Internal Medicine Exam Acute Kidney Injury 5

Question 1

A 55-year-old man with multiple myeloma presents with AKI, hypercalcemia, and Bence Jones proteinuria. Which mechanism directly causes AKI in this condition?

Accepted Answer

Light chain cast nephropathy obstructing tubular lumens

Answer

Myeloma cast nephropathy occurs when light chains (Bence Jones proteins) precipitate with Tamm-Horsfall protein in distal tubules, forming obstructing casts that cause AKI.

Question 2

Which approach to fluid resuscitation in AKI has been shown to be superior to normal saline in reducing the risk of hyperchloremic metabolic acidosis and worsening renal function?

Accepted Answer

Balanced crystalloids (Lactated Ringer's or PlasmaLyte)

Answer

Balanced crystalloids have lower chloride content than normal saline and have been shown in trials (SMART, SALT-ED) to reduce rates of major adverse kidney events.

Question 3

A 35-year-old pregnant woman at 36 weeks gestation develops AKI with thrombocytopenia, microangiopathic hemolytic anemia, and elevated liver enzymes. What is the most likely diagnosis?

Accepted Answer

HELLP syndrome

Answer

HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets) can cause AKI through TMA and is a severe complication of pre-eclampsia requiring urgent delivery.

Question 4

A 70-year-old man with AKI, low complement (C3, C4), RBC casts, and a history of recent streptococcal skin infection is most likely experiencing:

Accepted Answer

Post-infectious (post-streptococcal) glomerulonephritis

Answer

Post-streptococcal glomerulonephritis presents 1–4 weeks after skin or throat infection with RBC casts, complement consumption (low C3), and nephritic syndrome.

Question 5

During evaluation of AKI, a renal ultrasound shows bilateral small echogenic kidneys. What does this finding most likely indicate?

Accepted Answer

Chronic kidney disease as the underlying condition, not true AKI

Answer

Small echogenic kidneys on ultrasound indicate chronic scarring and fibrosis, suggesting the elevated creatinine reflects CKD rather than a true acute process.

Internal Medicine Exam Practice Test

Internal Medicine Exam Practice Test

Internal Medicine Exam Acute Kidney Injury 5