I82.210

Acute embolism and thrombosis of unspecified renal vein

Acute embolism and thrombosis of the unspecified renal vein, often referred to as Renal Vein Thrombosis (RVT), is a condition characterized by the sudden formation of a blood clot within the vein that drains blood from the kidney. This condition can lead to increased venous pressure within the renal parenchyma, causing congestion, swelling, and potentially acute kidney injury (AKI) or renal infarction. In adults, the most common underlying condition is nephrotic syndrome, particularly membranous nephropathy, which creates a hypercoagulable state. In neonates, RVT is usually associated with dehydration, polycythemia, or birth asphyxia. The 'unspecified' designation is used when medical documentation does not clarify whether the thrombus is located in the left or right renal vein. If untreated, acute RVT can lead to irreversible kidney damage or life-threatening complications such as pulmonary embolism if the clot dislodges and travels to the lungs.

Clinical Symptoms

Sudden onset of flank pain
Macroscopic or microscopic hematuria
Acute decline in renal function
Palpable, enlarged kidney
Nausea and vomiting
Fever
Proteinuria (often in the nephrotic range)
Oliguria (reduced urine output)
Edema (swelling), particularly in the lower extremities
Signs of pulmonary embolism such as sudden shortness of breath or chest pain

Common Causes

Nephrotic syndrome (especially membranous nephropathy)
Renal cell carcinoma (tumor invasion into the renal vein)
Abdominal or retroperitoneal trauma
Inherited hypercoagulable states (e.g., Factor V Leiden, Protein C or S deficiency)
Acquired hypercoagulable states (e.g., Antiphospholipid syndrome)
Extreme dehydration (common in neonates)
Complication of renal transplantation
Oral contraceptive use or hormone replacement therapy
Invasion or compression by extrinsic abdominal masses

Documentation & Coding Tips

Document the precise laterality to avoid unspecified codes whenever possible.

Example: Patient presents with acute onset left-sided flank pain and gross hematuria. Renal ultrasound with Doppler confirms an acute thrombosis within the left renal vein. Laterality is confirmed as left-sided. Plan includes anticoagulation for acute left renal vein thrombosis.

Billing Focus: Laterality (left vs. right) is the primary driver for code specificity in the I82.21 series.

Explicitly state the acuity of the thrombus as acute vs chronic.

Example: Imaging reveals a fresh, non-organized thrombus in the renal vein without evidence of collateral vessel development, consistent with an acute embolism. This is a new finding not present on imaging six months ago. Diagnosis: Acute embolism of the renal vein.

Billing Focus: Acuity distinguishes I82.210 (Acute) from I82.22 (Chronic).

Link the thrombosis to any underlying causative conditions such as Nephrotic Syndrome or malignancy.

Example: Acute renal vein thrombosis identified in the setting of known Membranous Nephropathy with massive proteinuria (8g/day). The thrombosis is considered a direct complication of the hypercoagulable state induced by Nephrotic Syndrome.

Billing Focus: Establishing a causal link supports the use of additional codes for the underlying condition (e.g., N04.1).

Document the presence or absence of associated Acute Kidney Injury.

Example: Acute renal vein thrombosis diagnosed via CT Angiography. Current serum creatinine is 2.4 mg/dL, up from a baseline of 1.0 mg/dL yesterday, meeting criteria for Stage 2 Acute Kidney Injury. RVT is the etiology of the AKI.

Billing Focus: Documentation of AKI (N17.9) as a complication of the thrombosis provides a more complete billing profile.

Specify the exact vessel involved if the embolism originates elsewhere or involves the IVC.

Example: The thrombus extends from the renal vein into the Inferior Vena Cava (IVC). Acute embolism and thrombosis of both the renal vein and the suprarenal IVC documented.

Billing Focus: Helps distinguish between I82.210 and I82.290 (Acute embolism and thrombosis of inferior vena cava).

Relevant CPT Codes

99214 - Office or other outpatient visit for the evaluation and management of an established patient, which requires a moderate level of medical decision making or 30-39 minutes of total time
Moderate complexity is common when managing anticoagulation and monitoring renal function in a stable patient.
99215 - Office or other outpatient visit for the evaluation and management of an established patient, which requires a high level of medical decision making or 40-54 minutes of total time
High MDM is justified if the thrombosis is causing acute renal failure or if there is a high risk of systemic embolization.
93975 - Duplex scan of abdominal, pelvic, scrotal contents and/or retroperitoneal organs; complete
The primary diagnostic modality for identifying renal vein thrombosis and assessing flow characteristics.
75831 - Venography, renal, unilateral, selective, radiological supervision and interpretation
Used when non-invasive imaging is inconclusive or as a precursor to thrombectomy.
37187 - Percutaneous transluminal mechanical thrombectomy, vein(s), including intraprocedural pharmacological thrombolytic injection and imaging guidance, primary
Treatment for acute, limb-threatening or organ-threatening venous thrombosis.
37212 - Transcatheter therapy, venous infusion for thrombolysis, any method, including intracatheter injection(s), original or subsequent, day 1
Active dissolution of the clot using thrombolytic agents like tPA.
74177 - Computed tomography, abdomen and pelvis, with contrast material(s)
CT angiography (CTA) is highly sensitive for detecting renal vein thrombosis and associated pathology.
99204 - Office or other outpatient visit for the evaluation and management of a new patient, which requires a moderate level of medical decision making or 45-59 minutes of total time
Moderate MDM is typical for the initial workup of a new thrombotic event and planning long-term therapy.
37191 - Insertion of intravascular vena cava filter, endovascular approach including vascular access, vessel selection, and radiological supervision and interpretation
Indicated if the renal vein thrombus is propagating and anticoagulation is contraindicated.
93976 - Duplex scan of abdominal, pelvic, scrotal contents and/or retroperitoneal organs; limited or follow-up study
Used to assess for clot resolution or propagation during treatment.