ETIOPATHOGENESIS OF PAKSHAGHATA – A CRITICAL PERUSAL

Introduction:

Pakshaghata one of the indriya pradoshaja vikara is mainly defined as 'hatvaikamarutahpakshamdakshinamvamamevava¹' , which means loss of strength in right or left half of the body. Similarly it is defined in contemporary science as rapid onset of neurological deficits resulting from diseases of the cerebral vasculature and its contents. In Charaka samhita, this disease is mentioned under the umbrella of Vataja nanatmaja vikara² which also comes under Madhyama roga marga³ . Nidana carries clinical importance both in terms of diagnosis and treatment. The nidana can be categorised under several sub-varients. There are several sets of nidana like chaturvidha sannikrishtadi nidana or doshahetvadi trividha nidana. Certain nidana are specific to certain disease, identifying those gives clue for diagnosis. But in majority of the diseases usually general sets of nidana are given in the classics. Even then nidana plays an important role in chikitsa, as the first line of treatment in any disease is nidanasya parivarjana. There are different causative factors leading vata prakopa as well as vata vyadhi. The same nidana obviously holds good for the pakshaghata also, as it is a vata prakopa janya vyadhi. So detail understanding of vata vyadhi nidana plays an important role in understanding Pakshaghata nidana.

Vatavyadhi nidana:

Vata prakopacomprises two sets of etiological factors one is Dhatukshaya and another is Margavarana. Abhighata⁵ is also an obvious factor for Vata prakopa but, that could be a cause for Dhatukshaya itself.

Dhatukshaya:

Clinical manifestation of Dhatukshaya takes place in two forms ⁶. One which requires immediate correction i.e, Sadyaksheena and the other requires programmed correction i.e, Chiraksheena. Acharya Charaka explained these variant mechanisms of Dhatukshaya in santarpaneeya adhyaya. By this one can conclude that there are two types of dhatukshaya that leads to vataprakopa, one is sadyaksheena and another is chiraksheena.

The symptoms of pakshaghataare expressed suddenly, but seldom gradual development of weakness may be seen in either one or both halves of the body. Stroke is a syndrome characterized by the acute onset of a neurologic deficit that persists for at least 24 hours, reflects focal involvement of the central nervous system, and is the result of a disturbance in the cerebral circulation. Stroke results from either of two types of cerebral vascular disturbance: ischemia or haemorrhage⁷ . On the other hand, cerebral atrophy is a degenerative pathology of the brain, gradually develops over a period of time which also mimics Pakshaghata or Sarvangavata. Cerebral atrophy can be generalized, which means that all of the brain has shrunk; or it can be focal, affecting only a limited area of the brain and resulting in decreased functions of the area which brain controls. If the cerebral hemispheres (the two lobes of the brain that form the cerebrum) are affected, conscious, thought and voluntary processes may be impaired⁸ .

Lakshana of Pakshaghata are usually acute hence all the nidana resulting in sadyaksheena are responsible for aggravating vatadoshaand there by pakshaghata. Among the descriptions of Vata prakopaka nidanas, there are nidanas which results in dhatukshaya such as shonita and malaatisrava⁹ .Shonitaatisravana may be considered as massive external bleeding leading to hypovolemia and water shed infarction. Malaatisravana refers to loss of dravadhatuas a consequence of Atisara, Chardi or Panchakarma Vyapat. These conditions lead to hypovolemia and reduced blood perfusion to brain leading to condition like stroke. Hence these nidana acts as pradhanikahetu, vyadhihetu or utpadakahetu¹⁰ .

On other hand, much of the nidanawill aggravate vata dosha on exposure for a considerable period repeatedly. Old age, infective pathology (bhootopaghata) are some other causes which are also responsible for Dhatukshaya ¹¹. These nidana will produce dhatukshaya gradually and may produce any Vatavyadhi including Pakshghata. As the manifestation of Dhatukshaya is gradual, the clinical expression may also be gradual. Cerebral atrophy is gradually a progressive illness of old age. Hence this variety of nidana may act as Vyabhichari hetu, dosha hetu or vyanjaka hetu. Hence Shonita, Dosha, Mala atisravana are considered as cause for dhatukshaya (Sadya) in turn leading to pakshaghata.

Margavarana:

Rasa Raktadi dhatu are carried by Vyana vata from the Hridaya all over the body, so does Preenanaand Jeevana of all the Dhatu and there by normal functions of dhatu are maintained. Occlusion in the Srotas carrying Rasa raktadi dhatus results in vata prakopa as their gati depends on Vyanavata ¹². There occurs Dhatukshaya distal to occluded site. Pitta and or kapha dosha are responsible for the occlusion at any part of body. Among the dhatu Rakta and Meda are important and these two dhatu are having Ashraya Ashrayibhava with Pitta and Kapha respectively. Maragavarana by medodhatu results in multiple disorders like Vatavyadhi, Pramehapidaka, vidradhi etc. Clinical manifestation of Margavarana depends on the site of Maargavarana¹³ .

Clinical manifestation of Margavaranais usually sudden i.e, animitta pradarshana of vyadhilakshana. Animitta refers to  akasmat which means sudden in onset¹⁴ . This sudden onset is due to chala guna of vata dosha which is provoked by Margavarana. But pathologically the course of Margavaranais gradual particularly Kaphadoshaja Margavarana. Dhamani praticchaya or the Dhamani upalepais the effect of excess Santarpana¹⁵ and is Kaphaja nanatmaja vikara¹⁶ .

Atherosclerosis is gradually progressive phenomena which may give rise to ischemia or infarction of the tissue by an atheroma at any part of the body. Cerebral infarction is usually attributed to partial or total occlusion of its regional microvasculature by thrombo-embolism. Cerebral atheroma is by far the most common underlying intimal vascular pathology¹⁷ .

Shonitadusthi:

Raktadhatu considered as fourth dosha, has got enough 18 importance in producing shirovikara . Acharya charaka in the context of kiyantashiraseeya Adhyaya mentions Prakupita vatadi dosha vitiates rakta dhatu at shiras, resulting in manifold neurological disorders. Haemorrhagic stroke clinically presents with symptoms such as headache, vomiting, altered sensorium and impaired motor functions. Same is described by Acharya Sushruta in the context of Vatavyadhi nidana where he mentions the symptoms of Pakshaghata as akarmanyata in ardha Shareera and achetanata. Here Achetenata refers to altered sensorium and sometimes there may be loss of consciousness which may be considered as sanyasa¹⁹ .

Mada, Moorcha and sanyasa are the presenting features in haemorrhagic stroke if not detected and treated in early stage. The causes of sanyasa as enumerated by Acharya charakaare madya, vishaand rudhira²⁰ . Madyaja sanyasacan be considered as acute alcohol intoxication with cerebrovascular accident. Rakta dusthi janya sanyasa is best correlated to that of haemorrhagic stroke.

Rogatikarshana:

Rogatikarshana results in dhatukshaya. Rogatikarshana is responsible for Upadrava/Nidanarthakara roga. Shonita dusthi lakshana described by Acharya Charaka such as shiroruk, Krodha prachurata, kampa, Sweda, Shareera dourgandhya, mada etc²¹ are well appreciated in case of hypertension also, which is one of the leading cause of cerebro vascular accident in present days. Hence rogatikarshana by Shonitadusthi (hypertension) may end up in Pakshaghata.

Incidence of stroke as a consequence of cardiac arrhythmias is increasing day by day, where cardiac emboli is the prime cause. Same has been well explained by Acharya charakain the context of apatantraka²² , where there will be involvement of Hridaya marma, which further leads to Pakshaghata by affecting shiromarma. Abhighata to shiras itself may results in Pakshaghata. Even injury to lohitaksha and kakshadhara marma are also said to manifest Pakshaghata.

Arbuda at marma Pradesha²³ like shiras may exhibit the features of Pakshaghata as in case of space occupying lesions and malignancies.

Discussion:

The nidana of Pakshaghata are segregated under Dhatukshaya and Margavarana. The term Dhatukshaya and Margavarana also signify the pathophysiology. Dhatukshaya signifies the effect of different etiological factors. Similarly the Margavarana too. In the same way these two terminologies also explain the pathological changes taken place in the course of illness.

Sudden onset of Dhatukshaya is one of the important reason for Vataprakopa as Sushruta clearly explains 'Pavanasya Param Kopam'. Hence an important cause of Pakshaghata.

Margavarana is a gradually progressive manifestation, but clinical manifestation takes place suddenly which is unpredictable. The Vyana vata is responsible for circulation of Rasa Raktadi drava dhatu in the body. When the Rasa Raktadi drava dhatu are obstructed by Kapha, Meda etc Vyana vata aggravates and results in clinical manifestation.

Bahya Abhighata to Shiramarma may result in Pakshaghata but depends on impact of trauma.

Shonitadusti, Hridroga, Arbuda or any such chronic illness may affect Shiro marma. Rogatikarshana results in Vataprakopaand acts as Doshaja Marmabhighata.

Conclusion:

Pakshaghata one among the Astha mahagada mainly resultant of dhatu Kshaya and Margavarana in addition to Abhighata. As Pakshaghata is of sudden onset only sadyaksheena can be taken into account. Whereas Symptomatology is sudden in Margavarana where pathology is a gradual phenomenon. The concept of Shonitadusthi pathology holds good for haemorrhagic stroke.