Biochemical Basis of Diseases

The below mentioned article provides a short note on the Biochemical Basis of Diseases.

Diseases having a Biochemical Basis:

a. Life depends upon biochemical reactions.

b. Health fully depends on the regulated and harmonious functioning of many bio­chemical reactions and processes that oc­cur in normal cells.

c. Diseases are caused by the alternations of structures; or the amounts of certain biomolecules; or disturbances of impor­tant biochemical reactions or processes.

d. Diseases are found as abnormalities in the structure and function of cells, organs, and systems generated by biochemical mecha­nisms.

e. Patients experience illnesses which reflect Psychologic, cultural, and other factors.

f. Physicians must treat the patients consid­ering social, psychological, cultural, eco­nomic, and other factors, but always de­pending on a sound knowledge of bio­chemical, physiologic, and pathologic mechanisms.

Diseases are Considered from a Biochemical Standpoint:

a. Many diseases are determined genetically.

b. All classes of biomolecules are affected in structure and function.

Biomolecules can be affected in genetic dis­eases. The primary defect resides in DNA, and the structures or functions of other biomolecules are affected secondarily.

c. Biochemical changes that cause disease may occur rapidly or slowly.

(i) Some diseases progress rapidly caus­ing death within minutes after coro­nary thrombosis on the fact that brain and heart particularly are very sensi­tive to lack of oxygen and fuel.

(ii) Life is threatened within hours at the excessive loss of water and electro­lytes in cholera.

(iii) Rapid and large changes of distribu­tion in the body of certain electro­lytes (e.g., K⁺) become hazardous very quickly because of the sensitivity of myocardial muscles to such changes.

(iv) Extensive change of pH can be toler­ated for a short time. Several years may be required for the build-up of a biomolecule to affect organ function.

d. Diseases are caused by deficiency or ex­cess of certain biomolecules.

(i) Deficiency of Vitamin A causes night blindness; whereas excessive intake of Vitamin A results in chronic states of toxicity.

(ii) Deficiency of Vitamin D results in rickets, but excess causes severe hypercalcemia.

(iii) The general causes of nutritional sec­ondary deficiency are the insufficient absorption, increased requirement, inadequate utilization, and increased excretion. Each of these causes occur by a number of diseases or conditions.

e. Almost every cell organelle is involved in the genesis of various diseases.

f. Different biochemical mechanisms can produce similar Pathologic, clinical, and laboratory findings.

(i) Many different bacteria and viruses can cause acute or chronic inflamma­tion.

(ii) Hepatomegaly occurs from accumu­lation of glucosylceramide, but more commonly it is due to heart failure or metastases.

(iii) Fibrosis of the liver (cirrhosis) is caused by chronic intake of ethanol, excess of copper causes Wilson dis­ease, and excess of iron causes pri­mary hemochromatosis.

(iv) A variety of inborn errors of metabo­lism can lead to mental retardation, and many conditions can result in ketosis.

(v) Calcium oxalate, magnesium ammo­nium phosphate, uric acid, and cys­tine—all form renal calculi (stones), but they accumulate for different bio­chemical reasons.

(vi) Distinct biochemical causes can pro­duce the same pathologic finding (e.g., cirrhosis), clinical finding (e.g., men­tal retardation), or laboratory finding (e.g., ketosis).

(vii) It is possible to distinguish among diseases by the history, physical ex­amination, and suitable laboratory tests.