Case:  An otherwise healthy, 85 year old was admitted with fever and altered mental status, no vomiting. Urinalysis showed WBC, RBC and positive nitrite; urine culture ordered (no blood cultures).  IV Cipro and IVF at 100 cc/hr started with clear liquid diet.  Vital signs were normal with Temp of 100.2°F, WBC 8,000.  Brain CT scan showed mild chronic atrophy.  Neurology consult requested, and  MRI of the brain and neuro-checks every 6 hrs were ordered.  Diagnosis was "acute mental status alteration due to UTI and fever".  What is the principal diagnosis and MS-DRG?

Answer:  As currently documented, UTI is the principal diagnosis (DRG 690 - UTI w/o MCC), even hough the focus of this admission is the symptom of altered mental status requiring extensive neurological evaluation.  The UTI itself could probably have been treated as an outpatient with oral Cipro, were it not for the mental status alteration.  However, as discussed in the Signs and Symptoms section of theCDI Pocket Guide, altered mental status is classified by ICD-9 as a Chapter 16 symptom code which cannot be sequenced as principal diagnosis when routinely associated with, or attributed to, a definitive diagnosis.  In this case, the altered mental status was attributed to the UTI.  

The solution to this diagnostic documentation and coding dilemma is clarification that the altered mental status actually represents metabolic encephalopathy which was the necessary cause and focus of admission in this case.  Encephalopathy (which is a definitive diagnosis, not a symptom) would then become the principal diagnosis resulting in the higher-weighted DRG 071 (Nonspecific Cerebrovascular Disorders w/ CC) that accurately reflects the patient's actual condition and severity of illness.