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Contents

On this page

  1. Original research article (full IMRaD)
  2. Case report (CARE-based, not IMRaD)
  3. Narrative review (loose, not IMRaD)
  4. Brief communication (journal-specific, not ICMJE-standardised)

Academy · Research Writing · Manuscript Templates

Manuscript Shells by Article Type: Original Research, Case Report, Narrative Review and Brief Communication

The International Committee of Medical Journal Editors (ICMJE) states that case reports and narrative reviews may take a less structured format than original research. Four article types require four different section shells, and applying one shell to all four commonly results in the omission of a section that a reviewer expects.

Pubrica AcademyWritten by a medical writing specialist Reviewed bya research writing reviewer Published10 October 2026 Last checked10 October 2026 Reading time8 minutes Sources2 peer-reviewed

The manuscript preparation guidance of the International Committee of Medical Journal Editors (ICMJE) states that a structured IMRaD format and a structured abstract are expected for original research, systematic reviews and meta-analyses, whereas case reports, narrative reviews and editorials may use a less structured or unstructured format. The four shells below reflect that distinction directly rather than imposing one structure on all four article types.

Learning objectives

  • The full IMRaD shell for an original research article.
  • The CARE-based shell for a case report, which is not IMRaD.
  • A narrative review shell, and why it is deliberately looser than IMRaD.
  • What a brief communication/short report shell typically looks like, and why it has no single owning standard.

Common misconceptions

  • “A case report should be forced into Introduction/Methods/Results/Discussion.” ICMJE itself places case reports in the less-structured category, and in practice they follow the CARE guideline's own structure — patient information, clinical findings, timeline, diagnostic assessment, therapeutic intervention, follow-up and outcomes — not IMRaD.
  • “"Brief communication" is an ICMJE-defined, standardised format.” ICMJE's own manuscript-preparation guidance does not define a brief communication or short report as a distinct category; it is a journal-specific article type, and each journal that offers it sets its own section and length rules.

Original research article (full IMRaD)

Structured abstract and full IMRaD are expected by ICMJE for original research1.

Structured abstract: Background / Methods / Results / Conclusions
1. Introduction — rationale, gap, objective/hypothesis
2. Methods — design, setting, participants, variables, data sources, bias handling, study size, statistical methods
3. Results — participant flow, descriptive data, outcome data, main results
4. Discussion — key results, limitations, interpretation, generalisability
5. Declarations — funding, competing interests, data availability, author contributions

Case report (CARE-based, not IMRaD)

In practice, case reports follow the CARE guideline's structure rather than IMRaD2.

Title / Keywords / Abstract (unstructured or brief structured)
1. Introduction — one or two sentences on why this case is worth reporting
2. Patient information — de-identified demographic and relevant history
3. Clinical findings
4. Timeline
5. Diagnostic assessment
6. Therapeutic intervention
7. Follow-up and outcomes
8. Discussion — strengths/limitations in relation to similar published cases
9. Patient perspective (where available and appropriate)
10. Informed consent statement

Narrative review (loose, not IMRaD)

ICMJE allows a less structured or unstructured format for narrative reviews, while still encouraging a description of how sources were located and selected1.

Abstract (unstructured, or background/aim/summary/conclusion)
1. Introduction — scope, why this topic, intended reader
2. How sources were located and selected (brief, not a full systematic-review methods section)
3. Thematic body sections (organised by sub-topic, not by IMRaD headings)
4. Gaps, controversies or open questions
5. Conclusion

Brief communication (journal-specific, not ICMJE-standardised)

ICMJE manuscript-preparation guidance does not define this as a category, so this shell should be treated as common convention rather than a cited rule, and the specific journal’s limits should be confirmed before it is used.

Short, often unstructured abstract
1. Brief introduction (often 1-2 paragraphs)
2. Combined or shortened Methods
3. Combined Results and Discussion (common in this format)
4. Tight word and reference limits (journal-specific — check instructions for authors)

Key points

Key points

Original research follows full IMRaD; a case report follows the CARE structure rather than IMRaD; a narrative review is deliberately less structured, in accordance with ICMJE guidance; and a brief communication has no ICMJE-standardised form, so its structure is determined by the specific target journal.

Practical application

Practical application

  1. The shell should be selected according to article type rather than habit. The article type of a manuscript should be confirmed before drafting, since IMRaD is inappropriate for three of the four types.
  2. Case reports should follow CARE rather than IMRaD section names. The sections should be Patient information, Clinical findings, Timeline, Diagnostic assessment, Therapeutic intervention, and Follow-up and outcomes, rather than Methods and Results.
  3. For a brief communication, the specific journal’s rules should be checked before this shell is used. Since ICMJE does not standardise this category, the target journal's own instructions for authors are the governing source, not a general template.

Frequently asked questions

Yes. A brief description of how sources were located and selected is encouraged even for a narrative review, although the full, registered methodology required of a systematic review is not.

CARE recommends including the patient’s own perspective where available and appropriate; however, it is not always obtainable or relevant, and its absence should be reported transparently rather than the perspective being fabricated.

The instructions for authors of the specific target journal always take precedence over a general shell such as this one.

References

  1. ICMJE. Preparing a Manuscript for Submission to a Medical Journal. read 10 October 2026. View ICMJE guidance
  2. CARE Group. CARE Case Report Guidelines. read 10 October 2026. View CARE guidelines

Every source above is a peer-reviewed article, a publisher’s record of one, or a standard issued by the body that owns it. Each carries the date it was last read. Where a standard moves, this article is revised rather than left up with a note.

How to cite this article

Pick your referencing style and copy it. Your university or target journal may vary the punctuation — check its guide if it has one.

Pubrica Academy. (2026, October 10). Manuscript Shells by Article Type: Original Research, Case Report, Narrative Review and Brief Communication. Pubrica. https://pubrica.com/academy/templates/manuscript-templates-by-article-type/

This article is written to be learned from. Cite it if you are referring to what it says; if you are using the evidence behind it, cite the sources listed above instead.

Article-type decision check

For use before drafting begins.

Is there new primary data being reported? → Original research, full IMRaD.
Is this a single patient's case? → CARE-based case report shell.
Is this a synthesis of existing literature without a registered systematic protocol? → Narrative review shell.
Does the target journal offer a short-format category? → Check that journal's own brief-communication rules first.

Pubrica AcademyWritten and maintained by Pubrica’s subject matter experts. Articles are revised when the underlying standards change, and each article states the date on which it was last reviewed.

How Pubrica can help

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