5 Coding and Documentation Challenges

A coder-physician dialogue

an HCPro audio conference presented on

October 20, 2010

James S. Kennedy, MD, CCS

and

Margi Brown, RHIA, CCS, CCS-P, CPC, CCDS

Acute Kidney Injury

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Clinical Scenario

• An 80 yo lady is admitted from the nursing home with fever, hypovolemia, and a urinary tract infection.– Day 1

• Dx: Attending: Sepsis due to UTI, Renal Azotemia• Creatinine 2.0, BUN 40 (baseline Cr = 1.0 mg/dl)

– Day 3 • Dx: Renal consult: Acute Kidney Failure with acute interstititial

nephritis likely due to acute pyelonephritis• Creatinine 1.5, BUN 30; Blood culture + for E.coli.

– Day 5• DC Summary Dx by the attending physician:

E.Coli sepsis due to UTIAcute Kidney Injury, resolving

• Creatinine 1.3, BUN 15 (elevated 0.3 mg/dl from baseline)

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How should the kidney function be coded?Is query necessary?

• 584.9 – Acute Kidney Injury• 584.8 – Acute Renal Failure associated with

other specified pathological lesion of the kidney– Acute Interstitial nephritis is a pathological lesion

• 593.9 – Unspecified disorder of the kidney and ureter– Acute renal disease– Acute renal insufficiency

• 790.6 – Other abnormal blood chemistry– Azotemia

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What is “Acute Kidney Injury”?• Acute Kidney Injury

– a common clinical syndrome defined as a sudden onset of reduced kidney function manifested by increased serum creatinine or a reduction in urine output.

• It is NOT the underlying renal pathology

– Currently a preferred term and synonym for acute renal failure or acute kidney failure.

• Some physicians may not agree

Resource: Srisawat N., Hoste, E., Kellum, JA. Modern Classification of Acute Kidney Injury. Blood Purification 2010;29:300–307.

Available for free at:http://tinyurl.com/AKI-2010-Review

• Acute Kidney Insufficiency– The same definition as acute kidney

injury, yet the rise of creatinine or fall of urine output fails to meet the acute kidney injury criteria

• Azotemia– a medical condition characterized by

abnormally high levels of nitrogen-containing compounds, such as urea (BUN) , creatinine, various body waste compounds, and other nitrogen-rich compounds in the blood.

• Uremia– A term used to loosely describe the

illness accompanying kidney failure, in particular the nitrogenous waste products associated with the failure of this organ

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Instigating Causes of Acute Kidney Injury

• Pre-renal– Hypovolemia

– Impaired Cardiac Output

– Shock

– Bilateral renal artery stenosis

• Post-renal– Urinary obstruction

– Ureteral obstruction in a patient with one kidney

• Renal– Glomerular

• e.g. glomerulonephritis

– Tubulointerstitial• e.g. tubulointerstitial

nephritis, acute tubular necrosis

– Vascular• e.g. renal vasculitis,

bilateral renal embolism.

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Renal Pathology Associated with Acute Kidney Injury

• Ischemia– focal tubular necrosis

at multiple points with large skip areas in between

– often accompanied by rupture of basement membranes and occlusion of tubular lumens by casts

• Toxins– Tubular necrosis,

primarily in the proximal tubules

• Certain toxins have characteristic findings

7Source: Kumar, Robbins and Cotran. Pathologic Basis of Disease, Professional Edition , 8th ed. :

ICD-9-CM Index to DiseasesNephropathy Toxic – 584.5 – Acute Renal Failure with lesion of tubular necrosis

Renal Pathology associated with Acute Kidney Injury

• Acute Interstitial Nephritis– rapid clinical onset– Histology shows interstitial edema, often accompanied by leukocytic

infiltration of the interstitium and tubules, and focal tubular necrosis. – Seen with acute pyelonephritis, transfusion reactions, and allergic

reactions to medications. • Malignant Nephrosclerosis

– Occurs in accelerated and malignant hypertension– Fibrinoid necrosis of the arterioles

• Thrombotic Microangiopathies– Occurs with Disseminated Intravascular Coagulation (DIC), Thrombotic

Thrombocytopenic Purpura, and Hemolytic-Uremic Syndrome– Patchy or diffuse cortical necrosis (described later) and subcapsular

petechiae

8Source: Kumar, Robbins and Cotran. Pathologic Basis of Disease, Professional Edition , 8th ed. :

Can Acute Renal Failure and ESRD co-exist?

• Question: – What is the appropriate code assignment for a patient with

documented acute kidney failure and end stage renal disease (ESRD) during the same admission? Is acute kidney failure an acute exacerbation of chronic kidney failure?

• Answer: – Acute kidney failure and chronic kidney failure are two separate

and distinct conditions. • Acute renal failure has an abrupt onset and is potentially reversible.

Chronic kidney failure progresses slowly over time and can lead to permanent kidney failure. The causes, symptoms, treatments, and outcomes of acute and chronic are different.

• End-stage renal disease is when the kidneys permanently fail to work. – If both acute and chronic kidney failure are clearly documented,

code both.

Coding Clinic, 3rd Quarter, 2010, page 15.

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Clinical Criteria of Acute Kidney Injury

• Two prevailing definitions of AKI/ARF exist, as outlined in the following table

http://ccforum.com/content/11/2/R31 – AKIN; http://ccforum.com/content/8/4/R204 - ADQIGNote: AKIN criteria requires 2 creatinine levels 48 hours apart and presumes that fluid resuscitation has occurred. Neither require that the patient receives dialysis.

Note: Most nephrologists equate “RISK” in RIFLE to be Acute Kidney Injury, even if it is not labeled as such. Further clarification from these authors is forthcoming.

Other Laboratory SupportingAcute Kidney Injury

• Elevated Fractional Excretion of Sodium– aka – FENa

– Calculation:Urine Na x Plasma Cr

Plasma Na x Urine Cr

– Interpretation• Less than 1 – Prerenal• Over 3 – Acute Tubular

Necrosis

• Abnormal Urinanalysis– Protein– Blood– Casts

• Radiology– Dilated kidneys showing

obstruction– Impaired perfusion of the

renal cortex.• Biomarkers

– Not ready for prime time– Urine NGAL– KIM-1– Cystatin C– Interleukin-18

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X 100

ICD-9-CM Index

• Injury– kidney - see Injury, internal, kidney

• acute (nontraumatic) 584.9

• Note that Acute Kidney Injury ONLY codes to 584.9, Acute Kidney Failure, unspecified,– It does NOT code to 584.5 through 584.8

• The title of 584.9, Acute Kidney Failure, unspecified is the only indication in ICD-9-CM that acute kidney injury is equivalent to acute renal failure or acute kidney failure, yet coders may not assume this, given its listing in the Index to Diseases.

– Coding Clinic opinion is needed to determine if acute kidney injury with a specified renal pathological lesion codes to 584.5 through 584.8.

• Otherwise, the physician must document “acute renal failure” or “acute kidney failure” to qualify for these codes.

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What code is assigned to the initials “AKI”?

• Airplane sickness 994.6• Akathisia, acathisia 781.0

– due to drugs 333.99– neuroleptic-induced acute

333.99

AKI IS NOT IN THE INDEX TO DISEASES

• Akinesia algeria 352.6• Akiyami 100.89• Akureyri disease (epidemic

neuromyasthenia) 049.8• Alacrima (congenital) 743.65• Alactasia (hereditary) 271.3

• AKI can mean either– Acute Kidney Injury– Acute Kidney Insufficiency

• 3M’s encoder software considers AKI to be Acute Kidney Injury– Coding Clinic 4th Q 2008, page

192-193 statesHow should AKI be coded? Answer: Assign code 584.9, Acute renal failure, unspecified, for a nontraumatic acute kidney injury (AKI).

• Even so, given that AKI is not in the Index to Diseases, it’s always best that a physician write the term out if it is to be compliantly coded

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What about Acute Renal Failure?

• Failure, Renal– acute 584.9

• with lesion of – necrosis

» cortical (renal) 584.6» medullary (renal) (papillary) 584.7» tubular 584.5

– specified pathology NEC 584.8

ICD-9-CM Table 584 Acute kidney failure

Includes Acute renal failureExcludes:

– following labor and delivery (669.3) – posttraumatic (958.5) – that complicating:

• abortion (634-638 with .3, 639.3) • ectopic or molar pregnancy (639.3)

• 584.5 Acute kidney failure with lesion of tubular necrosis

– Lower nephron nephrosis– Renal failure with (acute) tubular

necrosis– Tubular necrosis:

• NOS• acute

• 584.6 Acute kidney failure with lesion of renal cortical necrosis

• 584.7 Acute kidney failure with lesion of renal medullary [papillary] necrosis

– Necrotizing renal papillitis• 584.8 Acute kidney failure with

other specified pathological lesion in kidney

• 584.9 Acute kidney failure, unspecified

Acute kidney injury (nontraumatic)

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593.9 – Unspecified disorder of kidney and ureter (Not a CC at all)Acute renal insufficiency or acute renal disease

790.6 – Other abnormal blood chemistry (Not a CC at all)Azotemia

586 – Renal failure, unspecified – uremia (Not a CC; Level 2 in APR-DRG)

MS-DRG & APR-DRGMCC/CC Classification

584 Acute kidney failure • 584.5 Acute kidney failure with

lesion of tubular necrosis • 584.6 Acute kidney failure with

lesion of renal cortical necrosis • 584.7 Acute kidney failure with

lesion of renal medullary [papillary] necrosis

• 584.8 Acute kidney failure with other specified pathological lesion in kidney

• 584.9 Acute kidney failure, unspecified

Acute kidney injury (nontraumatic)

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← Major CC APR SOI = 4 APR ROM = 4← Major CC APR SOI = 4 APR ROM = 3← Major CC APR SOI = 4 APR ROM = 3← Major CC APR SOI = 4 APR ROM = 3← On October 1, 2010, CMS changed 584.9 from a MCC to a CC APR SOI = 4 (?) APR ROM = 3 (?)

The meaning of the word “with”

• ICD-9-CM Official Guidelines for 2011 – New addition– The word “with” should be interpreted to mean “associated

with” or “due to” when it appears in a code title, the Alphabetic Index, or an instructional note in the Tabular List.

– The word “with” in the alphabetic index is sequenced immediately following the main term, not in alphabetical order.

• Faye Brown’s ICD-9-CM Coding Handbook– Words such as “with” and “in” indicated that both elements in the

title must be present in the diagnostic or procedural statement.– Although these terms do not necessarily indicate a cause-effect

relationship, they occur together much of the time and the classification system indicates this relationship.

• Note – While Faye Brown is not official advice, it is written by Coding Clinic and should reflect their positions.

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The meaning of the word “with”

• Osteomyelitis (general) (infective) (localized) (neonatal) (purulent) (pyogenic) (septic) (staphylococcal) (streptococcal) (suppurative) (with periostitis) 730.2– due to or associated with

• diabetes mellitus 250.8 [731.8]

• Coding Clinic, 1st Quarter, 2004, pages 14-15

– ICD-9-CM assumes a relationship between diabetes and osteomyelitis when both conditions are present, unless the physician has indicated in the medical record that the acute osteomyelitis is totally unrelated to the diabetes.

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Even though this Coding Clinic advice is very clear for osteomyelitis associated with diabetes, some coders will not generalize this advice to other conditions labeled in a similar manner.

584.5 Acute kidney failure with lesion of tubular necrosis

• Acute tubular necrosis (ATN) is defined by acute kidney injury and tubular damage in the absence of significant glomerular or vascular pathology.– Tubular casts, red cells,

and protein may be seen in the urinanalysis.

– If the offending agent is removed, the kidneys usually repair themselves.

• Most common cause of renal pathology causing AKI– Ischemic

• Shock, hypotension– Toxic

• Radiological contrast media• Aminoglycosides• Cephalosporins• Amphotericin• Anesthetic agents• Antiviral agents• Thiazides• Calcineurin inhibitors• Herbal medications

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ICD-9-CM Index•Nephropathy

• Toxic – 584.5• Vasomotor – 584.5

584.6 Acute kidney failure with lesion of renal cortical necrosis

• Necrosis of the renal cortex, usually due to hypoperfusion– 2% of adult AKI– 20% of pregnancy-related AKI

• Related conditions– Pregnancy-related conditions

(more than 50% of cases) • Placental abruption• Infected abortion• Prolonged intrauterine fetal death• Severe eclampsia

– Neonatal conditions • Congenital heart disease• Fetal-maternal transfusion• Dehydration• Perinatal asphyxia

– Childhood conditions • HUS• Acute gastroenteritis with

dehydration

• Diagnosis– Contrast-enhanced CT

scanning • CT scanning with contrast are the

most sensitive imaging modality.• Diagnostic features include

absent opacification of the renal cortex and enhancement of subcapsular and juxtamedullary areas and of the medulla without excretion of contrast medium.

– Renal scanning • Diethylenetriamine pentaacetic

acid (DTPA) scan reveals markedly diminished perfusion with delayed or no function.

• Renal scan is the imaging technique of choice to diagnose renal cortical necrosis in transplant kidneys or if contrast-enhanced CT scanning are unavailable.

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584.7 Acute kidney failure with lesion of renal medullary [papillary] necrosis

• Necrosis of the papilla– Occurs with

cumulative toxicity from analgesic medication

• Tylenol• Goody Powders

– Sickle Cell disease– Acute pyelonephritis– Diabetes mellitus

21Photo Source: POLAND/PoznańSource: http://tinyurl.com/3ysws6c Photo reproduction governed by: http://creativecommons.org/licenses/by-sa/2.5/deed.en

584.8 Acute kidney failure with other specified pathological lesion in kidney

• Most of the codes of 580-583 would qualify as specified pathological lesions. Those that would not include:– 580.9 Acute glomerulonephritis

with unspecified pathological lesion in kidney

– 581.9 Nephrotic syndrome with unspecified pathological lesion in kidney

– 582.9 Chronic glomerulonephritis with unspecified pathological lesion in kidney

– 583.9 Nephritis & Nephropathy with unspecified pathological lesions

Category 583 includes "renal disease" so stated, not specified as acute or chronic but with stated pathology or cause.

• 583.8 Nephritis and nephropathy, not specified as acute or chronic with other specified pathological lesion in kidney– 583.81 in diseases classified

elsewhere – Code first underlying disease, as:

• amyloidosis (277.30-277.39) • diabetes mellitus (249.4, 250.4) • gonococcal infection (098.19) • Goodpasture's syndrome (446.21) • systemic lupus erythematosus

(710.0) • tuberculosis (016.0)

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581.81 (e.g. diabetic nephrosis) and 583.81 (e.g. diabetic nephropathy) would appear to qualify as a linking term to 584.8, Acute Renal Failure with other specified renal pathology, if not for the following Coding Clinic

584.8 vs. 584.9CC, 2nd Quarter, 2003, page 7

• Question: The patient is a 36-year-old female with a long-standing history of systemic lupus erythematosus admitted in acute renal failure secondary to the lupus nephritis. In this case, should the acute renal failure or lupus nephritis be sequenced as principal diagnosis?

• Answer: – Assign code 710.0, Systemic lupus erythematosus, as the principal

diagnosis. • The physician's documented that the patient was admitted for lupus

nephritis. – Code 584.9, Acute renal failure, unspecified– Code 583.81, Nephritis and nephropathy, not specified as acute or

chronic in diseases classified elsewhere.

Note that 584.8 - Acute kidney failure with other specified pathological lesion in kidney - was not recommended, even though 583.81 is coded as an “other” specified pathology and a direct link between the acute renal failure and the lupus nephritis.

Coding Clinic needs to clarify when to use 584.8 or 548.9 in light of ICD-9-CM conventions and the definition of the word “with” and “specified pathologic lesions”. In the meantime, this Coding Clinic will likely be used by RACs in their audits.

Acute Kidney InjurySummary

• Physician education is essential to identify acute kidney injury– Please use the academic articles provided

• For the most part, to code 584.5-584.8, physicians must document “acute renal failure” instead of “acute kidney injury”– Physicians must cite acute kidney injury’s underlying

pathology (e.g. ATN – Interstitial nephritis – renal cortical necrosis – toxic nephropathy) and, to be safe, link it to the acute renal failure.

– Uncertain diagnoses cannot be coded unless documented at the time of discharge.

• Contact Coding Clinic for official advice in how to code acute renal failure “with” the specified pathological lesions in 580-583.

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Clinical Scenario• An 80 y/o lady is admitted from the nursing home with fever,

hypovolemia, and a urinary tract infection.– Day 1

• Dx: Attending: Sepsis due to UTI, Renal Azotemia• Creatinine 2.0, BUN 40 (baseline Cr = 1.0 mg/dl)

– Day 3 • Dx: Renal consult: Acute Kidney Failure with acute interstititial

nephritis likely due to acute pyelonephritis• Creatinine 1.5, BUN 30; Blood culture + for E.coli.

– Day 5• DC Summary Dx by the attending physician:

E.Coli sepsis due to UTIAcute Kidney Injury, resolving

• Creatinine 1.3, BUN 15 (elevated 0.3 mg/dl from baseline)

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• Final codes: 038.42 + 995.91 + 599.0 + 584.9 + 580.89.• Even though the consultant wrote “acute renal failure”, it conflicts with

acute kidney injury written by the attending. • Pyelonephritis was “uncertain”, thus not coded.

Thank You

Questions?