Neonatal spasms

Neonatal convulsions are clinically defined as paroxysmal alterations of neurological functions - behavior, motor and vegetative functions. Epidemiologically, the dependence on gestational age is proven - neonatal convulsions occur in up to 20% of premature babies, on the contrary, they affect only 0.5% of mature newborns. About 90% of seizures occur in the first two days of life. It can be clinically significant paroxysms of tonic-clonic convulsions, but often the clinical picture is discrete and includes myoclonus, apnea, nystagmus or increased salivation.

Etiology

• in terms of timing, cramps in the first 120 minutes after birth occur most often due to VVV, withdrawal syndrome, hypoglycemia:

1. central causes,
   • perinatal brain damage – trauma, intracranial hemorrhage, brain edema, hypoxia,
   • congenital CNS defects – congenital hydrocephalus, cerebral dysgenesis, genetic causes,
   • transplacental infection of the CNS – CMV, toxoplasmosis,
   • febrile convulsions (typically after newborn age, at the earliest from 3 months),
2. metabolic causes,
   • hypoglycemia,
     • damage to the brain stem – asphyxia, bleeding,
     • diabetic fetopathy,
     • lack of glycogen – immaturity,
     • increased need for glucose – sepsis,
     • primary disorder of carbohydrate metabolism,
     • primary disorder of AMK metabolism,
     • primary disorder of fatty acid oxidation,
   • hypocalcemia,
     • damage to the brain stem – asphyxia, bleeding,
     • hypoparathyroidism,
     • hypomagnesemia,
     • hyperphosphatemia,
   • lack of pyridoxine – vitamin B6 dependent convulsions (genetically conditioned increased need for vit. B6, convulsions appear both in the first hours of life and also on the 4-5th day after birth, disappear after administration of high doses of vit. B6, disappear again after omission appear)
   • hypo/hypernatremia,
   • hyperbilirubinemia,
   • MAc,
   • hereditary metabolic disorders,
3. infection,
   • STORCH,
   • sepsis,
   • meningitis,
   • encephalitis,
4. other,
   • polycythemia,
   • core jaundice,
   • abstinence syndrome.

Classification of neonatal seizures based on clinical picture

• Basically, we distinguish 2 types of seizure movements: tonus = stiffening and clonus = jerking.

Subtle spasms

Premature babies are most at risk of convulsions

• These are paroxysmal deviations in the newborn's behavior in motor and vegetative manifestations, which are neither purely tonic, nor clonic, nor myoclonic,
• represent about 50% of newborn seizures, most often in newborns with low birth weight,
• manifested as horizontal deviation of the eyeballs, twitching of the eyes, repeated blinking, tremor of the eyelids, salivation, yawning, grimacing, apnea,
• limb movements may resemble rowing, boxing, cycling,
• on EEG multifocal repetitive sharp waves are present, predilectionally temporally.

Multifocal clonic convulsions

• They start on one or both limbs and uncoordinatedly move to other parts of the body.

Focal clonic convulsions

• Rhythmic twitches of muscle groups, the fast phase alternates with the slow,
• are localized and not associated with unconsciousness,
• do not occur before the age of 37,
• unlike tremor, clonic jerks are more pronounced and irregular.

Tonic convulsions

• Often as a generalized extension of HK and DK → resemble Decerebration Posture,
• breathing is raspy, eyes turn to the side.

Myoclonic seizures

• Fast isolated twitches of predilection flexor muscle groups,
• myoclonus may be isolated or repeated.

hyperexcitability, i.e. non-convulsive manifestations - jitteriness

• Abnormal eye gaze and bulbar movements are absent,
• it is possible to provoke a convulsive manifestation by an external stimulus,
• non-convulsive phenomena have a rhythmic character (epi-convulsions have a fast and slow component),
• absence of vegetative changes,
• stopping movement by passive flexion,
• normal US of the brain, normal EEG and physiological neurological findings.

Diagnostics

• Anamnesis,
• mother's medical history: drugs, nutrition, DM;
• birth history: asphyxia, trauma;
• physical examination, evaluation of clinical manifestations;
• laboratory examination:
  • hematological examination and hemocoagulation;
  • biochemistry: blood glucose, ions (especially calcium), urea, bilirubin and liver tests, ammonia, lactate, ABR;
  • inflammatory markers + culture;
  • liquor;
  • examination for sepsis/meningitis – blood culture, lumbar puncture;
  • toxicological examination;
  • metabolic screening;
  • neurological and ophthalmological examination;
  • imaging methods: ultrasound of the brain through the large fontanelle, EEG, CT, possibly MRI, EKG, eye examination;
• reaction to vitamin B6.

Differential diagnosis of neonatal convulsions according to etiology

• Stigmatization of the newborn → congenital CNS dysgenesis, genetic syndromes, DMP,
• trauma (LP, ultrasound, CT, MRI, neurological examination) → intracranial bleeding, brain edema, contusio cerebri,
• infection (LP, inflammatory markers, culture, IgM, neurological examination) → meningitis, meningoencephalitis, sepsis,
• perinatal asphyxia (Astrup, chest X-ray) → RDS, HIE,
• VCC (Astrup, EKG, ECHO, chest X-ray),
• abnormalities of the internal environment (gly, Na, Ca, Ca ioniz., Mg, pyridoxine) → imbalance of the internal environment,
• polyglobulia (Hb, Htk),
• abnormalities of amino acids and organic acids, MAC → DPM,
• abuse of medicines and drugs in the mother → abstinence syndrome,
• increased urea, creatinine, MAc → renal failure,
• normal biochemistry, inflammatory markers and imaging methods → benign familial neonatal convulsions, convulsions of unclear etiology.

Therapy

• Ensure basic vital functions – ventilation, circulation, thermoneutral environment,
• correction of the internal environment,
• 10% glucose 2 ml/kg i.v. as a bolus followed by 5 ml/kg/hour,
• 10% calcium gluconicum' 2 ml/kg i.v. within 10 min. under ECG control, then continuously or every 6 hours up to a total daily dose of 5 ml/kg,
• 10% MgSO₄ 1 ml/kg during 10 min. i.v., then 0.2 ml/kg every 6 hours,
• vitamin B6'' (pyridoxine) in pyridoxine-dependent convulsions (therapeutically 50–100 mg i.v., preventive substitution approx. 10 mg/kg/day p.o.);
• anticonvulsants':

Phenobarbital

• is the drug of choice in neonatology,
• doses: 15–20 mg/kg i.v. within 15 minutes, doses of 30–40 mg/kg are also possible, but only with ensured ventilation,
• daily maintenance dose is 5 mg/kg/d,
• necessary monitoring of cardiovascular functions → risk of hypotension and monitoring of serum levels.

Phenytoin

• if there is no therapeutic response to phenobarbital,
• dose: 15–20 mg/kg i.v. at a rate of 0.5–1 mg/kg/min,
• daily maintenance dose is 5 mg/kg/d,
• risk of arrhythmia and hypotension, necessary monitoring of serum levels.

Diazepam

• dose: 0.1–0.3–0.5 mg/kg i.v. slowly to a total dose of 1 mg/kg,
• has a rapid onset of therapeutic effect, the anticonvulsant half-life is on the order of minutes,
• with a rapid bolus of higher doses there is a risk of apnea,
• should not be administered to children with severe jaundice, as it increases the risk of core jaundice.

Links

Source

• HAVRÁNEK, Jiří: Newborn convulsions;
• MUNTAU, Ania. Pediatrics. 1. edition. Prague : Grada, 2009. ISBN 978-80-247-2525-3.