SNOMED CTSystematized Nomenclature Of Medicine – Clinical Terms

---An introduction ---

Dr Karanvir SinghMBBS, MS, FRCS (Glasgow)

Chief Medical Information OfficeApollo Hospitals

Systematized Nomenclature of Pathology (SNOP)

1965 CAP

Broad clinical terms included (SNOMED)1975 CAP

Logic basedSNOMED-RT2000 CAP

Read codes1980s NHS UK

Read codes v3Clinical Terms v3

CTV31990s NHS UK

SNOMED-CT2007 IHTSDO

India became a member of the IHTSDO2014

SNOMED-CT2002CAP

NHS UK

US UK

SNOMED CT

SNOMED CTerminology

Coding system vs TerminologyA 66 year old man was brought the accident and emergency department of a trauma center hospital with a history of near drowning in a boating accident. After initial resuscitation he was airlifted, from the holiday resort he was staying in, by a medical helicopter. On admission he was unconscious…

Coding system – ICD-10A 66 year old man was brought the accident and emergency department of a trauma center hospital with a history of near drowning in a boating accident. After initial resuscitation he was airlifted, from the holiday resort he was staying in, by a medical helicopter. On admission he was unconscious…

Boating accident 90.1Near drowning T75.1Unconscious R40.2

Terminology – SNOMED CT A 66 year old man was brought the accident and emergency department of a trauma center hospital with a history of near drowning in a boating accident. After initial resuscitation he was airlifted, from the holiday resort he was staying in, by a medical helicopter. On admission he was unconscious…

Man 339947000 Boating accident 43682008Near drowning 87970004Holiday resort 257636005 Medical helicopter 32472009Resuscitation 439569004Trauma center 36125001Accident emergency 394576009On admission 278307001Unconscious 418107008

• No history of diabetes• Father has cataract• Hip replacement is planned for

next month

Natural language processing

Natural language processing

Snomed CT • Is the most comprehensive, multilingual clinical healthcare

terminology in the world

• Allows very granular data capture that can be viewed at any other level of granularity

• Allows powerful analytics & decision support

Snomed CT • Is the most comprehensive, multilingual clinical healthcare

terminology in the world

• Allows very granular data capture that can be viewed at any other level of granularity

• Allows powerful analytics & decision support

Snomed CT • Is the most comprehensive, multilingual clinical healthcare

terminology in the world

• Allows very granular data capture that can be viewed at any other level of granularity

• Allows powerful analytics & decision support

Snomed CT • Is the most comprehensive, multilingual clinical healthcare

terminology in the world

• Allows very granular data capture that can be viewed at any other level of granularity

• Allows powerful analytics & decision support

Snomed CT • Is the most comprehensive, multilingual clinical healthcare

terminology in the world

• Allows very granular data capture that can be viewed at any other level of granularity

• Allows powerful analytics & decision support

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Snomed CT • Is the most comprehensive, multilingual clinical healthcare

terminology in the world

• Allows very granular data capture that can be viewed at any other level of granularity

• Allows powerful analytics & decision support

Snomed CT • Is the most comprehensive, multilingual clinical healthcare

terminology in the world

• Allows very granular data capture that can be viewed at any other level of granularity

• Allows powerful analytics & decision support

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Let us see how it is better than existing healthcare coding systemsLet us compare it with ICD-10

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More clinical terms

Codes for Ectopic Pregnancy in ICD-10 • ICD-10 has five codes (terms) only• Abdominal• Tubal• Ovarian • Others• Unspecified

Terms for Ectopic pregnancy in SNOMED CT

Abdominal pregnancy Membranous pregnancy

Aborted ectopic pregnancy Mesenteric pregnancy

Angular pregnancy Mesometric pregnancy

Cervical pregnancy Miscarriage of tubal ectopic pregnancy

Combined heterotopic pregnancy Multiple pregnancy involving intrauterine pregnancy and tubal pregnancy

Combined intrauterine and ovarian pregnancy Mural pregnancy

Combined pregnancy Ovarian pregnancy

Combined tubal and intrauterine pregnancy Rudimentary horn pregnancy

Compound ectopic Ruptured ectopic pregnancy

Cornual pregnancy Ruptured tubal pregnancy

Delivery of viable fetus in abdominal pregnancy Secondary abdominal pregnancy

Fallopian pregnancy Simultaneous intrauterine and extrauterine pregnancies

Fallopian tube pregnancy Tubal abortion

Heterotopic pregnancy Tubal pregnancy

Intraligamentous pregnancy Unruptured tubal pregnancy

Intraperitoneal pregnancy Viable fetus in abdominal pregnancy

Multiple ‘ancestors’

ICD-10 classification system has a problem

Look at how Pneumonia is classified

Pneumonia is all over the place!

Section Code TitleInfectious disorders B01.2 Varicella pneumonia

Infectious disorders B05.2 Measles complicated by pneumonia

Infectious disorders B20.6 HIV disease resulting in Pneumocystis carinii pneumonia

Diseases of respiratory system J10.0 Influenza with pneumonia, other influenza virus identified

Diseases of respiratory system J11.0 Influenza with pneumonia, virus not identified

Diseases of respiratory system J12 Viral pneumonia, not elsewhere classified

Diseases of respiratory system J13 Pneumonia due to Streptococcus pneumoniae

Diseases of respiratory system J14 Pneumonia due to Haemophilus influenzae

Diseases of respiratory system J15 Bacterial pneumonia, not elsewhere classified

Viral pneumonia

Infectious disease of lung

Lower respiratory tract infection

Disorder of lung

Disease

Viral infection

Infective pneumoniaViral respiratory

infection

Viral disease

Infectious disease

Poly-hierarchy in SNOMED CT

ICD is running out of codes• Since code numbers are the main stay of classification, and the

number of diseases are very large in number, ICD is running out of codes.• Multiple disorders are being grouped under one code

ICD is running out of codes• Since code numbers are the main stay of classification, and the

number of diseases are very large in number, ICD is running out of codes.• Multiple disorders are being grouped under one code

Snomed CT has no limits on the codes that can be usedNo sharing of codes by two different conditions

Comparison of existing coding systems

Coding system ICD-10 ICD-10 PCS LOINC NANDA CPT4 SNOMED CT

Diagnosis Yes No No Partial No Yes

Procedures / operations

No (except pregnancy

related)Yes No No Yes Yes

Laboratory No No Yes No No Yes

Nursing No No No Yes No Yes

Special context (e.g not diabetic)

No No No No No Yes

Meaning based analytics

No No No No No Yes

Will SNOMED CT replace ICD-10?Yes & No

• Clinical modules & analytics would benefit from SNOMED CT

• The medical records departments will continue ICD-10

Let us look at the nuts & bolts of SNOMED CT

These are four different conditions (clinical ideas)

1. Ischemic heart disease2. Angina3. Unstable angina4. Myocardial infarction5. Heart attack6. Cardiac infarction7. MI

Same clinical meaning (idea)

Each clinical idea is called a concept

Each concept has a (near) random concept number

1. Ischemic heart disease 414545008

2. Angina 194828000

3. Unstable angina 4557003

4. Myocardial infarction5. Heart attack6. Cardiac infarction7. MI

Same clinical meaning (idea) 22298006

The same concept has different translations

1. Ischemic heart disease 414545008 - cardiopatía isquémica

2. Angina 194828000 - angina de pecho

3. Unstable angina 4557003 - síndrome preinfarto

4. Myocardial infarction5. Heart attack6. Cardiac infarction7. MI

Same clinical meaning (idea) 22298006 - infarto de miocardio

Independent system of classificationConcept Concept IDIschaemic Heart Disease 414545008Angina 194828000Unstable Angina 4557003Myocardial Infarction 22298006Heart Attack 22298006Cardiac Infarction 22298006MI 22298006

In independent system of classificationConcept Concept IDIschaemic Heart Disease 414545008Angina 194828000Unstable Angina 4557003Myocardial Infarction 22298006Heart Attack 22298006Cardiac Infarction 22298006MI 22298006

Myocardial disease

Myocardial necrosis

Necrosis of an anatomical site

Thus…• Each clinical idea is a concept and has a unique concept number• Each concept number has multiple terms for it• In different languages…• There is no limit on the number of concepts. Hence different

conditions do not have to share the same code• Concepts are connected to other concepts (parents / children)

independent of their codes – multiple relationships• There are other relationships also, defining different properties of a

concept

How do multiple relationships help?

Cellulitis of foot

Disorder of foot

Cellulitis of lower limb

Is a child of…Is a

Understanding the logic part of SNOMED CT

Very powerful analytics

Multiple types of relationships

Cellulitis of foot

Disorder of foot

Cellulitis of lower limb

CellulitisFoot structure

Is aIs a

Associated morphologyFinding site

Cellulitis of foot

Disorder of foot

Cellulitis of lower limb

CellulitisFoot structure

Is aIs a

Associated morphologyFinding site

Cellulitis of toe

Cellulitis of heel

Is a

Is a

Cellulitis of foot

Disorder of foot

Cellulitis of lower limb

CellulitisFoot structure

Is aIs a

Associated morphologyFinding site

Cellulitis of toe

Cellulitis of heel

Is aIs a

Toe structureFinding

site

CellulitisAssociated morphology

Is a

Cellulitis of foot

Disorder of foot

Cellulitis of lower limb

CellulitisFoot structure

Is aIs a

Associated morphologyFinding site

Cellulitis of toe

Cellulitis of heel

Is aIs a

Toe structureFinding

site

Heel structureFinding

site

CellulitisAssociated morphology

CellulitisAssociated morphology

Is aIs a

Cellulitis of foot

Disorder of foot

Cellulitis of lower limb

CellulitisFoot structure

Is aIs a

Associated morphologyFinding site

Cellulitis of toe

Cellulitis of heel

Is aIs a

Toe structureFinding

site

Heel structureFinding

site

CellulitisAssociated morphology

CellulitisAssociated morphology

List me all foot problems

Is aIs a

Cellulitis of foot

Disorder of foot

Cellulitis of lower limb

CellulitisFoot structure

Is aIs a

Associated morphologyFinding site

Cellulitis of toe

Cellulitis of heel

Is aIs a

Toe structureFinding

site

Heel structureFinding

site

CellulitisAssociated morphology

CellulitisAssociated morphology

List me all patients with cellulitis

Is aIs a

Associated morphology = Cellulitis*Cellulitis of footCellulitis of foot excluding toeCellulitis of forearmCellulitis of foreheadCellulitis of gingivaCellulitis of groinCellulitis of handCellulitis of hand excluding fingerCellulitis of headCellulitis of heelCellulitis and abscess of lower legCellulitis and abscess of lower limbCellulitis and abscess of neckCellulitis and abscess of nose (external)Cellulitis and abscess of perineumCellulitis and abscess of shoulderCellulitis and abscess of submandibular regionCellulitis and abscess of temple region

Conditions with the word “Cellulitis” within it *Partial data

Associated morphology = Cellulitis*Cellulitis of footCellulitis of foot excluding toeCellulitis of forearmCellulitis of foreheadCellulitis of gingivaCellulitis of groinCellulitis of handCellulitis of hand excluding fingerCellulitis of headCellulitis of heelCellulitis and abscess of lower legCellulitis and abscess of lower limbCellulitis and abscess of neckCellulitis and abscess of nose (external)Cellulitis and abscess of perineumCellulitis and abscess of shoulderCellulitis and abscess of submandibular regionCellulitis and abscess of temple region

Beat kneeChronic recurrent streptoccocal erysipelasCutaneous erysipeloidDisseminated cutaneous erysipeloidErysipelasErysipelas of lower limbErysipeloidFacial erysipelasLocalized cutaneous erysipeloidLudwig's anginaOnychia of fingerPhlegmonPostpartum AND/OR puerperal erysipelasRecurrent erysipelasSeal finger

Conditions with the word “Cellulitis” within it

Conditions even without the word “Cellulitis”

*Partial data

How relationships help in decision support

Pick up all cases of cerebrovascular accident for consideration for thrombolytic therapy

Use it to identify potential cohorts for clinical trials for a new breast cancer drug.

Warn if the patient has any type of diabetes AND any type of kidney disease

How is it used in a hospital’s EMR?

The hospital’s EMR software Snomed CT

Record services (EMR) Terminology services (Snomed CT)

Patient Ram Lal, age 56, admitted with a diagnosis of HerniHerniaInguinal herniaIndirect inguinal herniaIndirect inguinal hernia with obstruction

Leveraging relationshipsWe can show all the SubType concepts of E in the operation list of a foot surgeon

Operations on the foot

SubTypes (All descendants)Operations on the foot

Foot joint operations

Foot incision

Division of muscle of

foot

Tenotomy of abductor hallucis muscle

How will clinicians benefit from it?The drawbacks of current coding system that are addressed by SNOMED CT

ICD-10 has very limited search – no synonyms• The doctor may search for any of these terms for the same diagnosis• Renal calculus• Renal stone• Nephrolith• Calculus in kidney• Kidney stone• Kidney calculus

• Only the term Calculus in Kidney exists in ICD-10 • Such issues are present with most diagnosis

No abbreviations in ICD-10 • The doctor may search by typing• COPD• MI• IHD

ICD-10 terms are not appropriate for printing What the doctor wants to write What is available in ICD-10 tables – prints as such

Chronic obstructive pulmonary disease Chronic obstructive pulmonary disease, Unspecified

Ureterocele Other specified disorders of kidney and ureter

Neonatal tetanus Other tetanus

Achlorhydria Other specified diseases of stomach and duodenum

Recurrent appendicitis Other appendicitis

Indirect inguinal hernia Inguinal hernia

Direct inguinal hernia Inguinal hernia

Strangulated inguinal hernia Unilateral or unspecified inguinal hernia, with obstruction, without gangrene

Hepatic encephalopathy Hepatic failure, not elsewhere classified

Bird flu (H5N1) Influenza due to certain identified influenza virus

Swine flu (H1N1). Influenza due to certain identified influenza virus

ICD-10 codes are not appropriate for printing What the doctor wants to write What is available in ICD-10 tables – prints as such

Chronic obstructive pulmonary disease Chronic obstructive pulmonary disease, Unspecified

Ureterocele Other specified disorders of kidney and ureter

Neonatal tetanus Other tetanus

Achlorhydria Other specified diseases of stomach and duodenum

Recurrent appendicitis Other appendicitis

Indirect inguinal hernia Inguinal hernia

Direct inguinal hernia Inguinal hernia

Strangulated inguinal hernia Unilateral or unspecified inguinal hernia, with obstruction, without gangrene

Hepatic encephalopathy Hepatic failure, not elsewhere classified

Bird flu (H5N1) Influenza due to certain identified influenza virus

Swine flu (H1N1). Influenza due to certain identified influenza virus

Summary• Snomed CT is the terminology that supports the EMR. On its own it

does nothing• It is very clinician friendly• It is multilingual• It allows very powerful data analytics• It augments decision support capabilities of an EMR