Clinic: Naja sp., African neurotoxic cobras
Examine for venom effects
Local Effects
- Mild / minimal
Neurological effects
- Descending flaccid paralysis
- Ptosis (not to be mixed up with tiredness / drowsiness; test: lid retraction with upward gaze).
- Double vision (external ophthalmoplegia)
- Difficulties to swallow (dysphagia) (bulbar paralysis) > inhalation of vomitus!
- Difficulties to lift the head when lying on the back (‘broken neck syndrome’)
- Cyanosis, shallow breathing, respiratory arrest (respiratory paralysis); respiratory arrest may be precipitated by obstruction of the upper airway by the paralysed tongue or inhaled vomitus.
- Weakness or loss of voluntary movement; movements of digits may still be possible, allowing the patient to communicate.
- Loss of consciousness and generalized convulsions caused by hypoxaemia in patients who have respiratory paralysis.
Species-specific envenoming pattern
The assessment of the envenoming pattern is based on the data from publication in which the identification of the snakes is clearly specified and in accordance with accepted criteria.
| Local effects1 | Neurological effects2 | |
| Naja haje | ||
| Naja melanoleuca | ||
| Naja nivea |
1Local effect
Mild / minimal (Warrell 2023, WHO 2010a).
2Neurological effects
Descending flaccid paralysis including respiratory muscles.
For references on the various venom effects, see 'Species-specific evidence' below
Clinical management
See also (Depending on the origin of the culprit)
Clinical Management: Central and Southern Africa
Clinical Management: North Africa, Near and Middle East
for advice on post-First Aid measures, diagnosis (clinical, laboratory) and treatment (supportive, antivenom).
First Aid
Any type of tourniquet follow links above.
Local treatment
Pain control
Tetanus prophylaxis
Standard wound care
WHO (2010b)
Systemic supportive treatment
A general understanding of emergency medicine is required, or can be found in emergency medicine guidelines, e.g. ABCDE approach, WHO-ICRC Basic Emergency Care.
Follow SAMPLE & ABCDE ApproAch
- ICRC Basic Emergency Care: approach to the acutely ill and injured (SAMPLE and ABCDE approach: first module)
Obey african neurotoxic cobras - specific features
see
- 'Species-specific envenoming pattern above'.
and
Key issues:
Respiratory failure
Lifesaving in neurotoxic snakebite envenoming (as supportive treatment and when Antivenoms are not available or fail):
Airway management
Breathing: Oxygen⇨assisted ventilation⇨mechanical ventilation
Neurotoxic effects are completely reversible, either in response to antivenom or spontaneously within 1-4 days of mechanical ventilation, ocular muscles within 2–4 days and full recovery of motor function within 3–7 days (Warrell 2023, WHO 2010a).
A trial of anticholinesterase drugs to improve neuromuscular transmissionappears is reasonable.
Specific treatment (antivenoms)
- National Snakebite Management Guidelines (2021) WHO Eswatini, Eswatini Antivenom Foundation
- World Health Organization(2023). Target product profiles for animal plasma-derived antivenoms: antivenoms for treatment of snakebite envenoming in sub-Saharan Africa
References
- National Snakebite Management Guidelines Kingdom of Eswatini 2021 https://eswatiniantivenom.org/newsite/wp-content/uploads/2021/12/WHO-Snake-Bite-Treatment-Protocol-Manuscript-A4.pdf
- Warrell DA. Venomous and poisonous animals.In: Farrar J, Garcia PJ, Hotez T, Junghanss T, Kang G, Laloo D (eds.). Manson’s tropical diseases. 24th ed. Elsevier; 2023.
- WHO (2010a) Guidelines for the prevention and clinical management of snakebite in Africa. https://www.who.int/publications/i/item/9789290231684
- WHO (2010b) Wound and lymphoedema management. WHO/HTM/NTD/GBUI/20101 I. 2010. https://www.who.int/publications/i/item/9789241599139
- WHO-ICRC Basic Emergency Care: approach to the acutely ill and injured (2018) https://www.who.int/publications-detail-redirect/basic-emergency-care-approach-to-the-acutely-ill-and-injured
- WHO ABCDE Approach https://cdn.who.int/media/docs/default-source/integrated-health-services-(ihs)/csy/bec-quick-cards/becp-edu29-pdf-en-finl.pdf?sfvrsn=2532d61b_2
- WHO Snakebite Information and Data Platform https://www.who.int/teams/control-of-neglected-tropical-diseases/snakebite-envenoming/snakebite-information-and-data-platform
Species-specific evidence
Naja anchietae
(described as N. haje, but actually N. anchietae!)
South Africa
Case reports
- Visser and Chapman (1978)
Bites in humans and in particular fatalities appear to be rare.
Naja guineensis
(described as N. melanoleuca)
Liberia
Case reports
- Stahel (1980)
1 patient
Signs & symptoms
Neurological effects
Ptosis, dysarthria, dyspnoea (Stahel 1980).
Naja haje
Nigeria
Case reports and review of the literature
- Warrell et al. (1976a).
3 cases; identification: 2 morphological, 1 description by bystanders.
Signs & symptoms
Local effects
Mild (Warrell et al. 1976a).
Neurological effects
Peripheral signs of paralysis (ptosis and signs and symptoms of other cranial nerve paralyses, paralysis of the extremities, paralysis of the respiratory musculature) (Warrell et al. 1976a).
Naja melanoleuca
Cameroon
Case reports
- Chippaux et al. (2024)
5 cases; identification: 1 morphological.
Naja nivea
South Africa
Case reports
- Blaylock et al. (1985)
2 cases; identification: morphological
Signs & symptoms
Local effects
Minimal local effects (Blaylock et al. 1985).
Neurological effects
Peripheral signs of paralysis (ptosis and signs and symptoms of other cranial nerve paralyses, paralysis of the extremities, paralysis of the respiratory musculature) (Blaylock et al. 1985).
References
- Blaylock RS, Lichtman AR, Potgieter PD. Clinical manifestations of Cape cobra (Naja nivea) bites. A report of 2 cases. S Afr Med J. 1985 Aug 31;68(5):342-4. PMID: 4035501. https://journals.co.za/doi/pdf/10.10520/AJA20785135_6057
- Chippaux, J.-P.; Madec, Y.; Amta, P.; Ntone, R.; Noël, G.; Clauteaux, P.; Boum, Y., II; Nkwescheu, A.S.; Taieb, F. Snakebites in Cameroon by Species Whose Effects Are Poorly Described. Trop. Med. Infect. Dis. 2024, 9, 300. DOI:10.3390/tropicalmed9120300
- Stahel (1980) Epidemiological aspects of snake bites on a Liberian rubber plantation. Acta Tropica 37: 367-374
- Visser and Chapman (1978) Snakes and snake bite. Venomous snakes and management of snake bite in Southern Africa. Purnell, Cape Town: 152
- Warrell DA, Barnes HJ, Piburn MF. Neurotoxic effects of bites by the Egyptian cobra (Naja haje) in Nigeria. Trans R Soc Trop Med Hyg. 1976a;70(1):78-9. PMID: 1265823. DOI:10.1016/0035-9203(76)90012-2