Welcome back to Medical Terminology Corner!
Let’s talk about a common disease that affects a lot of people and that is still not curable even though we have some very good and effective treatments for the disease – Diabetes. The name originated from old Greek: διαβαίνω: diabaino— cross, pass through, flow through).
“Diabetes” is the general term for multiple diseases with one common symptom – copious urination or polyuria (definition of the prefix poly- is many or excessive and –uria: urine). Most of the time when people use term “diabetes” they talk about diabetes mellitus – a disease with high glucose levels in the blood.
Ancient Greek physician Aretaeus from Cappadocia (30-90?A.D.) described excessive polyuria, that was related, in his opinion, to the abnormal water flow in the body.
Another type of diabetes – diabetes insipidus, although extremely rare, was known since old ages but, until 18th century, people did not know the difference between diabetes mellitus and diabetes insipidus. So then, diabetes with the urine that was sweet to taste (imagine that doctors in old ages had to taste patient’s urine) was called – diabetes mellitus
(from Latin mel — honey).
In the 19th and the beginning of the 20th centuries, there was a significant scientific research done on diabetes insipidus that was related to the abnormality of the central nervous system and posterior (back) lobe of the hypophysis (pituitary gland) or neurohypophysis, when neurohypophysis does not secrete enough of the antidiuretic hormone (ADH) or vasopressin. In other type of diabetes insipidus there are normal levels of vasopressin, but impaired response to the hormone from kidneys.
In clinical descriptions, the term “diabetes” most of the time means excessive thirst or polydipsia (the meaning of the -dipsia is thirst) and excessive urination or polyuria (seen in both – diabetes insipidus and diabetes mellitus), but there are other types of diabetes.
Diabetes mellitus is characterized by high levels of sugar in the blood while diabetes insipidus is a disease where kidneys are unable to conserve water.
Diabetes insipidus (DI) is a rare disease while diabetes mellitus is widely spread and very common. The causes, symptoms, treatment and prognosis for diabetes insipidus are different from diabetes mellitus.
|Diabetes Insipidus versus Diabetes Mellitus comparison chart|
|Diabetes Insipidus||Diabetes Mellitus|
|Characteristic symptoms||Excessive thirst, excess volume of severely diluted urine.||High blood sugar, excessive urination, increased thirst, increased hunger.|
|Incidence||3 in 100,000 people||7.7 per 1000 people|
|Causes||Deficiency of ADH. Brain tumor, head injury, medication such as lithium, genetics||Type 1 – Autoimmune Disease; Type 2 – Genetics, lifestyle, infection|
|Treatment||Typically desmopressin (nasal spray) or IM, IV hypertonic saline solution (3% or 5%). Thiazide diuretics.||Insulin, oral medications and lifestyle management|
|Prognosis||No effect on life expectancy||Up to 10 years shorter life expectancy|
“Diabetes” in general usage refers to diabetes mellitus, which is of 3 types — gestational, Type 1 and Type 2 diabetes.
Next time we will look into 3 types of diabetes mellitus or diabetes.