Gastroenteritis: This condition is characterized by inflammation of the gastrointestinal tract, often due to infection, which can cause nausea, vomiting, diarrhea, and abdominal pain. The stress of gastroenteritis can lead to a hypertensive urgency, and the infection can cause leukocytosis with an increase in neutrophils.

Urinary Tract Infection (UTI): A UTI can cause leukocytosis with neutrophilia and may lead to hypertensive urgency due to the body's stress response. Gastrointestinal symptoms like nausea and vomiting can occur, especially if the infection spreads to the kidneys (pyelonephritis).
Pneumonia: Pneumonia can cause leukocytosis with an increase in neutrophils and can lead to hypertensive urgency. While pneumonia primarily affects the lungs, systemic infection can cause gastrointestinal symptoms like nausea and vomiting.
Appendicitis: This is an inflammation of the appendix that can cause abdominal pain, nausea, vomiting, and diarrhea. The infection can lead to leukocytosis with neutrophilia, and the pain and stress of appendicitis can cause hypertensive urgency.

Sepsis: Although sepsis might not be the first consideration, it is crucial not to miss it due to its high mortality rate. Sepsis can cause all the mentioned symptoms, including hypertensive urgency (though hypotension is more common), leukocytosis with increased neutrophils, and gastrointestinal symptoms due to the systemic inflammatory response.
Abdominal Aortic Aneurysm (AAA): An AAA can cause abdominal pain and, if ruptured, can lead to a catastrophic drop in blood pressure. However, the initial presentation might include hypertensive urgency, and the stress of the condition can cause leukocytosis. Gastrointestinal symptoms can occur due to the aneurysm pressing on abdominal structures.
Pheochromocytoma: This rare tumor of the adrenal gland can cause episodic hypertension (including hypertensive urgency), and its diagnosis is critical due to the potential for severe complications. While less common, gastrointestinal symptoms can occur due to the systemic effects of excess catecholamines.

Vasculitis: Certain types of vasculitis, like polyarteritis nodosa, can cause hypertension, abdominal pain, and gastrointestinal symptoms due to the inflammation of blood vessels. Leukocytosis with neutrophilia can also occur.
Neuroendocrine Tumors: Some neuroendocrine tumors can produce vasoactive substances that lead to hypertensive episodes, gastrointestinal symptoms, and potentially leukocytosis due to the body's response to the tumor or its metastasis.