Uworld15 Flashcards
What is deficient in classic galactosemia?
galactose-1-phosphate uridyl transferase deficiency
What is deficient in essential fructosuria?
fructokinase deficiency.
Essential fructosuria is a benign disorder. Although affected patients are asymptomatic, their urine will test positive for a reducing sugar due to the presence of unmetabolized fructose
Deficiency of Vitamin B12 presentation
Vitamin B12 is obtained through the diet solely from animal sources, which places strict vegans at risk for dietary deficiency.
This deficiency takes years to develop due to the large hepatic vitamin B12 reserve, and presents with megaloblastic anemia and potentially irreversible neurologic deficits (eg, paraesthesia, weakness, and ataxic gait)
Mild cognitive impairment vs dementia diagnosis
Mild cognitive impairment is diagnosed when cognitive decline is present but activities of daily living (bathing, preparing meals, managing finances) are preserved.
In contrast, dementia is diagnosed when cognitive decline interferes with activities of daily living.
In patients with recurrent calcium nephrolithiasis, what meds can help prevent stone formation?
Thiazide diuretics effectively increase renal calcium reabsorption; decreasing urine Ca2+ excretion
What is an acoustic neuromas?
Schwanna cell derived tumors that typically arise from the vestibular portion of the vestibulocochlear nerve and are commonly located at the cerebellopontine angle (between the cerebellum and lateral pons).
Patients usually present with unilateral sensorineural hearing loss and tinnitus
What is pityriasis versicolor (tinea versicolor)?
a superficial skin infection caused by Malassezia species.
It causes erythematous, hyper or hypopigmented macules and patches.
Malassezia forms spores and hyphae, producing the characteristic “spaghetti and meatballs” appearance on KOH preparation light microscopy.
How does pregnancy affect respiratory drive?
The normal physiology of pregnancy involves chronic hyperventilation caused by elevated progesterone levels stimulating an increase in central respiratory drive,
This creates an expected respiratory alkalosis with metabolic compensation (increased renal bicarbonate excretion) that helps facilitate the transport of acidic wastes from, and the transport of oxygen to, the developing fetus
MOA of bevacizumab?
a monoclonal antibody that inhibits the binding of vascular endothelial growth factor (VEGF) to its receptor.
This inhibits angiogenesis and limits blood supply to tumors (ie, cancer starving therapy). However, it also impairs wound healing and can lead to wound dehiscence.
What is alternative splicing?
a process where the exons of a gene are reconnected in multiple ways during post-transcriptional processing.
This creates different mRNA sequences and subsequently, different protein isoforms.
It is a normal phenomenon in eukaryotes that greatly increases the biodiversity of proteins encoded by the genome.
What explains the rapid onset of action and short duration of action for propofol?
Propofol and other highly lipophilic drugs readily diffuse across membranes, quickly accumulating in tissues receiving high blood flow; this accounts for their rapid onset of action. These compounds are subsequently redistributed to organs receiving less blood flow, which explains their short duration of action.
Function of glutamate
Glutamate is the main excitatory neurotransmitter of the CNS, inducing postsynaptic neuron depolarization and calcium entry through the NMDA receptor,
Calcium entry programs the neuron to depolarize more robustly to repeated stimulation; this long term potentiation forms a molecular basis for memory, learning, and addiction.
Why are patients with cleft palate are at increased risk of chronic or recurrent acute otitis media?
Partly because of dysfunction of the muscles (eg, levator veli palatini) that contract against the soft palate to open the eustachian tube
What can provide on-site microbiologic confirmation for Group A strep?
Group A Strep (GAS) should be suspected in those with acute-onset sore throat, exudative tonsillopharyngitis, and no evidence of viral symptoms (eg, coryza, cough, conjunctivitis)
In office throat swab with rapid antigen detection testing (immunoassay for GAS antigens) can provide on site microbiologic confirmation, allowing for early initiation of treatment
What is polymyositis?
Polymyositis causes symmetric proximal muscle weakness.
Muscle biopsy reveals inflammation, necrosis, and regeneration of muscle fibers.
Over expression of major histocompatibility complex class I proteins on the sarcolemma leads to infiltration with CD8 T lymphocytes and myocyte damage
What class of drugs is associated with body fat redistribution?
Highly-active antiretroviral therapy (HAART) for HIV is commonly associated with body fat redistribution. Subcutaneous lipoatrophy involving the face and extremities is associated with nucleoside reverse transcriptase inhibitors (especially stavudine and zidovudine) and protease inhibitors. Central fat accumulation in the trunk and viscera can occur with any HAART regimen.
Cleft lip occurs due to?
failed fusion of the left or right maxillary prominence with the intermaxillary segment in early gestation.
Cleft palate occurs primarily when the palatine shelves fail to fuse. Cleft lip and palate can occur together or in isolation
How does neuropathy of the ilioinguinal nerve presents?
Presents with pain and allodynia in the anterior scrotum (labia majora in women), base of the penis (mons pubis), and medial thigh.
What can be used during stress testing to provoke areas of ischemic myocardium?
Stable angina results from fixed coronary artery stenosis that limits blood flow to downstream myocardium, preventing the myocardial oxygen supply from increasing during exertion.
Dobutamine mimics the effects of exercise and increases myocardial oxygen demand; it can be used during stress testing to provoke areas of ischemic myocardium, which can be recognized on imaging by a localized and transient decrease in contractility (ie, wall motion defect)
What is acute allergic contact dermatitis?
ACD, caused by a type IV (delayed) HSR to an antigen on the skin surface, typically presents with pruritic, erythematous, papulovesicular, weeping lesions.
Microscopically, acute ACD is characterized by spongiosis (ie, accumulation of fluid between keratinocytes in the epidermis)
What is intrapleural pressure at resting equilibrium?
The lungs generate a collapsing force and the chest wall generates an expanding force; the point at which these opposing forces are equivalent is the resting equilibrium of the respiratory system where alveolar pressure is equal to atmospheric pressure (ie, 0 cm H2O) and lung volume is the functional residual capacity.
The opposing forces create negative intrapleural pressure throughout the respiratory cycle; intrapleural pressure at resting equilibrium (ie, end-tidal expiration) is approximately -5 cm H2O.
What is lichen planus? Histopath?
Lichen planus presents with pruritic, purple/pink, polygonal papules and plaques that can affect the flexural surfaces of the wrists and ankles, along with the nails, oral mucous membranes, and genitalia.
histopath: hyperkeratosis (thickened stratum corner), bandlike lymphocytic infiltrate at the dermoepidermal junction, hypergranulosis (thickened granular layer), sawtooth rete ridges, and scattered eosinophilic colloid bodies
What is reactive arthritis?
Classic triad of reactive arthritis is nongonococcal urethritis, conjunctivitis, and arthritis.
It is an HLA-B27 associated arthropathy that occurs within several weeks following a genitourinary or enteric infection.
It belongs to the group of seronegative spondyloarthropathies (including ankylosing spondylitis) and can cause sacroiliitis in about 20% of cases.
Pauci-immune rapidly progressive glomerulonephritis frequently occurs as a manifestation of?
antineutrophil cytoplasmic antibodies (ANCA) associated vasculitides (eg, granulomatosis with polyangiitis, microscopic polyangiitis)
It is characterized by glomerular crescent formation without immunoglobulin or complement deposits.
What is the principal muscle of inspiration?
The diaphragm; innervated by the phrenic nerve (C3-5).
Although expiration is largely achieved through passive recoil, active expiration is aided by the internal intercostals (innervated by thoracic nerve rootlets) and abdominal muscles (innervated by thoracic and lumbar nerve roots)
Staphylococcal foodborne illness is due to?
the consumption of a preformed enterotoxin in contaminated food.
Most cases can be prevented by washing hands thoroughly prior to food preparation (prevents contamination) and ensuring proper refrigerated storage (prevents bacterial proliferation/enterotoxin production)
Chronic lymphocytic leukemia is a/w overexpression of?
BCL-2, an anti-apoptotic protein, on the mitochondrial membrane.
Treatment with a BCL inhibitors causes cancer cell death by promoting cytochrome c release from the mitochondria, which subsequently activates caspases.
What type of HSR is myasthenia gravis?
Myasthenia gravis results from an autoimmune type II (antibody mediated) HSR against skeletal myocyte surface acetylcholine receptors.
Goodpasture syndrome similarly involves autoantibodies against basement membrane collagen in the renal glomeruli and lung alveoli
What is dermatomyositis?
characterized by proximal muscle weakness (similar to polymyositis) and dermal manifestations (eg, heliotrope rash, Gottron papules).
Lab testing shows elevated muscle enzymes (eg, creatine kinase) and autoantibodies (eg, antinuclear, anti-Jo-1)
Initial treatment includes systemic glucocorticoids and evaluation for potential underlying malignancy
MOA of sulfonylureas (glyburide, glipizide)
Sulfonylureas inhibit the ATP-sensitive potassium channel on the pancreatic beta cell membrane, inducing depolarization and L-type calcium channel opening.
The increased Ca2+ influx stimulates beta cell insulin release independent of blood glucose concentrations, increasing the risk of hypoglycemia when meals are missed or during exercise
What is telomerase?
Critical shortening in telomere length can signal for programmed cell death.
Telomerase is a reverse transcriptase (RNA dependent DNA polymerase) that lengthens telomeres by adding TTAGGG repeats to the 3’ end of chromosomes.
Stem cells have long telomeres due to high telomerase activity, allowing them to proliferate indefinitely in a controlled manner.
Major histocompatobility complex (MHC) class II molecules are encoded by?
HLA-DP, HLA-DQ, and HLA-DR genes and present extracellular antigens processed in acidified lysosomes by antigen-presenting cells (eg, B cells, macrophages)
Absence of MHC class II expression impairs activation of B and T cells, resulting in a form of severe combined immunodeficiency
In patients with essential fructosuria, some of the dietary fructose load is converted by?
Essential fructosuria is a benign disorder of fructose metabolism caused by fructokinase deficiency.
In patients with essential fructosuria, some of the dietary fructose load is converted by hexokinase to fructose-6-phosphate, which can then enter glycolysis; this pathway is not significant in normal individuals
Indication of alveolar hemosiderin-laden macrophages
indicates alveolar hemorrhage.
They most commonly result from chronic elevation of pulmonary capillary hydrostatic pressure in the setting of left-sided heart failure.
What is an ependymomas?
Ependymomas orginate from the ependymal cells that line the ventricular system and the central canal of the spinal cord.
Ventricular ependymomas can block the flow of cerebrospinal fluid through the interventricular foramina, causing signs of increased intracranial pressure (eg, headache, papilledema) due to obstructive (noncommunicating) hydrocephalus
What is the relation of prevalence on positive predictive and negative predictive values?
As disease prevalence increases, the positive predictive values increases, and the negative predictive value decreases.
Traits of hep D virus
replication-defective RNA virus that is capable of causing infection only in the setting of coinfection with hep B. HBV provides hep B surface antigen for the HDV envelope
What is the primary virulence factor of strep pneumo?
polysaccharide capsule that inhibits opsonization and phagocytosis. The polysaccharide capsule of the most virulent strains is targeted by the pneumococcal vaccine, which confers immunity against those subtypes
Wilson disease is caused by?
defective copper transport within hepatocytes, which leads to impaired biliary excretion of copper. Hepatic copper accumulation eventually results in the release of free copper into the bloodstream and copper deposition into extrahepatic tissues (eg, basal ganglia, cornea)
What is Cori disease?
Glycogen debrancher deficiency.
Causes accumulation of glycogen with abnormally short outer chains (limit dextrin) due to the inability to degrade branch points.
Patients have hypoglycemia, ketoacidosis, hepatomegaly, muscle weakness and hypotonia
What is seen in opioid withdrawal?
Mydriasis (dilated pupils), abdominal pain, diarrhea, piloerection, lacrimation, and yawning.
It is generally nonlife threathening, unlike withdrawal from alcohol and benzodiazepines.
function of IL-4
IL-4 is produced by TH2 subset of T helper cells.
It facilitates proliferation of B cells and TH2 lymphocytes and stimulates antibody isotype switching to IgE which mediated type I HSR (allergic) reactions
MOA of azoles
Azoles inhibit the synthesis of ergosterol by the fungal cytochrome P450 enzymes. They also suppress the human P450 system, resulting in many drug-drug interactions
An obstructive lesion in a mainstem bronchus can prevent ventilation of an entire lung, leading to?
large-volume atelectasis and complete lung collapse.
CXR: unilateral opacification and deviation of the mediastinum toward the opacified lung
What is misclassification bias?
an incorrect categorization of subjects regarding their exposure, outcome status, or both.
In case-control studies, recall bias usually leads to misclassification of the exposure status.
Sleepwalking has what on EEG?
Sleepwalking, a common non-REM parasomnia of childhood, occurs during slow-wave stage (stage N3), which is characterized by delta waves on EEG.
Sleepwalking typically occurs during the first half of the night, when slow-wave sleep is most prominent
What is meralgia paresthetica?
caused by compression of the lateral femoral cutaneous nerve, typically due to tight clothing.
It presents with pain, paresthesia, and numbness in the lateral thigh without motor weakness.
Risk factors: obesity, pregnancy, and diabetes mellitus
What is antimullerian hormone?
produced by the testes and stimulates Mullerian duct involution so internal female structures (eg, fallopian tubes, uterus) do not develop.
The presence of these structures in a genotypic male suggest AMH def.
What occurs in asymptomatic left ventricular systolic dysfunction?
asymptomatic left ventricular systolic dysfunction is a common stage in the progression of heart failure.
Neurohormonal mechanisms, including the sympathetic nervous system and renin-angiotensin-aldosterone system, help maintain the asymptomatic period by increasing volume retention and peripheral resistance to maintain organ perfusion.
Although these mechanisms are beneficial in the short term, they are ultimately deleterious, increasing hemodynamic stress and cardiac remodeling that eventually lead to decompensated heart failure
What is stroke volume?
Stroke volume is the absolute volume of blood ejected from the LV with each contraction.
SV = LVEDV - LVESV
What is ejection fraction
the relative volume of blood ejected from the left ventricle with each contraction
EF= SV/ LVEDV
what is cardiac output?
the volume of blood ejected into the aorta per unit time
CO = SV x HR
The diagnosis of schizophrenia requires >2 of the following 5 symptoms:
delusions, hallucinations, disorganized speech, grossly disorganized behavior, and negative symptoms.
The total impairment duration must be >6 months
What is the treatment for wet age-related macular degeneration?
wet age-related macular degeneration is characterized by retinal neovascularization due to increased vascular endothelial growth factor (VEGF) levels.
Patients typically have acute vision loss and metamorphopsia with funduscopy showing a grayish-green subretinal membrane and/or subretinal hemorrhage.
Txt: smoking cessation and VEGF inhibitor therapy (eg, ranibizumab, bevacizumab)
What is the strongest single risk factor for further attempts and completed suicide?
History of a previous suicide attempt
Primary noctural enuresis (bed wetting at age >5 without prior nighttime urinary continence) is caused by?
a brain maturational delay in the development of bladder control
Where is the sinoatrial node located?
The sinoatrial node consists of specialized pacemaker cells located at the junction of the RA and the superior vena cava.
It is the site of earliest electrical activation in patients with sinus rhythm.
Mechanism of diphtheria toxin and pseudomonal exotoxin A?
act by ribosylating and inactivating elongation factor-2, inhibiting host cell protein synthesis and causing cell death
What is high altitude pulmonary edema?
presents with dyspnea and ough within several days of arrival at high altitude.
It is driven by reduced ambient oxygen, which leads to hypoxic pulmonary vasoconstriction and pulmonary arterial hypertension.
Individuals with unevenly distributed pulmonary vasoconstriction can develop areas of high capillary perfusion pressure that disrupts the alveolar-capillary membrane, leading to patchy bilateral pulmonary edema
What is Zollinger Ellison syndrome?
caused by gastrinomas located in the small intestine/pancreas and presents with peptic ulcers (especially distal duodenal ulcers), heartburn, and diarrhea.
Patients typically have elevated gastrin levels that rise in response to exogenous secretin adminstration.
In contrast, secretin inhibits release of gastrin from normal gastric G cells
What is highly characteristic of lupus nephritis?
Lupus nephritis from SLE can manifest as glomerulonephritis.
Immunofluorescence: full house with 3 immunoglobulin classes (IgG, IgM, IgA) and 2 complement components (C3, C1q) is highly characteristic.
Cancers of the pelvis, including the prostate, spread to the lumbosacral spine via?
the vertebral venous plexus, which in turn communicates with a number of venous networks, including the prostatic venous plexus.
the skeletal system is a common site of metastasis due to hematogenous seeding.
What medication can be used to aid the diagnosis of asthma?
Asthma is characterized by reversible airway obstruction, and lung function tests may be normal between exacerbations.
Bronchoprovocation can be used to aid diagnosis in patients with normal spirometry; methacholine is administered and followed by serial spirometry.
Patients with asthma demonstrate hyperresponsivity to the stimulus, leading to FEV1 reductions at lower doses than those without asthma
What is heard on auscultation for a ventricular septal defect?
Increased blood oxygen saturation between 2 right sided vessels or chambers indicates the presence of a left to right shunt.
If the abnormal oxygen increase occurs between the right atrium and the right ventricle, a ventricular septal defect is likely present.
Small VSDs produce a holosystolic murmur that is loudest over the lower left sternal border
MOA of aldosterone receptor antagonists (spironolactone, eplerenone).
Aldosterone acts on the principal and intercalated cells of the renal collecting tubules to increase resorption of sodium and water and increase excretion of potassium and hydrogen ions.
Aldosterone receptor antagonists inhibit these effects.
The primary cause of morbidity in acute rheumatic fever is?
heart failure from severe pancarditis.
Mitral stenosis develops years or decades after the original illness.
Joint involvement is usually transient
What is the attack rate?
ratio of the number of people who contract an illness divided by the number of people who are at risk of contracting that illness
In cardiac pacemaker cells, phase 0 depolarization is mediated by?
an inward flux of calcium.
This differs from phase 0 of cardiomyocytes and Purkinje cells, which results from an inward sodium current.
Femoral hernias can present with groin discomfort and a tender bulge on the upper thigh inferior to the inguinal ligament, lateral to the pubic tubercle and lacunar ligament. The structure that lies immediately lateral to the hernia within the femoral sheath is?
the femoral vein.
Incarceration and strangulation are common complications of femoral hernias.
Nasopharyngeal cancer is endemic in southern China due to genetic and dietary factors that promote nasopharyngeal epithelial pre-malignant lesions. In almost all cases, malignant transformation occurs due to?
infection of premalignant cells with Epstein Barr virus and the subsequent expression of oncogenic viral proteins.
MHC class II function
MHC class II is expressed on the surface of antigen presenting cells and presents to extracellular antigens to T cells after extracellular protein is degraded within acidified lysosomes.
Failure to acidify lysosomes would lead to deficient expression of MHC class II antigen complexes with subsequent impaired interaction between APCs and T cells
What is colonic diverticula?
Colonic diverticula form at weak points in the colon wall, typically in areas where the vasa recta penetrate through the smooth muscle.
As diverticula enlarge, the vasa recta are exposed and become vulnerable to chronic injury, which can lead to intraluminal hemorrhage and painless hematochezia
Which cells produce b-hCG?
b-hCG secretion begins with blastocyst implantation and syncytiotrophoblast invasion.
Syncytiotrophoblast cells arise from the outer layer of the blastocyst (trophectoderm) and produce b-hCG, which maintains corpus luteum progesterone production and supports the developing early pregnancy
What is chronic granulomatous disease?
results from defective NADPH oxidase.
Normally, this enzyme participates in the respiratory burst pathway to produce reactive oxygen species critical in intracellular pathogen killing.
Patients with CGD develop recurrent bacterial and fungal infections predominantly caused by 5 catalase-positive organism: staph aureus, burkholderia cepacia, serratia marcescens, nocardia, and aspergillus
What is tumor lysis syndrome?
Tumor lysis syndrome occurs when tumors with a high cell turnover are treated with chemotherapy.
The lysis of tumor cells causes intracellular ions, such as potassium and phosphorus, and uric acid (metabolite of tumor nucleic acid) to be released into serum.
Uric acid is soluble at physiologic pH, but it can precipitate in the normally acidic environment of distal tubules and collecting ducts.
The prevention of tumor lysis syndrome includes urine alkalinization and hydration, as high urine flow and high pH along the nephron prevents crystallization and precipitation of uric acid
What is andexanet alfa?
a factor Xa decoy that has no proteolytic effect. It is administered to patients on factor Xa inhibitors (eg, rivarixaban, apixaban) who have life threatening bleeding in order to reverse the anticoagulation effect
The optic nerve carries the afferent limb of the pupillary light reflex pathway, which activates?
the efferent limb bilaterally and causes both direct and consensual pupillary constriction.
Unilateral optic nerve lesions (eg, demyelination due to optic neuritis) can result in impaired pupillary constriction bilaterally when light enters the eye ipsilateral to the lesion.
When light enters the contralateral eye, pupillary constriction occurs normally in both eyes.
Estrogen containing contraceptive pills (combined estrogen/progestin oral contraceptive pills) are contraindicted in patients with?
migraine with aura due to the increased risk for ischemic stroke
What is alternative splicing?
a process by which a single gene can code for various unique proteins by selectively including or excluding different DNA coding regions (exons) into mature mRNA
Patients with advanced or castration resistant prostate cancer are often treated with?
an 17-alpha hydroxylase inhibitors (eg, abiraterone) which block the generation of androgens in the adrenal glands, testes, and tumor cells.
This reduces systemic androgen levels, which limit prostate cancer growth
How can myocardial infarction cause acute left ventricular failure and cardiogenic shock?
Decreased cardiac contractility leads to reduced cardiac output and hypotension.
In response, systemic vascular resistance is increased (via peripheral vasoconstriction) to maintain blood pressure.
The LV systolic failure increases LV end-diastolic pressure, which is transmitted backward to increase pulmonary capillary wedge pressure and pulmonary arterial pressure
What is the function of mRNA vaccines?
mRNA vaccines delivery mRNA molecules encoding foreign protein into the cytoplasm of host cells (particularly antigen presenting cells that avidly engulf the associated carrier compound). The mRNA is then translated by ribosomes and displayed on the cell surface, leading to a robust adaptive immune response.
Amatoxins inhibit what?
Amatoxins are found in a variety of poisonous mushrooms (eg, Amanita phalloides, known as death cap) and are potent inhibitors of RNA polymerase II (halting mRNA synthesis)
What are the changes that malignant cells undergo to metastasize from the site of origin?
They detach from other cells by down-regulating cadherins and detach from the basement membrane by altering integrin expression.
They secrete collagenases to create a path through the extracellular matrix and then enter the bloodstream and/or lymphatic system to disseminate.
What are the effects of glucocorticoids in reducing inflammation and limiting end organ damage in inflammatory diseases (eg, sarcoidosis)?
Decreased proinflammatory cytokine (IL-1, interferon-gamma_ production, increased anti-inflammatory cytokine (IL-10) production, and impaired migration of leukocytes (eg neutrophils) to sites of inflammation
What is minimal change disease?
the most common cause of nephrotic syndrome in children.
Systemic T-cell dysfunction leads to the production of glomerular permability factor, which causes podocytes foot process fusion and decreases the anionic properties of the glomerular basement membrane. The loss of negative charge leads to selective albuminuria
Nontyphoidal Salmonella is associated with?
Nontyphoidal Salmonella causes gastroenteritis that classically causes self-limited fever, vomitting and diarrhea.
Invasive disease can occur, including spread to the long bones (osteomyelitis), and risk is greatest in those with sickle cell disease, impaired immunity, or extremes of ages.
What is neurocysticerocosis?
Common in developing regions and usually presents years after infection with new onset seizure.
Physical examination, lab evaluation, and cerebrospinal fluid analysis are generally normal. However, brain imaging typically shows >1 cysts in various stages of viability
What is primary myelofibrosis?
a chronic myeloproliferative disorder associated with bone marrow fibrosis. Extramedullary hematopoiesis leads to marked expansion of the splenic red pulp with hematopoietic progenitor cells, resulting in massive splenomegaly.
Patients also usually have hepatomegaly, cytopenias, and peripheral smear abnormalities (eg, dacrocytes, nucleated red cells, immature granulocytes)
What is meta analysis?
A meta analysis groups results of several trials to increase statistical power and provide an overall pooled effect estimate
What is the clinical presentation of pertussis?
Pertussis should be considered in any adult who has not had updated vaccination boosters.
The clinical presentation is a paroxysmal cough lasting >2weeks that is associated with post-tussive emesis or inspiratory whoop after a severe coughing episode
What is vestibular schwannomas?
Arise from the vestibulocochlear nerve (CNVIII) and are usually located at the cerebellopontine angle.
These tumors can cause a range of symptoms by damaging the vestibulocochlear nerve (unsteadiness and ipsilateral sensorineural facial paresis).
Bilateral acoustic neuromas are associated with?
neurofibromatosis type 2
Obturator nerve injury presents with?
The obturator nerve is the only major nerve that exits the pelvis through the obturator foramen.
Nerve injury typically results from compression (eg, due to pelvic trauma, surgery, or tumor) and presents with weakness on thigh adduction and sensory loss over the distal medial thigh.
If HBeAg persists for several months and host anti-HBeAg remain at low or undetectable levels, suspect what?
chronic hepatitis B infection with high infectivity
What does decreased cardiac output in heart failure trigger?
triggers neuroendocrine compensatory mechanisms to maintain organ perfusion; however, the compensatory mechanisms are maladaptive over the long term.
Increased sympathetic output and activation of the renin-angiotensin-aldosterone system stimulate vasoconstriction and volume retention, compounding the hemodynamic stress on an already failing heart and creating a vicious cycle of decompensation.
What is hemoglobin F?
the predominant hemoglobin type in the second and third trimesters of pregnancy and during the first few months after birth.
HbF consists of 2 alpha and 2 gamma protein subunits (a2y2) and has a high affinity for oxygen, which facilitates oxygen transport across the placenta to the fetus.
HbA (a2b2) is the major hemoglobin in adults
What happens to the lung during normal aging?
gradual increase in ventilation-perfusion mismatch (due to basilar microatelctasis causing shunt effect) and increased dead space (loss of alveolar surface area). This manifests as a wider alveolar-arterial oxygen gradient (ie, decline in PaO2) without hypoventilation (normal PaCO2)
What is Wilson disease?
Wilson disease is associated with copper accumulation in the liver, brain, and cornea.
It can present in childhood or adolescence with abnormal liver function tests and/or neuropsychiatric symtoms.
Psychiatric symtpms may predate other manifestations and include personality changes, depression, mania, and/or psychosis
