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ORIGINAL ARTICLE
Year : 2012  |  Volume : 6  |  Issue : 2  |  Page : 92-97

Etiology and outcome of medical coma in a tertiary hospital in Northwestern Nigeria


1 Department of Medicine, Aminu Kano Teaching Hospital, Nigeria
2 Department of Anaesthesiology and Intensive Care, Aminu Kano Teaching Hospital, Nigeria
3 Department of Psychiatry, Aminu Kano Teaching Hospital, Nigeria

Date of Web Publication7-Mar-2013

Correspondence Address:
Owolabi F Lukman
Neurology unit, Department of Medicine, Aminu Kano Teaching Hospital, Bayero University, PMB 3452, Kano
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0331-3131.108130

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   Abstract 

Background: Medical coma is a common cause of admission in emergency unit, medical wards and intensive care unit. A better understanding of causes and outcome, especially in a resource poor setting, is key to planning and improving rational approach to the management of medical coma. The study was undertaken to evaluate common etiologies and outcome of non- traumatic coma among adult patients in a tertiary hospital in Kano, Northwestern Nigeria.
Materials and Methods: In this prospective observational study, adults patients in coma admitted to medical emergency unit of the Aminu Kano Teaching Hospital (AKTH), over a period of 19 months, were consecutively recruited. Etiology of coma was determined on the basis of history, clinical examination, relevant laboratory and radiological investigations. Outcome, over one month was recorded. Functional outcome of the survivors was assessed with Glasgow Outcome Scale.
Results: A total of 194 (140 males, 54 females) patients constituting 8.1% of all medical emergencies seen during the study period were recruited. GCS at presentation was 8 in eight (4.1%) patients, 7 in thirty (15.5%) patients, 6 in fifty eight (29.9%) patients, 5 in forty (20.6%) patients, 4 in 34 (17.5%) patients, and 3 in twenty four (12.4%) patients. Etiologies identified were infections (28.9%), toxic and metabolic causes (28.9%), and stroke (23.7%). Mortality was 49%. When compared with infective causes of coma as a whole, more deaths were recorded from strokes than infections (28/46 and 24/56 respectively), however, the difference was not statistically significant (p = 0.070) with OR of 1.4, 95% CI (0.97-2.08). There was a statistically significant difference (p = 0.023) between patients with admission GCS of 3-5 and 6-8.
Conclusion: Stroke, sepsis, diabetic emergencies and chronic kidney diseases were the most common etiologies of medical coma. Outcome of medical coma was comparable to what obtains in other places in the developing countries.

Keywords: Coma, etiology, mortality, outcome, predictors


How to cite this article:
Lukman OF, Datti MA, Geoffrey O, Yussuf AM, Musbau R, Shakira OD. Etiology and outcome of medical coma in a tertiary hospital in Northwestern Nigeria . Ann Nigerian Med 2012;6:92-7

How to cite this URL:
Lukman OF, Datti MA, Geoffrey O, Yussuf AM, Musbau R, Shakira OD. Etiology and outcome of medical coma in a tertiary hospital in Northwestern Nigeria . Ann Nigerian Med [serial online] 2012 [cited 2019 Dec 9];6:92-7. Available from: http://www.anmjournal.com/text.asp?2012/6/2/92/108130


   Introduction Top


Non traumatic or medical coma is a common cause of admission in emergency unit, medical wards and intensive care unit. It accounts for high morbidity and mortality. It can result from wide range of primary etiologies. Previous reports showed that infection was the most common etiology for coma in all age groups. [1],[2],[3] The acute and long-term prognoses in patients with these different conditions are of great importance for triage and treatment decisions. However, the number of published studies on medical coma in adult patient in Nigeria has been surprisingly small. A study in a tertiary hospital in Ibadan, Southwestern Nigeria reported stroke (33%), diabetic emergencies (12.5%), uremic encephalopathy and meningitides (11%) as the most common causes of medical coma in adults. [4] However, considerable regional diversity exists in these etiological factors with stroke and infectious diseases suggested to be more common in developing countries compared to developed countries. [4],[5],[6]

Due to regional variations in etiology, study of common etiologies of medical coma in different regions are required. It is also desirable that health care planners and providers know the common etiologies as well as the outcome of medical coma for the purposes of planning and resource allocation. [7] Thus, a better understanding of causes and outcome, especially in a resource poor setting, is key to improving the approach and to plan rational management of medical coma. Moreover, since knowledge of disease probability is crucial in terms of differential diagnosis, [8],[9] relative frequency of various causes of coma should be investigated in an actual cohort.

The current study was undertaken in an attempt to determine common etiologies and outcome of non traumatic coma among adult patients in a tertiary hospital in Kano, Northwestern Nigeria.


   Materials and Methods Top


In this prospective observational study, 194 Adults admitted consecutively to the medical emergency unit of the Aminu Kano Teaching Hospital (AKTH) over a period of 19 months (March 2008- September 2009) were recruited. Inclusion criteria was all adult patients in whom there was clinically confirmed Coma (Glasgow coma scale (GCS) score of ≤ 8). [1],[10],[11],[12],[13] Exclusion criteria comprised patients with coma of traumatic cause, patients whose coma was believed secondary to sedative drugs or alcohol, as almost all such subjects should recover fully with supportive treatment whatever their early signs [10] and patients whose relations did not consent to the study.

Assessment of clinical neurological status including level of consciousness and subtle cerebellar signs such as presence of nystagmus were carried out on all the patients.

Clinical signs studied were temperature, pulse volume, heart rate, blood pressure, coma severity by Glasgow coma scale (GCS), posturing, respiratory pattern, pupillary size, pupillary and corneal reflex, motor patterns, seizure and findings on fundoscopy.

The etiology of coma was determined on the basis of history, clinical examination and relevant laboratory investigations. Investigations, such as lumbar puncture, CT scan and metabolic work-up, depending on the clinical presentation were determined by the consultant in-charge.

Following initial evaluation at the accident and emergency unit, the patients were transferred to medical wards and on few occasions, intensive care unit where they had further treatment. Monitoring was carried on a daily basis for outcome for a minimum of 1 month.

Standard practice guidelines, as contained in the protocol of the teaching hospital, were used in the management of the patients.

Etiology of coma was classified into infectious, toxic-metabolic (uremic, hepatic, hypoxic, hypoglycemic and hyperglycemic encephalopathies), stroke and others.

Outcome, within one month of the onset of coma, was either death or survival.

Glasgow Outcome Scale (GOS) was used to assess functional outcome of the patients. [13],[14]

Analysis of data was carried out using the Statistical Package for Social Sciences (SPSS) program for Windows version 16.0 (SPSS Inc., Chicago, IL, USA). Univariate analysis was carried out using Pearson Chi-square for categorical variables. Scores on severity scale were compared using Chi-square for trend and student's t test for continuous variables and p <0.05 was adopted as significant level.


   Results Top


A total of 194 patients constituting 8.1% of medical emergencies seen during the study period were recruited in the study. They comprised 140 males with mean age of 53.3 ± 1.3 and 54 females with mean age of 54.6 ± 1.6 of the patients. [Table 1] highlights gender distribution across different age groups. One hundred and sixteen (59.8%) patients presented to the accident and emergency unit of the hospital within 24 hrs of onset of coma, seventy (36.1%) presented within 48 hours and eight (4.1%) patients presented within 72 hours. GCS at presentation was 8 in eight (4.6%) patients, 7 in thirty four (17.5%) patients, 6 in thirty six (18.6%) patients, 5 in thirty nine (20.1%) patients, 4 in thirty six (18.6%) patients, and 3 in forty (20.64%) patients. Neuroimaging was established in forty nine (25.3%) of the patients, predominantly in those with lateralizing signs and unexplained coma. The predominant causes were central nervous system (CNS) infections which occurred in fifty six (28.9%), toxic and metabolic causes in fifty six (28.9%) and stroke in forty six (23.7%). Sixteen out of thirty five with coma from infections who had HIV test were reactive and only five of them were already on antiretroviral drugs. Within the limits of available investigative facilities, etiology could not be established in sixteen (8%) patients [Table 2].
Table 1: Distribution of gender across age group of the patients


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Table 2: Distribution of etiology of coma


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During one month period of the study, eighty two patients (49%) died and one hundred and twelve patients survived. [Table 3] showed the distribution of outcome across the various etiological classes. When compared with infective causes of coma as a whole, more deaths were recorded in stroke group than in infection group (28/46 and 24/56 respectively) and p = 0.070. Compared with the toxic-metabolic group, more deaths occurred in stroke group (28/46 and 20/36 respectively) with p = 0.628. Mortality was higher (24/32 vs. 20/36) among patients with infective causes when compared with the toxic-metabolic category, however, the difference was not statistically significant (p = 0.889). In comparison with females, males had a higher gender specific mortality (72%) with a statistically significant difference (p = 0.001). Age specific mortality was highest (40%) in 50-59 age group. Out of the survivors, fifty three (27.3%) had normal or near normal recovery on GOS [Table 4].
Table 3: Distribution of outcome by etiology of coma


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Table 4: Status of outcome of the patients across etiological class on GOS


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There was a statistically significant difference (p = 0.001) between patients with admission GCS of 3-5 and 6-8 [Table 5].
Table 5: Evolution of patients according to initial GCS


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   Discussion Top


This study showed that almost one-tenth of medical emergencies seen at the tertiary health facility presented in coma. Medical coma has for long been a common mode of presentation in medical emergency unit in the tertiary hospital in Kano. [14] However, there has been lack of information on the etiological factors and outcome of medical coma in the facility. This study attempts to fill the gap left by paucity of data on coma in Kano and Northwestern Nigeria.

The figure (8.1%) obtained in this study, which is comparable to 10% reported by Obiako and his colleagues [4] in a study conducted in a tertiary hospital in Southwestern Nigeria, may not necessarily be a true reflection of the population as many comatose patients, for reasons of lack of awareness, poverty and poor means of transportation, may not make it to the hospital. These factors may also be responsible for the delay in presentation recorded in this study as over 40% of the patients presented after twenty four hours of developing coma.

In this study, 75% of the patients were males. Many studies had also reported a high male to female ratio in medical coma. [4],[15],[16] This male preponderance may portray the belief that males have more risky or disease promoting lifestyles than females and so are more likely to fall sick and present to hospital. [17]

The predominant etiological factors were infections, toxic and metabolic causes and stroke. The relative frequency of various causes of coma in our patients was similar to previous report outside Nigeria in spite of the geographic and technological differences. [9],[10],[11] However, when the etiological factors were considered individually, stroke appeared the most common cause. This finding agrees with the report of Obiako and his colleagues in southwestern Nigeria. [4] Previous reports from the study centre showed that stroke is a common neurological disorder in Kano, northwestern Nigeria. [18] It accounted for 77.6% of neurological admission. [19] This again emphasizes the need for stake holders in the health systems of developing countries to begin to take action towards developing and promoting infrastructure for stroke care. It is also essential to intensify efforts on stroke awareness among the populace and more importantly adopt a rational approach towards preventing stroke.

It is worthy of note that HIV infections , having excluded the other common immunosuppressive states, was the predisposing factor to infections in a number of the patients and a large number of these patients were unaware of their status despite free screening and treatment. According to World Health Organization (WHO) estimate, only 9.5% of women and 7.5% of men have ever been tested for HIV and received the test results in developing countries where data is available. [20] Therefore, effort should be geared towards such factor as cultural and health system obstacles to primary prevention and treatment of HIV.

In this study, pyogenic meningitis accounted for majority of the CNS infections. Kano, the study site, is situated within the sub-Saharan meningitis belt but the study was conducted outside meningitis epidemics suggesting that sporadic acute bacterial meningitis is not an uncommon of cause of coma in Kano.

Tuberculous meningitis was also a common infective cause in the current study. Sub-Saharan Africa has the highest TB- related death as well as per capita TB mortality in the world with Nigeria having the fourth largest cases of new TB cases annually. [20] According to WHO, HIV is the single most important factor behind Africa's TB resurgence and Africa has the largest number of people known to be infected with HIV and TB. [19],[20],[21] In our setting, patients with tuberculosis tend to present late. This delay in seeking medical attention partly explains dissemination of the disease with involvement of the central nervous system as seen in some of our patients.

Uremic encephalopathy appeared to be one of the most common toxic and metabolic causes of coma in our study. This finding agrees with reports from studies elsewhere. [4],[15],[16] Chronic Kidney disease (CKD) is one of the world's major public health problems and the prevalence of Kidney failure is rising steadily. [22],[23] Afolabi and his colleagues, in a study conducted in southwestern Nigeria reported a prevalence of CKD in the study population and its association with modifiable risk factors. [24] WHO statistics revealed that the death rate from intrinsic kidney and urinary tract disease was one million in the year 2002, ranking twelfth on the list of major causes of death. [22] In Nigeria, the situation is such that CKD represents about 8-10% of hospital admission [25] and many of the patients presented for the first time in coma, which may be attributed to lack of awareness about the disease, prohibitive cost of health care services and use of alternative treatment like spiritual healing and traditional healers. [26]

Diabetic emergencies, as previously reported by other workers, [4],[15],[16] accounted for a large proportion of causes of coma in our study. A number of deaths due to hyperglycemic emergencies are attributable to failure to recognize and treat the underlying precipitating factors, rather than the metabolic disturbances especially in the elderly. Infection remains the most important precipitating factor in the development of diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS). Omission of insulin or inadequate doses of insulin are frequent precipitating factors, particularly for DKA. [27] On the other hand, hypoglycemic coma are often sequel to drug overuse or use of drugs without meal.

Worthy of note, is the absence of cases of coma from cerebral malaria in contradistinction to reports from some other African countries. [5],[28] Paucity of coma secondary to malaria in the present study is consistent with the epidemiological understanding that severe morbidity is limited by the development of immunity under the stable endemic conditions prevailing in much of Africa. [28]

Definitive diagnosis could not be reached in about 8% of the patients. This figure, which must be viewed in the context of limited investigative facilities, is comparable to that reported in similar studies in some other developing countries. [5],[28]

The mortality rate of 49% recorded in the present study, although comparable to report from other places, [5],[11],[29] was less than 76% previously reported in Ibadan, [17] southwestern Nigeria. This difference could be ascribed to a higher proportion of coma from metabolic encephalopathy which arguably has a better recovery rate in this study. Nonetheless, the figure is less than those reported in certain developed countries where patients received better emergency and intensive care. For instance, Sune and his colleagues reported mortality rate of 26.5%, however, thirty percent of the study population was treated at an intensive care unit. [6] Moreover, late presentation, inadequate manpower and insufficient diagnostic and resuscitation facilities as well as dearth of intensive care facilities may partly account for the higher mortality often recorded in the developing countries. The Intensive Care at the study site is a 4-bedded facility and serves as a general ICU for Kano, Jigawa and Katsina states, all in Northwestern Nigeria which is grossly inadequate. Access to this vital care is often very competitive and bed occupancy is 75-100%. Early presentation and early access to intensive care facility could have influence the outcome of patients with low GCS. Patients with low GCS are at risk of aspiration of regurgitated stomach content which sharply increases morbidity and mortality.

Significant difference in outcome between patients with moderate and low GCS found in this study agrees with reports elsewhere. [11] This finding emphasizes the utility of GCS as a simple tool of prognostication in comatose patients.

However, this study has certain limitations. Not all the patients underwent all diagnostic investigations and autopsy was not conducted on those that died to confirm the cause of death. Being predominantly a Muslim population, consent to conduct autopsy is usually not granted. Nevertheless, the study, being the first of its kind in the region provides a preliminary database with the view to reducing mortality from medical coma.


   Conclusion Top


Stroke, sepsis, diabetic emergencies and chronic kidney diseases were the most common etiology of medical coma in AKTH. Medical coma was associated with high mortality rate, the benefit of preventive measures as well as adequate intensive care services cannot be overemphasized.

 
   References Top

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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]



 

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