As always when I present any coding lecture, I will stick to my style in this post as well firstly to describe (i) the basic anatomy of the visual system and its connections, (ii) explain how this “machinery” functions to produce vision. (iii) what happens when this “machinery” malfunctions and (iv) end with the appropriate International Statistical Classification of Diseases and Related Health Problems, 10th Revision, 2010 edition,  (ICD-10) codes to apply along with any peculiarities and nuances, if any. However, I will be brief as possible with (i), (ii) and (iii) for posts like this one so as not to be too lengthy and burdensome to the reader passing through this website-blog.

My plan is to discuss conditions affecting the ocular muscles, disorders of refraction and accommodation, visual disturbances  and cover visual impairment and blindness in this post.

We normally gaze with each eye coming to the same point in space, that is to say that the eyes are aligned in the same direction. This is called binocular vision.  Coordinated eye movements also allows us the ability to see in 3-D. All this is possible with the aid of the extraocular muscles  around the eyes.

Problems arise when there is lack of coordination between eyes where the eyes are not parallel and not aligned with one another. They then prevent the gaze of each eye to enable binocular vision and affecting depth perception (3-D vision). One or both eyes may turn inward, and the patient is cross-eyed. He or she will have double vision and/or there is visual loss in one eye without the ability to see in 3-D. One or both eyes may also turn out, especially seen in paediatric cases.

Conditions affecting the ocular muscles affecting binocular movement include strabismus. Forms of strabismus include esotropia characterised by a turning inward of one or both eyes and exotropia when the eye is turned out.

Strabismus in ICD-10 is part of the disorders of ocular muscles affecting binocular movement. It is grouped under the ICD-10 codes block of H49 to H52. However, the classification of strabismus in ICD-10 is differentiated by the category H50 for all conditions that involves lack of coordination between the extraocular muscles affecting binocular movement and another category H40 which is for conditions caused by the paralysis of the lateral rectus muscle. Within the category H50, ICD-10 provides codes for the different types of esotropia and exotropia, i.e monocular, alternating and intermittent. H51 is the third category for all other disorders of binocular movement.

Myopia, also called nearsightedness and hypermetropia, also called farsightedness are common disorders of refraction and accommodation. Disorders of refraction and accommodation would not be complete if I do not mention here about astigmatism and presbyopia. The category H52 includes myopia, hypermetropia, astigmatism and presbyopia among others.

Many conditions listed under visual disturbances in ICD-10 can be symptoms of another condition, for example vascular disease, diabetes and congenital conditions.

Amblyopia (also known as ‘lazy eye’, is loss of vision in an eye which is otherwise healthy), blurred vision (patient suffers a loss of sharpness of vision and the inability to see small details), diplopia (double vision) causing a patient to see two objects instead of one and scotomas (blind spots) are areas in the field of vision that have been partially altered resulting in an area of partially diminished or entirely deteriorated visual acuity, surrounded by a normal field of vision.

Blurred vision is reported under code H53.8 Other visual disturbances, unlike all the other specified visual disturbances each with a separate ICD-10 code.

Do take note that the code for scintillating scotoma is not found under the subcategory H53.4 Visual field defects along with other types of scotomas, but you will find it is listed under subjective visual disturbances with the ICD-10 code H53.1

Before I go on to relate ICD-10 codes relevant to visual Impairment and blindness, I think it is worthwhile to understand the word perception in relation to the eye.

Martin (2008, p.180) explains that perception “is an internal representation of our external environment.” When a person becomes aware of, knows, or identifies an object by means of the senses (in this case the eyes), this act or faculty of perceiving, or apprehending by means of the senses or of the mind, cognition, and understanding is said to be visual perception. One hypothesis according to Martin (2008) is called ‘what’ vs. ‘how’ which postulates  that the visual system is divided into two or more streams of information. The ‘what’ pathway mediates the conscious recognition of objects and scenes. The ‘how’ pathway provides visuospatial information (ability to process and interpret visual information about where objects are in space) directly into the motor systems (the part of the central nervous system that is involved with movement) to guide our actions. Thus, different aspects of visual perceptions such as movement, depth, colour and shape are processed separately.

When a patient lacks in visual perception due to physiological or neurological factors, they are considered to have a form of visual impairment or blindness . Visual impairment is a chronic visual deficit situation when a patient complains that every day functioning is impaired. Eyeglasses or contact lenses cannot correct this impairment.

Total blindness is the other situation when there is a complete lack of form and there is no visual light perception.

Visual impairment including blindness in ICD-10 is classified to H54. A table below H54 gives a classification of severity of visual impairment. The definitions of codes, for example “Visual impairment category 5” is the definition for the code H54.0 Blindness, binocular is referred from this table. From the table, total blindness must be coded to H54.0 since the patient’s vision is deficit due to no visual light perception and because the definition of code H54.0 is “Visual impairment category 5”

In the next post, let’s examine (i) the two categories in the other disorders block of codes, nystagmus and other irregular eye movements and intraoperative and postoperative complications, (ii) conditions affecting the eyes that originate during the perinatal period, and (iii) traumatic injuries of the eye and ocular adnexa.

References:

1. Gerard, JT & Bryan, D 2012, Principles of Anatomy & Physiology, 13th edn, John Wiley & Sons, Inc, New Jersey, USA
2. Martin, JT 2008, An Introduction to the Visual System,  2nd edn, Cambridge University Press, Cambridge, UK
3. Michael, M & Valerie, OL 2012, Human anatomy, 3rd edn, The McGraw-Hill Companies, Inc., New York, USA
4. Phillip, T 2012, Seeley’s principles of anatomy & physiology, 2nd edn, The McGraw-Hill Companies, Inc., New York, USA
5. World Health Organization 2011, Volume 1 Tabular list, International Statistical Classification of Diseases and Related Health Problems 10th Revision, 2010 edn, Geneva, Switzerland

As I wrote some weeks ago in the post APDC: Relevant conditions and scenarios that affects the eyes – Part 1 (this link will open in a new tab of your current browser window), in this new instalment post of coding diseases of the eye and adnexa, I shall discuss about cataracts affecting the lens, conditions affecting the choroid and retina, on to glaucoma characterised by damage of the optic nerve, and to end this post with some conditions affecting the vitreous body and globe and their appropriate coding.

ICD 10 has one (1) block ranging from codes H25-H28 for all disorders of lens within the Chapter VII Diseases of the eye and adnexa (H00-H59). Within this block, a Health Information Management (HIM) / Medical Records (MR) practitioner  will find four (4) sub-divisions (subcategories) of three (3) category categories of codes. The first sub-division H25 is for the single condition affecting the older population group – the senile cataract, three-character categories which I believe have been selected or grouped because of their frequency, severity or susceptibility to public health intervention.  The second, third and fourth sub-divisions i.e H26, H27 and H28 are grouped among diseases with some common characteristic as well as allowing many different but rarer conditions. As always there is a provision for ‘other’ conditions to be classified. Do take note that H25 to H27 each has a category for ‘unspecified’ conditions.

The results from the last known national eye survey conducted in 1996 to determine the prevalence of blindness and low vision and their major causes among the Malaysian population of all ages, cataract was the leading cause of blindness (39%) followed by retinal diseases (24%) and another result finding showed that uncorrected refractive errors (48%) and cataract (36%) were the major causes of low vision.

When coding cataracts in the young population, cataracts present at birth takes it place among the codes in the Chapter XVII Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99). Code H26.0 is only for cataracts diagnosed until later in life of new-borns namely infantile cataracts present early in life, but are not present at birth. Also take note that the subcategory for infantile and juvenile cataracts includes the descriptor presenile.

Cataracts caused by an underlying inflammatory disorder example cataract in chronic iridocyclitis are included in the category “Complicated cataract (H26.2)”.  Remember the option to use additional external cause code (Chapter XX), if desired, to identify drug in the case for drug-induced cataract or if desired, to identify cause in the case for traumatic cataract.

Two codes are required  for diabetic cataract, a special coding condition, whereby the coder has to go elsewhere to find the code for the underlying generalised disease and also report the code H28.0 since diabetic cataract is indeed a manifestation in a particular organ or site, in this case the eye and specifically the lens. This is the principle of the dagger and asterisk system which provides alternative classifications. Always code the primary code for the underlying disease which will be marked with a dagger (†) and code the optional additional code for the manifestation to be marked with an asterisk (*), in this case H28.0 The eye specialties everywhere normally have a desire to see diabetic cataract classified to the Chapter VII for this manifestation when it was the reason for medical care.

Now, for example when the diabetes is not identified as type 2? How do you code?

Rationally, I would code to E11.3 as the dagger code because of the following connection which is (i) you are directed from H28.0* – diabetic cataract to go to the block E10-E14 with common fourth character .3+, (ii) then I look up the block diabetes mellitus (E10-E14) from the Chapter IV Endocrine, nutritional and metabolic diseases (E00-E90), I find first “With ophthalmic complications, Diabetic: .3+, cataract (H28.0*) as among a list of fourth-character subdivisions for use with categories E10-E14 and type II, a inclusion term is listed below E11, and finally, (iii) since the coder is required to “See before E10 for subdivisions”. In summary, the asterisk code H28.0* leads me to find E11.3 from the above mentioned connection.

The category H33 lists codes regarding retinal detachments, when the retina is pulled or lifted away from its normal position. When there is a retinal break, detachment may or may not happen. Horseshoe tear, a type of retinal detachment with no retinal break is quite commonly reported and is given the code H33.3

What if you are presented with the main term “congenital macular degeneration” as the diagnosis? How will you find the correct code? You could look at congenital first, and you will be directed to find the condition. The condition is macular degeneration. Finding macular, you will locate degeneration (H35.3), and then to find hereditary (H35.5) at the second level.  This is the way your find your way in the Alphabetic Index forest of codes.

Glaucoma is another serious condition of the eye, actually it is a group of diseases of the eyes characterised by damage of the optic nerve which can lead to permanent damage to the optic nerve, loss of peripheral vision, and eventually, blindness. You may encounter some that are chronic and some that are acute while coding glaucoma.

In ICD 10, glaucoma that is described as congenital glaucoma is reported with a code from glaucoma described as childhood, infantile, juvenile, or congenital are all reported as congenital glaucoma with a code from Chapter XVII Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99) unlike in the past revision, ICD 9 when glaucoma that is described as childhood, infantile, or juvenile is reported with a code from the Chapter 6 – Nervous System and Sense Organ.

Glaucoma may be secondary to eye trauma,  eye inflammation, to other eye disorders and maybe even drugs. You may use the additional code, if desired, to identify cause or use the additional external cause code (Chapter XX), if desired, to identify drug.

You may not find any specific code for glaucoma associated with vascular disorders this time around in ICD 10, and the likely code to pick will be H40.8 Other glaucoma.

Endophthalmitis is to me the most common condition I had encountered for all conditions affecting the globe, affecting multiple structures of the eye, such as inflammation, degenerative conditions, and retained foreign bodies. Infact the inclusion clause “disorders affecting multiple structures of eye” included below H44 Disorders of globe already confirms this. By the way, endophthalmitis is an inflammatory condition within the intraocular cavities affecting the aqueous or vitreous humor. However, the ICD 10 does not differentiate between the terms acute, chronic, and unspecified endophthalmitis anymore but you can look up the Alphabetic Index and locate the qualifying terms like acute and subacute listed there under the lead term endophthalmitis, and the go find the appropriate code H44.0 Purulent endophthalmitis.

Coding vitreous haemorrhage in ICD 10 has changed, it now stands alone as H43.1, unlike in ICD 9.

Incidentally I have delayed writing this kind of posts as it required pulling together all my resources, understanding all the diseases and conditions in this Chapter, and finally a desirable post for the reader I wish to convince into reading a technical post like this one.

Readers, I think I have not more than three (3) more instalment posts on coding diseases of the eye and adnexa.

Happy coding!

References:

1. Gerard, JT & Bryan, D 2012, Principles of Anatomy & Physiology, 13th edn, John Wiley & Sons, Inc, New Jersey, USA
2. Michael, M & Valerie, OL 2012, Human anatomy, 3rd edn, The McGraw-Hill Companies, Inc., New York, USA
3. Phillip, T 2012, Seeley’s principles of anatomy & physiology, 2nd edn, The McGraw-Hill Companies, Inc., New York, USA
4. World Health Organization 2011, Volume 1 Tabular list, International Statistical Classification of Diseases and Related Health Problems 10th Revision, 2010 edn, Geneva, Switzerland
5. Zainal, M, Ismail, SM, Ropilah, AR, Elias, H, Arumugam, G, Alias, G, Fathilah, J, Lim, TO, Ding, LM and Goh, PP 2002, Prevalence of blindness and low vision in Malaysian population: results from the National Eye Survey 1996, British Journal of Ophthalmology, September; 86(9): 951–956., viewed 27 Nov 2013, <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1771293/>

In everyday International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) Version 2010 coding, answers to your coding questions can be found by reviewing or referring to the ICD-10 coding books. However, in this post I like to highlight some key documentation elements for the eye and adnexa.

On of the first things to take note when coding diseases of the eye and adnexa is when a Health Information Management (HIM) / Medical Records (MR) practitioner coder will find codes with the letter H shared among two chapters of the ICD-10.

I am sure a HIM / MR practitioner must already know that the ICD-10 classification is divided into 21 chapters, the first character of any ICD-10 code is a letter, one letter is generally associated with a particular chapter, except for some letters like the letter H will be found among codes in both Chapter VII, Diseases of the eye and adnexa and Chapter VIII, Diseases of the ear and mastoid process.

I shall not be detailed in this post but I intend to lead a discussion of the various diseases, disease processes, disorders, injuries, and conditions, some diagnostic statements related to diseases of the eye and adnexa.  I shall confine to infectious diseases of the eye, neoplasms of the eye, eyelid disorders, the lacrimal system, the conjunctiva, and end with the sclera, cornea, iris, and ciliary body.

One of the common diseases of the eye and adnexa are due to infections of the eye. I can quickly relate to viral conjunctivitis, eye infections that often involves the conjunctiva that are reported with codes from Chapter 1 Certain Infectious and Parasitic Diseases.  My experiences have shown that only a few eye infections are reported with codes from Chapter 1 while I think the vast majority of eye infections are reported with codes from Chapter 7 – Diseases of the Eye and Adenxa.  Do take note of some types of conjunctivitis that are reported with a single code from Chapter 1.

All parts of the eye may be affected by neoplasms. which may be primary, secondary (metastatic) or benign. Coders then will need to rush into Chapter II – Neoplasms and look up for example, the malignant neoplasms of eye and adnexa under ICD-10 code C69.

Symptoms that include eyelid tenderness or pain, increased tearing, and sensitivity to light are reported as chalazion, when the Meibomian gland (tiny oil gland in the eye) duct is blocked. Blepharitis is an inflammation of the eyelash follicles, along the edge of the eyelid. Entropions, when there is a turning inward of the eyelid so that the eyelashes rub against the surface of the eye can irritate the eye and in severe cases may cause corneal abrasion, ulcer, or scarring. Entropions may be acquired or congenital.  Acquired entropions and ectropions are two conditions that occurs primarily in the elderly (senile populations). Coding chalazion, blepharitis, but less of entropions and etropions (you probably get to code these two if you work at a hospital or eye centre with an eye speciality) are some common diagnoses I have encountered.

Look out for subtle differences in coding for example when coding chronic enlargement of the lacrimal gland as against chronic dacryadenitis. When dacryadenitis is reported alone, then assign code to H04.0 Chronic enlargement of the lacrimal gland, but assign code H04.4 when chronic dacryadenitis is reported.

Several conditions affect the sclera, cornea, iris and ciliary body which are structures in the anterior chamber of the eye. I can think of the cornea which is subject to inflammatory conditions such as corneal ulcer and keratitis, and conditions commonly affecting the iris and ciliary body which include inflammatory conditions such as iritis, iridocylitis, or cyclitis, and even cysts which may form in the iris or ciliary body. Disorders of sclera, cornea, iris and ciliary body are found in the block H15 to H22.

In the next instalment, I shall discuss about cataracts which is the single very common condition affecting the lens, conditions affecting the choroid and retina, moving on to glaucoma which is actually a group of diseases of the eyes characterised by damage of the optic nerve, and end with some conditions affecting the vitreous body and globe.

References:

1. Gerard, JT & Bryan, D 2012, Principles of Anatomy & Physiology, 13th edn, John Wiley & Sons, Inc, New Jersey, USA
2. Michael, M & Valerie, OL 2012, Human anatomy, 3rd edn, The McGraw-Hill Companies, Inc., New York, USA
3. Phillip, T 2012, Seeley’s principles of anatomy & physiology, 2nd edn, The McGraw-Hill Companies, Inc., New York, USA
4. World Health Organization 2011, Volume 1 Tabular list, International Statistical Classification of Diseases and Related Health Problems 10th Revision, 2010 edn, Geneva, Switzerland

In the International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) Version 2010, the Chapter VII: Diseases of the eye, adnexa is dedicated specifically for diseases of the eye and adnexa.

In this first part and the next post(s) dedicated to relevant conditions and scenarios that affects the eyes, I like to present most (if not all) the relevant conditions and scenarios that affects the eyes, which are considered as the most complex of the four special sense organs.

The relevant conditions and scenarios that affects the eyes are those affecting the structures that are specifically related to vision as well as accessory structures. The eyeball, optic nerve, and brain are the structures related to vision typically activated by a stimulus, such as light, in the external environment which is detected by the cells of the eye, thereby sending electrical impulses to the visual center and other parts of the brain. In addition to allowing light perception, the eye performs other tasks such as color differentiation and depth perception. The accessory structures include the eyebrows, eyelids, ocular muscles, and lacrimal glands.

As you can see from the anatomy of the human eye in the image below, the eye is divided into three layers: the fibrous tunic (also referred to as the scleretic coat – the external layer of the eye divided into two parts, the sclera, also called the white of the eye, and the anterior cornea), vascular tunic (also referred to as the uvea or choroid coat – this is the middle layer of the eye and structures contained in the vascular tunic include the choroid, ciliary body and iris), and lastly the retina (the inner layer of the eye, which is composed primarily of nervous tissue including various types of cells for the primary function of image formation).

As I am not a eye care trained nurse nor an ophthalmologist to provide a full length description of conditions and scenarios  affecting the human eye (nonetheless it is pointless doing so, when one can gain such knowledge from any good Anatomy and Physiology academic textbook), and so I shall confine myself to my perspective of past coding experiences and knowledge of common and top conditions and scenarios affecting the human eye that Health Information Management (HIM) / Medical Records (MR) practitioners may also encounter in their everyday coding duties.

If a HIM / MR practitioner reader was to examine closely the Chapter VII, he or she will find (to my best knowledge) the following ICD-10 categories relevant to the eye and adnexa with conditions and scenarios which demand eye care:

C69.*** Malignant neoplasm

D31.*** Benign neoplasms

H01.***: Conditions of the eyelid

H02.***: Entropions

H04.***: Conditions of the lacrimal system

H05.***: Conditions of the orbit

H10.***: Conjunctival conditions

H15.***: Conditions of the sclera

H16.***: Keratoconjunctivitis

H17.***: Conditions of the cornea

H18.***: Keratopathies

H20.***: Conditions of the iris

H21.***: Disorders of iris and ciliary body

H25.***: Cataracts

H26.***: Cataracts, other

H27.**: Conditions of the lens

H30.**: Chorioretinal conditions

H31.***: Conditions of the Choroid

H33.**: Conditions of the retina

H34.***: Retinal occlusions

H35.***: Retinal changes

H40.***: Glaucoma

H43.***: Vitreous codes

H44.***: Disorders of vitreous body and globe

H44.6**: Unspecified retained (old) intraocular foreign bodies

H47.***: Neuropathies

H51.***: Convergence disorders

H52.***: Refraction Disorders

H53.***: Amblyopia/visual field defects

H54.***: Blindness

H55.***: Nystagmus

H57.***: Pupillary Disorders and ocular pain

H59.***: Disorders following Surgery

R**.***: Sign and symptom codes (headache, weakness, malaise, fever, shock)

R00 – R99: Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified as in the case of abnormal results of function studies of peripheral nervous system and special senses, e.g abnormal electroretinogram [ERG]

S**.***x: S Codes – injury, poisoning and certain other consequences of external causes, involving injury of eye and orbit

T**.***x: T Codes – e.g. FB in cornea

T74.***: adult and child abuse, neglect and maltreatment, using additional code, if desired, to identify current injury to the eye and adnexa (if any)

T36 -T50: Poisoning by drugs, medicaments and biological substances: poisoning by topical agents primarily affecting skin and mucous membrane and by ophthalmological, otorhinolaryngological and dental drugs e.g ophthalmological drugs and preparations as in the case of eye anti-infectives

X00 – X99: External causes of morbidity from e.g exposure to smoke, fire and flames

V01 – V99: External causes of morbidity due to transport accidents

Z00-Z99: Factors influencing health status and contact with health services, e.g examination of eyes and vision

The above list is inclusive of the nine (9) block of codes for coding conditions and scenarios related to eye and adnexa ranging from H00 to H59 in Chapter VII. However, the list also includes codes which are not classifiable to Chapter VII, as you as the interested reader can figure out from the exclusion note right at the beginning of this chapter. Attention is also required  when asterisk categories for this chapter are provided also at the beginning of this chapter for several disorders and glaucoma in diseases classified elsewhere.

Thus, HIM / MR practitioners need to be alert to coding correctly for eye care when they encounter conditions and scenarios  affecting the human eye which were not reported by any eye care speciality, signs and symptoms not specifically eye care, injuries and accident to the eye, top peripheral codes applicable to eye care such as diabetes and hypertension, Late Effect Codes listed as “Sequela” and foreign body in the eye(s).

In the next part, I plan to present a variety of diseases, disorders, injuries, and other conditions involving the eye and adnexa. I will present some images to present the anatomy and physiology of more commonly encountered conditions involving the eye and adnexa, expanding from there to provide a better understanding regarding the part of the eye or adnexa affected and how these conditions affect function.

Following the images of the more commonly encountered various diseases, disease processes, disorders, injuries, and conditions, I will of course present the ICD-10 codes and any coding concepts and guidelines relevant to Chapter VII.

References:

1. Gerard, JT & Bryan, D 2012, Principles of Anatomy & Physiology, 13th edn, John Wiley & Sons, Inc, New Jersey, USA
2. Michael, M & Valerie, OL 2012, Human anatomy, 3rd edn, The McGraw-Hill Companies, Inc., New York, USA
3. Phillip, T 2012, Seeley’s principles of anatomy & physiology, 2nd edn, The McGraw-Hill Companies, Inc., New York, USA
4. World Health Organization 2011, Volume 1 Tabular list, International Statistical Classification of Diseases and Related Health Problems 10th Revision, 2010 edn, Geneva, Switzerland

Burns are common conditions seen in the Emergency Room (ER) / Department (ED) when a traumatic injury results in tissue loss or damage on body region(s). Caroline and Mary (2012 p. 1206) classify burns “according to the mechanism of injury and according to burn depth and size”,

An example of an ER / ED case is when a 56 year old man presents with an  electrical burn while undertaking mechanical repairs to his car when his metal wrist watch had made contact with part of the electrical system. Although electrical burns can be potentially life threatening, especially if caused by electric shocks due to exposure to electricity current or lightning, this patient experienced immediate pain from an injury to the radial aspect of his right wrist with subsequent skin changes and discomfort at the periphery of the lesion.

Image credit: BMJ 2013;346:f2856

The ER / ED doctor will assess to estimate the total body surface area and depth of this burn as seen from the photograph (left), and manage this ED / ER case.

Other common examples of burns seen in the ER / ED are thermal burns as a result of direct contact with heat sources – example caused by steam, hot water scalds, and flames, electrical burns as well chemical burns caused by exposure to strong acids,
alkalis, or other substances such as detergents or solvents especially affecting the skin and eyes, and radiation burns from exposure to radioactive sources, such as the ionizing radiation used in industry, or therapeutic radiation.and sunburns.

The International Classification of Diseases (ICD), 10th Revision: Version 2010 provides several codes to classify burns.

Burns are classified under the Chapter XIX Injury, poisoning and certain other consequences of external causes (S00-T98) and spread across three (3) blocks, from T20 to T32.

From within the codes from T20 to T32 for burns under the Chapter XIX, they are grouped into three (3) groups, namely codes from burns of external body surface, specified by site (T20-T25) – example of a site is the head and neck site, to burns confined to eye and internal organs (T26-T28), and burns  of multiple and unspecified body regions (T29-T32).

Health Information Management (HIM) / Medical Records (MR) practitioners must take note that when the site of the burn is unspecified but the burn is  classified according to extent of body surface involved, then the codes from T31 category is to be used as the primary code only . However, it may be used as a supplementary code, if desired, with categories T20-T25 or T29 when the site is specified. 

Image credit: TBSA rule of nines, Caroline and Mary (2012 p. 1208)

Doctors who record the assessment for burns use some modification of the “rule of nines” (as above) for estimating percentage of body burned from the total body surface area (TBSA). The body is divided into multiples of 9%. For instance, one arm equals 9% and the entire back equals 18%.

HIM / MR practitioners must also be aware of the codes assigned to sequelae (a residual condition) of burns, corrosions and frostbite at T95.

References:

1. Caroline, BR & Mary, TK 2012, Textbook of basic nursing, 10th edn, Wolters Kluwer Health, Lippincott Williams & Wilkins, Philadelphia, USA
2. Mitchell, CJ, Ahmad, Z and Khan, MS 2013, An unusual burn, Endgames, 25 May 2013, vol. 346, British Medical Journal, BMJ Publishing Group Ltd, London
3. World Health Organization 2011, Volume 1 Tabular list, International Statistical Classification of Diseases and Related Health Problems 10th Revision, 2010 edn, Geneva, Switzerland