Pathognomonic

"Pathognomonic" is a term predominantly employed in the realm of medicine, signifying a sign or symptom that is so characteristically associated with a particular disease or condition that its presence confirms the diagnosis beyond any reasonable doubt. The term "pathognomonic" amplifies the diagnostic certainty of a condition compared to a regular diagnostic sign or symptom. Recognizing pathognomonic signs is vital in clinical practice as they allow for prompt and accurate diagnosis, ensuring timely and appropriate treatment.

Definition and Origin

• Term: Pathognomonic (occasionally spelled "pathognomic")
• Definition: A sign or symptom that is so distinctive to a specific disease or condition that its mere presence confirms the diagnosis unequivocally.
• Etymology: Derived from the Greek words "pathos" (disease) and "gnomon" (indicator).

Clinical Importance

Identifying a pathognomonic sign in a patient can greatly aid in the diagnostic process, allowing for rapid intervention and reducing the reliance on more costly or invasive diagnostic measures. However, it's crucial to understand that many diseases don't possess pathognomonic signs, necessitating comprehensive clinical evaluations.

Examples

Disease	Sign
Cytomegalovirus infection	Owl's eye appearance of inclusion bodies
Hodgkin's lymphoma	Reed-Sternberg cells (giant mono- and multinucleated cells) upon microscopy
Lyme disease	Erythema chronicum migrans
Inclusion body myositis	Filamentous material seen in inclusion bodies under electron microscopy
Hypocalcemia	Trousseau sign and Chvostek sign
Tetanus or Strychnine poisoning	Risus sardonicus
Measles	Koplik's spots
Wilson's disease	Kayser–Fleischer ring
Diphtheria	Pseudomembrane on tonsils, pharynx, and nasal cavity
Chronic hemorrhagic pancreatitis	Grey-Turner's sign (ecchymosis in flank area)
Cholera	Rice-watery stool
Enteric fever	Rose spots on the abdomen
Meningitis	Kernig's sign and Brudzinski's sign
Angina pectoris	Levine's sign (hand clutching of chest)
Patent ductus arteriosus	Machine-like murmur
Parkinson's disease	Pill-rolling tremors
Whipple's disease	Oculo-masticatory myorhythmia
Acute myeloid leukemia	Auer rod
Multiple sclerosis	Bilateral internuclear ophthalmoplegia
Pericarditis	Pericardial friction rub
Rheumatic fever	Aschoff bodies
Rabies	Hydrophobia and negri bodies
Gout	Tophi
MASC	ETV6-NTRK3
Acute tubular necrosis	Muddy brown casts
Granulosa cell tumour	Call-Exner bodies
Malakoplakia	Michaelis–Gutmann bodies
Narcolepsy (with cataplexy)	Cataplexy
Endodermal sinus tumor	Schiller–Duval body
Sickle cell disease	Vaso-occlusive crises

See also

• AIDS defining clinical condition
• List of eponymous medical signs
• Medical sign
• Sine qua non