Acute kidney injury associated with acute fatty liver of pregnancy: An update on a rare clinical entity

Table 1 Characteristic features of acute kidney injury in acute fatty liver of pregnancy

Feature	Description
Incidence	Occurs in 60%-70% of AFLP cases (vs < 15% in HELLP)
Clinical severity	Often moderate to severe; RRT required in < 5%
Initial presentation	AKI may be an early or presenting feature
Liver function tests	AST/ALT: Moderately elevated (< 300 IU/L)- Bilirubin: Markedly elevated. GGT: Usually normal (↑ in viral hepatitis)
Differentiation	AFLP: Microvesicular steatosis → cholestasis → ↑ bilirubin > transaminases. HELLP/Hepatitis: Hepatocellular necrosis → ↑. AST/ALT > bilirubin- 20% of AFLP cases may overlap with HELLP- May show features of TMA
Metabolic disturbances	Hyperuricemia: Markedly raised (hepatic + renal causes). Acidosis: Mixed lactic and anion gap acidosis
Urinalysis	Mild-moderate proteinuria in about 70%; hematuria uncommon
AKI type/urine output	Non-oliguric AKI: Common in mild/prerenal cases- Oliguric AKI (about 20%): Often from ATN or hepatorenal-like physiology. Rare postpartum cases present abruptly with oliguria and MODS
Recovery pattern	Typically rapid after delivery with supportive care. Most recover in 1-3 weeks. Delayed in MODS
Liver vs kidney recovery	Liver: Transaminases drop rapidly post-delivery; bilirubin and synthesis markers recover slowly. Kidney: Gradual, linear recovery
Post-recovery issues	Rare delayed/biphasic recovery. Risk of second hits (sepsis, DIC, volume depletion). Temporary RRT may be needed. Usually reversible (renal cortical necrosis very rare)
Renal histopathology	Commonly ATN without glomerular/immune complex involvement; tubular fatty acid deposition reported

AKI: Acute kidney injury; RRT: Renal replacement therapy; AST: Aspartate aminotransferase; ALT: Alanine aminotransferase; GGT: Gamma glutamyl transferase; HELLP: Hemolysis, elevated liver enzymes, and low platelets; DIC: Disseminated intravascular coagulation; MODS: Multiple organ dysfunction syndrome; ATN: Acute tubular necrosis; TMA: Thrombotic microangiopathy; AFLP: Acute fatty liver of pregnancy.