NKHS and Differences b/w DKA & NKHS ( medicine)
Reading File
Finding Sources
Finding Sources
Reading File
Reading File
Finding Sources
Reading File
Reading File
Finding Sources
Reading File
Reading File
Finding Sources
Reading File
I now have comprehensive information from multiple authoritative sources. Let me compile the full answer.
Non-Ketotic Hyperosmolar State (NKHS / HHS) and DKA vs NKHS
Also called Hyperosmolar Hyperglycemic State (HHS) or Hyperglycemic Hyperosmolar Non-Ketotic State (HONKS). It is a life-threatening emergency of diabetes, predominantly type 2.
1. Definition / Diagnostic Criteria for HHS
| Parameter | Value |
|---|---|
| Blood glucose | >600 mg/dL (33.3 mmol/L), often 600-1200 mg/dL |
| Serum osmolality | >320 mOsmol/L (effective) |
| Arterial pH | >7.3 |
| Serum bicarbonate | >18 mEq/L |
| Serum ketones | Absent or trace |
| Anion gap | Normal or minimally elevated |
Goldman-Cecil Medicine, p. 2484
2. Pathophysiology of HHS
The underlying mechanism differs from DKA in one key respect - relative (not absolute) insulin deficiency:
- Relative insulin deficiency + inadequate fluid intake are the core triggers
- Insulin is still sufficient to suppress lipolysis and prevent significant ketone production - this is the fundamental reason ketosis is absent
- Portal vein insulin concentrations are higher in HHS than DKA - this suppresses hepatic ketogenesis
- Insulin deficiency still causes: hepatic glucose production (glycogenolysis + gluconeogenesis) and impaired skeletal muscle glucose uptake
- Hyperglycemia induces osmotic diuresis - leading to profound intravascular volume depletion
- The patient (usually elderly) cannot compensate with adequate fluid intake - dehydration worsens
- Hemoconcentration and reduced GFR further reduce glucose excretion, worsening hyperglycemia (vicious cycle)
- Lower counterregulatory hormones and free fatty acids have been found in HHS vs DKA in some studies
Why no ketosis? The exact mechanism is incompletely understood. Hypotheses:
- Residual insulin suppresses lipolysis
- Insulin/glucagon ratio does not favor ketogenesis
- The liver may be less capable of ketone body synthesis in this state
Harrison's 22e, p. 3262; Goldman-Cecil, p. 2483
3. Who Gets HHS?
- Predominantly elderly patients with type 2 DM
- Several-week history of polyuria, weight loss, diminished oral intake
- Debilitating conditions (prior stroke, dementia) or social situations that impair water intake
Precipitating factors:
- Infection (sepsis, pneumonia) - most common
- Myocardial infarction
- Stroke
- Medications (diuretics, steroids, atypical antipsychotics)
- Non-compliance with medications
4. Clinical Features of HHS
- Profound dehydration (more severe than DKA - fluid deficit may be 8-12 L)
- Hypotension, tachycardia
- Altered mental status (confusion, lethargy, coma) - up to 10% present in frank coma; correlates with degree/duration of hyperosmolality
- GI symptoms (nausea, vomiting, abdominal pain) are notably absent or mild (in contrast to DKA)
- No Kussmaul respirations (no significant acidosis)
- No fruity/ketotic breath
- Focal neurological deficits possible (aphasia, hemisensory/motor deficits)
5. Laboratory Findings in HHS
| Lab | HHS Finding |
|---|---|
| Blood glucose | 600-1200 mg/dL (markedly elevated, often >1000 mg/dL) |
| Serum osmolality | >320 mOsm/L (effective); may be >350 |
| Serum Na | Normal or elevated (corrected Na is usually high) |
| Ketones | Absent or trace (+/-) |
| β-hydroxybutyrate | <1.0 mmol/L |
| Bicarbonate | >18 mEq/L |
| pH | >7.3 |
| Anion gap | Normal or slightly elevated (lactic acidosis) |
| BUN/Creatinine | Moderately elevated (prerenal azotemia) |
Corrected sodium: Add 1.6 mEq/L to measured Na for every 100 mg/dL rise in glucose above normal.
Harrison's 22e, Table 416-7, p. 3262
6. Management of HHS
A. Fluids (most important)
- Initial: 1-3 L of 0.9% normal saline over first 2-3 hours to stabilize hemodynamics
- Fluid deficit is often greater than DKA (accumulated over days to weeks)
- If serum Na >150 mEq/L, switch to 0.45% saline
- Then transition to hypotonic fluids (0.45% saline, then D5W) to replace free water deficit
- Free water deficit can be 8-12 L or more
Caution: Do NOT correct hyperosmolality too rapidly - risk of worsening neurologic function (cerebral edema)
B. Insulin
- Start insulin only after fluids have been initiated (unlike DKA where fluids + insulin together)
- Insulin IV: 0.05 units/kg/h fixed-rate infusion (lower rate than DKA)
- When glucose drops to 200-250 mg/dL, add dextrose to IV fluids and reduce insulin rate to 0.02-0.1 units/kg/h
C. Potassium
- Replace aggressively once urine output confirmed and K <5.5 mEq/L
- Large total-body K deficits despite normal/elevated initial serum K
D. Bicarbonate
- Not required (pH typically >7.3)
E. Treat precipitant
- Identify and aggressively treat underlying cause (infection, MI, stroke)
7. DKA vs HHS - Differences at a Glance
This is the key comparison table, based on Harrison's 22e (Table 416-7) and Goldman-Cecil:
| Feature | DKA | HHS (NKHS) |
|---|---|---|
| Diabetes type | Usually Type 1 | Usually Type 2 |
| Age | Younger | Elderly |
| Onset | Rapid (hours to 1 day) | Gradual (days to weeks) |
| Insulin deficiency | Absolute | Relative |
| Blood glucose | 250-600 mg/dL | 600-1200 mg/dL (higher) |
| Serum osmolality | >300 mOsm/L (mild-mod) | >320-350 mOsm/L (profound) |
| Serum Na | 125-135 mEq/L (low) | 135-145 mEq/L (normal/high) |
| Ketones | +++ (prominent) | Absent or trace |
| β-hydroxybutyrate | >3.0 mmol/L | <1.0 mmol/L |
| Bicarbonate | <18 mEq/L | >18 mEq/L |
| Arterial pH | 6.8-7.3 (low) | >7.3 (normal) |
| Anion gap | Elevated (high AG metabolic acidosis) | Normal or mildly elevated |
| Kussmaul breathing | Present | Absent |
| Nausea/vomiting/abd pain | Prominent | Absent or mild |
| Mental status change | Mild to moderate | Severe (coma more common) |
| Fruity breath | Yes | No |
| Dehydration | Moderate (4-6 L) | Severe (8-12 L, more profound) |
| Fluid deficit | Moderate | More pronounced |
| Lipolysis | Prominent (FFA released) | Suppressed by residual insulin |
| Precipitant | Missed insulin, infection | Infection, stroke, MI, dehydration |
| Mortality | ~1-5% | Up to 15% (higher) |
| Insulin therapy | Start immediately | Start after fluids; lower dose (0.05 u/kg/h) |
| Bicarbonate therapy | Sometimes (if pH <7.0) | Not needed |
Harrison's 22e, p. 3260-3263; Goldman-Cecil, pp. 2483-2485; Robbins Pathology, p. 749
8. Key Points to Remember
- No ketosis in HHS because residual insulin suppresses lipolysis - this is the cardinal distinction from DKA
- Higher glucose, higher osmolality in HHS than DKA
- Higher mortality in HHS (up to 15%) despite less acidosis - due to older age, comorbidities, and delayed presentation
- Fluids first in HHS, with more cautious correction rate than DKA to avoid cerebral edema
- A mixed picture (both HHS + DKA features) can occur in some type 2 diabetics with severely depressed insulin secretion
- In HHS, measured serum Na may appear normal or low despite severe dehydration due to the dilutional effect of hyperglycemia - always correct for glucose
- Precipitating illness must be identified - sepsis and pneumonia are the most frequent triggers
Sources: Harrison's Principles of Internal Medicine 22e, p. 3260-3263; Goldman-Cecil Medicine, pp. 2483-2485; Robbins & Kumar Basic Pathology, p. 749
This is a shared conversation. Sign in to Orris to start your own chat.