USMLE Part 1 Review

A common cause of diarrhea in travelers, characterized by watery or brown/green diarrhea. Often caused by Escherichia coli (ETEC) producing heat-labile (HL) or heat-stable (HS) toxins.

A type of bacterial infection that can cause bloody diarrhea and is commonly associated with poultry consumption.

A serious infection of the colon caused by Clostridium difficile, characterized by bloody diarrhea and abdominal pain.

A life-threatening complication of C. difficile characterized by fever, abdominal distension, and potential for colon perforation.

A parasitic infection that can cause bloody diarrhea and is often acquired through contaminated water or food.

A common cause of gastroenteritis that can cause watery diarrhea, often in crowded settings.

A condition characterized by fluid accumulation in the pericardial sac, causing pressure on the heart.

Radial traction on the outside of airways keeps them open.

When a person sits or stands, both ventilation and perfusion increase from the apex to the base of the lung.

Strep pneumo (Streptococcus pneumoniae) is the most common cause of otitis media.

Oral amoxicillin is the first-line treatment for otitis media.

Amoxicillin/clavulanate is used to treat recurrent otitis media.

Tympanostomy tubes are placed when a child has had three or more ear infections in six months or four or more in a year.

Pseudomonas aeruginosa is the most common cause of otitis externa.

Topical ciprofloxacin and hydrocortisone drops are used to treat otitis externa.

Alcohol-acetic acid drops can help prevent otitis externa in people with constant water exposure.

Carbamide peroxide drops can be used to remove earwax buildup.

An acid-base disturbance characterized by low carbon dioxide (CO2), high pH, normal oxygen (O2), and normal bicarbonate (too acute to change). This occurs in the first 20 minutes of aspirin toxicity due to aspirin's effect on the respiratory center.

A mixed acid-base disturbance with both metabolic acidosis and respiratory alkalosis. This occurs after 20 minutes of aspirin toxicity due to aspirin's metabolic effects and its ongoing respiratory stimulation.

Treatment for aspirin toxicity involves administration of sodium bicarbonate. It increases urinary excretion of salicylates by alkalinizing the urine, making them easier to eliminate.

Treatment for tricyclic antidepressant (TCA) toxicity involves intravenous sodium bicarbonate. It works by displacing the TCA from its binding sites on myocardial sodium channels, improving cardiac function.

A condition of high calcium levels in the blood, usually defined as a calcium level above 10.2 mEq/L.

Treatment for mild hypercalcemia (10.2-12 mEq/L) involves intravenous normal saline (0.9% NaCl).

Treatment for moderate hypercalcemia (12-14 mEq/L) involves intravenous normal saline (0.9% NaCl) if asymptomatic. If symptomatic, bisphosphonates (e.g., pamidronate) are added.

Treatment for severe hypercalcemia (14 mEq/L or higher) involves intravenous normal saline (0.9% NaCl) and bisphosphonates.

A rare association where high calcium levels in the blood are accompanied by excessive urination (polyuria). It suggests nephrogenic diabetes insipidus, a condition where the kidneys are unresponsive to ADH, leading to water loss.

Obesity is the most common risk factor for osteoarthritis.

Methotrexate is a dihydrofolate reductase inhibitor, which blocks folate metabolism and ultimately DNA synthesis.

Anti-CCP antibodies are more specific for rheumatoid arthritis than rheumatoid factor (RF).

Septic arthritis (SA) is a serious infection of a joint. It typically presents with a warm, red, painful joint and requires immediate medical attention.

A patient with a prosthetic joint is at highest risk for septic arthritis compared to any other patient group.

Insulin resistance leads to abnormal GnRH pulsatile release, which negatively impacts reproductive hormone balance.

Abnormal pulsatile GnRH secretion disrupts the LH/FSH ratio, leading to high LH and low FSH levels.

In anovulation, the follicle is not ready for ovulation, so high LH levels stimulate it anyway, leading to a non-ovulatory cycle.

The follicle, unable to ovulate due to the high LH/FSH ratio, remains in the ovary and transforms into a cyst.

LH stimulates the production of androgens in the theca interna cells of the ovary in females. It also stimulates Leydig cells in males.

FSH stimulates the granulosa cells in the ovary to produce aromatase, which converts androgens into estrogens. FSH also prepares follicles for ovulation.

Weight loss is considered the first-line treatment for PCOS, especially in patients with high BMIs.

Oral contraceptives are used in PCOS for managing symptoms, especially when pregnancy is not desired. Clomiphene is used to induce ovulation when pregnancy is desired and other treatments have failed.

PCOS increases the risk of endometrial cancer because there's an excess of estrogen without adequate progesterone to balance it out.

Flutamide, an anti-androgen, is used initially to block androgen action, followed by leuprolide, a GnRH agonist, to suppress testosterone.