There are multiple causes of malignant hypertension (hypertensive crisis), including the following:
Medication noncompliance
Renovascular diseases, such as renal artery stenosis, polyarteritis nodosa, and Takayasu arteritis
Renal parenchymal disease including glomerulonephritis, tubulointerstitial nephritis, systemic sclerosis, hemolytic-uremic syndrome, systemic lupus erythematosus
Endocrine dysfunction, such as pheochromocytoma, Cushing disease, primary hyperaldosteronism, renin-secreting tumor
Coarctation of aorta; drugs or other exposures, including cocaine, phencyclidine, sympathomimetics, erythropoietin, cyclosporine
Antihypertensive medication withdrawal
Amphetamines
Central nervous system disorders, such as head injury, cerebral infarction, and cerebral hemorrhage