TBL 6 - Encephalopathies; hepatic, anoxic, hypoxic, HTN

asterixis - define

- Asterixis is the inability to maintain a particular posture due to metabolic encephalopathy. - Abnormal diencephalic function leads to the characteristic liver flap noted when the arms and wrists are held in extension. - Asterixis is also present in patients with uremia, barbiturate toxicity, and some cases of pulmonary disease. As such, asterixis is not pathognomonic for HE.

prognosis of anoxic-hypoxic encephalopathy

- Cerebral hypoxia is an emergency condition that needs to be treated right away. The sooner the oxygen supply is restored to the brain, the lower the risk for severe brain damage and death. - The outlook depends on the extent of the brain injury. This is determined by how long the brain lacked oxygen, and whether nutrition to the brain was also affected

mild cerebral hypoxia - symptoms (2)

- Change in attention (inattentiveness) - Poor judgment - Uncoordinated movement

severe cerebral hypoxia - symptoms (2)

- Complete unawareness and unresponsiveness (coma) - No breathing - No response of the pupils of the eye to light

hypertensive encephalopathy - define

- Hypertensive encephalopathy refers to the transient migratory neurologic symptoms that are associated with the malignant hypertensive state in a hypertensive emergency. - The clinical symptoms are usually reversible with prompt initiation of therapy. - The clinical manifestations of hypertensive encephalopathy are due to increased cerebral perfusion from the loss of blood-brain barrier integrity, which results in exudation of fluid into the brain.

hypertensive encephalopathy - approach for reduction of HTN.

- In chronically hypertensive patients, autoregulation is altered and shifted upward to maintain a relatively constant CBF at a higher MAP range. - When therapy is initiated, it is important to consider the baseline blood pressure in order to avoid excessive blood pressure reduction and prevent cerebral ischemia. It is usually safe to reduce MAP by 25% and to lower the diastolic blood pressure to 100-110 mm Hg.

Wenicke-Korsakoff encephalopathy

- Korsakoff's psychosis are the acute and chronic phases. - Wernicke encephalopathy typically comes on suddenly, and you'll need treatment right away. Symptoms include confusion, loss of muscle coordination, and trouble with your vision. Korsakoff syndrome happens more slowly. It's a long-term, ongoing problem that damages the part of your brain that handles memory - caused by a deficiency in the B vitamin thiamine. - Thiamine plays a role in metabolizing glucose to produce energy for the brain.

hepatic encephalopathy - differential diagnosis (6)

- Metabolic encephalopathy related to anoxia, hypoglycemia, hypokalemia, hypo- or hypercalcemia, or uremia - Head trauma, concussion, subdural hematoma - Transient ischemic attack (TIA), ischemic stroke - Alcohol intoxication, Alcohol withdrawal syndrome - Confusion due to medications or illicit drugs - Meningitis, encephalitis - Wilson disease - Reye syndrome - Wernicke-Korsakoff syndrome

hepatic encephalopathy - define

- Reversible altered mental and neuromotor functioning occurring in association with acute or chronic liver disease and/or portal systemic shunting - The prominent features are confusion, impaired arousability, and a "flapping tremor" (asterixis).

hypertensive encephalopathy - pathophysiology

- The clinical manifestations of hypertensive encephalopathy are due to increased cerebral perfusion from the loss of blood-brain barrier integrity, which results in exudation of fluid into the brain. - With persistent elevation of the systemic blood pressure, arteriolar damage and necrosis occur. The progression of vascular pathology leads to generalized vasodilatation, cerebral edema, and papilledema

hepatic encephalopathy - three classifications

- Type A: resulting from acute liver failure - Type B: resulting from portosystemic bypass or shunting - Type C: resulting from cirrhosis

hepatic encephalopathy - prognosis

- With appropriate treatment, acute HE often resolves. Chronic liver disease - HE recurs. - With each recurrence, HE is more difficult to treat—the degree of improvement with treatment is reduced and the mortality rate approaches 80%.

hypertensive encephalopathy - retinal changes (4)

- papilledema, - hemorrhage, - exudates, - cotton-wool spots (see the images below). Although papilledema is usually considered a more severe finding, it actually does not confer worse survival than hemorrhages and exudates alone.

mechanism of action of lactulose syrup

1st line medications for HE - non-absorbable disaccharide with laxative action that decreases colonic transit time and bacterial digestion that acidifies the colon to promote ammonia excretion - : 30 to 45 mL PO up to every hour for goal of 3 to 6 bowel movements per day. Decrease to 15 to 30 mL BID when ≥3 bowel movements per day.

cerebral hypoxia - define and three examples

Brain cells are very sensitive to a lack of oxygen. Some brain cells start dying less than 5 minutes after their oxygen supply disappears. - Breathing in smoke (smoke inhalation), such as during a fire - Carbon monoxide poisoning - Choking - Diseases that prevent movement (paralysis) of the breathing muscles, such as amyotrophic lateral sclerosis (ALS) - High altitudes - Pressure on (compression) the windpipe (trachea) - Strangulation

hepatic encephalopathy - risk factors (4)

In patients with underlying liver disease, precipitating factors include: - Infection (overt or occult, including spontaneous bacterial peritonitis [SBP]) - GI hemorrhage - Use of sedative or opiate drugs - Fluid or electrolyte disturbance (Na+, K+, Mg2+ most common) - Transjugular intrahepatic portosystemic shunt (TIPS—a radiologically inserted shunt to lower portal pressure)

hypertensive encephalopathy - etiologies (6)

The most common cause of hypertensive encephalopathy is abrupt blood pressure elevation in a chronically hypertensive patient. - Chronic renal parenchymal disease - Renovascular hypertension - Withdrawal from hypertensive agents (eg, clonidine) - Encephalitis, meningitis - Pheochromocytoma, renin-secreting tumors - Sympathomimetic agents (eg, cocaine, amphetamines, phencyclidine [PCP], and lysergic acid diethylamide [LSD]) - Eclampsia and preeclampsia - Ingestion of tyramine-containing foods or tricyclic antidepressants in combination with monoamine oxidase inhibitors (MAOIs)

anoxic-hypoxic encephalopathy - three causes

occurs when blood flow to the brain is disrupted, essentially starving the brain and preventing it from performing vital biochemical processes. - Cardiac arrest (when the heart stops pumping) - Cardiac arrhythmia (heart rhythm problems) - Complications of general anesthesia - Drowning - Drug overdose - Injuries to a newborn that occurred before, during, or soon after birth such as cerebral palsy - Stroke - Very low blood pressure

hepatic encephalopathy and serum ammonia levels

serum ammonia level is elevated in 90% of patients with HE; levels affected by infusion of amino acid solutions, opiate administration (constipation), uremia, tissue breakdown, burns, trauma, or infection