test
Pts with active TB and weak/ impaired cell (lymphocytic) immune response (T cell anergy) Immunocompromised (HIV) Improper injection technique Recent infection ( within 8/52)
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