What is the ICD-10 (International Classification of Diseases, 10th Revision) code for a patient with a history of hypertension presenting with severely elevated blood pressure and evidence of end-organ damage?

ICD-10 Code for Hypertensive Emergency

The ICD-10 code for hypertensive emergency is I16.0 (hypertensive crisis with acute organ damage), I16.1 (hypertensive crisis without acute organ damage, also called hypertensive urgency), or I16.9 (hypertensive crisis, unspecified). 1

Code Selection Based on Clinical Presentation

For hypertensive emergency specifically (severely elevated BP WITH acute target organ damage), use I16.0. 1, 2

When to Use I16.0 (Hypertensive Emergency)

• Blood pressure typically >180/120 mmHg WITH evidence of acute hypertension-mediated organ damage (HMOD) 3, 4
• Acute target organ damage includes:
  • Neurologic: hypertensive encephalopathy, intracranial hemorrhage, acute ischemic stroke 3, 4
  • Cardiac: acute myocardial infarction, acute left ventricular failure with pulmonary edema, unstable angina 3, 4
  • Vascular: aortic dissection or aneurysm 3, 4
  • Renal: acute kidney injury, thrombotic microangiopathy 3, 4
  • Ophthalmologic: bilateral retinal hemorrhages, cotton wool spots, papilledema (malignant hypertension) 3, 4
  • Obstetric: severe preeclampsia or eclampsia 3, 4

When to Use I16.1 (Hypertensive Urgency)

• Severely elevated BP (typically >180/120 mmHg) WITHOUT acute target organ damage 3, 2
• The ICD-10-CM code I16.0 has been validated with 100% sensitivity and 96% specificity for identifying hypertensive urgency in research settings 2

When to Use I16.9 (Hypertensive Crisis, Unspecified)

• Use when documentation is insufficient to determine presence or absence of acute organ damage 1

Additional Coding Considerations

Obstetric-Specific Codes Take Priority

• For severe hypertension in pregnancy, use obstetric-specific codes instead of I16 codes 1:
  • Severe preeclampsia: O14.10, O14.12, O14.13, O14.14, O14.15 1
  • HELLP syndrome: O14.20, O14.22, O14.23, O14.24, O14.25 1
  • Eclampsia: O15.00, O15.02, O15.03, O15.1, O15.2, O15.9 1
  • Preexisting hypertension with superimposed preeclampsia: O11.1, O11.2, O11.3, O11.4, O11.5, O11.9 1

Critical Documentation Requirements

The presence or absence of acute target organ damage—not the absolute BP number—determines whether to code as I16.0 versus I16.1. 3, 4

• Document specific BP measurements (typically >180/120 mmHg) 3, 5
• Document specific evidence of acute organ damage if present (laboratory values, imaging findings, clinical symptoms) 3, 4
• Document time course (acute versus chronic findings) 3, 4
• The rate of BP rise may be more clinically important than the absolute value, particularly in patients with chronic hypertension who have altered autoregulation 3

Common Coding Pitfalls to Avoid

• Do not code asymptomatic severe hypertension as I16.0—this requires evidence of acute organ damage 3, 4
• Do not confuse isolated subconjunctival hemorrhage with malignant hypertensive retinopathy—only bilateral retinal hemorrhages, cotton wool spots, or papilledema qualify as acute target organ damage 3
• Do not use I16 codes for pregnancy-related hypertensive emergencies—use obstetric-specific O-codes instead 1
• Remember that up to 20-40% of patients with malignant hypertension have secondary causes requiring additional diagnostic codes 3, 4