Eponymous Triads

Medical triads, tetrads, and pentads are shorthand diagnostic groupings which combine sets of three, four, or five characteristic clinical features. These clusters of signs, symptoms, or pathological findings serve as memorable patterns that help recognise, recall, and communicate specific conditions.

In medicine, a triad is a set of three clinical features that, when found together, strongly suggest a diagnosis; tetrad and pentad extend the idea to four and five linked features. These are teaching tools and memory aids rather than proofs. They can useful in pattern recognition, but are also historically slippery with credit rarely applied to the true originator, and many variants abound.

Etymology: triad from Greek triás (τριάς, “group of three”), tetrad from tetrás (τετράς), pentad from pentás (πεντάς).

TRIADS

Amyand’s triad

• Amyand’s hernia
• Appendicitis
• Undescended testis

Coined by Dhanasekarapandian et al in 2018 who published the case of a 35-day-old infant with an irreducible right inguinal hernia, inflamed appendix, and gangrenous undescended testis managed by appendicectomy, orchidectomy, and herniotomy.

• Claudius Amyand (c.1680-1740) was an French-born English surgeon
• Dhanasekarapandian V, Shanmugam V, Jagannathan M. Amyand’s Hernia, Appendicitis, and Undescended Testis: The Amyand’s Triad. J Indian Assoc Pediatr Surg. 2018 Jul-Sep;23(3):169-170.

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Charcot’s Triad

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Dieulafoy’s Triad (Appendicitis) [Triade de Dieulafoy]

Triad of physical findings indicating acute appendicitis outlined by Dieulafoy to differentiate appendicitis from intestinal lithiasis and other causes of abdominal pain.

• Tenderness at McBurney’s point (douleur au point de Mac-Burney)
• Cutaneous hyperaesthesia (hyperesthésie cutanée)
• Involuntary muscular guarding (défense musculaire)

• Georges-Paul Dieulafoy (1839-1911) was a French Clinician
• Dieulafoy G. Lithiase intestinale et entéro-colite. Clinique médicale de l’Hôtel-Dieu de Paris, 1898: I: 296 [trois signes caractéristiques de l’appendicite]

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Dieulafoy’s Triad (functional blindness)

Triad suggestive of functional/hysterical blindness described by Dieulafoy in his clinical lectures at Hôtel-Dieu de Paris.

• Sudden onset of blindness (cécité à début brusque)
• Preserved pupillary light reflexes (conservation des réflexes pupillaires)
• Normal fundoscopic exam (intégrité du fond de l’œil)

Confirmed and cited by Crouzon (1915) in wartime neuropsychiatric observations of sudden blindness without organic findings. Multiple cases published e.g. cécité temporaire provoquée par l’éclatement d’obus à proximité

• Georges-Paul Dieulafoy (1839-1911) was a French Clinician
• Dieulafoy G. Deux case de cécité hystérique. Clinique Médicale de l’Hôtel-Dieu de Paris, 1904; V: 75 [triade symptomatique de la cécité hystérique]

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Horner syndrome (1869)

Horner syndrome, also known as oculosympathetic paresis, is a neurological disorder caused by disruption of the sympathetic pathway from the hypothalamus to the eye and face. It manifests with a classic triad of

• Ptosis: Drooping of the upper eyelid due to paralysis of the superior tarsal muscle
• Miosis: Constricted pupil due to loss of sympathetic innervation to the dilator pupillae muscle
• Anhidrosis: Absence of sweating on the affected side of the face

Horner first described the condition clinically in 1869, expanding on earlier experimental work by Claude Bernard (1813-1878). His description helped localize the lesion within the sympathetic chain and distinguish central from peripheral lesions.

1869 – Horner reported the findings of ptosis, miosis, enophthalmos in a 40-year-old peasant woman in Über eine Form von Ptosis. He also observed increased skin temperature and dryness of the ipsilateral face.

• Johann Friedrich Horner (1831-1886) was a Swiss ophthalmologist
• Horner F. Über eine Form von Ptosis. Klinische Monatsblätter für Augenheilkunde 1869;7:193-198

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Meigs Triad (1934)

Triad of ascites with hydrothorax in association with benign ovarian tumour, that is cured after tumour resection.

• Ascites
• Pleural effusion (hydrothorax)
• Benign ovarian fibroma (or fibroma-like tumour)

1934 – In his book Tumors of the Female Pelvic Organ Meigs noted a recurrent pattern of fluid accumulation in association with benign ovarian fibromas.

1937 – Meigs and John W. Cass published a more detailed clinical series in American Journal of Obstetrics and Gynecology, reporting seven cases of ovarian fibromas accompanied by ascites and hydrothorax. This was the first formal articulation of the syndrome as a distinct clinical entity.

A pelvic tumor, ascites, and hydrothorax occurred together in all seven cases…In each case the operative removal of the ovarian fibroma was followed by prompt and complete disappearance of both the abdominal and the thoracic fluids.

Meigs, Cass 1937

Both fluid accumulations resolve spontaneously after tumour removal. It is a diagnosis of exclusion, requiring histological confirmation of a benign tumour and elimination of metastatic disease.

• Joe Vincent Meigs (1892-1963) was an American obstetrician and gynecologist
• Meigs JV. Tumors of the Female Pelvic Organs. New York, NY. 1934: 262–3.
• Meigs JV, Cass JW Fibroma of the ovary with ascites and hydrothorax, with a report of seven cases. American Journal of Obstetrics and Gynecology 1937; 33: 249-267.

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Merseburger Triad

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Moschcowitz triad (pericardial effusion)

In 1933 Moschcowitz published A new sign of pericardial effusion, in which he described three physical examination findings that, when present together, are indicative of pericardial effusion:

• Widening of the area of cardiac dullness.
• Abrupt transition from pulmonary resonance to cardiac dullness.
• Extension of cardiac dullness into the second intercostal space

I have found that the conjunction of three signs is usually conclusive in determining the diagnosis of pericardial effusion; in the order of their importance, they are: (1) widening of the area of cardiac flatness, (2) abrupt transition from pulmonary resonance to cardiac flatness and (3) widening of the cardiac dullness in the second intercostal space. No one of these signs, taken singly, is conclusive, but together they form a triad which is thoroughly reliable, as confirmed by roentgen examination or at autopsy.

Moschcowitz 1933

Moschcowitz emphasized that while each sign individually might not be conclusive, their combination provides a reliable diagnostic indicator for pericardial effusion, as confirmed by roentgen examination or autopsy

• Eli Moschcowitz (1879-1964) was a Hungarian born, American pathologist and physician
• Moschcowitz E. A new sign of pericardial effusion. JAMA. 1933; 100(21):1663-1664

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Quincke’s triad (hemobilia)

• Right hypochondrium pain
• Jaundice
• Gastrointestinal bleeding (haematemesis and melena)

1871 – Heinrich Quincke published a detailed case of hepatic artery aneurysm rupture leading to bleeding into the biliary tree. He associated three cardinal features now recognised as Quincke’s triad:

1975 – Eddy Davis Palmer (1917-2010) first documented use of the term Quincke’s triad of hemobilia in the second edition of his textbook Practical Points in Gastroenterology as:

Quincke’s triad of hemobilia consists of GI hemorrhage, biliary colic, and jaundice.

• Heinrich Irenaeus Quincke (1842-1922) was a German physician
• Quincke H. Ein fall von Aneurysma der Leberarterie. Berliner Klinische Wochenschrift 1871; 8: 349-352 [Hepatic artery aneurysm. Described triad of biliary tract haemorrhage]

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Rigler’s Triad (1941)

Radiographic features pathognomonic for gallstone ileus, a mechanical small bowel obstruction caused by the migration of a gallstone into the gastrointestinal tract via a biliary-enteric fistula

• Ectopic gallstone (often radiopaque and located in the intestinal lumen)
• Small bowel obstruction (evident as dilated small bowel loops)
• Pneumobilia (air in the biliary tree or gallbladder lumen)

The specific signs which permit a roentgenologic diagnosis of this condition are evidences of dynamic ileus, presence of gas or contrast medium in the biliary tract and direct or indirect visualization of the calculus. 

Rigler, JAMA 1941

• Leo George Rigler (1896-1979) was an American radiologist
• Rigler LG, Borman CN, Noble JF. Gallstone obstruction: pathogenesis and roentgen manifestations. JAMA. 1941; 117(21): 1753-1759

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Saint’s triad (1946)

Saint’s triad refers to the clinical coexistence of three conditions:

• Hiatal hernia
• Cholelithiasis (gallstones)
• Diverticular disease (diverticulosis of colon)

…the importance of considering the possibility of multiple separate diseases in a patient whenever his or her history and the results of the physical examination were atypical of any single condition.

1946 – Charles F. M. Saint (1886–1973), Professor of Surgery at the University of Cape Town, anecdotally highlighted the importance of suspecting multiple coexisting diseases when clinical signs diverged from classic presentations.

1948 – Radiologist C.J.B. Muller at Johannesburg General Hospital published the first clinical report of Hiatus hernia, diverticula and gall stones* : Saint’s triad in three patients.

• Charles Frederick Morris Saint (1886-1973) was an English-born South African surgeon
• Muller CJB. Hiatus hernia, diverticula and gall stones* : Saint’s triad. South African Medical Journal 1948; 22(11): 376-382

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Virchow’s Triad

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Whipple’s triad

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Zieve’s triad (1958)

Acute alcohol-induced hepatic injury and fatty liver disease. The syndrome typically follows a binge or withdrawal phase in chronic alcohol use. Episodes resolve with abstinence and supportive management.

• Jaundice
• Haemolytic anaemia
• Transient hyperlipidaemia

1958 – First described by Leslie Zieve as a distinct, self-limited syndrome of haemolysis, jaundice, and hyperlipidaemia in patients with alcoholic steatohepatitis. The haemolysis is thought to result from altered red blood cell membrane composition due to hepatic dysfunction and elevated plasma lipids.

• Leslie Zieve (1915-2000) was an American hepatologist
• Zieve L. Jaundice, hyperlipemia and hemolytic anemia: a heretofore unrecognized syndrome associated with alcoholic fatty liver and cirrhosis. Ann Intern Med. 1958 Mar;48(3):471-96

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PENTADS

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TETRADS

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