In our last discussion of Altered Mental Status for DUMMIES – Part I we talked about easy to remember mnemonics which can aid you in the approach to the differential in the patient with altered mental status. Today we’ll begin to discuss the “approach” when beginning your evaluation and work-up.
altered mental status
Definition: A changed level of awareness or mental state that falls short of unconsciousness.
Examples: Confusion, disorientation, or stupor (which, if of sudden onset, may constitute a medical emergency).
When first evaluating the patient who may be altered. We have always been taught to start with the ABCs (airway, breathing, circulating) when beginning our initial exam. At the same time the experienced provider will be using all their senses. Sights (trauma, hygiene, skin color, sclera, conjunctiva, mucous membranes), smells (alcohol, ketones, the stale smell of urine or the unmistakable stench of the GI bleed), touch (temperature, clammy, diaphoresis).
With time and experience, your subconscious will immediately begin “thin slicing,” as Malcolm Gladwell puts it in his book Blink. The term “thin slicing” means making very quick inferences about the state, characteristics or details of an individual or situation with minimal amounts of information and is used subconsciously in any patient encounter. In seconds, your subconscious will immediately begin analyzing the patient’s appearance, their clothes, skin, hygiene, body language, eye contact, speech, thought process, do they appear agitated, in pain, scared, etc.
Speak with the EMTs and Paramedics. They are a wealth of information and can often provided details regarding the cleanliness and temperature of the home, was there food in the refrigerator, pill bottles, alcohol, elicit drugs, etc. History, history, history. If possible, speak with any family, nursing home staff or the primary care provider who could provide additional details regarding the patient’s baseline mental status, use of elicit drugs, psychiatric history and recent changes in health or medications.
As we begin our initial clinical approach obtain a full set of vital signs, this may often include a rectal core temperature (consider hypothermia or heat stoke) and should always include a finger-stick blood glucose in any altered patient. Intravenous access and blood samples will often be obtained as standing orders by nursing staff. As part of the initial rapid bedside testing, consider and electrocardiogram – looking for evidence of acute ischemia, arrhythmia, Q-T prolongation, AV blocks or evidence of electrolyte abnormality.
When ordering labs, electrolytes are critical. A patient who has been binge drinking beer (large free-water content), a hyperglycemic patient with pseudohyponatremia and polydipsia or a patient with psychogenic polydipsia may have profound hyponatremia (often with a serum sodium <110 mEq/L ) and may have been seizing. Common causes of hyponatremia include: excessive water ingestion, history of diuretic use, history of congestive heart failure, renal failure, or cirrhosis, history of adrenal insufficiency or glucocorticoid dependency, history of malignancy and history of SIADH.
Patients with a history of large amounts of salt ingestion, or a history of excessive sweating or GI loss (diarrhea, vomiting) may have hypernatremia (often with a serum sodium often >155mEq/L). Patients with hypo- or hypernatremia may present with nausea, headache, weakness, lethargy, coma, seizure, respiratory failure.
Blood test: Serum Sodium
Consider Metabolic Acidosis: and use the mnemonic CAT MUDPILES or Hard UP as a reminder of the differential.
C = Carbon monoxide, Cyanide
A = Alcoholic ketoacidosis
T = Toluene
M = Methanol
U = Uremia
D = Diabetic ketoacidosis
P = Paraldehyde, Phenformin
I = Iron, Isoniazid
L = Lactic acidosis
E = Ethylene glycol
S = Salicylates poisoning
H = Hyperventilation (chronic)
A = Acetazolamide, Acids (e.g., hydrochloric), Addison’s disease
R = Renal tubular acidosis
D = Diarrhea
U = Ureterosigmoidostomy
P = Pancreatic fistulas and drainage
S = Saline (in large amounts) (hyperchloremic metabolic acidosis)
Continuing with electrolytes:
Patients with a history of malignancy or hyperparathyroidism may have hypercalcemia (often with a serum calcium >14mg/dL) and may present with nausea, vomiting, weakness, polyuria and constipation. Just remember bones, kidney stones, abdominal groans, psychiatric moans.
On the other hand, patients with a history of liver or kidney disease, hypoparathyroidism or Vitamin D deficiency may have hypocalcemia (often with a serum calcium <7.5mg/dL) and may present with generalized weakness, tetany, seizure, coma. With hypocalcemia you may also find a Chvostek sign (facial tetany), or a Trousseau sign (carpopedal spasm).
Blood test: Serum Calcium
Patient’s with a history of hypothyroidism or autoimmune thyroiditis (Hashimoto’s) may present with myxedema coma. On exam evaluated the neck for a surgical scar or goiter. The metabolic pathways in these patients are slowed down and these patient’s can present with hypothermia, hypotension, hypoglycemia, hypoventilation, non-pitting edema in soft tissues, seizures, lethargy, and coma. Myxedema coma is an endocrine emergency and should be treated aggressively. The mortality rate can be as high as 40 % !
However, patients with hyperthyroidism (Graves’ disease, toxic multinodular goiter) can develop thyroid storm. On exam you may find an abnormal thyroid (goiter, nodular) or ophthalmopathy (proptosis). Patients may present with vomiting, diarrhea, tachycardia, hyperthermia, anxiety, delirium, lethargy, coma. Untreated hyperthyroidism may lead to congestive heart failure with hypotension and arrhythmias.
Blood test: TSH
Encephalopathy is a term that means brain disease, damage, or malfunction. Encephalopathy can present a very broad spectrum of symptoms that range from mild, such as some memory loss or subtle personality changes, to severe, such as dementia, seizures, coma, or death.
Common causes of encephalopathy include:
Uremic encephalopathy – patient’s with a history of renal insufficiency or end stage renal disease or missed dialysis. On initial exam look for an AV fistula or dialysis catheter. Encephalopathic patients may also have asterixis on exam.
Blood test: BUN/Creatinine
Hepatic encephalopathy – patient’s with a history of cirrhosis or end-stage liver disease. These patient’s can also initially present with a GI bleeding or spontaneous bacterial peritonitis and can develop cerebral edema.
Blood test: Ammonia
Wernicke’s Encephalopathy – patient’s with a history of alcohol dependence or malnutrition. These patient’s may present with the classic triad of “confusion, ataxia and ophthalmoplegia”
Always ask about current prescription, new medications, recent dosage changes or recently stopped medications (? withdrawal). Don’t forget to ask about over-the-counter medications, medications in the home prescribed to other family members, herbs, supplements, illicit drug use, etc.
During your physical exam, look for evidence of some of the classic toxidromes. Anticholinergic, cholinergic, opioid, sympathomimetic or sedative-hypnotic.