The medieval origins of the concept of hypertension.

Despite the well-known history of hypertension research in the modern era, like many other cardiovascular concepts, main points in the medieval concept of this disease and its early management methods remain obscure. This article attempts to make a brief review on the medieval origin of the concept of this disease from the Hidayat of Al-Akhawayni (?-983 AD). This article has reviewed the chapter of "Fi al-Imtela" (About the Fullness) from the Hidβyat al-Muta'allimin fi al-Tibb (The Students' Handbook of Medicine) of Al-Akhawayni. The definition, symptoms and treatments presented for the Imtela are compared with the current knowledge on hypertension. Akhawayni believed that Imtela could result from the excessive amount of blood within the blood vessels. It can manifest with symptoms including the presence of a pulsus magnus, sleepiness, weakness, dyspnea, facial blushing, engorgement of the vessels, thick urine, vascular rupture, and hemorrhagic stroke. He also suggested some ways to manage al-Imtela'. These include recommendations of changes in lifestyle (staying away from anger and sexual intercourse) and dietary program for patients (avoiding the consumption of wine, meat, and pastries, reducing the volume of food in a meal, maintaining a low-energy diet and the dietary usage of spinach and vinegar). Al-Akhawayni's description of "Imtela," despite of its numerous differences with current knowledge of hypertension, can be considered as medieval origin of the concept of hypertension.

INTRODUCTION

Hypertension is an important worldwide health challenge and is known as a leading risk factor for mortality. It carries important concomitant risks of cardiovascular and kidney disease.[1]

Present-day knowledge on hypertension is clearly indebted to the previous efforts made in this field.[23] The first description of blood pressure in the modern era was made by Stephen Hales in 1733.[4] Very early description of hypertension as a disease is attributed to Thomas Young in 1808.[3] The invention of the cuff-based sphygmomanometer was done by Scipione Riva-Rocci in 1896 and made the easy measurement of blood pressure in the clinic possible.[5]

Despite the well-known history of hypertension research in the modern era, main points in the medieval concept of this disease and its early management methods remain obscure.[6789] This article attempts to make a brief review on the medieval origin of the concept of this disease from the Hidayat of Al-Akhawayni (?-983 AD).

AL-AKHAWAYNI (?-983 AD)

Al-Akhawayni Bukhari (Abū Bakr Rabī, ibn-e-Ahmad Akhawaynī Bukhārī), also known as Joveini, was a 10th century Persian practitioner[10] [Figure 1]. He was born in the city of Bukhara in old Persia.[11] He was trained in medicine under the supervision of Abu al-Qasem Maqanei, a Rhazes' follower.[12] Al-Akhawayni was familiar with medical knowledge of his predecessors such as Hippocrates, Aristotle, Galen, and Rhazes.[1011] He also criticized their views in some cases. He has described different clinical findings in the field of neurology, psychiatry cardiology, and other fields of medicine for the first time.[1112131415]

Figure 1

Fabricated portrait of Al-Akhawayni Bukhari (?-983 AD), by Miss. Mahtab Asabakhsh (born in 1994). Reproduced with permission from Yarmohammadi et al. J Neurol. 2014;261(3):643-5

Hidāyat al-Muta'allimin fi al-Tibb (The Students' Handbook of Medicine) is the only known medical book that remained from Al-Akhawayni.[13] The importance of this comprehensive medical encyclopedia is that it is the first text on medicine written in the Persian language.[10] The Hidayat is divided into three parts and 200 chapters. The first part (51 chapters) provides general information on the four basic humors (akhlat) human faculties (qowa) and pneumata (arwah) (as the basis of the medieval physiologic science), and ancient anatomical points on different organs. The second part (130 chapters) discusses diseases of different organs. The third part reviews general diseases such as fevers.[14]

THE CLINICAL DESCRIPTION OF ‘IMTELA’

In one of the Hidayat's chapter entitled “Fi al-Imtela' (About the Fullness)”, Akhawayni described a disease with manifestations similar to those related to what is known today as hypertension. In his opinion, the disease could result from the excessive amount of blood within the blood vessels. He believed that in patients with al-Imtela', the total amount of blood is not normal. However, the quality is normal and could carry out its functions.[15] According to Al-Akhawayni, al-Imtela' can manifest itself with symptoms including the presence of a pulsus magnus, sleepiness, weakness, and dyspnea. After these general descriptions, he explained the possibility of an acute event occurring with this disease as follows: “… when severe facial blushing, engorgement of the vessels [superficially located in the head and the neck], and protrusion of the eyes occur,… there is concern that a vessel [of the brain] becomes ruptured and uncontrollable bleeding occurs, or ‘sakteh’ [stroke] occurs … and there is the threat of death …; epistaxis may occur …”. It is noteworthy that Al-Akhawayni in discussing the causes of stroke in Sakteh (stroke) chapter of Hidayat described al-Imtela' as the etiology of hemorrhage within the cranial cavity. He also criticized Rhazes' (865-925 AD) notion on hemorrhagic stroke. These aforementioned descriptions could correspond to an early explanation of hypertension, its crisis, and the associated hemorrhagic stroke.[141516]

SUGGESTED TREATMENTS

Al-Akhawayni suggested some ways to manage al-Imtela'. These include recommendations of changes in lifestyle and dietary program for patients (comparable to the two mainstays of hypertension management in modern medicine).[14] For example, he counseled staying away from anger and sexual intercourse, avoiding the consumption of wine, meat, and pastries, reducing the volume of food in a meal, and maintaining a low-energy diet (ghalilol ghaza).[14] In spite of some controversies, according to the current body of knowledge, anger, meat, carbohydrates, heavy alcohol intake, and high calorie foods are harmful to patients with hypertension. Moreover, sexual activity in those patients can be associated with risk of cardiovascular events.[1718]

The dietary usage of spinach and vinegar were two of Al-Akhawayni's recommendations.[4] At present, there is evidence which defends the benefits of such substances as a dietary complement for patients with hypertension.[1920] Another important point is that Al-Akhawayni prohibited the addition of garlic to the diet of patients with intracranial hemorrhage.[14] In modern medicine, it has been established that this herb has anticoagulant effects.[21]

Along with the aforementioned methods for the long-term management of al-Imtela', Al-Akhawayni recommended venesection (phlebotomy in modern nomenclature) as a therapy, especially in cases of sudden aggravation of disease.[14] Table 1 outlines the clinical presentation, life style modifications, and treatments suggested for al-Imtela (as described by Akhawayni)[14] compared with those of modern medicine.[2223]

Table 1

Comparison of clinical presentation, life style modifications, and treatments suggested for al-Imtela (as described by Akhawayni) and hypertension

CONCLUSION

Physical approaches to medical entities are supposed to be mainly a postrenaissance phenomenon. Physical basis of the concept of hypertension (intravascular liquid pressure) and the instruments needed for its measurement was not available during the medieval period. However, philosophical approach of the medieval scientists compensated their lack of physical knowledge and instruments in some cases. The definition and description of “al-Imtela'” as a disease with multiple similarities with the current concept of hypertension can be explained under the light of this fact.

The disease of “al-Imtela'” was not described by Akhawayni for the first time; rather it has been mentioned by Greek physicians such as Galen and Hippocrates.[24] However, their description to this disease differed from Akhawayni's. They remarked this disease as a result of waste products retention in the body. They did not make a clear clinical description on the symptoms of this disease. However, they suggested therapeutic approaches similar to those of Al-Akhawayni. This point shows that like other cases, Al-Akhawayni's early description on the concept of hypertension was based on his clinical experiences as well as knowledge of his predecessors.