D59.3 Hemolytic-uremic syndrome

Name of the Condition

• Hemolytic-uremic syndrome (ICD-10 Code: D59.3)

Summary

Hemolytic-uremic syndrome (HUS) is a condition characterized by the triad of hemolytic anemia, thrombocytopenia, and acute kidney injury. It results from the abnormal destruction of red blood cells, leading to the formation of small blood clots in small blood vessels, which can impair kidney function and other organs. HUS is often associated with infections or other triggers that cause endothelial damage and microangiopathic changes.

Causes

The primary cause of HUS is the production of Shiga toxin by certain strains of Escherichia coli (STEC), typically from contaminated food or water. Other causes include infections with other bacteria, viruses, or parasites, as well as non-infectious triggers such as certain medications, autoimmune disorders, or genetic mutations affecting complement regulation. The toxin or other triggers damage the lining of blood vessels, leading to clot formation and organ injury.

Risk Factors

• Ingestion of contaminated food or water (e.g., undercooked meat, unpasteurized dairy)
• Recent gastrointestinal infection with STEC or other pathogens
• Use of certain medications (e.g., chemotherapy, immunosuppressants)
• Underlying conditions affecting complement pathways (e.g., atypical HUS)
• Young age (children under 5 are most commonly affected)

Symptoms

• Fatigue and weakness
• Pale or yellowish skin (jaundice)
• Dark urine (hemoglobinuria)
• Decreased urine output or oliguria
• Swelling (edema) in hands, feet, or face
• Bruising or bleeding (due to low platelets)
• Confusion or seizures (in severe cases)

Diagnosis

Diagnosis involves a combination of clinical evaluation and laboratory tests. Blood tests assess anemia, thrombocytopenia, and kidney function (e.g., creatinine, BUN). Urinalysis may show blood or protein. Stool cultures or PCR can identify STEC. Additional tests, such as ADAMTS13 activity or complement factor levels, may be performed to distinguish between typical and atypical HUS. Imaging or renal biopsy may be used in complex cases.

Treatment Options

• Supportive care: Fluid management, blood pressure control, and dialysis for kidney failure
• Antibiotics or antivirals if an infectious cause is identified
• Plasma exchange (plasmapheresis) for atypical HUS or severe cases
• Medications to manage symptoms (e.g., antihypertensives, erythropoietin for anemia)
• Discontinuation of triggering medications if applicable

Prognosis and Follow-Up

Prognosis varies depending on the cause and severity. Typical HUS from STEC often resolves with supportive care, but kidney damage may persist. Atypical HUS or severe cases may require long-term management, including plasma therapy or eculizumab. Follow-up includes monitoring kidney function, blood counts, and blood pressure. Long-term complications, such as chronic kidney disease or hypertension, may develop.

Complications

• Acute kidney injury or chronic kidney disease
• Neurological issues (seizures, stroke)
• Hypertension
• Gastrointestinal complications (e.g., bowel ischemia)
• Recurrence, particularly in atypical HUS

Lifestyle & Prevention

• Practice food safety: Cook meat thoroughly, avoid unpasteurized dairy, and wash produce
• Maintain good hygiene, especially after handling raw meat or using the bathroom
• Stay hydrated and avoid unnecessary medications that may trigger HUS
• For atypical HUS, genetic counseling may be recommended for families

When to Seek Professional Help

Seek immediate medical attention if you experience symptoms like decreased urine output, severe fatigue, jaundice, or unexplained bruising, especially after a recent infection or exposure to contaminated food. Prompt evaluation is critical to prevent kidney damage or other complications.

Tips for Medical Coders

Document the underlying cause (e.g., STEC infection, medication-induced) when available, as it may impact coding specificity. For atypical HUS, note any associated complement pathway abnormalities or genetic factors. Ensure documentation supports the triad of hemolytic anemia, thrombocytopenia, and acute kidney injury to justify the D59.3 code. Avoid coding for HUS without clear clinical correlation to the diagnostic criteria.