Altered mental status (AMS) is a nonspecific term that describes disorders of mental awareness ranging from confusion to coma. Implicit in its vagueness is a wide breath of differential diagnosis that must be considered by medical providers. Some patients may have congenital or acquired causes of baseline change of mental status from an expected "normal" range of human experience. This pathway does not include these patients, but rather patients who have an acute change in their baseline mental awareness.

References:

1. Altered mental status in older emergency department patients.
   Wilber ST,
   Emerg. Med. Clin. North Am. 2006 May;24(2):299-316, vi.
2. Altered states of consciousness.
   Avner JR,
   Pediatr Rev 2006 Sep;27(9):331-8.

AMS may present without a clear source. In these situations a through history and physical examination should focus on identifying both the cause and progression of the altered level of consciousness. In a large majority of cases the inciting factor is evident from this aspect of the evaluation alone.

References:

1. 
   
   
2. Altered mental status: evaluation and etiology in the ED.
   Kanich W, Brady WJ, Huff JS, Perron AD, Holstege C, Lindbeck G, Carter CT,
   Am J Emerg Med 2002 Nov;20(7):613-7.

The differential diagnosis of AMS is broad and complex. For the most part the history and physical should guide diagnostic workup of these patients. However, many of these patients present with an undifferentiated story that requires a large workup.

References:

1. Acute pancreatitis.
   Quinlan JD,
   Am Fam Physician 2014 Nov;90(9):632-9.
2. Altered states of consciousness.
   Avner JR,
   Pediatr Rev 2006 Sep;27(9):331-8.
3. Early Aggressive Hydration Hastens Clinical Improvement in Mild Acute Pancreatitis.
   Buxbaum JL, Quezada M, Da B, Jani N, Lane C, Mwengela D, Kelly T, Jhun P, Dhanireddy K, Laine L,
   Am. J. Gastroenterol. 2017 May;112(5):797-803.

Herniation is a potentially devastating complication of neurologic injury/hydrocephalus and unless an early suspicion and quick action is taken may result in death or profound complications.

The primary goal in patients with increased ICP is to maintain Cerebral blood fow (CBF) as predicted by Ohm's law:

References:

1. Intracranial Hypertension and Cerebral Hypoperfusion in Children With Severe Traumatic Brain Injury: Thresholds and Burden in Accidental and Abusive Insults.
   Miller Ferguson N, Shein SL, Kochanek PM, Luther J, Wisniewski SR, Clark RS, Tyler-Kabara EC, Adelson PD, Bell MJ,
   Pediatr Crit Care Med 2016 05;17(5):444-50.

AMS may present without a clear source. In these situations a through history and physical examination should focus on identifying both the cause and progression of the altered level of consciousness. In a large majority of cases the inciting factor is evident from this aspect of the evaluation alone.

References:

1. 
   
   
2. Altered mental status: evaluation and etiology in the ED.
   Kanich W, Brady WJ, Huff JS, Perron AD, Holstege C, Lindbeck G, Carter CT,
   Am J Emerg Med 2002 Nov;20(7):613-7.

Herniation is a potentially devastating complication of neurologic injury/hydrocephalus and unless an early suspicion and quick action is taken may result in death or profound complications.

The primary goal in patients with increased ICP is to maintain Cerebral blood fow (CBF) as predicted by Ohm's law:

References:

1. Intracranial Hypertension and Cerebral Hypoperfusion in Children With Severe Traumatic Brain Injury: Thresholds and Burden in Accidental and Abusive Insults.
   Miller Ferguson N, Shein SL, Kochanek PM, Luther J, Wisniewski SR, Clark RS, Tyler-Kabara EC, Adelson PD, Bell MJ,
   Pediatr Crit Care Med 2016 05;17(5):444-50.