Study guide
4.1 Nervous System Conditions for CDI
Certified Clinical Documentation Specialist CCDS
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1 Introduction & Exam Overview
1.1 Current Exam Facts 1.2 Eligibility Pathways and the 2,000-Hour Year 1.3 Allowed Resources and Test-Day Rules 1.4 Recertification, Fees, and How This Guide Maps the Eight Domains
2 IPPS Foundations
2.1 How IPPS Works and How CMS Updates It 2.2 MS-DRG Assignment, Relative Weights, and Grouping 2.3 Provider and Clinical Staff Documentation Duties under IPPS
3 Severity, CMI, Medical Necessity, and Oversight
3.1 CC versus MCC Recognition and CC Exclusion Lists 3.2 Case Mix Index and Why CDI Tracks It 3.3 Two-Midnight Rule, Medical Necessity of Setting, and Principal Diagnosis 3.4 MAC, RAC, CERT, OIG, and Denial-Vulnerable Practices
4 Nervous and Respiratory System CDI
4.1 Nervous System Conditions for CDI 4.2 Acute and Chronic Respiratory Failure, ABGs, and Ventilation Support 4.3 Pneumonia, COPD, PE, Pleural Effusion, and Respiratory Infections
5 Circulatory, Digestive, Hepatobiliary, Musculoskeletal, and Skin CDI
5.1 Circulatory Disorders 5.2 Digestive and Hepatobiliary Disorders 5.3 Musculoskeletal and Skin
6 Endocrine, Nutrition, Kidney, and Hematologic CDI
6.1 Diabetes, Dehydration, and Obesity 6.2 Malnutrition Criteria, Severity, and Audit Risk 6.3 AKI, CKD Staging, UTI, and Urinary Stones 6.4 Anemia, Coagulation, Sickle Cell, Lymphoma, and Leukemia
7 Infectious Disease, Other MDCs, and Clinical Indicator Tools
7.1 Sepsis, Severe Sepsis, Postoperative and Other Infections 7.2 Mental, Substance Use, Injuries/Toxicology, and HIV-Related Conditions 7.3 Medications, Diagnostic Tests, and Abbreviations as Clinical Indicators
8 Health Record Elements and Query Triggers
8.1 Which Record Elements Support Diagnosis and Procedure Codes 8.2 Attending versus Radiologist, Pathologist, and Other Providers 8.3 When a Physician Query Is Warranted 8.4 When Queries Are Not Appropriate
9 Query Timing, Verbal Queries, Formats, and Clinical Indicators
9.1 Concurrent, Retrospective, Pre-Bill, and Prospective Timing 9.2 Verbal Queries and Required Documentation 9.3 Open-Ended, Multiple-Choice, and Yes/No 9.4 Clinical Indicators and How to Source Them
10 Compliant Query Practice and Clinical Validation
10.1 Compliant versus Leading and Other Noncompliant Queries 10.2 ACDIS/AHIMA 2026 Guidelines for Achieving a Compliant Query Practice 10.3 Clinical Validation and Diagnoses without Clinical Support
11 CDI Program Metrics
11.1 Productivity, Query Volume, and Provider Response Rates 11.2 CMI, CC/MCC Capture, and High-Frequency DRGs 11.3 SOI/ROM as CDI Program Performance Metrics
12 Physician Metrics, PEPPER, Forecasting, and Public Data
12.1 Measuring Physician Documentation Performance 12.2 PEPPER, Forecasting, Hospital Financial Data, and Public Reporting
13 CDI Roles, Coder Collaboration, and Physician Education
13.1 Roles and Responsibilities of the CDI Specialist 13.2 Coder Roles Working with a CDI Department 13.3 Physician Education Tools, Forms, and Presentations
14 Provider Communication and DRG Reconciliation
14.1 Non-Confrontational Communication and When Verbal Beats Written 14.2 Working DRG versus Final DRG Reconciliation
15 Official Guidelines, Principal Diagnosis, and Secondary Diagnosis
15.1 Official Guidelines, Cooperating Parties, Updates, and AHA Coding Clinic 15.2 Principal Diagnosis Selection 15.3 Secondary Diagnosis Reporting Criteria
16 Sequencing, Coding Conventions, and POA Indicators
16.1 Sequencing When Two Diagnoses Equally Meet PD; Working DRG with Multiple Diagnoses 16.2 Integral Signs/Symptoms, the With Convention, and Uncertain Diagnoses 16.3 Present-on-Admission Indicator Assignment and Payment Impact
17 Hospital-Acquired Conditions, Disposition, and ICD-10-PCS Essentials
17.1 CMS Hospital-Acquired Condition Payment Provision 17.2 Discharge Disposition, Transfer Payment, Principal Procedure, and ICD-10-PCS Essentials
18 Ethics, Privacy, and Leading Queries as Compliance Failures
18.1 ACDIS Code of Ethics and CDI Goals beyond Reimbursement 18.2 HIPAA, Minimum Necessary, and Record Confidentiality 18.3 Leading Queries as a Compliance Failure
19 DRG Creep, OIG Oversight, PEPPER, and the False Claims Act
19.1 DRG Compliance, DRG Creep, and the OIG Work Plan 19.2 PEPPER Compliance Risks and the False Claims Act
20 Mortality Index, Observed-to-Expected Ratios, and Quality Data Sources
20.1 Documentation Impact on Mortality Index (SOI/ROM) 20.2 Mortality Reviews and Observed-to-Expected Ratios 20.3 Abstracted versus Claims-Based Quality Data
21 CMS Quality Programs, PSIs, and Infection versus Complication Codes
21.1 HVBP, HAC Reduction Program, HRRP, 30-Day Mortality, and Hospital IQR 21.2 PSI 90 Components and PSIs beyond the Composite 21.3 Healthcare-Associated Infections versus Complication Codes
4.1 Nervous System Conditions for CDI
Key Takeaways Explain This Topic AI
The word CVA is unfinished documentation: query for ischemic versus hemorrhagic infarction, laterality, vessel territory if the provider already named it, and whether hemiparesis or hemiplegia is a current deficit of this acute event rather than a remote sequela.
Altered mental status is a symptom. Query for encephalopathy type and cause. Metabolic encephalopathy can group as an MCC when a provider documents it, clinical indicators support it, and it is not inherent to the principal diagnosis.
A single provoked seizure is not epilepsy. Status epilepticus is a separate high-acuity diagnosis. A brief post-ictal period is not automatically metabolic encephalopathy.
Cerebral edema on a radiology report and a low GCS on sedatives are indicators, not codes. First-time capture of a new diagnosis uses a nonleading multiple-choice query, not a yes/no that plants the diagnosis.
The August 2026 ACDIS/AHIMA query standard still requires sourced clinical indicators, clinically relevant options, an open-ended Other please specify choice, independent provider judgment, and no reimbursement or quality-outcome language.
Last updated: September 2026
4.1 Nervous System Conditions for CDI
Quick Answer: Inpatient CDI does not finish with CVA, AMS, or seizure. Query for stroke type and laterality , the type and cause of encephalopathy, epilepsy versus a provoked seizure versus status epilepticus , clinically significant cerebral edema , and pathologic coma versus sedation . Metabolic encephalopathy can group as an MCC when a provider documents it, indicators support it, and it is not inherent to the principal diagnosis. The 2026 ACDIS/AHIMA query standard requires nonleading, clinically relevant options plus Other, please specify (or similar) and forbids reimbursement or quality-outcome language.
The Association of Clinical Documentation Integrity Specialists ( ACDIS ) Certified Clinical Documentation Specialist (CCDS) exam puts nervous-system work in Domain II (anatomy, physiology, pathophysiology, pharmacology, and terminology). Items are mostly application and analysis. You are not asked to recite a corticospinal tract. You are asked whether the record supports a reportable diagnosis , whether a query is the right tool, and whether a tempting MCC is clinically inherent to the condition that occasioned the stay.
This independent ExamFinch section helps learners study those inpatient skills. It is not an ACDIS product and does not claim partnership, official review, or approval by ACDIS, the American Health Information Management Association ( AHIMA ), the American Hospital Association ( AHA ), or the Centers for Medicare & Medicaid Services ( CMS ).
Acute cerebrovascular accident versus the word stroke
Cerebrovascular accident (CVA) at the bedside is a family of diseases: ischemic cerebral infarction , intracerebral hemorrhage (ICH) , subarachnoid hemorrhage (SAH) , and sometimes hemorrhagic conversion of an infarct. Those entities do not group the same way. A problem list that says only CVA is unfinished work.
Clinical indicators that a stroke is acute this admission include sudden focal deficits, an elevated National Institutes of Health Stroke Scale (NIHSS) , a last-known-well timestamp, thrombolysis with alteplase or tenecteplase, mechanical thrombectomy, a diffusion-weighted MRI lesion, a large-vessel occlusion on CT angiography, or a hematoma on noncontrast CT. Those indicators do not let the CDI specialist code the CTA. They let you query the provider for a specific diagnostic statement.
Query for ischemic versus hemorrhagic disease (and conversion if neurosurgery describes it); laterality of the infarct and of hemiparesis, hemiplegia, or monoplegia; whether a deficit is a current condition under treatment or only a remote sequela; dominant versus nondominant side when paralysis laterality is known; and acute event versus personal history of CVA with no new deficit and no acute infarct or hematoma.
Original scenario. Ms. R., 71, arrives with dense left face-arm-leg weakness, NIHSS 14. Noncontrast CT shows no blood. CTA shows a right M1 occlusion. She receives tenecteplase and proceeds to thrombectomy with TICI 2b reperfusion. The day-2 progress note says CVA, improving. The discharge summary says history of CVA with residual weakness. Concurrent CDI should not recode the stay as a late-effect stroke and should not invent a middle-cerebral-artery code from the radiology header. A nonleading query asks the attending to specify ischemic infarction versus hemorrhage, laterality, and whether left hemiparesis is a current deficit of this acute event. Cite NIHSS, CTA, thrombolysis, and the exam. Do not mention case mix or SOI.
Transient ischemic attack (TIA) is a transient episode without infarction. If deficits persist and MRI shows restricted diffusion, the clinical diagnosis may have become infarction — only a provider makes that change. Do not upgrade TIA because you prefer the diffusion-weighted image.
Hemiplegia and hemiparesis that are evaluated and treated can meet Uniform Hospital Discharge Data Set (UHDDS) secondary-diagnosis criteria (clinical evaluation, treatment, extra monitoring, or extended length of stay). Weak in a nursing flowsheet is not the same documentation. If dominance is never stated, query rather than assuming that right-handedness equals left-hemisphere dominance without a provider link. ICD-10-CM has default assumptions for unspecified dominance; a query is cleaner than silently accepting the default when occupational therapy already recorded handedness.
Present-on-admission ( POA ) for a community-onset stroke worked up in the emergency department before the inpatient order is Y . Hemorrhagic conversion that clearly begins after admission is a different POA conversation and must follow the record, not a CDI preference for a CC.
Medications that support acuity without substituting for a diagnosis include tenecteplase or alteplase, aspirin after hemorrhage is excluded, a heparin infusion for selected dissections or stents, and nimodipine when aneurysmal SAH vasospasm prevention is underway.
Encephalopathy: type, cause, and the inherent-condition trap
Altered mental status (AMS) , confusion, delirious, and not at baseline are symptoms. Domain II expects you to seek a type (metabolic, toxic, hepatic, hypertensive, anoxic or hypoxic, septic, unspecified) and a cause (hyponatremia, uremia, hypercapnia, drug accumulation, hypotension after return of spontaneous circulation, and so on).
Type Typical indicators (not automatic codes) CDI watch-out
Metabolic encephalopathy Acute confusion plus a metabolic driver: uremia, dysnatremia, hypoglycemia, hypercapnia, or mixed derangements Possible MCC when documented, supported, and not inherent to the principal diagnosis
Toxic encephalopathy Intoxication, polypharmacy, alcohol, or sedative accumulation Do not relabel withdrawal or overdose without the provider's diagnostic words
Hepatic encephalopathy Cirrhosis, asterixis, lactulose or rifaximin, ammonia if obtained Often the identity of a decompensated-liver admission — watch double counting
Hypertensive encephalopathy Hypertensive emergency with acute brain dysfunction, often vasogenic edema Not a synonym for chronic hypertension plus forgetfulness
Anoxic/hypoxic encephalopathy Cardiac arrest, prolonged hypoxia, delayed awakening after ROSC Imaging may lag; still need a provider diagnosis
Septic encephalopathy AMS in documented infection with organ dysfunction Linkage to sepsis versus a separate metabolic process is a query, not a guess
Metabolic encephalopathy as a possible MCC. MS-DRG logic can treat specified encephalopathies as MCCs. You do not memorize an unpublished relative-weight table for the exam. You do memorize the clinical-validation and inherent-condition traps . If the principal diagnosis is already a condition whose definition includes encephalopathy (hepatic encephalopathy as the reason for admission in decompensated cirrhosis), adding a second metabolic encephalopathy MCC because sodium is 128 is a denial magnet. If the principal diagnosis is community cellulitis, the patient is newly oriented only to self, BUN is 64, sodium is 118, and lactulose is not in play, a nonleading query for type and cause is the CCDS skill.
Never put please document metabolic encephalopathy so this case has an MCC in a query. The August 2026 ACDIS/AHIMA Guidelines for Achieving a Compliant Query Practice bar reimbursement and quality-outcome language. Cite the indicators (GCS 13, sodium 118, BUN 64, CAM-ICU positive) and leave independent judgment with the provider.
Original scenario. Mr. K. is admitted for lower-extremity cellulitis. At 02:00 he is GCS 13, CAM-ICU positive, sodium 119 mEq/L, and glucose 41 mg/dL after insulin. The hospitalist writes AMS, likely Na. CDI sends a multiple-choice query with clinically relevant choices: metabolic encephalopathy related to hyponatremia; metabolic encephalopathy related to hypoglycemia; toxic encephalopathy; AMS explained by fever and pain without a separate encephalopathy diagnosis; other, please specify; unable to determine. That is type and cause. It is not a yes/no that introduces a new diagnosis. Under the 2026 guidance, yes/no queries may not introduce a new diagnosis .
Do not invent a CMS-mandated sodium cutoff. Ammonia, the basic metabolic panel, the arterial blood gas, TSH, B12, EEG, and the medication list are indicators. Delirium and encephalopathy are not interchangeable chase words; if the record uses both loosely, query rather than swapping them to pursue an MCC. Hypertensive encephalopathy is a hypertensive emergency with acute brain dysfunction, not chronic hypertension plus mild forgetfulness. Anoxic encephalopathy after cardiac arrest needs a provider diagnosis; a CT that does not show herniation yet neither codes it nor rules it out.
Seizures, epilepsy, and status epilepticus
A provoked seizure (alcohol withdrawal, tramadol, hypoglycemia, acute ICH) is not automatically epilepsy . Epilepsy is a chronic predisposition to unprovoked seizures. Status epilepticus — ongoing seizure activity or incomplete recovery between seizures, often treated with benzodiazepines, a loading antiseizure medication, continuous EEG, and sometimes intubation — is a different, higher-acuity diagnosis than had a seizure in the field.
Do not code epilepsy from a single withdrawal seizure. Do not code status from an EEG technician's preliminary comment. Do not relabel a post-ictal state as metabolic encephalopathy unless the provider documents a separate encephalopathic process. Treatments that function as indicators include lorazepam, a midazolam infusion, levetiracetam or fosphenytoin loads, propofol or pentobarbital for refractory status, and a continuous EEG order.
Original scenario. A 44-year-old with alcohol-use disorder seizes once in the ED, receives 2 mg lorazepam, returns to baseline in 25 minutes, and has a normal EEG the next morning. The ED note copies epilepsy from an old problem list. Neurology writes provoked withdrawal seizure, not epilepsy. CDI should query or clarify the outdated problem list rather than report chronic epilepsy. The 25-minute post-ictal period does not, by itself, establish metabolic encephalopathy.
Cerebral edema and coma
Radiology language of loss of sulci, blurring of gray-white differentiation, or edema is query bait , not a code. Many large infarcts have expected swelling. Clinically significant cerebral edema is suggested when the team uses hypertonic saline, mannitol, controlled hyperventilation, an external ventricular drain, or hemicraniectomy, or when neurosurgery documents herniation risk. Then ask the treating provider to diagnose or exclude clinically significant cerebral edema. Because a yes/no query cannot introduce a new diagnosis, first-time capture is usually multiple-choice , including other/please specify and an option that the imaging change is expected infarct swelling without a separate edema diagnosis.
Coma is not propofol for ventilator synchrony, is not groggy, and is not a GCS 3T that is entirely iatrogenic. Pathologic coma (structural, anoxic, metabolic) needs a provider statement. Induced coma is a treatment . If the record mixes them, query. A GCS of 8 or less often accompanies an intubation decision; it remains an indicator, not a coma code.
Putting the AMS query together
Source every indicator (ED history and physical, basic metabolic panel, arterial blood gas, CT, GCS, CAM-ICU, drug list). Offer only clinically relevant options — do not offer hypertensive encephalopathy for a blood pressure of 138/84, and do not offer hypernatremia for sodium 122. Include Other, please specify . Keep reimbursement words out. If you are validating a diagnosis already written that looks unsupported, multiple-choice with confirmed with support, ruled out, no longer valid, and an alternative diagnosis is the 2026-preferred clinical-validation pattern. Verbal queries still need date, time, people, indicators with source, a nonleading statement, options if any, and a response that reaches the permanent health record before coding.