The elderly population is generally defined as individuals aged 65 years and above.[1] Altered mental status (AMS) represents a collection of clinical manifestations rather than a single diagnosis, encompassing disturbances in cognition, attention, arousal, or level of consciousness. It is a broad, nonspecific term used to describe acute or chronic alterations in awareness, mental clarity, or attentiveness.[2] AMS includes a range of neurological dysfunctions—from mild confusion to coma—and may manifest as delirium, stupor, dementia, or other cognitive disturbances. In everyday language, AMS is often described as confusion, unusual behavior, disorientation, lethargy, agitation, hallucinations, or inattentiveness.[3] Delirium, a term sometimes used interchangeably with AMS, is defined as an acute disorder of attention and cognition that commonly occurs in the elderly due to a combination of predisposing and precipitating factors.[4] In older adults, AMS may present as reduced attention span, impaired mobility, changes in appetite, decreased social interaction, or other subtle behavioral alterations. This heterogeneous condition is clinically important as it is associated with longer hospital stays, higher complication rates, and increased mortality, making early detection and prompt evaluation essential.[5–7] Patients with AMS can exhibit a wide spectrum of consciousness levels, ranging from deep coma to agitation or combativeness. These variations are measured using the Richmond Agitation–Sedation Scale (RASS), which provides a simple, logical, and reliable method to assess a patient’s neurological state. The RASS has demonstrated high validity and reproducibility in medical and surgical intensive care units, among both ventilated and non-ventilated, sedated and non-sedated adults.[8] In elderly patients, delirium, acute confusional states, and AMS may coexist. The Brief Confusion Assessment Method (bCAM) is a useful screening tool for detecting delirium and consists of four clinical features: AMS or fluctuating mental course, Inattention, Altered level of consciousness, and Disorganized thinking. A patient is considered delirious when both feature 1 (AMS or fluctuating course) and feature 2 (inattention) are present, along with either feature 3 (altered level of consciousness) or feature 4 (disorganized thinking).[9] In contrast to younger individuals, AMS in the elderly tends to be more persistent and multifactorial, as aging predisposes them to several neurological, metabolic, and infectious vulnerabilities.[3] Conditions affecting nearly any organ system—such as infections, vascular events, inflammatory disorders, or metabolic imbalances—may contribute to AMS in this population.[4,10] The present study was undertaken to evaluate the clinical and etiological profile of acute AMS in elderly patients, aiming to enhance understanding of its causes, guide timely management, and reduce associated morbidity and mortality. Studying AMS in older adults is especially relevant in developing countries like India, where early recognition can prevent progression to severe outcomes such as coma or vegetative state, and significantly reduce the financial and caregiving burden on families. Given the limited number of existing studies, there is a pressing need for larger-scale research to better elucidate the pathophysiology, clinical spectrum, and prognosis of AMS in the elderly.

Study Design and Setting This prospective observational study was conducted at the Department of General Medicine, PGIMER & Capital Hospital, Bhubaneswar, Odisha, a tertiary care teaching hospital catering to a large rural and semi-urban population in southern Odisha. The study was carried out over a one-year period, from May 1, 2019, to October 30, 2020, among elderly patients presenting with altered mental status (AMS) to the Emergency Department (ED) and Medical Intensive Care Unit (ICU). A total of 140 consecutive elderly patients (aged ≥65 years) who presented with any alteration in sensorium—ranging from hyperactivity or delirium to drowsiness, hypoactivity, or coma, as described by the patient’s relatives or attendants—were enrolled in the study. Inclusion and Exclusion Criteria Inclusion criteria: • Patients aged 65 years and above. • Those presenting with acute or subacute change in mental status, including restlessness, confusion, agitation, lethargy, stupor, or coma. Exclusion criteria: • Terminally ill patients who were chronically bedridden or comatose at baseline. • Patients with trauma-related AMS, such as those with head injury or post-traumatic neurological impairment. Data were collected using a structured pro forma developed in accordance with the study objectives. After obtaining written informed consent from each participant or their next of kin, detailed information was recorded, including: • Demographic profile and baseline characteristics. • Clinical history, including the nature and duration of altered sensorium. • Physical and systemic examination findings. • Neurological examination, including assessment of consciousness and orientation. • Laboratory and imaging investigations relevant to identifying etiology. Each patient’s neurological status at admission was assessed using the Richmond Agitation–Sedation Scale (RASS). The RASS score was documented and categorized based on the patient’s mental and behavioral response, as previously described in literature.[8] A simple random sampling technique was used for patient selection. The collected data were entered into Microsoft Excel and analyzed using descriptive statistics. Frequencies and percentages were used for categorical variables, while means and standard deviations (SDs) were calculated for continuous variables. The sample size was determined based on the estimated prevalence of mental disorders among the elderly population using the following parameters: Parameter Description Value P Estimated prevalence of mental disorder in elderly 0.15 (1-α) Confidence level 0.95 Z Z value corresponding to 95% confidence 1.96 Δ Absolute precision 0.07 N Calculated minimum sample size 140 Thus, a minimum sample size of 140 patients was considered adequate to meet the statistical requirements for this study.[11]

A total of 140 elderly patients presenting with altered mental status (AMS) were included in the study. The demographic, clinical, biochemical, and etiological findings are summarized below. Among the study participants, 87.1% had at least one comorbidity, while 12.9% had none (Table 1). Table 1: Distribution of Comorbidities among Elderly Patients with AMS (n = 140) Comorbidity n Percentage (%) None 18 12.9 Hypothyroidism 1 0.7 Hypothyroidism + Diabetes Mellitus + Hypertension 3 2.1 Diabetes Mellitus 6 4.3 Diabetes Mellitus + Hypertension 39 27.9 Diabetes Mellitus + Hypertension + BPH 2 1.4 Diabetes Mellitus + Hypertension + CVA 3 2.1 Diabetes Mellitus + Hypertension + Seizure Disorder 2 1.4 Hypertension 28 20.0 Hypertension + BPH + CVA 2 1.4 Hypertension (isolated repeat entry merged) — — Hypertension + CVA 3 2.1 Hypertension + Malignancy 2 1.4 Benign Prostatic Hypertrophy (BPH) 3 2.1 Treated Case of Tuberculosis 1 0.7 Malignancy 2 1.4 Ischemic Heart Disease (IHD) 3 2.1 IHD + Diabetes Mellitus + Hypertension 8 5.7 IHD + Hypertension 2 1.4 IHD + COPD + BPH + CVA + Seizure Disorder 1 0.7 Parkinsonism 2 1.4 Parkinsonism + Diabetes + Hypertension 3 2.1 Parkinsonism + Hypertension 2 1.4 Parkinsonism + CVA 2 1.4 COPD 2 1.4 COPD + Hypothyroidism + CKD + Hypertension 1 0.7 COPD + Diabetes Mellitus + Hypertension 2 1.4 COPD + Hypertension + Malignancy 1 0.7 Total 140 100 BPH – Benign Prostatic Hypertrophy; CVA – Cerebrovascular Accident; COPD – Chronic Obstructive Pulmonary Disease; CKD – Chronic Kidney Disease; IHD – Ischemic Heart Disease. The most common associated condition was hypertension, observed either alone or in combination with other systemic illnesses in a substantial number of patients (20.0%). Diabetes mellitus with hypertension was the most frequent comorbid combination (27.9%), followed by isolated hypertension (20.0%) and ischemic heart disease (IHD) either alone (2.1%) or in combination with diabetes and hypertension (5.7%). Other notable comorbidities included chronic obstructive pulmonary disease (COPD) (1.4%), benign prostatic hypertrophy (BPH) (2.1%), and Parkinsonism (2.1%). A small number of cases also reported malignancy, chronic kidney disease (CKD), and treated tuberculosis. This highlights that the majority of elderly patients with AMS had multiple chronic medical conditions, particularly cardiovascular and metabolic disorders. The distribution of hemoglobin levels revealed that 59.3% of patients were anemic to varying degrees (Table 2). Table 2: Hemoglobin Distribution among Elderly Patients with AMS (n = 140) Hemoglobin Level (g/dL) n Percentage (%) Normal (Males: 13.5–17.5 g/dL; Females: 12–16 g/dL) 57 40.7 Mild Anemia (11–11.9 g/dL in females; 11–12.9 g/dL in males) 38 27.1 Moderate Anemia (8.1–10.9 g/dL) 39 27.9 Severe Anemia (Hb < 8 g/dL) 6 4.3 Total 140 100.0 Mild anemia was seen in 27.1%, moderate anemia in 27.9%, and severe anemia in 4.3% of patients. Only 40.7% of the study population had normal hemoglobin levels. This indicates that anemia is a prevalent contributor to altered sensorium in elderly individuals, potentially exacerbating cerebral hypoxia and cognitive dysfunction. Serum sodium disturbances were common (Table 3). Table 3: Serum Sodium Distribution among Elderly Patients with AMS (n = 140) Serum Sodium Level (mEq/L) n Percentage (%) Normal (136–145) 69 49.3 Mild Hyponatremia (130–135) 27 19.3 Moderate Hyponatremia (125–129) 11 7.9 Severe Hyponatremia (<125) 33 23.5 Total 140 100.0 mEq/L – Milliequivalents per liter While 49.3% of patients had normal sodium levels, the remaining 50.7% demonstrated hyponatremia of varying severity. Mild hyponatremia (130–135 mEq/L) was observed in 19.3%, moderate (125–129 mEq/L) in 7.9%, and severe hyponatremia (<125 mEq/L) in 23.5% of cases. Hyponatremia, especially in elderly individuals on diuretics or multiple medications, is known to precipitate confusion and altered consciousness, underscoring its clinical significance in AMS. As shown in Table 4, hypoalbuminemia was extremely prevalent, seen in 87.1% of the subjects, while only 12.9% had normal serum albumin levels. Table 4: Serum Albumin Levels among Elderly Patients with AMS (n = 140) Serum Albumin Level (g/dL) n Percentage (%) Normal (3.5–5.5 g/dL) 18 12.9 Hypoalbuminemia (<3.5 g/dL) 122 87.1 Total 140 100.0 g/dL – grams per deciliter This finding suggests that malnutrition, chronic illness, and inflammatory states contribute significantly to the pathophysiological background of AMS in the elderly. The etiological distribution of AMS among the elderly is detailed in Table 5. Table 5: Various Etiologies of Altered Mental Status (AMS) in the Elderly (n = 140) Etiology of AMS n Percentage (%) CVA – Infarct 35 25.0 CVA – Infarct + Hypoglycemia 1 0.7 CVA – Infarct + Septic Encephalopathy (Pneumonia) 8 5.7 CVA – Infarct + Septic Encephalopathy (Urosepsis) 3 2.1 CVA – Infarct + Hyponatremia (Drug-related) 1 0.7 CVA – Infarct + Hypoglycemia (Drug-induced) 1 0.7 CVA – Infarct + Hypoglycemia (Sepsis-induced) 1 0.7 CVA – Bleed 14 10.0 Septic Encephalopathy (Pneumonia) 2 1.4 Septic Encephalopathy (Pneumonia) + Hyponatremia 2 1.4 Septic Encephalopathy (Pneumonia + Urosepsis) 2 1.4 Septic Encephalopathy (Pneumonia + Urosepsis) + Hyponatremia 2 1.4 Septic Encephalopathy (Pneumonia + Urosepsis) + Uremia 2 1.4 Septic Encephalopathy (Pneumonia) + Hypoglycemia (Sepsis) 3 2.1 Septic Encephalopathy (Urosepsis) 7 5.0 Septic Encephalopathy (Urosepsis) + Hyponatremia (Drug-related) 2 1.4 Septic Encephalopathy (Urosepsis) + Uremia 2 1.4 Hyponatremia (Drug-related) 21 15.0 Hyponatremia – SIADH 4 2.9 Hyponatremia (Hypovolemic) 2 1.4 Hyponatremia (Multifactorial) 3 2.1 Hyponatremia + Congestive Cardiac Failure 2 1.4 Hypoglycemia (Drug-induced) 3 2.1 Hypoglycemia (Sepsis-related) 6 4.3 Hypoglycemia (Hepatocellular Carcinoma) 1 0.7 Meningoencephalitis (Tubercular) 2 1.4 Meningoencephalitis (Tubercular) + Septic Encephalopathy (Pneumonia) 1 0.7 Meningoencephalitis (Viral) 3 2.1 Meningoencephalitis (Viral) + Septic Encephalopathy (Urosepsis) 1 0.7 Seizure Disorder + Metabolic Encephalopathy + Septic Encephalopathy (Pneumonia and Urosepsis) 1 0.7 Seizure Disorder 3 2.1 Seizures (Scar Epilepsy) + Septic Encephalopathy (Urosepsis and Pneumonia) 1 0.7 Hypertensive Leukoencephalopathy 1 0.7 Total 140 100.0 CVA – Cerebrovascular Accident; SIADH – Syndrome of Inappropriate Antidiuretic Hormone Secretion; AMS – Altered Mental Status; COPD – Chronic Obstructive Pulmonary Disease. The most common primary cause identified was cerebrovascular accident (CVA), accounting for 35 cases (25%) of infarct and 14 cases (10%) of intracerebral hemorrhage. Several patients exhibited multifactorial etiologies, such as CVA in combination with metabolic or infective insults. Septic encephalopathy was another major category, associated with pneumonia, urosepsis, or both, either alone or combined with hyponatremia, uremia, or hypoglycemia. Altogether, infection-related encephalopathy accounted for approximately one-fifth of the total cases. Hyponatremia (isolated or multifactorial) contributed to around 22–23% of cases, whereas hypoglycemia was implicated in nearly 8% of patients, either drug-induced or secondary to sepsis. Other less common causes included meningoencephalitis (tubercular or viral), seizure disorders, and hypertensive leukoencephalopathy. Thus, CVA and metabolic/infective causes together accounted for the vast majority of AMS cases in the elderly population. The level of consciousness on presentation, assessed by the Richmond Agitation–Sedation Scale (RASS), varied widely among patients (Table 6). Table 6: Richmond Agitation–Sedation Scale (RASS) Scores among Elderly Patients with Altered Mental Status (n = 140) RASS Score n Percentage (%) –5 (Unarousable / Deep Coma) 6 4.3 –4 (Very Sedated / Minimal Response) 14 10.0 –3 (Moderate Sedation) 10 7.1 –2 (Light Sedation) 17 12.1 –1 (Drowsy / Not Fully Alert) 53 37.9 +1 (Restless / Anxious but Calm) 34 24.3 +2 to +4 (Agitated to Very Combative) 6 4.3 Total 140 100.0 RASS – Richmond Agitation–Sedation Scale The majority (37.9%) were drowsy but arousable (RASS –1), while 24.3% were restless or mildly anxious (+1). A smaller proportion exhibited deeper levels of sedation — 12.1% had light sedation (–2), 7.1% moderate sedation (–3), and 4.3% were unarousable (–5). Conversely, 4.3% of patients were markedly agitated or combative (+2 to +4). These findings suggest that most elderly AMS patients presented with fluctuating levels of drowsiness and mild agitation, consistent with the clinical spectrum of delirium or metabolic encephalopathy rather than deep coma. These findings underscore that altered mental status in the elderly is a multifactorial condition, often arising from the interplay of vascular, metabolic, infectious, and nutritional factors.

Acute alteration in mental status (AMS) represents one of the most common neurological emergencies among the elderly and requires urgent diagnosis and management. Clinicians in emergency departments (EDs) often face challenges in identifying its underlying causes because of overlapping clinical presentations and multiple comorbidities. Severe impairment, such as coma or stupor (RASS –5 to –4), demands immediate stabilization regardless of etiology. Previous studies have shown that delirium in older adults carries a 12-month mortality of 10–26%, and AMS generally predicts poorer short-term outcomes compared with those without delirium. A meta-analysis confirmed that delirium in the elderly independently increases morbidity and mortality, irrespective of baseline dementia or comorbid illnesses [12]. In our study at PGIMER & Capital Hospital, Bhubaneswar, males and females were almost equally represented, differing from earlier reports that showed male predominance [13–15]. Some previous work noted that elderly women with delirium more frequently had hypertension, hyponatremia, cardiac disease, or dementia [16]. The near-equal gender ratio in our cohort may reflect improved healthcare access among older women in this region. The most common comorbidities were hypertension (20%), diabetes mellitus with hypertension (27.9%), and ischemic heart disease (7.8%), alone or in combination. Comparable findings were reported by other investigators, who observed multiple chronic illnesses—particularly cardiovascular and metabolic disorders—in 80–85% of elderly patients with AMS [17,18]. These conditions predispose individuals to vascular or metabolic brain injury, increasing susceptibility to acute cognitive impairment. Metabolic disturbances play a major role in AMS among older adults. In our series, anemia was present in about 60%, consistent with its contribution to cerebral hypoxia and cognitive dysfunction. Hyponatremia, found in 50.7%, was the leading metabolic abnormality—especially severe hyponatremia (<125 mEq/L), accounting for nearly one-fourth of all cases. Similar observations were made by John et al., Thakur et al., Khurana et al., and Zieschang et al., who reported hyponatremia as the most frequent biochemical derangement associated with AMS in elderly populations [13,14,17,19]. Hypoglycemia was identified in roughly 8% of patients, mainly related to antidiabetic medications or sepsis-induced metabolic changes. Although lower than the 29.7% reported in some studies [20], it remains a significant, reversible cause of AMS. Hypoalbuminemia, seen in 87%, indicates poor nutritional status, chronic disease, and systemic inflammation—all contributing to increased neurological vulnerability in the elderly. Consistent with earlier Indian and international data, cerebrovascular accidents (CVAs) were the predominant cause of AMS, accounting for 35% of cases—of which 71% were ischemic and 29% hemorrhagic. This finding agrees with previous studies identifying stroke as the most frequent non-traumatic neurological cause of AMS in the elderly [21–23]. Infectious and septic causes—notably pneumonia and urosepsis leading to septic encephalopathy—were seen in nearly 20% of subjects, matching earlier evidence that infection-related delirium is common among geriatric patients [14,17,24,25]. Additionally, hyponatremia-related encephalopathy, hypoglycemia, and multifactorial etiologies (about 24%) contributed to AMS, consistent with studies highlighting the mixed nature of acute confusion syndromes in older adults [26,27]. Less frequent causes included viral or tubercular meningoencephalitis, seizure disorders, and hypertensive leukoencephalopathy. Prior literature emphasizes that classical meningeal signs such as fever, headache, and neck stiffness may be absent in elderly individuals; hence, lumbar puncture should be considered even in afebrile cases presenting with AMS [12,28]. The Richmond Agitation–Sedation Scale (RASS) showed that most patients were mildly drowsy (RASS –1) or restless (+1), reflecting fluctuating consciousness typical of delirium and metabolic encephalopathy. A smaller proportion (4%) were in deep coma (RASS –5), while another 4% exhibited severe agitation (+2 to +4). These findings indicate that the majority of AMS cases were partially responsive, underscoring the importance of early recognition and correction of reversible factors. Our findings corroborate earlier work showing that AMS in the elderly is multifactorial, most often resulting from a combination of cerebrovascular, metabolic, infectious, and nutritional causes. Previous reports have documented that delirium leads to prolonged hospitalization, higher rates of institutionalization, and increased mortality [20–22]. Risk factors such as fever or hypothermia, azotemia, infection, psychoactive drug use, and dementia remain well-established contributors to AMS [20]. Limitations This hospital-based study included a moderate sample size (n = 140), which may limit generalizability. Being cross-sectional, it did not assess long-term outcomes or recurrence. Moreover, data collection coincided with the COVID-19 pandemic, which likely affected patient admissions and follow-up. Larger prospective studies are warranted to explore prognostic indicators and develop preventive strategies.

In conclusion, AMS in elderly patients is frequently associated with multiple comorbidities, anemia, hyponatremia, and hypoalbuminemia, with stroke and sepsis being the predominant etiologies. Early recognition of metabolic and infectious triggers, along with comprehensive management of chronic illnesses, can significantly improve recovery and reduce mortality among this vulnerable population.

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