(CNN) -- In December, Randa Adnan said, her husband weighed just over 200 pounds. Visiting him in an Israeli hospital this week, Randa said, she found her 33-year-old spouse, Khader Adnan, now weighs no more than 121 pounds.
"It is something beyond description, as there is no sign of life in him -- this is how I found him," she said.
The dramatic and life-threatening loss of weight comes as Khader Adnan passes day 55 in a hunger strike to protest his arrest and detention by Israeli security personnel on December 17 of last year.
The nearly two-month protest marks the longest hunger strike in Palestinian history and is a high-stakes move that is bringing increasing scrutiny to Israeli's arrest and detention policies for Palestinians.
Adnan -- known as a West Bank leader of the Palestinian Islamic Jihad, an Iranian backed militant group that has killed scores of Israelis in suicide bombings and rocket attacks -- was arrested in his home near the West Bank city of Jenin by a group of armed Israeli security personnel.
The day after his arrest, said his wife, Adnan began his hunger strike after a team of Israeli interrogators subjected him to a process of humiliation, insult and verbal abuse.
His wife and lawyers say Adnan continued to be mistreated, suffering under long periods of solitary confinement, continuous and abusive interrogation sessions, and multiple strip searches.
On December 30, Adnan's health had deteriorated enough that Israeli prison officials moved him to a hospital facility. He has refused treatment from Israeli doctors, but has been allowed to meet with representatives of the Israeli branch of Physicians for Human Rights, which in a statement expressed "grave concern" about his medical condition.
This week, Adnan's wife was allowed to see him in the hospital and described his appearance as being like a "caveman." She said he appeared dirty and emaciated with long hair, nails and beard, and he was manacled to his bed with only his left arm free.
Responding to criticism that it is not doing enough to help Adnan, the Israeli Prison Authority released a statement saying his case was being handled "strictly according to the law" with "special attention being given to his humanitarian situation."
The Israeli military has said little about why Adnan was arrested, releasing only a short three-sentence statement reading:
"Khader Adnan was arrested with an administrative warrant for activities that threaten regional security. This warrant was authorized by judicial review. An appeal was filed by the defendant against this decision and is currently under review."
Adnan is being held under a controversial Israeli military procedure known as "administrative detention" that allows Israel to hold detainees indefinitely on security grounds. The process also allows for detention based on secret evidence and there is no requirement to charge the detainees or to allow them to stand trial.
As of December 2011, Israel held 307 Palestinians as administrative detainees, according to the Israeli human rights group B'Tselem, marking a 40% increase from a year earlier.
While the practice has always been a lightning rod for criticism, Adnan's hunger strike has prompted growing demonstrations in the West Bank and Gaza and led other Palestinian prisoners to take up hunger strikes in support.
"Israeli authorities continue to use administrative detention to detain Palestinians without any charges whatsoever," said Anne Harrison, Amnesty International's deputy director for the Middle East. "These have included individuals who should not have been arrested at all and were prisoners of conscience."
While Adnan's wife strongly denies that her husband is a member of Islamic Jihad, the Gaza-based group issued a statement saying it would hold Israel responsible for any harm that came to him. Photos and tributes to Adnan fill a website maintained by the militant group.
In a special judicial hearing held at the hospital Thursday, Adnan appeared before the military judge in a wheelchair while his attorney argued that his administrative detention should be appealed.
"We have laid down our claims trying to convince the judge that this is a totally wrong decision," attorney Jawad Boulos told CNN. But despite arguing that his client's rapidly declining health should be considered, Boulos is not expecting a break in the case.
"After my experience in this field of administrative detention orders, I am not optimistic," he said.