Diagnosis
Diagnostic guidelines and criteria have only recently been proposed despite the prevalence of cachexia and varying criteria, the primary features of cachexia include progressive depletion of muscle and fat mass, reduced food intake, abnormal metabolism of carbohydrate, protein, and fat, reduced quality of life, and increased physical impairment.Historically, body weight changes were used as the primary metrics of cachexia, including low body mass index and involuntary weight loss of more than 10%. Using weight alone is limited by the presence of edema, tumor mass and the high prevalence of obesity in the general population. Weight-based criteria do not take into account changes in body composition, especially loss of lean body mass. In the attempt to include a broader evaluation of the burden of cachexia, diagnostic criteria using assessments of laboratory metrics and symptoms in addition to weight have been proposed. The criteria included weight loss of at least 5% in 12 months or low body mass index (less than 22  kg/m2) with at least three of the following features: decreased muscle strength, fatigue, anorexia, low fat‐free mass index, or abnormal biochemistry (increased inflammatory markers, anemia, low serum albumin). In cancer patients, cachexia is diagnosed from unintended weight loss of more than 5%. For cancer patients with a body mass index of less than 20  kg/m2, cachexia is diagnosed after the unintended weight loss of more than 2%.
Long-term untreated papilledema leads to visual loss, initially in the periphery but progressively towards the center of vision.Physical examination of the nervous system is typically normal apart from the presence of papilledema, which is seen on examination of the eye with a small device called an ophthalmoscope or in more detail with a fundus camera. If there are cranial nerve abnormalities, these may be noticed on eye examination in the form of a squint (third, fourth, or sixth nerve palsy) or as facial nerve palsy. If the papilledema has been longstanding, visual fields may be constricted and visual acuity may be decreased. Visual field testing by automated (Humphrey) perimetry is recommended as other methods of testing may be less accurate. Longstanding papilledema leads to optic atrophy, in which the disc looks pale and visual loss tends to be advanced. Causes
"Idiopathic" means of unknown cause. Therefore, IIH can only be diagnosed if there is no alternative explanation for the symptoms. Intracranial pressure may be increased due to medications such as high-dose vitamin A derivatives (e.g., isotretinoin for acne), long-term tetracycline antibiotics (for a variety of skin conditions) and hormonal contraceptives. There are numerous other diseases, mostly rare conditions, that may lead to intracranial hypertension. If there is an underlying cause, the condition is termed "secondary intracranial hypertension". Common causes of secondary intracranial hypertension include obstructive sleep apnea (a sleep-related breathing disorder), systemic lupus erythematosus (SLE), chronic kidney disease, and Behçets disease. Mechanism
The cause of IIH is not known.