Neonatal Maladjustment Syndrome

This is a descriptive term for a set of symptoms. Foals may show signs of being a "dummy foal" associated with septicemia, bacterial meningitis (rare), hypoxic encephalopathy from unobserved birth asphyxia, brain edema or hemorrhage, reversion to fetal cortical status, or congenital lesions in the CNS (hydrocephalus).

Editor's Comment - It is impossible for most clinicians to perform a full battery of tests to sort these etiologies out and some treatment must be administered without a conclusive diagnosis. Always treat concurrently for infection until absolutely proven otherwise. While the cause has previously been considered to be hypoxic encephalopathy, our studies suggest it is caused by a reversion or persistence of fetal cortical status - This is when the biochemistry required to keep the foal sedated and quiet in utero persists and at birth the "wake up" call does not occur [1]. Watch for new treatments to come forth soon.

I. Clinical Signs

May or may not be associated with an apparently normal birth. Signs develop within 72 hours of birth.

Loss of awareness of environment, recumbency, inability to stand, disorientation, struggling randomly, loss of affinity for mare and nursing, poor suck reflex, blindness, seizures, opisthotonus, airway origin bark ("Wanderbarker") may be heard in some foals although this is rare.

Duration of symptoms last 1 day in most cases (with early treatment) and up to 5 days or more in others.

II. Suspected Originating Factors [2]

Hypoxic encephalopathy suspected in 92% of cases in earlier study [2]

Placental problems 55%, gestational problems 21%, premature placental separation 34%, dystocia 30%.
Overall 59% had delivery that included dystocia or premature placental separation.

Septicemia

Earlier studies indicated up to 50% develop a component of bacterial infection if no antibiotic treatment.
Recent studies all incorporated aggressive antimicrobial treatment and reported good outcomes with supportive care.
Meningitis (rare cause) (See Infections).
Congenital lesions - Hydrocephalus most common.

Reversion to fetal cortical status
Editor's Comment - This is a term I have used to describe the brain activity of these compromised foals. We have the hypothesis that signals that "wake" the foal up from an in utero or "fetal cortical state" have failed in some of these foals and neuropharmacological modulation may provide some benefit (See Treatment).
CNS hemorrhage or edema.
Metabolic insults - Hypoglycemia, electrolyte alterations, acidosis, hypothermia.
Endotoxins.
In utero infection.

III. Prognosis

1. Excellent prognosis (80% survival) reported with intensive care and lack of significant bacterial component [2].
2. Older study reported if any one of the following, only 30% survival [3].

1. Positive blood culture
2. <400 mg serum IgG.
3. Diarrhea.
4. Occult blood in feces or gastric reflux.
5. Abnormal thoracic radiographs.
6. Abnormal behavior at birth

3. After 5 days, if no improvement, prognosis is poor; after 6 days even worse in one study [3].
4. If they recover, "are they going to be normal?" A farm manager or owner often asks.
   Editor's Comment - Best guess answer is "Yes" with example being Kentucky derby winner Strike The Gold who was a "dummy" foal.

IV. Diagnostic Workup

1. Work up as described in Initial Evaluation and Minimum Data Base.
2. Serum creatinine kinase elevated in 61%, which may reflect birth hypoxia and muscle damage [2]
3. Serum Creatinine elevated in 32% [2].
   This is not due to kidney damage but reflects difficult birth and entry of fetal kidney waste products found in allantoic and fluids into foal circulation.
   Editor's Comment - Check urine to be sure. If there is significant kidney disease you will usually find abnormalities with increased blood or glucose or casts, etc. Remember normal foals have proteinuria in the first 36-48 hrs.

V. Therapy

1. Don’t over-hydrate and contribute to CNS edema -be careful with fluid volumes (See Fluid and Electrolyte Balance).
2. Antimicrobials always because of open gut and high risk of infection (See Guidelines for Drug Use in Equine Neonates).
3. Nutrition: Tube feed with colostrum and milk. Parenteral nutrition if needed and nursing care (See Parenteral Nutrition and Enteral Nutrition).
4. Oxygen insufflation, respiratory stimulants if needed (See Respiratory Therapeutics).
5. CNS treatment to stimulate "I have been born" signal (Editor's Comment - These are experimental - Not a recommendation but a sharing of what some have used and had some improvement, or none at all)

1. Pergolide (0.5 mg-1.0 mg once daily orally for 48 hrs).
2. Naloxone 5 mg IV once. Editor's Comment - See References [4] and [5].
   Editor's Comment - Pregnenolone pathway inhibitors (check new literature in the next year or two).
   Apply "Madigan squeeze method" [6]

6. Apply 20 min of thoracic squeezing (See foal restraint and reference [6]).
7. Treat for cerebral edema

1. 10% DMSO solution intravenously at 0.5-1 gm/kg (for 50 kg foal add 45 ml of 90% DMSO solution into 500 ml of 5% dextrose).
2. Mannitol - 0.25 gm/kg IV q 6-8 hrs for 24 hr. Editor's Comment - This drug does not enhance brain hemorrhage and we use it in many NMS foals.
3. Flunixin meglumine 0.5-1.0 mg/kg q 12 h for 24 hr.

8. Treat seizures (See Neonatal Seizures).
9. Inotropes and vasopressors (See Shock (SIRS)).
10. Ileus, colic, gastrointestinal ulcers (See Gastroduodenal Ulcers).