Cumulative Uworld Notes Flashcards
How does CMV virus infect?
- CMV can be acquired thru transfusion of leukocyte-laden blood products, as the virus infects leukocytes of granulocyte that are its defining characteristics
- Encapsulated, lactose fermenting, gram-negative bacillus that appears mucoid in culture.
Draw out characteristics of gram-negative bacteria
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Explain the symptoms of bipolar disorder.
- Irritable mood, hyperactivity, pressured speech, DEC need for sleep, and grandiose delusions = manic episode. Patients with one or more lifetime manic episodes have bipolar I disorder. Manic episodes can occur WITH or WITHOUT psychotic features (i.e. delusions, hallucinations).
- Delusions, if presents, are mood congruent (grandiose themes involving special talent and powers) but can also be mood incongruent. Most bipolar I patients will experience both major depressive and manic episodes, but depressive episodes are NOT required for diagnosis
What is positive predictive value? (PPV)
-Answers the question: If the test result is positive, what is the probability that a pt. has the disease? PPV is calculated as the proportion of subject who truly have the disease among all those with a positive test result.
What is negative predictive value (NPV)?
-Answers the question: If the test result is negative, what is the probability that a pt. doesn’t have the disease? It is calculated as a proportion of subjects who are truly free of disease among all those with a negative test result.
What is oppositional defiant disorder? How does it differ from antisocial, borderline, or conduct disorder?
- Oppositional defiant disorder: behavioral disorder of childhood characterized by argumentative and defiant behavior toward authority figures. It does NOT involve the more severe violations of the basic rights of others seen in conduct disorder
- Antisocial personality disorder: characterized by a pattern of disregard for and violation of the rights of others and is not diagnosed in individuals under age 18.
- Borderline personality disorder involves a pervasive pattern of marked impulsivity, unstable moods and relationships, and recurrent suicidal behavior or self-mutilation.
- conduct disorder involves behaviors that are more severe and aggressive than oppositional defiant disorder (ODD). Think physical aggression, or cruelty towards people or animals, destruction of property, or typical pattern of stealing or deceit.
Explain MOA of trazodone
-Serotonin modulator (antagonizes postsynaptic serotonin receptors and inhibits serotonin reuptake) and has minimal effects on NE and dopamine. Additional properties include α-adrenergic blockade (can cause orthostatic hypotension and priapism), and histamine H1 receptor antagonism that may underlie its sedating effect.
Explain what a crossover study is
-In crossover study, subjects are randomly allocated to a sequence of 2 or more treatments given consecutively. A washout (not treatment) period is often added between treatment intervals to limit the confounding effects of prior treatment.
What is a drawback of crossover trials? What is done to counteract this?
- the effects of one treatment may “carry over” and alter the response to subsequent treatments.
- The washout period is designed to be long enough to allow the effects of prior treatment to wear off
What is a case-control study?
-Designed by selecting patients with a particular disease (cases) and without the disease (controls) and then determining their previous exposure status
What is a case series?
A descriptive study that tracks patients with a known condition (i.e. particular exposure, risk factor, or disease) to document natural history or response to treatment. Unlike case-control, a case series is a qualifying study that cannot quantify statistical significance
What is a cross-sectional study?
AKA prevalence study. Characterized by the simultaneous measurement of exposure and outcome. It is a snapshot study design that frequently uses surveys. Are inexpensive and easy to perform
What is a prospective cohort study?
Are organized by selecting a group of individuals (i.e. cohort), determining their exposure status, and then following them over time for development of the disease of interest. Sometimes the exposure status is determined retrospectively and patients are tracked from the point of exposure onward, typically using medical records.
Explain what odds ratio is
It is a measure of association between an exposure and an outcome. Represents the odds that an outcome occurred in the presence of a particular exposure compared to the odds that the outcome occurred in the absence of that exposure. Used in case-control studies.
What is relative risk?
Risk of disease in the exposed divided by risk of disease in the non-exposed.
What are the stages of change?
1) Precontemplation: not thinking about behavior modification
2) Contemplation: Thinking about behavior modification
3) Preparation: Planning behavior modification
4) Action: Putting plan into action
5) Maintenance: maintaining new behavior
What is a confounder bias? How is it controlled so it doesn’t affect outcome?
- A confounder is associated with both exposure and outcome and affects the measure of association between exposure and outcome, such that there initially appears to be a statistically significant association between the 2 on crude analysis (ex: shoe size INC, IQ INC). However, once the results are stratified by the confounding variable, the association disappears.
- Matching is used in case-control studies in order to control confounding. Matching variables should always be the potential confounders of the study (i.e. age, race). Cases and controls are then selected based on matching variables so that both groups have a similar distribution in accordance with the variables.
What is conversion disorder?
- Neurologic symptom incompatible with any known neurologic disease; often acute onset associated with stress. It is a type of somatic symptom disorder characterized by symptoms or deficits of voluntary motor and/or sensory function that are incompatible with any recognized neurological condition and can’t be explained by another medical or mental disorder.
- Symptoms must be neurological and include weakness, paralysis, gait disturbance, blindness, diplopia, aphonia, anesthesia, and seizures (aka psychogenic or non-epileptic seizures).
Why can’t incidence measures be directly measured in case-control studies?
Incidence measures (i.e. relative risk or relative rate) can’t be directly measured in case-control studies b/c the people being studied are those who already have the disease. Relative risk and relative rate are calculated in COHORT studies, in which people are followed over time for developing the disease
What is risk and how is it calculated?
- Risk is the probability of developing a disease over a certain period of time.
- Calculate by dividing the number of affected subjects by the total number of subjects in the corresponding exposure group
What is the treatment of choice for OCD?
Serotonergic antidepressants (SSRIs)
What is acetylcholine involved in, in the CNS? Degeneration of it is associated with what pathology?
ACh is involved primarily in arousal, memory, and learning. Degeneration of cholinergic neurons is associated with Alzheimer dementia
What is norepinephrine involved in terms of psychiatrics? What pathophysiology is it associated with when NE levels are DEC? What other neurotransmitter is involved with this particular pathogenesis?
-NE is a catecholamine involved in mood, anxiety, alertness, learning, and memory. DEC neurotransmission of NE and serotonin has been implicated in pathophysiology of depression.
Which of the following factors most INC a patient’s risk of dying by suicide?
a) Access to firearms
b) Acute illness with pain
c) Age
d) Marijuana usage
e) Marital status
The majority of complete suicides occur with the use of a firearm. Access to guns significantly INC risk of death by suicide.
What medication is most appropriate agent for long term management of a patient with bipolar disorder?
Valproate (anticonvulsant) has mood stabilizing properties and is an effective maintenance treatment of bipolar disorder
How do you diagnose schizophrenia?
Requires greater than or equal to 2 of the following 5 symptoms: delusions, hallucinations, disorganized speech, grossly disorganized behavior, and negative symptoms. One of these must be delusions, hallucinations, or disorganized speech. Total illness duration must be greater than or equal to 6 months (including prodromal and residual periods) with greater than or equal to 1 month of active symptoms
Pyruvate dehydrogenase picmonic
http://www.picmonic.com/learn/pyruvate-dehydrogenase-deficiency_151
G6PD deficiency
http://www.picmonic.com/learn/g6pd-deficiency_436
G6PD mechanism
http://www.picmonic.com/learn/g6pd-mechanism_438
Neural plate gives rise to what?
Neural tube and neural crest cells
Notochord becomes what?
Nucleus pulposus of intervertebral disc in adults
Forebrain (prosencephalon) becomes what?
1) Telencephalon -> cerebral hemispheres (walls) and Lateral ventricles (cavities)
2) Diencephalon -> Thalamus, hypothalamus (walls) and Third ventricle (cavities)
Midbrain (mesencephalon) becomes what
Mesencephalon -> Midbrain (walls) and Aqueduct (cavities)
Hindbrain (rhombencephalon)
1) Metencephalon -> Pons and cerebellum (walls) and upper part of fourth ventricle
2) Myelencephalon -> Medulla (walls) and lower part of fourth ventricle (cavities)
Where are serotonin releasing neurons located in the CNS?
Raphe nuclei
Antidepressants such as selective serotonin reuptake inhibitors, serotonin norepinephrine reuptake inhibitors, and tricyclic antidepressants inhibit serotonin reuptake at which synapses?
Raphe nucleus (of the brainstem)
Where is the raphe nuclei located in and what role does it have?
Raphe nuclei is located in pons, midbrain, and medulla, and axons from these cell bodies project throughout CNS to synapse on cerebral cortex, thalamus, hypothalamus, cerebellum, hippocampus, and spinal cord.
These neurons play role in sleep-wake cycle, anxiety, mood, psychosis, sexuality, eating behavior, and impulsivity.
The caudate nucleus and putamen form what structure and what role does that structure have? Give an example of a pathology associated with it.
Caudate nucleus and putamen form the STRIATUM which functions in motor activities.
Huntington disease, there is loss of cholinergic and GABA-releasing neurons in striatum
What does the locus ceruleus house? (think neurotransmitter). Where is it located?
Houses norepinephrine-secreting neurons that participate in activation of “fight or flight” response to physical and emotional stressors.
Located in dorsal pons. These neurons are implicated in some anxiety symptoms, but they are not serotonergic and not affected by SSRIs.
The nucleus basalis of Meynert houses what type of neurons? What pathology is associated with it?
Houses cell bodies of cholinergic neurons.
Alzheimer disease, these neurons secrete DEC amounts of acetylcholine
Where is the red nucleus located and what is it involved in?
Located in anterior midbrain
Its neurons participate in motor coordination of upper extremities
The substantia nigra contains what neurotransmitter? Which pathology is associated with it?
Contains dopaminergic neurons.
Parkinson disease, these neurons are depleted of dopamine
What is opisthotonos and what is it associated with?
Contractions of back muscles resulting in backward arching due to clostridium tetani infection
Vibrio cholera stimulates what release from where that causes the extreme fluid secretion seen in cholera?
Serotonin release from enterochromaffin cells in GI tract is stimulated by Vibrio cholera enterotoxin. INC serotonin release contributes to extreme fluid secretion.
What are organophosphates? How do they work? What are the symptoms associated with organophosphate poisoning?
Organophosphates are cholinesterase inhibitors. They inhibit breakdown of acetylcholine, leading to cholinergic excess.
Symptoms of organophosphate poisoning include salivation, lacrimation, diaphoresis, bradycardia, and bronchospasm
(refer to picmonic)
How do you treat organophosphate poisoning?
Treat using muscarinic antagonists (atropine) and pralidoxime (PAM), a drug that reactivates acetylcholinesterase by binding organophosphates and decoupling them from the enzyme
How does ataxia telangiectasia present clinically?
Autosomal recessive resulting from defect in DNA-repair genes. The DNA of patients is hypersensitive to ionizing radiation. Manifests as cerebellar ataxia, oculocutaneous telangiectasias, repeated sinpulmonary infections, and an INC incidence of malignancy.
What are some inherited disorders caused by deficient DNA-repair enzymes? (5)
1) Ataxia telangiectasia-characterized by DNA hypersensitivity to ionizing radiation
2) Xeroderma pigmentosum, DNA hypersensitive to UV radiation, causing premature skin aging and INC risk of skin cancer (malignant melanoma and squamous cell carcinoma)
3) Fanconi anemia - caused by hypsersensitivity of DNA to cross-linking agents
4) Bloom syndrome - characterized by generalized chromosomal instability. INC susceptibility to neoplasms too.
5) Hereditary nonpolyposis colorectal cancer (HPNCC) occurs due to defect in DNA mismatch-repair enzymes. Leads to INC susceptibility to colon cancer
Alzheimer disease
Neurofibrillary tangles in neocortex
Parkinson disease
Loss of neurons in substantia nigra
Huntington disease
Atrophy of caudate nucleus
Vit. B12 deficiency and syphillis
Posterior column involvement
Parkinsonism
Presence of Lewy bodies is characteristic
Alteration of gene expression in Huntington disease occurs how?
Hypo-acetylated histones bind tightly to DNA and prevent transcription of genes in their associated regions. Alteration of gene expression in Huntington disease occurs in part due to deactylation of histones. This prevents transcription of certain genes that code for neurotrophic factors, contributing to neuronal cell death.
Acetylating histones normally does what?
Weakens the DNA-histone bond and makes DNA segments more accessible for transcription factors and RNA polymerases, enhancing gene transcription.
-In Huntington, abnormal huntingtin gene causes INC histone DEactylation, silencing the genes necessaey for neuronal survival.
Which step of neurotransmission is affected when voltage gated calcium channels are selectively inhibited?
Fusion and release of neurotransmitter vesicles
Voltage gated sodium channels are important for generation and propagation of action potentials. When action potential reaches axon terminal, voltage gated calcium channels open and allow influx of calcium, which is essential for fusion and release of neurotransmitter vesicles into the synaptic cleft.
What hypnotic agent is known to have anxiolytic, muscle relaxant, and anticonvulsant actions? Explain its MOA
Benzodiazepines INC frequency of opening of the CNS GABAa receptor-chloride channels and have anxiolytic, anticonvulsant, and muscle relaxant effects as well as sedative hypnotic effects.
Pain that WORSENS on inspiration is referred to what? What is indicative of?
Inflammation of the pleura
Referred as pleuritic chest pain
What are Kulchitsky cells?
Enterochromaffin cells/neuroendocrine cells found throughout conducting zone of tracheobronchial tree. These cells secrete peptide hormones that regulate airway and vascular tone.
Cells of origin for small cell carcinoma of the lung.
What are clara cells?
Nonciliated, dome-shaped cells found within airways of conducting zone and respiratory bronchioles. These cells secrete a surfactant like material which coat luminal surface of bronchioles to prevent luminal adhesion so that should they collapse (as they often do), these bronchioles are able to reexpand.
What comprises the conducting zone of the lungs?
Conducts air from outside into alveolar-respiratory zone, where gas exchange occurs. NO ACTUAL GAS EXCHANGE OCCURS in conducting zone, thus, it comprises the anatomic DEAD SPACE.
Consists of nose, pharynx, trachea, bronchi, and terminal bronchioles.
Compised of first 16 generations (branches) of respiratory tree. As generation number INC (and airway DEC in size), there is a DEC in amount of mucus-secreting cells, cilia, submucosal glands, and cartilage in airway walls
What comprises the respiratory zone of the lungs?
This zone participates in gas exchange. Begins at generation 17 with the respiratory bronchioles and alveolar ducts, terminating blindly as alveolar sacs or acini.
The alveolus is fundamental unit of gas exchange and as generation number INC, an INC number of alveoli are present, culminating in alveolar sacs, which consist solely of alveoli
Tidal volume (TV)
amount of air drawn into lungs during normal respiration
normally about 500mL
Inspiratory reserve volume (IRV)
Volume of air that can be inhaled during a max inspiration beyond the tidal volume
Expiratory reserve volume (ERV)
Volume of air that can be exhaled in a forced expiration beyond the tidal volume
Normally 1,200mL
Residual volume (RV)
Amount of air that remains in lungs at end of max respiration. Cannot be measured by spirometry.
Total lung capacity (TLC)
TLC = RV + ERV + TV + IRV
Combination of all lung volumes
Vital capacity (VC)
Volume that can be exhaled after max inspiration. Includes everything but RV. VC INC with male gender, physical conditioning, and body size, and DEC with age.
VC = ERV + TV + IRV
Functional residual capacity (FRC)
Volume remaining in lungs after normal expiration. It is the resting or equilibrium volume of the lungs. B/c it includes RV, cannot be calculated with normal spirometry.
FRC = ERV + RV
Inspiratory capacity (IC)
Max volume that can be inspired after a normal expiration
IC = IRV + TV
Explain FEV1/FVC ratio and implications
Forced expiratory volume in 1 sec (FEV1): volume of air that can be forcibly expired in one 1 sec after a full inspiration
Forced vital capacity (FVC): volume of air that can be forcibly expired after a full inspiration
FEV1/FVC ratio: is normally about 0.8, means that 80% of VC can be forcibly expired in the 1st second. Obstructive lung disease produces a reduced ratio (0.8).
S1 heart sound
Closure of tricuspid and mitral valves. Marks end of diastole because filling of the ventricles is complete.
S2 Heart sound
Closure of pulmonic and aortic valves, referred to as P2 and A2 respectively. Marks end of systole b/c ejection of blood from the ventricle has been completed.
During inspiration, intrathoracic pressure becomes more negative, “sucking” more blood back into the right atrium from the vena cava, INC venous return. This INC right ventricular preload, leading to larger right ventricular stroke volume, prolonging duration in which pulmonic valve is open (needs more time to eject all that extra blood). This moves P2 after A2 and causes the S2 sound to be split (physiologic splitting - normal).
On expiration, this does not occur and P2 and A2 occur at same time, causing S2 sound to not be split.
Fixed splitting (heart)
When splitting occurs on both inspiration and expiration. Occurs with an atrial septal defect (ASD) b/c there there is a hole between the two atria.
B/c there is a left to right shunt present (b/c left atrial pressures are higher than right atrial pressures), the right ventricle always has INC preload, and the pulmonic valve will always close AFTER the aortic valve.
