USMLE Step 2 CK flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

DKA potassium rule

In DKA, hold insulin and replete potassium if serum K <3.3 mEq/L; insulin shifts potassium intracellularly and can precipitate fatal arrhythmia.

FeNa in prerenal AKI

Fractional excretion of sodium <1% suggests prerenal azotemia; >2% suggests intrinsic renal injury such as acute tubular necrosis.

STEMI reperfusion window

Primary PCI is preferred if achievable within 90 minutes of first medical contact; fibrinolysis is used when PCI cannot be done within 120 minutes and no contraindications exist.

COPD oxygen target

In acute COPD exacerbation with risk of hypercapnia, titrate oxygen to SpO2 88-92% to avoid worsening carbon dioxide retention.

Nephrotic syndrome criteria

Nephrotic syndrome requires proteinuria >3.5 g/day, hypoalbuminemia, edema, and hyperlipidemia; minimal change disease is the most common cause in children.

Primary hypothyroidism labs

Primary hypothyroidism shows elevated TSH with low free T4; central hypothyroidism shows low or inappropriately normal TSH with low free T4.

Parkland burn formula

Give 4 mL lactated Ringer's per kg per percent total body surface area burned in 24 hours; half is given in the first 8 hours from burn time.

Tension pneumothorax action

Immediate needle decompression followed by tube thoracostomy; do not wait for imaging when hypotension and respiratory distress are present.

Massive hemothorax threshold

Chest tube output >1500 mL immediately or >200 mL/hour for 2-4 hours suggests massive hemothorax and may require thoracotomy.

Postop fever timeline

Atelectasis commonly causes fever in the first 24-48 hours; urinary infection around 3-5 days; wound infection around 5-7 days; drug fever later.

Appendicitis classic pain

Periumbilical pain that migrates to the right lower quadrant with McBurney point tenderness and leukocytosis suggests acute appendicitis.

Pediatric maintenance fluids

Use the 4-2-1 rule: 4 mL/kg/hour for the first 10 kg, 2 mL/kg/hour for the next 10 kg, and 1 mL/kg/hour for each additional kg.

Croup treatment

Dexamethasone is given for croup; nebulized epinephrine is added for moderate to severe stridor or retractions, with observation afterward for rebound symptoms.

Kawasaki diagnostic criteria

Fever ≥5 days plus ≥4 of conjunctivitis, oral mucous change, rash, extremity changes, or cervical lymphadenopathy; treat with IVIG and aspirin.

Intussusception imaging sign

Abdominal ultrasound shows a target sign; air or contrast enema is both diagnostic and therapeutic in stable children with intussusception.

Febrile seizure definition

A febrile seizure occurs in children 6 months to 5 years, is generalized, lasts under 15 minutes, and occurs once in 24 hours.

Preeclampsia severe features

Blood pressure ≥160/110, platelets <100,000, liver enzymes >2 times normal, creatinine >1.1, pulmonary edema, or cerebral/visual symptoms define severe preeclampsia.

Magnesium sulfate eclampsia

Give a 4-6 g IV loading dose then 1-2 g/hour; monitor deep tendon reflexes, respiratory rate, and urine output for magnesium toxicity.

Postpartum hemorrhage cause

Uterine atony is the most common cause; treat with uterine massage, oxytocin, then other uterotonics, and tranexamic acid if bleeding persists.

Gestational diabetes screening

Screen at 24-28 weeks with a 50-g glucose challenge; abnormal results are followed by a 100-g, 3-hour oral glucose tolerance test.

Ovarian torsion management

Sudden unilateral pelvic pain with nausea and an adnexal mass suggests torsion; Doppler may be normal, and prompt laparoscopy is required.

Serotonin syndrome signs

Clonus, hyperreflexia, hyperthermia, and autonomic instability after serotonergic drugs; stop offending agents and give supportive care, with cyproheptadine in severe cases.

Neuroleptic malignant syndrome

Fever, lead-pipe rigidity, autonomic instability, and altered mental status after antipsychotics; stop the drug and treat with dantrolene or bromocriptine.

Alcohol withdrawal treatment

Benzodiazepines are first-line for alcohol withdrawal; give thiamine before glucose to prevent Wernicke encephalopathy in at-risk patients.

Bipolar mania criteria

Elevated or irritable mood with increased energy for at least 1 week plus ≥3 symptoms such as decreased sleep, pressured speech, and distractibility.

Schizophrenia diagnosis

Requires ≥2 core symptoms for a significant portion of 6 months, with at least 1 month of active symptoms and functional decline.

Colorectal screening ages

Average-risk adults should begin colorectal cancer screening at age 45 and continue through age 75 with colonoscopy or other approved tests.

Lung cancer screening criteria

Annual low-dose CT is recommended for adults 50-80 with ≥20 pack-year smoking history who currently smoke or quit within 15 years.

Statin decision threshold

For adults 40-75 with ≥1 cardiovascular risk factor, start a statin if the 10-year atherosclerotic cardiovascular disease risk is ≥10%.

HIV screening recommendation

Screen all adults 15-65 at least once for HIV; repeat screening is recommended for people at increased risk.

Hepatitis C screening

Screen all adults 18-79 once for hepatitis C antibody, with RNA testing for positive results; screen pregnant patients and high-risk groups.

Shingles vaccine age

Recombinant zoster vaccine is recommended for adults ≥50 years and for immunocompromised adults ≥19 years, given as a 2-dose series.