# Renal Thrombotic Microangiopathy due to Hypertensive Emergency

## TL;DR

This case report describes a rare instance of kidney damage caused by a severe blood pressure crisis, highlighting the importance of early diagnosis and treatment.

## Contribution

The paper presents a case of renal TMA caused by hypertensive emergency, an underrecognized cause.

## Key findings

- Renal TMA due to hypertensive emergency can be diagnosed using renal pathology showing schistocytes and tubular necrosis.
- An 'onion-skin' lesion was observed in the renal pathology of the presented case.
- Prompt blood pressure control is critical in managing TMA caused by hypertensive emergency.

## Abstract

Thrombotic microangiopathy (TMA) is characterized by microvascular thrombosis, microangiopathic hemolytic anemia (MAHA), and thrombocytopenia. TMA can lead to acute kidney injury (AKI) due to the formation of thrombi within the renal microvasculature causing ischemic injury. AKI in the setting of TMA requires early recognition, comprehensive serologic evaluation, and timely intervention due to the risk of irreversible renal damage. Due to many potential causes, both hereditary and acquired, the workup of renal TMA includes analysis of ADAMTS13 activity, genetic testing, and antibody analysis to rule out extraneous etiologies. Ultimately, renal pathology is used to confirm the diagnosis. Recommended treatment of renal TMA is dependent on the underlying etiology and varies from therapeutic plasma exchange and anticomplement therapy to renal replacement therapy and supportive care. This case report highlights an underrecognized cause of renal TMA: hypertensive emergency. Pathological histology imaging of renal tubules can be used to diagnose renal TMA due to evidence of schistocytes and tubular necrosis. Diagnosing TMA can have life-saving consequences as delayed hemodialysis can be fatal. Renal pathological imaging should be an important diagnostic tool when presented with hypertension cases, especially those associated with the aforementioned symptoms. Blood pressure control is the primary focus for management of hypertensive emergency-associated TMA. We present a case of TMA-associated AKI in a hypertensive patient that had a characteristic onion-skin lesion seen on renal pathology.