Viral or Bacterial Meningitis: This condition can cause headache, vertigo, and vomiting due to inflammation of the meninges. The presence of AKI and hypotension could be secondary to severe infection leading to sepsis, which affects multiple organ systems including the kidneys and cardiovascular system.

Dehydration and Electrolyte Imbalance: Severe dehydration can lead to headache, vertigo, and vomiting. If not promptly addressed, it can progress to hypotension and acute kidney injury (AKI) due to decreased renal perfusion.
Inner Ear Infection (Labyrinthitis): While primarily causing vertigo and vomiting, severe cases can lead to systemic symptoms including headache. Hypotension and AKI might be less directly related but could occur in the context of severe dehydration or secondary infection.
Medication Side Effects: Certain medications can cause these symptoms as side effects, including headache, vertigo, and vomiting. AKI and hypotension could be related to specific drug toxicities or allergic reactions affecting renal function and blood pressure regulation.

Subarachnoid Hemorrhage: A life-threatening condition that can present with sudden severe headache, vertigo, and vomiting. Hypotension and AKI could occur due to the body's response to the hemorrhage, including potential renal effects from blood pressure fluctuations and catecholamine release.
Stroke or Transient Ischemic Attack (TIA): Although more commonly associated with focal neurological deficits, certain types of stroke (like cerebellar stroke) can cause vertigo and vomiting. AKI and hypotension might be seen in the context of a systemic response to a large stroke or as a result of hospital-acquired complications.
Severe Infection (Sepsis): Sepsis from any source can lead to hypotension and AKI. The initial presentation might include non-specific symptoms like headache, vertigo, and vomiting, especially if the infection involves the CNS or inner ear.

Multiple Sclerosis: An exacerbation of multiple sclerosis could potentially cause a wide range of neurological symptoms, including headache, vertigo, and vomiting, though AKI and hypotension would be less common presentations.
Vestibular Migraine: While typically causing vertigo and headache, a severe episode could potentially lead to vomiting. However, AKI and hypotension would be unusual complications.
Cerebellar Abscess: A rare condition that could present with headache, vertigo, and vomiting due to increased intracranial pressure and cerebellar dysfunction. Systemic complications like AKI and hypotension could occur in advanced cases.