When There Are Acute Changes In Mental Status In Patients With Diabetes

Author(s): 
Adam Lang, BS, and Kathleen Satterfield, DPM, FACFAOM

   Septic shock can result from the sudden release and uptake of endotoxins. This can cause confusion, coma, fever, hypotension, tachycardia, tachypnea and renal failure, among other things. Gram-negative and gram-positive aerobic and anaerobic bacteria are known culprits.17

   Diagnostic tests for septic foot include complete blood count (CBC) with differential count, erythrocyte sedimentation rate (ESR), SMA-12 (complete metabolic panel), HgA1c, blood culture, X-rays, magnetic resonance imaging, non-invasive vascular testing, gram stain and culture.18

Why One Would Consider Stroke In The Differential Diagnosis

   Stroke. Although this patient did not demonstrate any focal neurological deficits, one could still consider stroke due to his acute change in mental status. It is known in various studies that patients with diabetes have a higher relative risk for developing stroke than non-diabetics.19,20 Cardiovascular autonomic neuropathy (CAN) is common in diabetes and often develops secondary to prolonged hyperglycemia, microangiopathy, macroangiopathy, distal symmetrical polyneuropathy, elevated HgA1c levels, retinopathy and other known complications of diabetes.21

   Cardiovascular autonomic neuropathy alone is an increased risk factor for stroke in patients with diabetes and can be a major player in “silent ischemia” due to accelerated cerebral vascular damage and changes in cerebral blood flow.20-22 Proteinuria (≥20 and 295 µmol/L are known to be a strong predictor for cerebral vascular events in type 2 diabetes.24 A neurosurgery or cardiovascular consult might be warranted as well for this patient.

What You Should Know About Diagnostic Testing And Lab Values

   The most common etiologies of mental status changes are related to changes in the patient’s blood work. Blood panels will show abnormalities in electrolytes, white blood cell (WBC) counts, sodium, ammonia and glucose levels among others. Fluctuations in all of these can cause acute mental status changes.

   In this particular patient, the treating physician should consider the more obvious potential cause of infection. One can determine this through blood cultures, ESR and WBC counts. The physician may also rule out stroke by obtaining a computed tomography (CT) scan, if warranted, after a thorough neurologic exam. This patient had no neurologic deficits so the CT was unnecessary.

   Less likely for this patient are etiologies such as trauma leading to subdural hematoma, alcohol, opiates, uremia, trauma, heat stroke, psychiatric issues, porphyria, poisons, seizure and shock.

   In addition to discovering an abnormally high glucose level upon admission, the treating physician also ordered an arterial blood draw and a Chem 12. The patient’s blood culture was negative after 24 hours. Urinalysis was positive for ketones and negative for bacteria. Arterial pH was less than 7 while serum bicarbonate was less than 10. Serum ketones were positive. The anion gap was (Na+) – (Cl+HCO3) >12.

Final Notes

   The well-trained podiatrist has made the diagnosis before he or she orders the MRI. One orders the advanced study to confirm the diagnosis and not to make the diagnosis. It is much the same way with a well-made referral.

   By the time attendings questioned the residents and medical students about the potential etiology, they had determined the two most likely diagnoses: diabetic ketoacidosis or an infection-related etiology. A bedside check of the patient’s blood sugar, although extremely high at 650, was not definitive for ketoacidosis because it would often be elevated in the presence of an infection.

   The residents performed a physical examination, which did not reveal a neurologic deficit, and the lower extremity exam did not indicate an extensive foot infection. The wound did not probe deeply. There was no cellulitis and only slight exudates.

   The patient received a referral for an internal medicine consultation. Physicians ordered labs for the internist to review.

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