Surgical sieve

The surgical sieve is a nickname for a type of thought process in the medical profession. It has several purposes. Firstly, it is a typical example of how to organise a structured examination answer for medical students and doctors when they are challenged with a question. It is also a way of constructing answers to questions from patients and their relatives in a logical manner, and structuring articles and reference texts in medicine. Some text books put emphasis on using the surgical sieve as a basic structure of diagnosis and management of illnesses.

The 'Sieve'

Although there are several versions around the world with slight variations, the surgical sieve usually consist of the following types of process in the human body in any particular order:

1. Congenital
2. Acquired:

• Environmental
• Neoplastic
• Metabolic
• Infective
• Traumatic
• Autoimmune
• Vascular
• Inflammatory
• Degenerative
• Idiopathic

Example 1

Question: What are the causes of an acute confusional state in a patient?

Answer: The causes can be divided into:

1. Neoplastic: brain tumour, carcinomatosis
2. Metabolic: electrolyte imbalance, DKA, hypoglycaemia, SIADH
2. Infective: sepsis, local infection
3. Traumatic: head injury, Intracranial hemorrhage, shock
4. Autoimmune: thyroid disease
5. Vascular: CVA, TIA, vascular dementia
6. Inflammatory: infection, systemic inflammatory response syndrome
7. Degenerative: Alzheimer's Disease, dementia
8. Idiopathic

Example 2

Question: What are the causes of splenomegaly?

Answer: The causes can be divided into:

1. Neoplastic: CML, metastases, myeloproliferative disorders
2. Metabolic: Gaucher's disease, mucopolysaccharidoses, amyloidosis, Tangier disease
2. Infective: AIDS, mononucleosis, septicaemia, TB, brucellosis, malaria , infective endocarditis
3. Traumatic: haematoma, rupture
4. Autoimmune: rheumatoid arthritis, SLE
5. Vascular: portal vein obstruction, Budd-Chiari syndrome, haemoglobinopathies (Sickle-cell disease, thalassemia)
6. Inflammatory: sarcoidosis
7. Degenerative: nil
8. Idiopathic: Idiopathic thrombocytopenic purpura

Example 3

Robbins Pathologic Basis Of Disease is an internationally used reference textbook in pathology. Its chapters under the heading 'General Pathology' can be considered to be a version of the surgical sieve:

3. Acute and chronic inflammation
4. Tissue Repair
5. Hemodynamic Disorders
6. Genetic Disorders
7. Diseases of Immunity
8. Neoplasia
9. Infectious Diseases
10. Environmental and Nutritional Pathology

Use in popular culture

The surgical sieve is frequently used by House MD, who is a doctor in the TV series House in order to diagnose the diseases that his patients are suffering from. In some episodes various forms of the surgical sieve are scribbled onto House's whiteboard while his team struggle to diagnose difficult cases. In the episode 'Paternity' the mnemonic 'MIDNIT' is used to run through the sieve (metabolic, inflammation, degenerative, neoplastic, infection, trauma). Another mnemonic running in some medical schools is VITAMIN (Vascular, Infective/Inflammatory, Traumatic, Autoimmune, Metabolic, Iatrogenic/Idiopathic and Neoplastic) but is missing Congenital, Degenerative disease/Developmental, Endocrine/Environmental and Functional. The mnemonic can be elongated to VITAMIN CDEF to include the others.