- The recent spike in deaths due to acute encephalitis syndrome (AES) in northern districts of Bihar is associated with a condition called hypoglycemic encephalopathy.
- Districts in North Bihar including Muzaffarpur, Vaishali, Sitamarhi, Samastipur, Sheohar, East and West Champaran are witnessing upsurge in the Acute Encephalitis Syndrome cases.
- Acute Encephalitis Syndrome is a spectrum of diseases classified based on similar clinical syndromes.
- It is primarily a neurological condition characterized by sudden onset of fever and altered consciousness.
- It can be caused by different viruses, bacteria, fungus, parasites, spirochetes, toxins etc.
In focus: Hypoglycemic Encephalopathy
- While encephalitis causes 15% of the AES cases, the recent outbreak of AES in Bihar is associated with a biochemical found in litchi that is known to cause hypoglycemia in undernourished children.
- The AES condition caused due to litchi is called Hypoglycemic Encephalopathy.
Difference between Encephalitis and Hypoglycemic Encephalopathy
- Encephalitis is a mosquito borne viral disease transmitted by Culex Mosquitoes.
- Hypoglycemic Encephalopathy is caused mainly by a toxin that hinders synthesis of glucose in the body.
- In case of encephalitis, fever precedes brain dysfunction.
- On the other hand, in cases of hypoglycaemic encephalopathy, fever is after the onset of brain dysfunction.
- Under encephalitis, blood sugar level is normal in children.
- Under hypoglycaemic encephalopathy, hypoglycemia is the main cause of death.
Litchi and Hypoglycemic Encephalopathy
- A study in 2015 established a relationship between consumption of litchi and AES.
- Most of these cases are associated with exposure to a toxin in litchi (hypoglycin A and methylene cyclopropylglycine (MCPG).
- In 2017, another team of researchers confirmed the role of the toxin methylene cyclopropyl glycine (MCPG).
Glucose synthesis in the body
- In normal circumstances, after a period of fasting, the blood sugar level in the body dips.
- In such a situation, glycogen (a polysaccharide) in the liver is broken down into simple sugar glucose restoring the sugar levels in the blood.
- When glycogen reserve in the liver is exhausted, the body oxidizes the fatty acid into glucose.
MCPG and hypoglycemia
- Methylene cyclopropyl glycine (MCPG) present in litchi blocks the fatty acid oxidation leading to hypoglycemia.
- Thus in case of under-nourished children, who have low/no glycogen in the liver, fatty acid oxidation into glucose is hindered by MCPG after a prolonged period of no food intake.
- Low sugars level in blood results in lack of supply to brain leading to drowsiness, disorientation and even unconsciousness.
- Besides when fatty acid conversion is halted, amino acids are released to brain cells.
- The amino acids cause brain oedema (filling up of water) resulting in swelling of the brain cells resulting in seizures, coma and finally death.
Prevention and Treatment
- Undernourished children should not go empty stomach.
- Ensure they do not eat litchi empty stomach.
- Infusion of 10% dextrose restores blood sugar and also stops the production of amino acid that causes swelling of brain cells.
- 3% saline solution reduces brain oedema through the process of osmosis.