Medical assessor guidance note 22

Digestive system: use of medications and assessment of the colon, rectum and anus

This material is issued by the Motor Accidents Authority under s.65(2) of the Motor Accidents Compensation Act 1999 (the Act) in the interests of promoting accurate and consistent medical assessments under the Act. The interpretation provided here is not legally binding but represents the clinically recommended interpretation in an area where more than one interpretation of existing provisions may be possible. This recommended interpretation is publically available. Any medical assessment which does not adopt this interpretation should be accompanied by clinical justification for the interpretation adopted, supported by full, robust reasons.


The Motor Accidents Authority Permanent Impairment Guidelines – Guidelines forthe assessment of permanent impairment of a person injured as a result of a motor vehicle accident 1 October 2007 (MAA Guidelines): Chapter 8 page 50.

The American Medical Association Guides to the Evaluation of Permanent Impairment, 4th edition (AMA 4 Guides): Chapter 10 Table 3, page 241 and Table 4, page 243.


Following a motor accident regular opiate medications may be prescribed or taken which may result in the development of chronic constipation, aggravation of pre-existing constitutional haemorrhoids with rectal bleeding and/or the development of an anal fissure. Signs and symptoms of colonic, rectal or anal disease due to opiate medications may be reversible upon cessation of the medication or following appropriate treatment, however haemorrhoids and/or an anal fissure may become chronic.

Issue requiring clarification

Taking account of the above information Medical Assessors must determine whether there is an impairment, and if so, whether the impairment is caused by the motor accident and whether it is permanent and able to be assessed.

Preferred interpretation

Is there an impairment caused by the motor accident:

For a diagnosis of colonic, rectal or anal disease due to opiate medication there must be a history, which may be confirmed within the documents, that the onset of specific colonic, rectal or anal signs and/or symptoms was contemporaneously related to the use of opiate medication post motor accident.

Is the impairment permanent:

To determine whether or not any impairment is permanent, there should be consideration of the current condition with regard to current treatment, any ongoing and/or proposed treatment (by their General Practitioner or specialist) and the efficacy of any current and/or proposed treatment.

Assessment of impairment

In cases where there is a clear relationship between the onset of specific signs and symptoms and the commencement and continuing use of opiate medication, the Medical Assessor may regard this injury as Class 1 impairment (Table 3, p 241 AMA 4 Guides).

Note: Table 3 requires the presence or absence of several factors including: signs and symptoms of colonic or rectal disease and limitation of activities, special diet or medication is not required and no systemic manifestations are present and weight and nutritional state can be maintained at a desirable level or there are no sequelae after surgical procedures.

Depending on the specificity and severity of signs and symptoms of colonic and rectal impairment or anal complications the Medical Assessor may assess the impairment in the lower range of Table 3 or Table 4 (for example: 0%-2%).

Note: Constipation is a symptom and assessment of Class 1 impairment requires signs and symptoms. Assessment of constipation alone is assessed as 0% WPI.

Note: Table 4 Class 1 requires the presence or absence of several factors including: signs of organic anal disease are present, or there is anatomic loss or alteration or mild incontinence or anal symptoms are mild, intermittent and controlled by treatment. (Table 4, p 243 AMA 4 Guides).

The Medical Assessor should provide reasons explaining why they determined the selected Table, Class and degree of permanent impairment with reference to the presence or absence of all requirements listed in the relevant Table.

Justification for preferred interpretation

The preferred interpretation and methodology as outlined above is suggested to promote consistency of assessment.

Issued by:

Injury Strategy Branch

November 2015