There are some scenarios SS deems as Critical Cases which will be expedited and receive special case processing.

"1. Terminal Illness (TERI)
A case is designated critical when the claimant's illness is alleged or identified as terminal (i.e., untreatable, irreversible, and expected to end in death)."

"2. Veteran 100 Percent Permanent and Total (VPAT)
A case is designated critical when the claimant has received a 100 percent permanent and total (100% P&T) disability compensation rating from the Department of Veterans Affairs (VA)."

"3. Military Casualty/Wounded Warrior (MC/WW) Case
A case is designated critical when the claim involves any current or former member of a military service who:
Sustained an illness, injury, or wound;
Is alleging a physical or mental impairment, regardless of how the impairment occurred, or where it occurred (i.e., United States or on foreign soil); and
Sustained the impairment while on active duty status on or after October 1, 2001."

"4. Compassionate Allowances (CAL)
The CAL process identifies diseases and other medical conditions that invariably qualify under the Listing of Impairments (20 CFR Appendix 1 to Subpart P of Part 404—Listing of Impairments). For more information about the CAL initiative, see POMS DI 11005.604.
Most CAL cases are identified at the initial level of adjudication, but a new condition that develops later can also qualify for CAL processing. Subsequent identification, including at the hearing level, may be based solely on a claimant's allegation or on new medical evidence of a condition included on the CAL list of impairments."

"5. Dire Need Case (DRND)
A dire need situation exists when a claimant alleges any of the following circumstances:
The claimant is without food and is unable to obtain it.
The claimant lacks medicine or medical care and is unable to obtain it, or the claimant indicates that access to necessary medical care is restricted because of a lack of resources.
The claimant lacks shelter (e.g., without utilities such that his or her home is uninhabitable, homelessness, expiration of a shelter stay, or imminent eviction or foreclosure with no means to remedy the situation or obtain shelter)."

"6. Potentially Violent
ODAR staff may designate the case as critical if there is an indication that the claimant is suicidal, homicidal, or potentially violent."

http://www.ssa.gov/OP_Home/hallex/I-02/I-2-1-40.html