Firecracker practice test Flashcards
Tay Sachs inheritance and what enzyme is deficient and what accumulates
Autosomal Recessive
-hexosaminidase A. This leads to the accumulation of GM2 gangliosides
Henoch-Schönlein purpura (HSP)
small-vessel vasculitis that is characterized by immunoglobulin A (IgA), C3, and immune complex deposition in arterioles, capillaries, and venules
- most common systemic vasculitis in children.
- triad of palpable purpura on the buttocks and legs, arthralgias, and abdominal pain
- About half of cases follow an upper respiratory infection
ASA overdose presentation and treatment
agitation, confusion, vomiting, and vertigo. Other symptoms include gastrointestinal distress and tinnitus Aspirin stimulates the respiratory center and initially causes a drop in the pCO2 and a subsequent respiratory alkalosis. This is followed by an anion-gap metabolic acidosis Tx: Sodium Bicarb (alkalizes the serum and urine), and potentially dialysis if severe
Growth media used to confirm Cholera infection
grows flat yellow colonies on thiosulfate citrate bile salts sucrose (TCBS) agar (V. cholerae is an oxidase-positive, motile organism)
Chorda Tympani
Branch of facial nerve responsible for taste of anterior 2/3 of tongue
Uniparental disomy
inheritance of both chromosomes of a homologous pair from a single parent.
-UPD causes about 25% of Prader-Willi cases. UPD usually arises when a trisomic cell line early in embryogenesis converts to a disomic cell line (trisomic rescue). In the case of Prader-Willi syndrome, if the disomic pair is maternally inherited, they will both be imprinted and no functional paternal copies will be inherited, thus causing Prader-Willi syndrome.
the best test for iron deficiency anemia (best sensitivity and specificity)
serum ferritin, NOT serum iron levels
Treatment of giant cell arteritis (temporal arteritis)
Prednisone (promptly!), or any high dose corticosteroids
most common form of SCID is caused by a mutation in
interleukin 2 receptor subunit gamma (IL2RG) gene on the X chromosome. This gene encodes a common subunit for the following cytokine receptors: IL-2, IL-4, IL-7, IL-9, IL-11, IL-15, and IL-21. Lack of signaling through multiple cytokine receptors impairs lymphocyte development, maturation, and function. IL-2, in particular, is essential for the proliferation and differentiation of T cells
With emphysema, lung compliance is?
Lung compliance is increased, not decreased, in emphysema.
The pathological hallmark of emphysema is destruction of alveolar walls due to increased elastase activity. Because of this, elastic recoil fibers are lost and lung compliance increases. This results in enlarged airspaces and a barrel shaped chest
Adverse effects of loop diuretics (Furosemide, bumetanide, torsemide)
OHHH DANG):
· Ototoxicity
· Hypokalemia
· Hypocalcemia
· Hypomagnesemia
· Dehydration
· Allergy (sulfa)
· Nephritis
· Gout
approximately 50% of people with giant-cell arteritis also have____
polymyalgia rheumatica (a rheumatologic disorder that causes pain and stiffness of the large muscle groups, most frequently the shoulders and hips. Patients typically present with weakness and soreness in the morning and after rest, along with overall fatigue)
Renal blood flow (starting at renal artery, ending at R atrium)
Renal artery → segmental artery → interlobar artery → arcuate artery → interlobular artery → afferent arteriole → glomerular capillaries → efferent arteriole → peritubular capillaries → interlobular vein → arcuate vein → interlobar vein → renal vein → IVC (inferior vena cava) → right atrium
first line treatment for Torsades De Pointes
Magnesium sulfate (used for treatment of Long QT syndrome, which predisposes to an increased risk of sudden cardiac death that is secondary to torsades de pointes)
Treatment of Bipolar 1 Disorder (ideas of grandeur, irritable and intense mood), and what needs to be checked prior to administering med?
- Lithium: most commonly causes HYPOthyroidism so thyroid studies are recommended before treatment is begun. Also causes Nephrogenic DI, resulting in a hyperosmotic volume contraction
- Valproic Acid
- Carbamezapime
What do Bacillus Cereus, Escherichia coli (ETEC) and Vibrio cholerae all have in common?
The enterotoxin works through ADP ribosylation that activates Gs and increases cAMP, leading to watery diarrhea from secretion of sodium cations, chloride anions, and water
Bacilus Cereus: reheated rice, cause food poisoning (an aerobic spore-forming Gram-positive bacillus. Bacillus cereus can contaminate uncooked food)
Cranial bleed that extends across multiple suture lines
Subdural hematoma: tearing of the cerebral bridging veins due to tensile or shear forces. On CT scan, these lesions are readily identified as large, crescent shaped collections surrounding the brain
Baby is born with protrusion of abdominal contensts outside of abdominal wall is called….(with no overlying sac)
gastroschisis (congenital malformation characterized by a defect in the anterior abdominal wall, allowing abdominal viscera to protrude freely with no overlying sac. One cause of gastroschisis is abnormal involution of the right umbilical vein, resulting in ischemia and weakness of abdominal wall on the right side of the umbilicus)
H. influenzae
gram-negative pleomorphic coccobacilli. The organism is fastidious and grows on chocolate agar supplemented with factors V (NAD) and X (hematin)
- the most common cause of mucosal infections (otitis media, conjunctivitis, bronchitis)
- The initial stage in the development of bacterial meningitis in infants and young children is frequently a URI, then invades the bloodstream, where its capsule allows it to evade phagocytosis. The organism is able to cross the blood-brain barrier and infect the meninges.
- HaEMOPhilus causes Epiglottitis (“cherry red” in children), Meningitis, Otitis media, and Pneumonia.
Ewing’s sarcoma
Anaplastic small blue cell malignant tumor D . Extremely aggressive with early metastases, but responsive to chemotherapy.
- commonly affects the pelvis and metaphysis of long tubular bones
- It is classically associated with an “onion-skin” appearance on radiographic imaging, which represents reactive periosteum
- Associated with t(11;22) translocation causing fusion protein EWS-FLI 1. 11 + 22 = 33 (Patrick Ewing’s jersey number)
Ewing Sarcoma vs Osteosarcoma
Osteosarcoma: 2nd most common 1° malignant bone tumor (after multiple myeloma). Bimodal distribution: 10–20 years old (1°), > 65 (2°). Predisposing factors: Paget disease of bone, bone infarcts, radiation, familial retinoblastoma, Li-Fraumeni syndrome (germline p53 mutation). Metaphysis of long bones, often around knee
Ewing Sarcoma: Boys < 15 years old. Commonly appears in diaphysis of long bones, pelvis, scapula, ribs. Anaplastic small blue cell malignant tumor D . Extremely aggressive with early metastases, but responsive to chemotherapy. “Onion skin” periosteal reaction in bone. Associated with t(11;22)
idiopathic pulmonary fibrosis (IPF)
Dypsnea on exertion, Bilateral crackles in base of the lungs, clubbing of the fingertips and honeycombing of the lungs in addition to reticular opacities on CT scan
- IPF occurs when an environmental insult (smoking in some cases) causes repeated cycles of alveolar epithelial damage that leads to pathologic repair in genetically predisposed individuals
- decreased vital capacity on spirometry, decreased residual volume and total lung capacity could be expected
internuclear ophthalmoplegia
caused by a lesion involving the medial longitudinal fasciculus (MLF), often a demyelinating lesion in the context of multiple sclerosis. As a result, the motor nuclei of the abducens nerves (cranial nerve VI) are unable to communicate with the motor nuclei of the oculomotor nerves (cranial nerve III)
Monday disease
industrial exposure: development of tolerance for the vasodilating action during the work week and loss of tolerance over the weekend tachycardia, dizziness, headache upon reexposure.
sx are very similar to nitroglycerin toxicity
Cystic Fibrosis inheritance and likelihood of passing on to child
Autosomal Resessive (remember, if a family member has affected siblings, the chances of this individual being a carrier is 2/3. This number needs to be multiplied by the prevelence of CF (say 1/25 as well as 1/4 if both husband and wife are carriers). In total the chance of having a kid is:
2/3 x 1/25 x 1/4 = 1/150
Dermatomyositis (triad, lab findings)
- symmetric proximal muscle weakness, (the distinctive feature of this disease)
- heliotrope rash, (which is reddish-purple in color with a mask-like distribution involving the cheeks, nasal bridge, and eyelids)
- Gottron’s papules (which are flat-topped, erythematous, hyperkeratotic papules usually overlying the metacarpophalangeal or interphalangeal joints)
- Elevated creatine phosphokinase, aldolase, alanine aminotransferase, aspartate aminotransferase, and lactic acid dehydrogenase reflect the presence of muscle inflammation
angiofibroma
a benign vascular tumor and is typically found in adolescent males. Presenting symptoms include recurrent nosebleeds and unilateral nasal obstruction. Although benign, these tumors are aggressive and may erode into adjacent structures such as the cranial cavity and cause diplopia
-may also obstruct the eustachian tube, causing conductive hearing loss
specificity
specificity is defined as the proportion of subjects with a negative test result who truly do not have the disease (TN), over the total number of subjects who truly do not have the disease (TN+FP)
Principal cells in the kidney respond to?
BOTH aldosterone (Na reabsorption, K excretion) and ADH (aquaporin insertion)
Ménière’s disease
caused by a paroxysmal accumulation of endolymph fluid
Treated with diuretics
Ménétrier disease
rare, acquired, premalignant disease of the stomach characterized by massive gastric folds, excessive mucous production with resultant protein loss, and little or no acid production
Neutrophil demargination
seen when treating with prednisone, a glucocorticoid. Demargination is the release of neutrophils from the pulmonary vasculature endothelium, where they are usually attached. In this process, neutrophils, found along the vessel walls, move into circulation, raising the apparent white blood cell count
How do you intensify the murmur of HOCM and why?
Valsalva or standing up: decrease preload This occurs because reduced ventricle size further narrows the LVOT and enhances the ability of the mitral valve to obstruct the LVOT
Alkaptonuria (ochronosis)
Congenital deficiency of homogentisate oxidase in the degradative pathway of tyrosine to fumarate pigment-forming homogentisic acid accumulates in tissue. Autosomal recessive. Usually benign.
*CANNOT BREAK DOWN TYROSINE FULLY AND HOMOGENISTATE OXIDASE BUILDS UP*
Findings: dark connective tissue, brown pigmented sclerae, urine turns black on prolonged exposure to air. May have debilitating arthralgias (homogentisic acid toxic to cartilage).
Excess tyrosine worsens this condition
Von Gierke disease
Type 1 glycogen storage disease. Deficient Glucose-6-phosphatase, Autosomal resessive
Findings: Severe fasting hypoglycemia, glycogen in liver, blood lactate, triglycerides, uric acid, and hepatomegaly
Treatment: frequent oral glucose/cornstarch; avoidance of fructose and galactose
Mitral Stenosis (murmur and future risk)
Follows opening snap (due to abrupt halt in leaflet motion in diastole, after rapid opening due to fusion at leaflet tips). Delayed rumbling late diastolic murmur (interval between S2 and OS correlates with severity). LA >> LV pressure during diastole. Often occurs 2° to rheumatic fever. Chronic MS can result in LA dilatation.
-patients with mitral stenosis are at risk for thromboembolic disease due to stasis of blood in the left atrium. Clots can be disseminated throughout the systemic circulation, although stroke is of obvious concern. An embolic stroke may cause unilateral limb paresis
Dead space in lung
the area that is not participating in gas exchange
-When there is ventilation of the alveoli but inadequate perfusion of the lungs relative to the ventilation, the V/Q ratio increases and a functional (alveolar) dead space is created.
Otosclerosis
autosomal dominant disorder in which the ossicles of the middle ear become fused. This is the most common cause of conduction hearing loss in the elderly
Presbycusis
age related loss of inner hair cells at the base of the basilar membrane. It is characterized by a progressive loss in high frequency hearing and is the most common cause of sensorineural hearing loss in the elder
Damage to the neck of the humerus most likely results in damage to what artery and what nerve ?
artery: posterior circumflex humeral artery
nerve: axillary nerve (deltoid and teres minor) resulting in inability to abduct the shoulder, deltoid atrophy, and numbness over the lateral shoulder
Thiazide diuretics (names, location, mechaism, and side effects)
Chlorthalidone, hydrochlorothiazide
Thiazide diuretics act to inhibit the sodium-chloride channels of the distal convoluted tubule of the nephron. They are first line for essential HTN HF, idiopathic hypercalciuria, nephrogenic diabetes insipidus, osteoporosis
Side effects :
Decreased serum levels of:
- K+ (hypokalemia)
- Na+ (hyponatremia)
- H+ (metabolic alkalosis)
Increased serum levels of (mnemonic: GLUC):
- Glucose (hyperglycemia)
- Lipids (hyperlipidemia)
- Uric Acid (hyperuricemia may precipitate gout)
- Ca2+ (hypercalcemia)
-Also, sulfa allergy
Autoimmune Hemolytic Anemia
Extrinsic, Hemolytic, Normocytic anemia where antibodies attack red blood cells. 2 versions: cold or warm
Cold: (IgM)—acute anemia triggered by cold; seen in CLL, Mycoplasma pneumonia infections, and infectious Mononucleosis (“cold weather is MMMiserable”)
Warm: (IgG)—chronic anemia seen in SLE and CLL and with certain drugs (e.g., α-methyldopa) (“warm weather is Great”)
usually Coombs +
Sx: fatigue following a viral illness, livedo reticularis (lacy, purple rash involving the lower extremities) and acrocyanosis (dark, purple to gray skin discoloration seen on the most distal parts of the body)
Brown-Sequard Syndrome
Hemisection of the spinal cord
- ipsilateral signs of upper motor neuron damage (hyperreflexia, positive Babinski sign) due to the severing of the lateral corticospinal tract
- ipsilateral loss of proprioception, fine touch, and vibration sensation due to damage of the dorsal columns
- Contralaterally, patients experience a loss of pain and temperature sensation below the lesion due to spinothalamic tract trauma
The relationship between lead levels and vitamin C intake?
Increasing vitamin C, will increase absorption of Iron, which will decrease absorption of lead from GI tract.
Direct vs indirect hernias
Direct: medial to epigastric artery. More common in older men as abd wall weakens with age. Goes through the external (super cial) inguinal ring only. Covered by external spermatic fascia
Indirect: Goes through the internal (deep) inguinal ring, external (super cial) inguinal ring, and into the scrotum. Enters internal inguinal ring lateral to inferior epigastric artery. Occurs in infants owing to failure of processus vaginalis to close (can form hydrocele). Covered by all 3 layers of spermatic fascia
- *MDs don’t LIe:**
- *M**edial to inferior epigastric artery = Direct hernia.
- *L**ateral to inferior epigastric artery = Indirect hernia.
Lenticulostriate artery stroke (lacunar stroke)
the internal capsule carries descending corticospinal and corticobulbar tracts as well as ascending somatosensory information. The absence of any cortical signs, such as aphasia, spatial neglect, or motor apraxia, suggests a small lacunar stroke affecting a deep subcortical structure rather than a full vascular territory infarct (such as a middle cerebral artery infarct)
-often due to unmanaged HTN. sx are Contralateral hemiparesis/ hemiplegia.
calculating odds ratio
OR = (exposed cases/unexposed cases)/(exposed non-cases/unexposed non-cases).
The numerator of an odds ratio consists of the odds that the exposure occurred among patients with the condition. These odds are defined as the probability that the exposure occurred among patients with the condition divided by the probability that the exposure did not occur among patients with the condition:
Cushing reflex to head injury
the physiologic response to increased intracranial pressure, which leads to insufficient blood flow to the brain due to compression of the cerebral vasculature. There are three main components of this reflex:
1. bradycardia
2. hypertension
3. hypoventilation
all in an attempt to maintain cerebral perfusion
How to calculate GFR
GFR≈CCR=(PCr/UCr)xV
Ucr is the urine concentration of creatinine, PCr is the plasma concentration of creatinine, and V is the flow rate of urine (in mL/minute).
cystinuria
autosomal recessive defect in a membrane transporter in the renal proximal tubule for the amino acids cysteine, ornithine, arginine, lysine (COAL). Cysteine concentration is high in the urine, and cysteine precipitates form.
Causes nephrolithiasis (kidney stones)
Treatment: alkalization of the urine and hydration
Ataxia-Telangiectasia
Defects in ATM gene p failure to repair DNA double strand breaks p cell cycle arrest.
typically develop normally for the first few years of life, but have difficulty developing a normal gait
Triad (AAA):
- cerebellar defects (Ataxia)
- spider Angiomas (telangiectasia)
- IgA defciency.
Dx: serum alpha-fetoprotein (AFP) at least two standard deviations above normal for age is diagnostic of the disorder, with a sensitivity of approximately 95 percent
Renal tubular acidosis
Type 1
Type 2
Type 4
disorder of the renal tubules that leads to normal anion gap (hyperchloremic) metabolic acidosis.
Type 1 (distal) : Defect in ability of α intercalated cells to secrete H+ no new HCO3− is generated metabolic acidosis. Associated with hypokalemia
Type 2 (proximal): Defect in PCT HCO3− reabsorption excretion of HCO3− in urine and subsequent metabolic acidosis. Urine is acidi ed by α-intercalated cells in collecting tubule. Associated with hypokalemia. Caused by Carbonic Anhydrase inhibitors (acetazolamide)
Type 4 (hyperkalemic): Hypoaldosteronism hyperkalemia NH3 synthesis in PCT NH4+ excretion. Causes: aldosterone production
sarcoidosis
Sarcoidosis is an autoimmune, inflammatory disease of unknown etiology that causes the development of granulomas in various organs. The lungs are most commonly affected, and the presence of bilateral hilar lymphadenopathy is highly suggestive of sarcoidosis. Serum angiotensin converting enzyme has relatively poor sensitivity and specificity for sarcoidosis, however if elevated it is also suggestive of the disease
5% of patients develop involvement of the nervous system
Vestibular Schwanoma (acoustic neuroma)
benign tumor of the Schwann cells surrounding the eighth cranial nerve. It most commonly presents with unilateral hearing loss or vertigo, but when large can compress the seventh nerve, resulting in a peripheral pattern of facial weakness
Bilateral acoustic schwannomas -> Neuro fibromatosis type 2
