Hemolytic uremic syndrome

Thrombotic thrombocytopenic purpura is a thrombotic microangiopathy caused by severe ADAMTS13 deficiency that lets ultralarge von Willebrand factor multimers drive platelet microthrombi; the key dyad of microangiopathic hemolytic anemia plus thrombocytopenia without another cause mandates the PLASMIC score, an ADAMTS13 activity and inhibitor level, and emergent plasma exchange started before results return.

Disseminated intravascular coagulation is a secondary, systemic activation of coagulation and fibrinolysis, most often from sepsis, that simultaneously consumes platelets and clotting factors, causing microvascular thrombosis and bleeding. Diagnosis rests on a laboratory constellation, thrombocytopenia, prolonged PT and aPTT, low fibrinogen, and elevated D-dimer, in a predisposing clinical setting, and management centers on treating the underlying trigger while replacing blood components only for active or high-risk bleeding.

Clostridioides difficile infection is toxin-mediated colitis that follows disruption of normal colonic flora, most often by antibiotics, and ranges from watery diarrhea to fulminant colitis with shock, ileus, or megacolon. Diagnosis rests on unformed stool testing (NAAT and/or toxin EIA) in a patient with three or more unformed stools in 24 hours, and treatment is chosen by IDSA/SHEA severity grade, oral vancomycin or fidaxomicin for 10 days, escalating to high-dose vancomycin plus IV metronidazole for fulminant disease.

Escherichia coli is a gram-negative bacillus that causes most urinary tract infections and catheter-associated bloodstream infections, plus distinct diarrheagenic syndromes including travelers' diarrhea (ETEC) and hemorrhagic colitis with hemolytic uremic syndrome (EHEC/STEC). Diagnosis rests on culture with syndrome-specific colony-count thresholds, and management ranges from short-course oral antibiotics for cystitis to strictly supportive, antibiotic-avoiding care for EHEC.

Acute kidney injury is a sudden rise in serum creatinine or fall in urine output from prerenal, intrinsic, or postrenal causes, defined and staged by KDIGO criteria. Management targets the underlying cause, corrects volume and electrolyte derangements, and escalates to renal replacement therapy for refractory hyperkalemia, acidosis, volume overload, or uremia.

HELLP syndrome is a thrombotic microangiopathy of pregnancy, a severe-feature variant of preeclampsia defined by hemolysis, transaminases at least twice the upper limit of normal, and a platelet count under 100,000/uL. Delivery is the only curative treatment; management pairs blood pressure control and magnesium sulfate seizure prophylaxis with prompt, gestational-age-guided delivery.

New-onset hypertension after 20 weeks of gestation with proteinuria or end-organ dysfunction, driven by abnormal placental spiral artery remodeling and widespread endothelial dysfunction. Eclampsia is preeclampsia complicated by seizures; magnesium sulfate treats and prevents seizures, and prompt delivery is the only definitive cure for both.

Sepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection, identified by an acute rise in SOFA score of 2 points or more in a patient with known or suspected infection. Survival depends on recognizing the pattern early and completing the hour-1 bundle: lactate, blood cultures before antibiotics, broad-spectrum antibiotics such as cefepime 2 g IV every 8 hours, and 30 mL/kg crystalloid for hypotension or a lactate of 4 mmol/L or higher.