O23.02 Infections of kidney in pregnancy, second trimester

Name of the Condition

• Infections of kidney in pregnancy, second trimester
• ICD-10 Code: O23.02

Summary

Infections of the kidney during the second trimester of pregnancy, also known as pyelonephritis, involve bacterial infection of the renal parenchyma and collecting system. This condition is a serious complication of urinary tract infections (UTIs) and requires prompt medical attention to prevent maternal and fetal harm. Hormonal and anatomical changes during pregnancy increase susceptibility to UTIs that can progress to kidney infection.

Causes

Pyelonephritis in the second trimester typically results from ascending bacterial infection, most commonly caused by Escherichia coli. Pregnancy-related changes, such as ureteral dilation and reduced urinary flow, facilitate bacterial ascent from the lower urinary tract to the kidneys.

Risk Factors

• Previous history of UTIs or pyelonephritis.
• Asymptomatic bacteriuria during pregnancy.
• Structural urinary tract abnormalities.
• Diabetes mellitus.
• Immunosuppression.
• Prolonged labor or catheterization.

Symptoms

• Fever, chills, or flank pain (unilateral or bilateral).
• Costovertebral angle tenderness.
• Nausea, vomiting, or abdominal pain.
• Dysuria, frequency, or urgency.
• Cloudy or foul-smelling urine.
• Fatigue or malaise.

Diagnosis

Diagnosis is confirmed through urinalysis (showing pyuria, bacteriuria, or positive nitrites), urine culture (to identify the causative organism and guide antibiotic therapy), and blood tests (to assess for systemic involvement). Imaging may be used cautiously to evaluate for complications.

Treatment Options

Treatment typically involves hospitalization for intravenous antibiotics, followed by oral antibiotics to complete the course. Close monitoring of maternal and fetal status is essential. Hydration and pain management may also be provided.

Prognosis and Follow-Up

With prompt treatment, most cases resolve without long-term complications. Follow-up includes repeat urine cultures to ensure infection clearance and monitoring for recurrence. Fetal outcomes generally improve with timely intervention.

Complications

• Preterm labor or delivery.
• Sepsis or septic shock.
• Acute respiratory distress syndrome (ARDS).
• Low birth weight or fetal growth restriction.
• Maternal renal impairment (rare).

Lifestyle & Prevention

• Maintain good hydration to promote urinary flow.
• Practice proper hygiene (e.g., wiping front to back).
• Urinate before and after sexual activity.
• Treat asymptomatic bacteriuria if identified.
• Avoid bladder irritants (e.g., caffeine, alcohol).

When to Seek Professional Help

Seek immediate care for fever, severe flank pain, or signs of systemic infection (e.g., chills, confusion). Persistent symptoms after treatment or recurrent infections also warrant evaluation.

Tips for Medical Coders

Code O23.02 is specific to kidney infections occurring in the second trimester of pregnancy. Document the trimester and confirm the infection involves the kidney (not other urinary tract sites). Ensure clinical documentation supports the diagnosis and trimester to justify code assignment.